EP0234877A1 - Method of and apparatus for casting - Google Patents
Method of and apparatus for casting Download PDFInfo
- Publication number
- EP0234877A1 EP0234877A1 EP87301464A EP87301464A EP0234877A1 EP 0234877 A1 EP0234877 A1 EP 0234877A1 EP 87301464 A EP87301464 A EP 87301464A EP 87301464 A EP87301464 A EP 87301464A EP 0234877 A1 EP0234877 A1 EP 0234877A1
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- European Patent Office
- Prior art keywords
- mould
- cavity
- metal
- support
- primary source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D23/00—Casting processes not provided for in groups B22D1/00 - B22D21/00
- B22D23/006—Casting by filling the mould through rotation of the mould together with a molten metal holding recipient, about a common axis
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D18/00—Pressure casting; Vacuum casting
- B22D18/04—Low pressure casting, i.e. making use of pressures up to a few bars to fill the mould
Definitions
- This invention relates to a method of and apparatus for making a casting by feeding molten metal from a source of the molten metal into a mould cavity through an ingate below the top of the mould cavity.
- the invention is particularly, but not exclusively, concerned with a method and apparatus for making a casting by feeding molten metal generally upwardly from the source thereof into the mould cavity through an ingate at the bottom of the mould cavity, for example, by pumping the metal upwardly under low pressure from a reservoir disposed below the level of the mould cavity through an ingate at the bottom of the mould cavity.
- a majority of the time taken to make a casting by this method is occupied in waiting for the metal to solidify in the mould cavity before the source of metal can be placed out of feeding relationship with the mould cavity and placed in feeding relationship with a further mould cavity and the casting cycle repeated.
- An object of the invention is to provide a method of and an apparatus for making a casting in which the rate of production of castings is improved compared with known methods and apparatus.
- a method of making a casting comprising the steps of, at a casting station, feeding molten metal from a primary source of molten metal into a mould cavity through an ingate below the top of the mould cavity, placing the cavity out of feeding relationship with the primary source by changing the orientation of the cavity relative to the force due to gravity to prevent flow of molten metal from the cavity towards the primary source and to permit flow of metal from a secondary source to the cavity, the cavity being continuously connected to the primary source during said change of orientation, transferring the mould cavity to a cooling station spaced from the casting station and, at the cooling station, permitting molten metal to flow to the cavity from the secondary source whilst the metal in the cavity solidifies.
- an ingate at the bottom of the mould cavity is intended to cover not only an ingate which opens through a bottom wall of the cavity but also an ingate which opens through a side wall of the cavity with at least part of the ingate being disposed within the bottom half of the overall height of the mould cavity and preferably with the bottom part of the ingate being at or substantially at the level of the bottom wall of the cavity. It is however much preferred that the ingate opens through said bottom, upwardly facing, wall of the cavity so that the flow of metal through the ingate is substantially vertically upwardly.
- the metal in the mould cavity may be subjected to a low pressure we mean for example, sufficient pressure only to ensure that the cavity is filled and to maintain a small head, for example, I to 3 inches of metal equivalent, to ensure that the cavity remains full whilst the cavity is placed out of said feeding relationship.
- a low pressure we mean for example, sufficient pressure only to ensure that the cavity is filled and to maintain a small head, for example, I to 3 inches of metal equivalent, to ensure that the cavity remains full whilst the cavity is placed out of said feeding relationship.
- the low pressure is less than I bar, although, if desired, the pressure may be higher than this.
- an apparatus for making a casting comprising a primary source for molten metal, a mould having a mould cavity, feed means to feed molten metal, in use, from the primary source into the mould cavity through an ingate below the top of the mould cavity, when the mould is at a casting station, means for placing the mould cavity out of feeding relationship with the primary source comprising means for changing the orientation of the mould cavity relative to the force due to gravity to prevent flow of molten metal from the cavity towards the primary source and to permit of flow of metal from a secondary source to the cavity, means continuously to connect the cavity with the primary source during said change of orientation, means to transfer the mould cavity to a cooling station spaced from the casting station where at molten metal may flow to the cavity from the secondary source whilst the metal in the cavity solidifies.
- FIG. 1 there is shown an apparatus for making metal castings comprising a primary source 10 of molten metal I I connected by a launder system 12 to a mould support 13. Supported on the mould support 13 is a mould 14 having a mould cavity 15.
- the metal I I to be cast is in this example an aluminium alloy known as LM 25 but may be any other aluminium alloy or any other metal castable by a "low pressure" means for example magnesium, zinc, lead, copper and alloys of any of these. Ferrous metals may also be cast. Of course the precise components used are chosen so as to be suitable for the metal to be cast.
- the primary source 10, in the present example, comprises a melter/holder furnace 16 comprising a refractory lined reservoir vessel 17 having a rectangular base 18 and vertical side and end walls 19,20 respectively.
- a roof 21 extends across the whole width of the vessel 17 but stops short of the end walls 20 to provide a charging well 22 and a pump well 23 at opposite ends of the vessel.
- the roof 21 comprises a generally horizontal rectangular top part 24 and vertical side and end walls 25 and 26 respectively.
- the roof 21 comprises suitable refractory material and within the roof are provided electrical radiant heaters 27.
- the temperature of the heaters 27 and the number thereof and the area of the top part 24 of the roof are arranged so as to provide sufficient heat to melt ingots fed into the vessel 17 at the charging well 22 and to maintain the metal molten in the remainder of the vessel.
- a downwardly depending refractory wall 28 is provided at the charging well end of the vessel to separate the charging well 22 from the main heating part of the vessel whilst downwardly depending and upwardly extending refractory walls 29, 30 are provided at the pump well end of the vessel to define a casting vessel region , 31 within which a pump 32, separate from the vessel 17 is provided.
- the pump is an electromagnetic pump which pumps metal from the region 31 through a riser tube 33.
- a filter 34 may be provided between the walls 29 and 30 to filter metal entering the casting vessel region 31.
- the riser tube 33 and pump 32 provide a passage which has a lower end immersed in the molten metal and an upper end externally of the vessel 17 and an intermediate portion which extends through the free upper surface 34 of the molten metal.
- any other form of suitable pump separate from the reservoir vessel 17 may be provided such as a pressure pump in which metal is drawn into a body disposed within the reservoir and discharged therefrom by variation of pressure within the body through a riser tube as described in connection with the pump 32.
- the metal may be pumped upwards through a riser tube, corresponding to the riser tube 33, by providing the primary source as a reservoir vessel which has an air tight enclosure and pressurizing the whole of the interior of the vessel to force metal upwardly through the riser tube which, preferably, provides a passage having a lower end immersed in the molten metal, an upper end externally of the vessel and an intermediate portion which extends upwardly through the free upper surface of the molten metal.
- the primary source as a reservoir vessel which has an air tight enclosure and pressurizing the whole of the interior of the vessel to force metal upwardly through the riser tube which, preferably, provides a passage having a lower end immersed in the molten metal, an upper end externally of the vessel and an intermediate portion which extends upwardly through the free upper surface of the molten metal.
- This version is particularly suitable where the metal to be cast is a ferrous metal since the electromagnetic pump 32 illustrated is not suitable for use with ferrous metals
- the metal is pumped, the metal may be fed to the reservoir vessel in molten state rather than in solid state if it is desired not to provide the primary source 16 in the form of a melter/holder furnace.
- the riser tube 33 comprises part of the launder system 12 and from the upper end of the riser tube 33 there extends a generally horizontal but slightly upwardly inclined conduit 35.
- the riser tube 33 and conduit 35 are surrounded by thermally insulating material 36 and may be provided with heaters.
- the conduit 35 is connected to the mould support 13 by a separable rotary joint 37.
- the joint 37 permits of rotation about a horizontal axis, between the mould support 13 and the conduit 35 and also permits of movement of the mould support 13 from a casting station CA as shown in Figures I to 4 to a cooling station CO spaced from the casting station.
- the mould support 13 comprises a steel open-topped box 38 containing a refractory mass 39 in which is formed a conduit 40 for molten metal which extends generally horizontally from an entry port 41 to a header portion 42 which extends generally upwardly to an exit port 43 of the mould support.
- the volume of the header portion 42 is arranged so as to contain sufficient metal to provide a secondary source of molten metal for the feeding of the cavity 15 as hereinafter to be described.
- the mould 14 Supported on the top surface 44 of the mould support is the mould 14.
- the mould 14 comprises cope and drag parts 45, 46 respectively, comprising bonded sand and defining there between the mould cavity 15 in which at least one core 47 is disposed.
- the cope and drag parts 45, 46 comprise mould boxes 48 within which the bonded sand is disposed and the cavity 15 is provided with an ingate 49.
- each mould may contain one or more cores.
- the or each cavity may be connected to one or more header portions by one or more ingates for the or each cavity.
- header, mould cavity and ingate are to be understood to refer also to these in the plural.
- the cope and drag parts may be made in boxless form, one example of which is described hereinafter with reference to Figure 5, and/or the mould may comprise more than two parts.
- the steel box 38 is releasably connected to a manipulator 50 provided with a clamp plate 51 by which the mould 14 is clamped to the mould support 13.
- Clamp plate 51 is moveable in the direction of the arrow A whilst the manipulator is capable of moving the mould box 38 horizontally in the direction of the arrow B vertically in the direction of the arrow E and it can rotate the box 38 ( and hence the mould 14 together with the mould support 13 ) about a horizontal axis H-H as indicated by the arrow C and about a vertical axis as indicated by the arrow D.
- the rotatable joint 37 permits of rotation between the first and second conduits 35, 40 and provides a seal therebetween.
- the joint 37 comprises a first member 52 received in a recess in the refractory mass 39 with a jointing gasket 39a therebetween and hence fixed relative to the conduit 40.
- the member 52 has a frusto-conical recess 53 therein which co-operates with a part spherical surface 54 of a second member 55 fixed relative to the conduit 35.
- the members 52, 55 are made of refractory or refractory faced materials which can maintain a seal therebetween and not abrade each other unduly typically relatively hard material and the other less hard.
- a mould 14 is clamped to the upper surface 44 of the mould support 13 by the clamping plate 51 of the manipulator 50 and the manipulator 50 manipulates the assembly so as to move the sealing surfaces 53, 54 of the rotary joint 37 into sealing engagement, with the mould 14 disposed above the mould support 13 at the casting station CA, as shown in Figures I and 4.
- the pump 32 is then operated to pump metal upwardly out of the vessel 17 through the riser tube 33, conduit 35, the passage defined within and surrounded by the sealing means 52-55 and hence into the conduit 40 of the mould support 13 and then upwardly to fill the header portion 42 and then to pass into the mould cavity 15 upwardly through the ingate 49.
- Metal movement is essentially upwards and therefore the benefits of "uphill" filling are achieved, namely lack of turbulent flow downwardly under gravity thereby avoiding entrainment of oxide and other particles in the metal surface thereby avoiding sources of defect nucleation.
- the ingate and mould cavity are designed so that the cavity is filled without any or at Jeast any substantial flow of metal downwardly.
- the pressure of the metal in the mould is maintained at a desired low pressure as described hereinbefore.
- the manipulator 50 is operated to rotate the mould support/mould assembly 13, 14 about the axis H-H through 180° to invert the support mould assembly 13, 14 to the orientation shown in Figure 2.
- the mould cavity is placed out of feeding relationship with the primary source 16 and into feeding relationship with the secondary source 42 when the pressure in the pump is removed to allow the molten metal to fall back through the riser tube 33 out of the conduit 40 and at least partly out of the conduit 35 to the level shown in Figure 2.
- the metal may fall completely out of the conduit 35 and riser tube 33 to lie at the same level as the metal surface 34 in the vessel 17.
- the pressure may be reduced before or whilst the mould is being inverted to permit of some flow of metal towards the primary source 10.
- a reserve volume may be provided at the opposite end of the mould cavity 15 to the header 42 of a volume to ensure that the cavity remains filled during inversion.
- the cavity may be allowed to become partially emptied and then refilled from the secondary source when inverted.
- the header 42 remains containing metal and thereby, when the mould is inverted, maintains a pressure on the mould in the cavity 15 and feeds the cavity whilst the metal in the cavity 15 solidifies.
- header is now positioned above the mould cavity 15 heating of the mould cavity by convection from the header or headers is not possible and so the presence of the header does not delay solidification of metal as a result of convection.
- the manipulator 50 is operated to move the mould/mould support assembly 13, 14 from the casting station CA by moving the assembly horizontally in the direction of the arrow B away from the launder 12 so separating the surfaces 53, 54 of the joint 37.
- the manipulator 50 is then operated to rotate the mould support/mould assembly 13, 14 about a vertical axis as indicated by the arrow D and then lowered in the direction of the arrow E so as to move the assembly to the cooling station CO, see Figure 4 whereat the mould 14 is disposed on a cooling track or conveyor.
- the plate 51 is then released so that the manipulator 50 can be disengaged from the assembly whilst the weight of the-mould support 13 maintains a seal between the surface 44 thereof and the now upper most surface of the mould 14 until the metal in the cavity 15 has solidified.
- the manipulator 50 After the manipulator 50 has separated from the mould support 13 by movement in the direction of arrow B it is rotated about the vertical axis as indicated by the arrow D so as to proceed to a loading station where, after rotation through 180° about the axis H-H, it is engaged with another mould support assembly and mould.
- the manipulator then moves the further mould support and mould into feeding relationship with the reservoir 17 at the casting station CA surface by moving a surface, corresponding to the surface 53 hereinbefore described, of the new mould support into sealing engagement with the surface 54 of the joint member 55 fixed relative to the conduit 35. Then the cycle is repeated by again causing the pump 32 to pump metal upwardly into the new mould cavity.
- the mould support is lifted clear of the mould 14 by any suitable means and returned to the loading station to have a further mould positioned thereon for reuse.
- the shape of the header portion 42 is designed to permit the solidified header to remain behind with the mculd 14 when the mould support 13 is lifted therefrom after solidification.
- the manipulator 50 may be provided with a plurality of clamp plates 51 and means for releasably agaging a mould box, for example four at locations disposed radially around he vertical axis so that operations may be performed sequentially at each location. For example, casting at the casting station, lowering to the cooling track at the cooling station, movement of the mould box to a cleaning station and pick up of a new mould at the loading station. This would realize greater productivity.
- a mould 414 corresponding to the mould 14 of the first described embodiment is of boxless form and made of bonded sand in conventional manner.
- the mould 414 comprises cope and drag parts 445, 446 respectively and a mould cavity 415 is defined therein in which at least one core 447 is disposed; although, of course, in this as in all embodiments if desired the mould cavity may be without any core.
- the cope part 445 contains a header portion 442 and a conduit 440 comprising a feed passage 406 and a running passage 407.
- the mould support 413 is of reduced height compared with the embodiment previously described and the refractory mass 439 is in the form of a insulating slab.
- the box 438 may be in the form of a frame in which the refractory mass 439 is retained by a clamping ring 405.
- the refractory slab 439 closes the open section of the part 407 of the conduit 440.
- header 442 and conduit 440 is part of the mould 414 as is the entry port 441.
- the primary source and launder are as described in connection with the first embodiment and hence only the end of the launder 412 adjacent the mould 414 is shown.
- a rotary joint 437 permits of rotation about a horizontal axis, between the mould 414 and the conduit 435 and also permits of movement of the mould 414 from a casting station CA, shown in Figure 5 to a cooling station similar to the station CO shown in Figures to 4.
- the rotatable and separable joint 437 permits of rotation between the conduits 435 and 440 and provides a seal therebetween.
- the joint 437 comprises a first member 452 received in a recess in the sand of the cope part 445 and is in the form of a refractory dished washer.
- the outwardly facing surface of the washer 452 co-operates with an annular surface 454 of a second member 455 fixed relative to the conduit 435.
- a seal is maintained between the surface 454 and the outwardly facing surface 453 of the washer 452 by an axial load therebetween imposed by the apparatus.
- the washer 452 may contain a filter element of wire fibre-glass or refractory mesh, if desired.
- This arrangement has the advantage of economy, since the header and feed conduit is in the mould; simplicity of sealing, since it is necessary to provide only a simply refractory washer 452; versatility, in that the mould support 413 may be the same for all moulds irrespective of a desired header configuration or feed conduit configuration since each casting type has its own secondary source and feed conduit.
- a seal is effected between the bottom of the mould 414 and the refractory mass 439 by a face to face contact under load only, with the clamping ring 405 acting as a sealing "chill" should metal find a small escape path.
- the conduit part 406 has a downward inclination in the filling position. This inclination is shown exagerated in Figure 5 and in practice an initial relatively slow flow rate will not create turbulent conditions as metal flows slightly downwardly along the conduit part 406 and the conduit parts 406 and 407 will quickly fill so that subsequent filling can be carried out rapidly without turbulence at a free surface.
- conduit part 406 may be horizontal as shown in Figure 5 b .
- FIG. 6 another modification of the apparatus as described with reference to Figures I to 4 is illustrated and the same reference numerals, but preceded by a figure I, are used for corresponding parts as were used in Figures I to 4.
- a mould 114 corresponding to the mould 4 of the first described embodiment is made of unbonded sand using an in situ destroyabie pattern such as expanded polystyrene and in which a conduit 140 and header portion 142 corresponding to the conduit 40 and header portion 42 of the first described embodiment are defined in unbonded sand using a polystyrene pattern.
- a mould box 148 contains unbonded sand 160.
- a polystyrene pattern 161 Embedded in the sand 160 is a polystyrene pattern 161, a part 161 a of which defines the mould cavity 1 ' 15 and has a part 161b which defines the ingate 149.
- the pattern 161 parts 161a, (61b are formed integrally with a further pattern part 161c which defines the header portion 142 and conduit 140.
- the pattern part 161c is formed with a part, in the present example formed as three legs 161d, which stands on the upwardly facing surface 162 of the bottom wall of the mould box 148, and preferably locating means are be provided to prevent lateral movement of the pattern
- an adhesive may be provided between the surface 162 and the bottoms of the legs
- the pattern 161 is thus supported and retained in position solely as a result of the above described engagement between the legs 161d and the surface 162.
- the pattern part 161a may be formed separately from and attached to the pattern part
- the pattern 161 may terminate at the upper or lower end of the ingate 149 and be attached to a hollow refractory channel member, shown in dotted line at 163, the interior of which provides the header portion 142 and conduit 140, and if necessary, the ingate 149.
- the refractory channel member 163 is provided with a formation to stand on the surface 162 such as legs 1 63a similar to the legs
- a rotary and separable joint 137 permits of rotation about a horizontal axis between the mould 114 and the conduit 135 and also permits of movement of the mould 114 away from a casting station, shown in Figure 5, to a cooling station similar to that shown at CO in Figure 4.
- the rotary and separable joint 137 permits of rotation between the conduit 135 and conduit 140 and provides a seal therebetween.
- the joint 137 comprises a first member 152 received on the end of the pattern part
- the washer 152 is firmly attached to the pattern part 161c (or the refractory channel member 163) but is completely free of attachment to or location by the mould box 148.
- the recess 170 is of greater diameter than the washer 152 so as to' provide a circumferentially extending space 172 therebetween.
- the washer 152 is positioned on the pattern part 161c (or channel member 163) at such a position as to be adjecent the wall 173 of the recesss 170 so as to prevent passage of sand between the washer and the mould box 148 during filling of the mould box with unbonded sand.
- the washer is positioned by virtue of a counter bore 174 formed therein of the appropriate depth so that the washer is correctly positioned in relation to the surface 173 when the legs ⁇ 6td (or 163a) are correctly positioned on the surface 162.
- the pattern 161 (or conduit member 163) is totally disconnected from the mould box 148 in the region of the entry port 141 and the pattern (or conduit member 163) receive no support nor any location whatsoever from the mould box 148 in the region of the entry port 141. All the support and location being provided solely by the above described engagement of the legs 161d, (163a) with the surface 162.
- the outwardly facing surface of the washer 152 co-operates with an annular surface 154 of a second member 155 fixed relative to the conduit 135. A seal is maintained between the surface 154 and the outwardly facing surface 153 of the washer 152 by an axial load therebetween imposed by the apparatus.
- the washer 152 may contain a filter as described hereinbefore in connection with the washer 452 shown in Figure 5.
- the sand 160 is compacted around the pattern(s) or (pattern(s) and refractory channel member) in conventional manner, for example, by vibration and/or application of vacuum.
- a flexible sealing member 164 either a rubber sheet or 'cling film' or other suitable material, is retained by a clamp plate 165 and the mould box 148 is provided with a exit port 166 connected to a vacuum pump to enable a vacuum to be drawn to take off products of evaporation of the pattern 160 part 162 if provided and to retain consolidation of the sand.
- the mould box 148 is releasable connected to a manipulator identical to the manipulator 50 and the casting operation is as described hereinbefore in connection with the first embodiment except that there is no separation of a mould support from a mould.
- the whole assembly remains at the cooling station or is moved along the cooling track until the metal has solidified sufficiently for the vacuum to be released and the sand poured out of the mould box 148.
- the mould box 148 is moved to a moulding station where a new pattern(s) (or pattern(s) and refractory channel member) is introduced, washer 152 assembled thereto, and unbonded sand poured therearound followed by consolidation of the sand, application of vacuum and reengagement by the manipulator for movement into feeding relationship with the reservoir 17 at the casting station CA.
- the mould box 148 may be a unitary construction or may, as shown in Figure 6, comprise two parts which may be permanently or releasably connected together. If desired, the whole or part of the bottom wall of the mould box may be separate from the side walls thereof and may, for example, be provided by a suitable support surface against which the side walls abut.
- the mould support 113 may be substantially as described in connection with the embodiment described with reference to Figures I to 4, namely, comprising a refractory mass in which a conduit 240 and header portion 242 are defined in the same way as the conduit 40 and header portion 42 of the Figures I to 4 embodiment as is a rotary joint corresponding to the joint 37.
- a gasket 270 of refractory material is positioned on the top surface 244 of a mould support 213 and a pattern 261 corresponding to the pattern 161 of the Figure 5 embodiment is rested thereon and sand is poured into a mould box 248 prior to consolidation.
- the gasket 270 prevents the sand from filling the header portion 242.
- the casting operation is essentially as described in connection with the first embodiment in that after cooling at the cooling station CO for a sufficient period of time for the metal to solidify adequately, the mould support 213 is lifted away from the mould 214 whilst solidification in the mould continues.
- a further flexible seal closure may be provided between the mould support 213 and the mould 214 so that the vacuum is maintained after the mould support 213 has been removed.
- the mould support 213 is then moved back to the loading station for assembly of a further mould 214 thereon followed by a movement by the manipulator of the new assembly back into feeding relationship with the reservoir 17.
- a mould support 313 comprising a steel box 338 is mounted for rotation about a horizontal axis H-H by bearings 370 the outer races of which are carried on uprights 371.
- the box 338 has mounted thereon a manipulator means 372 which comprises a clamp plate 373 moveable in the direction of the arrow F by a pneumatic ram 374.
- the box 338 contains a refractory mass 339 within which is defined a conduit portion 340 which has an upwardly extending end part 34a.
- the upper surface of the refractory mass 339 receives and supports a mould 314 made as described in connection with the first embodiment described with reference -to Figures I to 4 thus comprising cope and drag parts 345, 346 and is arranged to be clamped to the mould support 313 by the clamping plate 373 of the manipulator 372.
- the mould 314 has a mould cavity 315 defined by the cope and drag parts 345, 346 and has at least one core 347 therein.
- An ingate 349 communicates with a header portion 342 which is connected in communication with the upwardly extending part 340a of the conduit 340.
- a gasket 375 is disposed betwen the surface 376 of the mould and the surface 344 of the mould support 313 to provide a seal there between.
- the apparatus is provided with a primary source of metal 316 which comprises a holding furnace 317 to which metal is fed in molten state and pumped therefrom, by pressurising the interior of the vessel 317,through a riser tube 333 and launder system 312 corresponding to that of the first embodiment.
- the metal may be pumped from the holding furnace 317 by using a pump separate from the furnace such as a pump similar to the electro magnetic pump 32 or pressure pump described in connection with the embodiment of Figures to 4.
- the primary source may be provided by a melter/holder furnace and fed therefrom as described in connection with the embodiment of Figures 1 to 4.
- the conduit part 335 is connected to the mould support 313 and in particular the conduit 340 thereof by a rotary joint 337 which, in the present embodiment is not capable of separation but only of rotation.
- the rotary joint is made between refractory faced parts 352 and 355 provided with cooperating sealing surfaces 353, 354 which, in the present example, are annular. Surfaces 353, 354 are maintained in sealing engagement by resilient biasing means such as coil compression springs 377 and sufficient flexibility is built into the launder system 312 to permit such biasing to occur.
- a mould 314 is picked up at a loading station by a suitable mechanical handling means and moved into position to rest on the surface 344 of the mould support 313 with a gasket 375 there between.
- the manipulator 372 is then activated to clamp the mould 314 in position with the clamping plate 373.
- the vessel 317 is then pressurized to pump metal upwardly through the conduit 335 and into the conduit 340 and hence upwardly through the part 340a thereof into the header portion 342, ingate 349 and cavity 315.
- the mode of upward feeding is therefore essentially as described within the previous embodiment and the same advantages accrue.
- the mould support 313 and mould 314 supported thereon are rotated about the axis H-H through 180 0 by a suitable rotating mechanism and then the applied metal pressure is removed and the metal in the conduit 340 allowed to flow back into the reservoir. Again the metal may be lowered to the extent that the conduit 340 is empty whilst metal still remains in at least part of the riser tube or metal may be allowed to fall back within the riser tube to the same level as the free surface of the metal in the reservoir 17.
- the mould 314 is lowered from contact with the mould support 313 by lowering the clamping plate 373.
- the thus inverted mould can then be removed laterally by a suitable mechanical handling device.
- a head of metal is maintained by the enlarged header portion 342 of the ingate 349 in the mould itself so that a, reduced, pressure is maintained applied to the metal in the mould cavity 315 and to feed the cavity 315 during solidification.
- a small residual volume of metal will not fully drain towards the reservoir adjacent to the ingate, when in the inverted position and, if this is not retained by its oxide film and surface tension, provision may be made to prevent it flowing from the mould by providing a gutter as shown at 378.
- the embodiment shown in Figure 8 may be modified for use with a mould made of non-bonded sand using an in situ destroyable pattern simply by providing a suitable moulding box containing unbonded consolidated sand surrounding such a pattern in place of the mould 314 described herein before.
- the expanded polystyrene pattern may provide the whole of the mould cavity 315, ingate 349 and header portion 342.
- the header portion 342 and ingate 349 may be provided by a refractory shell.
- a filter such as the filter F shown in dotted line in Figure I may be placed in the path of flow of metal from the reservoir to the mould cavity to further control movement of contaminates to the mould cavity.
- the filter in the example illustrated is a disc of ceramic filter material located between the first member 52 and the refractory mass 39 in place of the jointing gasket 39a.
- the or each of said longitudinal axes may be offset from the axis of rotation so as to perform a circular orbital motion around said axis.
- the mould cavity as a whole may be moved in a circular or other path, for example elliptical or an irregular path about a horizontal or substantially horizontal axis to change the orientation of the mould cavity relative to the force due to gravity. Any motion which results in a complete or partial inversion of the mould cavity is to be regarded as falling within the ambit of this invention and of the appended claims.
- the cavity has been fully inverted that is, rotated through 180 0 from the position it occupies during filling, if desired, it may be only partially inverted, the angular disposition of the feeds from the primary source and from the secondary source being such as to prevent flow of metal from the cavity towards the primary source and to permit flow of metal from the secondary source to the cavity when the mould have been inverted to the desired extent.
- inverted is used in the claims hereof to refer to both such partial inversion as well as full inversion.
- the metal is fed by being subjected to a pressure above atmospheric
- the metal may be fed from the primary source into the mould cavity by imposing a pressure below atmospheric in the mould cavity and the metal in the primary source being subject to a higher pressure.
- the mould cavity has been completely filled with metal from the primary source prior to the commencement of changing the orientation of the mould cavity relative to the force due to gravity.
- the mould cavity may be only partially filled prior to the commencement of change in orientation, the "head" required for partial filling being maintained by the pump during change in orientation, the mould cavity then being further filled by virtue of flow of metal from the primary source.
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- Mechanical Engineering (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Glass Compositions (AREA)
- Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
Abstract
Description
- This invention relates to a method of and apparatus for making a casting by feeding molten metal from a source of the molten metal into a mould cavity through an ingate below the top of the mould cavity. The invention is particularly, but not exclusively, concerned with a method and apparatus for making a casting by feeding molten metal generally upwardly from the source thereof into the mould cavity through an ingate at the bottom of the mould cavity, for example, by pumping the metal upwardly under low pressure from a reservoir disposed below the level of the mould cavity through an ingate at the bottom of the mould cavity.
- ' Hitherto foundries have made castings by this method by allowing the metal to solidify within the mould cavity and subsequently placing the mould cavity out of feeding relationship with the source of molten metal and placing a further mould cavity in feeding relationship with the source of the metal for repetition of the method.
- A majority of the time taken to make a casting by this method is occupied in waiting for the metal to solidify in the mould cavity before the source of metal can be placed out of feeding relationship with the mould cavity and placed in feeding relationship with a further mould cavity and the casting cycle repeated.
- An object of the invention is to provide a method of and an apparatus for making a casting in which the rate of production of castings is improved compared with known methods and apparatus.
- According to one aspect of the invention we provide a method of making a casting comprising the steps of, at a casting station, feeding molten metal from a primary source of molten metal into a mould cavity through an ingate below the top of the mould cavity, placing the cavity out of feeding relationship with the primary source by changing the orientation of the cavity relative to the force due to gravity to prevent flow of molten metal from the cavity towards the primary source and to permit flow of metal from a secondary source to the cavity, the cavity being continuously connected to the primary source during said change of orientation, transferring the mould cavity to a cooling station spaced from the casting station and, at the cooling station, permitting molten metal to flow to the cavity from the secondary source whilst the metal in the cavity solidifies.
- Other, optional features of this aspect of the invention are as set out in Claims I to 9 hereof.
- In this specification reference to an ingate at the bottom of the mould cavity is intended to cover not only an ingate which opens through a bottom wall of the cavity but also an ingate which opens through a side wall of the cavity with at least part of the ingate being disposed within the bottom half of the overall height of the mould cavity and preferably with the bottom part of the ingate being at or substantially at the level of the bottom wall of the cavity. It is however much preferred that the ingate opens through said bottom, upwardly facing, wall of the cavity so that the flow of metal through the ingate is substantially vertically upwardly.
- Where in this specification it is stated that the metal in the mould cavity may be subjected to a low pressure we mean for example, sufficient pressure only to ensure that the cavity is filled and to maintain a small head, for example, I to 3 inches of metal equivalent, to ensure that the cavity remains full whilst the cavity is placed out of said feeding relationship. Typically the low pressure is less than I bar, although, if desired, the pressure may be higher than this.
- According to another aspect of the invention we provide an apparatus for making a casting comprising a primary source for molten metal, a mould having a mould cavity, feed means to feed molten metal, in use, from the primary source into the mould cavity through an ingate below the top of the mould cavity, when the mould is at a casting station, means for placing the mould cavity out of feeding relationship with the primary source comprising means for changing the orientation of the mould cavity relative to the force due to gravity to prevent flow of molten metal from the cavity towards the primary source and to permit of flow of metal from a secondary source to the cavity, means continuously to connect the cavity with the primary source during said change of orientation, means to transfer the mould cavity to a cooling station spaced from the casting station where at molten metal may flow to the cavity from the secondary source whilst the metal in the cavity solidifies.
- Other optional, features of this aspect of the invention are as set out in
Claim 10 to 32 hereof. - Accordingly to another aspect of the invention we provide a casting when made by the method of the first aspect or using the apparatus of the second aspect of the invention.
- Embodiments of the invention will now be described by way of example with reference to the accompanying drawings wherein.
-
- FIGURE I is a diagramatic cross-sectional view through a first embodiment of the invention showing an apparatus in position ready for feeding metal from a primary source into the mould cavity.
- FIGURE 2 shows the apparatus of Figure I after filling of the mould cavity with metal from the primary source.
- FIGURE 3 is a fragmentary cross-sectional view on the line 3-3 of Figure I.
- FIGURE 4 is a diagramatic plan view of the apparatus of Figure I.
- FIGURE 5 is a fragmentary diagramatic cross-sectional view through part of a second embodiment of the invention which is a modification of the embodiment shown in Figures I to 4,
- FIGURE 5a is a section on the line 5a-5a of Figure 5,
- FIGURE 5b is a fragmentary cross-sectional view through a modification of the embodiment shown in Figure 5.
- FIGURE 6 is a fragmentary diagramatic cross-sectional view through part of a third embodiment of the invention which is a further modification of the embodiment shown in Figures I to 4,
- FIGURE 7 is a fragmentary diagramatic cross-sectional view through part of a fourth embodiment of the invention which is a further modification of the embodiment shown in Figures I to 4, and
- FIGURE 8 is a diagramatic cross sectional view through a fifth embodiment of the invention.
- Referring now to Figures I to 4, there is shown an apparatus for making metal castings comprising a
primary source 10 of molten metal I I connected by alaunder system 12 to amould support 13. Supported on themould support 13 is amould 14 having amould cavity 15. The metal I I to be cast is in this example an aluminium alloy known asLM 25 but may be any other aluminium alloy or any other metal castable by a "low pressure" means for example magnesium, zinc, lead, copper and alloys of any of these. Ferrous metals may also be cast. Of course the precise components used are chosen so as to be suitable for the metal to be cast. - The
primary source 10, in the present example, comprises a melter/holder furnace 16 comprising a refractory linedreservoir vessel 17 having arectangular base 18 and vertical side andend walls roof 21 extends across the whole width of thevessel 17 but stops short of theend walls 20 to provide a charging well 22 and a pump well 23 at opposite ends of the vessel. - The
roof 21 comprises a generally horizontal rectangulartop part 24 and vertical side andend walls roof 21 comprises suitable refractory material and within the roof are providedelectrical radiant heaters 27. - The temperature of the
heaters 27 and the number thereof and the area of thetop part 24 of the roof are arranged so as to provide sufficient heat to melt ingots fed into thevessel 17 at the charging well 22 and to maintain the metal molten in the remainder of the vessel. A downwardly dependingrefractory wall 28 is provided at the charging well end of the vessel to separate the charging well 22 from the main heating part of the vessel whilst downwardly depending and upwardly extendingrefractory walls pump 32, separate from thevessel 17 is provided. In the present example the pump is an electromagnetic pump which pumps metal from theregion 31 through ariser tube 33. If desired afilter 34 may be provided between thewalls casting vessel region 31. Theriser tube 33 andpump 32 provide a passage which has a lower end immersed in the molten metal and an upper end externally of thevessel 17 and an intermediate portion which extends through the freeupper surface 34 of the molten metal. - If desired any other form of suitable pump separate from the
reservoir vessel 17 may be provided such as a pressure pump in which metal is drawn into a body disposed within the reservoir and discharged therefrom by variation of pressure within the body through a riser tube as described in connection with thepump 32. - Alternatively, and not illustrated, the metal may be pumped upwards through a riser tube, corresponding to the
riser tube 33, by providing the primary source as a reservoir vessel which has an air tight enclosure and pressurizing the whole of the interior of the vessel to force metal upwardly through the riser tube which, preferably, provides a passage having a lower end immersed in the molten metal, an upper end externally of the vessel and an intermediate portion which extends upwardly through the free upper surface of the molten metal. This version is particularly suitable where the metal to be cast is a ferrous metal since theelectromagnetic pump 32 illustrated is not suitable for use with ferrous metals - Furthermore, however the metal is pumped, the metal may be fed to the reservoir vessel in molten state rather than in solid state if it is desired not to provide the
primary source 16 in the form of a melter/holder furnace. - The
riser tube 33 comprises part of thelaunder system 12 and from the upper end of theriser tube 33 there extends a generally horizontal but slightly upwardlyinclined conduit 35. Theriser tube 33 andconduit 35 are surrounded by thermally insulatingmaterial 36 and may be provided with heaters. - The
conduit 35 is connected to themould support 13 by a separablerotary joint 37. The joint 37 permits of rotation about a horizontal axis, between themould support 13 and theconduit 35 and also permits of movement of themould support 13 from a casting station CA as shown in Figures I to 4 to a cooling station CO spaced from the casting station. - The
mould support 13 comprises a steel open-topped box 38 containing arefractory mass 39 in which is formed aconduit 40 for molten metal which extends generally horizontally from anentry port 41 to aheader portion 42 which extends generally upwardly to anexit port 43 of the mould support. The volume of theheader portion 42 is arranged so as to contain sufficient metal to provide a secondary source of molten metal for the feeding of thecavity 15 as hereinafter to be described. - Supported on the
top surface 44 of the mould support is themould 14. In the present example themould 14 comprises cope anddrag parts mould cavity 15 in which at least onecore 47 is disposed. - The cope and
drag parts mould boxes 48 within which the bonded sand is disposed and thecavity 15 is provided with aningate 49. - Although in the example illustrated there is only a single mould cavity and a single header portion connected directly to the cavity by an
ingate 49, if desired a plurality of cavities may be provided in each mould. The or each cavity may contain one or more cores. The or each cavity may be connected to one or more header portions by one or more ingates for the or each cavity. For example, there may be a single header portion having a channel from which a plurality of ingates extend. Where there are a plurality of cavities there may be a single ingate for each cavity or a plurality of ingates for at least some of the cavities. Hereinafter reference to header, mould cavity and ingate are to be understood to refer also to these in the plural. If desired the cope and drag parts may be made in boxless form, one example of which is described hereinafter with reference to Figure 5, and/or the mould may comprise more than two parts. - The
steel box 38 is releasably connected to amanipulator 50 provided with aclamp plate 51 by which themould 14 is clamped to themould support 13.Clamp plate 51 is moveable in the direction of the arrow A whilst the manipulator is capable of moving themould box 38 horizontally in the direction of the arrow B vertically in the direction of the arrow E and it can rotate the box 38 ( and hence themould 14 together with the mould support 13 ) about a horizontal axis H-H as indicated by the arrow C and about a vertical axis as indicated by the arrow D. - The
rotatable joint 37 permits of rotation between the first andsecond conduits joint 37 comprises afirst member 52 received in a recess in therefractory mass 39 with a jointing gasket 39a therebetween and hence fixed relative to theconduit 40. Themember 52 has a frusto-conical recess 53 therein which co-operates with a partspherical surface 54 of asecond member 55 fixed relative to theconduit 35. Themembers - In use, a
mould 14 is clamped to theupper surface 44 of themould support 13 by the clampingplate 51 of themanipulator 50 and themanipulator 50 manipulates the assembly so as to move the sealing surfaces 53, 54 of the rotary joint 37 into sealing engagement, with themould 14 disposed above themould support 13 at the casting station CA, as shown in Figures I and 4. Thepump 32 is then operated to pump metal upwardly out of thevessel 17 through theriser tube 33,conduit 35, the passage defined within and surrounded by the sealing means 52-55 and hence into theconduit 40 of themould support 13 and then upwardly to fill theheader portion 42 and then to pass into themould cavity 15 upwardly through theingate 49. Metal movement is essentially upwards and therefore the benefits of "uphill" filling are achieved, namely lack of turbulent flow downwardly under gravity thereby avoiding entrainment of oxide and other particles in the metal surface thereby avoiding sources of defect nucleation. - Preferably the ingate and mould cavity are designed so that the cavity is filled without any or at Jeast any substantial flow of metal downwardly.
- The pressure of the metal in the mould is maintained at a desired low pressure as described hereinbefore.
- As soon as the mould is filled and with the above described pressure being maintained the
manipulator 50 is operated to rotate the mould support/mould assembly support mould assembly primary source 16 and into feeding relationship with thesecondary source 42 when the pressure in the pump is removed to allow the molten metal to fall back through theriser tube 33 out of theconduit 40 and at least partly out of theconduit 35 to the level shown in Figure 2. Alternatively, if desired the metal may fall completely out of theconduit 35 andriser tube 33 to lie at the same level as themetal surface 34 in thevessel 17. - Further alternatively, but not desirably, the pressure may be reduced before or whilst the mould is being inverted to permit of some flow of metal towards the
primary source 10. In this case a reserve volume, not shown, may be provided at the opposite end of themould cavity 15 to theheader 42 of a volume to ensure that the cavity remains filled during inversion. Alternatively, the cavity may be allowed to become partially emptied and then refilled from the secondary source when inverted. - The
header 42 remains containing metal and thereby, when the mould is inverted, maintains a pressure on the mould in thecavity 15 and feeds the cavity whilst the metal in thecavity 15 solidifies. - It should be noted that because the header is now positioned above the
mould cavity 15 heating of the mould cavity by convection from the header or headers is not possible and so the presence of the header does not delay solidification of metal as a result of convection. - As soon as the metal in the
conduit 35 of the laundersystem 12 has cleared the joint 37 themanipulator 50 is operated to move the mould/mould support assembly launder 12 so separating thesurfaces manipulator 50 is then operated to rotate the mould support/mould assembly mould 14 is disposed on a cooling track or conveyor. Theplate 51 is then released so that themanipulator 50 can be disengaged from the assembly whilst the weight of the-mould support 13 maintains a seal between thesurface 44 thereof and the now upper most surface of themould 14 until the metal in thecavity 15 has solidified. - After the
manipulator 50 has separated from themould support 13 by movement in the direction of arrow B it is rotated about the vertical axis as indicated by the arrow D so as to proceed to a loading station where, after rotation through 180° about the axis H-H, it is engaged with another mould support assembly and mould. The manipulator then moves the further mould support and mould into feeding relationship with thereservoir 17 at the casting station CA surface by moving a surface, corresponding to thesurface 53 hereinbefore described, of the new mould support into sealing engagement with thesurface 54 of thejoint member 55 fixed relative to theconduit 35. Then the cycle is repeated by again causing thepump 32 to pump metal upwardly into the new mould cavity. - In the meantime,after solidification of the metal in the
cavity 15 and theheader portion 42, the mould support is lifted clear of themould 14 by any suitable means and returned to the loading station to have a further mould positioned thereon for reuse. - The shape of the
header portion 42 is designed to permit the solidified header to remain behind with themculd 14 when themould support 13 is lifted therefrom after solidification. - It is considered that in a situation where 5-8 castings an hour can be made by hitherto known technique; by using the method and apparatus described above in the region of 25-30 castings may be made per hour which is, of course, a very substantial increase in casting rate and this increase is achieved with no change in the quility and yield obtained with previously known methods.
- If desired the
manipulator 50 may be provided with a plurality ofclamp plates 51 and means for releasably agaging a mould box, for example four at locations disposed radially around he vertical axis so that operations may be performed sequentially at each location. For example, casting at the casting station, lowering to the cooling track at the cooling station, movement of the mould box to a cleaning station and pick up of a new mould at the loading station. This would realize greater productivity. - Referring now to Figure 5, a modification of the apparatus as described with reference to Figures I to 4 is illustrated and the same reference numerals, but preceded by a figure 4, are used for corresponding parts as were used in Figures to 4. In this modification a
mould 414 corresponding to themould 14 of the first described embodiment is of boxless form and made of bonded sand in conventional manner. Themould 414 comprises cope and dragparts mould cavity 415 is defined therein in which at least onecore 447 is disposed; although, of course, in this as in all embodiments if desired the mould cavity may be without any core. - In this embodiment the cope
part 445 contains aheader portion 442 and aconduit 440 comprising afeed passage 406 and a runningpassage 407. - The
mould support 413 is of reduced height compared with the embodiment previously described and therefractory mass 439 is in the form of a insulating slab. Thebox 438 may be in the form of a frame in which therefractory mass 439 is retained by aclamping ring 405. Therefractory slab 439 closes the open section of thepart 407 of theconduit 440. - Thus, in this embodiment the
header 442 andconduit 440 is part of themould 414 as is the entry port 441. The primary source and launder are as described in connection with the first embodiment and hence only the end of thelaunder 412 adjacent themould 414 is shown. A rotary joint 437 permits of rotation about a horizontal axis, between themould 414 and theconduit 435 and also permits of movement of themould 414 from a casting station CA, shown in Figure 5 to a cooling station similar to the station CO shown in Figures to 4. The rotatable and separable joint 437 permits of rotation between theconduits first member 452 received in a recess in the sand of the copepart 445 and is in the form of a refractory dished washer. The outwardly facing surface of thewasher 452 co-operates with anannular surface 454 of a second member 455 fixed relative to theconduit 435. - A seal is maintained between the
surface 454 and the outwardly facingsurface 453 of thewasher 452 by an axial load therebetween imposed by the apparatus. - The
washer 452 may contain a filter element of wire fibre-glass or refractory mesh, if desired. - The sequence of operations is as described in connection with the first embodiment and in this case, when in the inverted position, the
conduit 440 is drained fully leaving the secondary source orheader 442 full. - This arrangement has the advantage of economy, since the header and feed conduit is in the mould; simplicity of sealing, since it is necessary to provide only a simply
refractory washer 452; versatility, in that themould support 413 may be the same for all moulds irrespective of a desired header configuration or feed conduit configuration since each casting type has its own secondary source and feed conduit. - A seal is effected between the bottom of the
mould 414 and therefractory mass 439 by a face to face contact under load only, with theclamping ring 405 acting as a sealing "chill" should metal find a small escape path. - The
conduit part 406 has a downward inclination in the filling position. This inclination is shown exagerated in Figure 5 and in practice an initial relatively slow flow rate will not create turbulent conditions as metal flows slightly downwardly along theconduit part 406 and theconduit parts - If desired the
conduit part 406 may be horizontal as shown in Figure 5b. - Referring now to Figure 6 another modification of the apparatus as described with reference to Figures I to 4 is illustrated and the same reference numerals, but preceded by a figure I, are used for corresponding parts as were used in Figures I to 4. In this modification a
mould 114 corresponding to themould 4 of the first described embodiment is made of unbonded sand using an in situ destroyabie pattern such as expanded polystyrene and in which aconduit 140 andheader portion 142 corresponding to theconduit 40 andheader portion 42 of the first described embodiment are defined in unbonded sand using a polystyrene pattern. - In this embodiment a
mould box 148 containsunbonded sand 160. Embedded in thesand 160 is apolystyrene pattern 161, a part 161 a of which defines themould cavity 1'15 and has apart 161b which defines theingate 149. Thepattern 161 parts 161a, (61b are formed integrally with a further pattern part 161c which defines theheader portion 142 andconduit 140. - The pattern part 161c is formed with a part, in the present example formed as three legs 161d, which stands on the upwardly facing
surface 162 of the bottom wall of themould box 148, and preferably locating means are be provided to prevent lateral movement of the pattern |6| relative to the mould box. For example an adhesive may be provided between thesurface 162 and the bottoms of the legs |6|d or a socket, not shown, may be provided in or on thesurface 162 in which the bottom ends of the legs 161d can be received. Thepattern 161 is thus supported and retained in position solely as a result of the above described engagement between the legs 161d and thesurface 162. - If desired the pattern part 161a may be formed separately from and attached to the pattern part |6|b which may be formed integral with or separately from and attached to the pattern part 161c and likewise the pattern part 161d may be formed integral with or separately from and attached to the pattern part |6|c.
- Alternatively the
pattern 161 may terminate at the upper or lower end of theingate 149 and be attached to a hollow refractory channel member, shown in dotted line at 163, the interior of which provides theheader portion 142 andconduit 140, and if necessary, theingate 149. In this case therefractory channel member 163 is provided with a formation to stand on thesurface 162 such aslegs 1 63a similar to the legs |6|d described hereinbefore. - The primary source and launder are as described in connection with the first embodiment and hence only a
member 155 corresponding to the member 455 of the embodiment described with reference to Figure 5 is shown. A rotary and separable joint 137 permits of rotation about a horizontal axis between themould 114 and the conduit 135 and also permits of movement of themould 114 away from a casting station, shown in Figure 5, to a cooling station similar to that shown at CO in Figure 4. The rotary and separable joint 137 permits of rotation between the conduit 135 andconduit 140 and provides a seal therebetween. The joint 137 comprises afirst member 152 received on the end of the pattern part |6|c (orrefractory channel member 163 when provided) and accomodated in arecess 170 in the side wall 171 of themould box 148 and is in the form of a refractory washer. Thewasher 152 is firmly attached to the pattern part 161c (or the refractory channel member 163) but is completely free of attachment to or location by themould box 148. To that end therecess 170 is of greater diameter than thewasher 152 so as to' provide acircumferentially extending space 172 therebetween. Thewasher 152 is positioned on the pattern part 161c (or channel member 163) at such a position as to be adjecent the wall 173 of therecesss 170 so as to prevent passage of sand between the washer and themould box 148 during filling of the mould box with unbonded sand. The washer is positioned by virtue of acounter bore 174 formed therein of the appropriate depth so that the washer is correctly positioned in relation to the surface 173 when the legs <6td (or 163a) are correctly positioned on thesurface 162. - It will be seen, therefore, that the pattern 161 (or conduit member 163) is totally disconnected from the
mould box 148 in the region of theentry port 141 and the pattern (or conduit member 163) receive no support nor any location whatsoever from themould box 148 in the region of theentry port 141. All the support and location being provided solely by the above described engagement of the legs 161d, (163a) with thesurface 162. - The outwardly facing surface of the
washer 152 co-operates with anannular surface 154 of asecond member 155 fixed relative to the conduit 135. A seal is maintained between thesurface 154 and the outwardly facingsurface 153 of thewasher 152 by an axial load therebetween imposed by the apparatus. Thewasher 152 may contain a filter as described hereinbefore in connection with thewasher 452 shown in Figure 5. - The
sand 160 is compacted around the pattern(s) or (pattern(s) and refractory channel member) in conventional manner, for example, by vibration and/or application of vacuum. A flexible sealing member 164, either a rubber sheet or 'cling film' or other suitable material, is retained by aclamp plate 165 and themould box 148 is provided with aexit port 166 connected to a vacuum pump to enable a vacuum to be drawn to take off products of evaporation of thepattern 160part 162 if provided and to retain consolidation of the sand. - The
mould box 148 is releasable connected to a manipulator identical to themanipulator 50 and the casting operation is as described hereinbefore in connection with the first embodiment except that there is no separation of a mould support from a mould. The whole assembly remains at the cooling station or is moved along the cooling track until the metal has solidified sufficiently for the vacuum to be released and the sand poured out of themould box 148. Thereafter themould box 148 is moved to a moulding station where a new pattern(s) (or pattern(s) and refractory channel member) is introduced,washer 152 assembled thereto, and unbonded sand poured therearound followed by consolidation of the sand, application of vacuum and reengagement by the manipulator for movement into feeding relationship with thereservoir 17 at the casting station CA. - If desired the
mould box 148 may be a unitary construction or may, as shown in Figure 6, comprise two parts which may be permanently or releasably connected together. If desired, the whole or part of the bottom wall of the mould box may be separate from the side walls thereof and may, for example, be provided by a suitable support surface against which the side walls abut. - In a modification of the embodiment described with reference to Figure 6 and illustrated in Figure 7 in which the same reference numerals but preceded by a figure 2 are used for corresponding parts as were used in Figures I to 4 the mould support 113 may be substantially as described in connection with the embodiment described with reference to Figures I to 4, namely, comprising a refractory mass in which a
conduit 240 andheader portion 242 are defined in the same way as theconduit 40 andheader portion 42 of the Figures I to 4 embodiment as is a rotary joint corresponding to the joint 37. In this case agasket 270 of refractory material is positioned on thetop surface 244 of amould support 213 and apattern 261 corresponding to thepattern 161 of the Figure 5 embodiment is rested thereon and sand is poured into amould box 248 prior to consolidation. Thegasket 270 prevents the sand from filling theheader portion 242. In this modification the casting operation is essentially as described in connection with the first embodiment in that after cooling at the cooling station CO for a sufficient period of time for the metal to solidify adequately, themould support 213 is lifted away from themould 214 whilst solidification in the mould continues. If desired to facilitate this, a further flexible seal closure may be provided between themould support 213 and themould 214 so that the vacuum is maintained after themould support 213 has been removed. Themould support 213 is then moved back to the loading station for assembly of afurther mould 214 thereon followed by a movement by the manipulator of the new assembly back into feeding relationship with thereservoir 17. - Referring now to Figure 8, there is shown a further embodiment of the invention and the same reference numerals but preceded by a figure 3 have been used for corresponding parts as were used in Figure I to 4. In this embodiment a
mould support 313 comprising asteel box 338 is mounted for rotation about a horizontal axis H-H bybearings 370 the outer races of which are carried onuprights 371. Thebox 338 has mounted thereon a manipulator means 372 which comprises aclamp plate 373 moveable in the direction of the arrow F by apneumatic ram 374. Thebox 338 contains arefractory mass 339 within which is defined aconduit portion 340 which has an upwardly extending end part 34a. - The upper surface of the
refractory mass 339 receives and supports amould 314 made as described in connection with the first embodiment described with reference -to Figures I to 4 thus comprising cope and dragparts mould support 313 by the clampingplate 373 of themanipulator 372. Themould 314 has amould cavity 315 defined by the cope and dragparts core 347 therein. An ingate 349 communicates with aheader portion 342 which is connected in communication with the upwardly extending part 340a of theconduit 340. - A
gasket 375 is disposed betwen thesurface 376 of the mould and thesurface 344 of themould support 313 to provide a seal there between. The apparatus is provided with a primary source of metal 316 which comprises a holding furnace 317 to which metal is fed in molten state and pumped therefrom, by pressurising the interior of the vessel 317,through a riser tube 333 and laundersystem 312 corresponding to that of the first embodiment. If desired, alternatively, the metal may be pumped from the holding furnace 317 by using a pump separate from the furnace such as a pump similar to the electromagnetic pump 32 or pressure pump described in connection with the embodiment of Figures to 4. Further alternatively the primary source may be provided by a melter/holder furnace and fed therefrom as described in connection with the embodiment of Figures 1 to 4. - The
conduit part 335 is connected to themould support 313 and in particular theconduit 340 thereof by a rotary joint 337 which, in the present embodiment is not capable of separation but only of rotation. The rotary joint is made between refractoryfaced parts system 312 to permit such biasing to occur. - In use, a
mould 314 is picked up at a loading station by a suitable mechanical handling means and moved into position to rest on thesurface 344 of themould support 313 with agasket 375 there between. Themanipulator 372 is then activated to clamp themould 314 in position with the clampingplate 373. - The vessel 317 is then pressurized to pump metal upwardly through the
conduit 335 and into theconduit 340 and hence upwardly through the part 340a thereof into theheader portion 342, ingate 349 andcavity 315. The mode of upward feeding is therefore essentially as described within the previous embodiment and the same advantages accrue. - When the
mould cavity 315 is filled and whilst pressure is maintained, of the same magnitude as previously described, themould support 313 andmould 314 supported thereon are rotated about the axis H-H through 1800 by a suitable rotating mechanism and then the applied metal pressure is removed and the metal in theconduit 340 allowed to flow back into the reservoir. Again the metal may be lowered to the extent that theconduit 340 is empty whilst metal still remains in at least part of the riser tube or metal may be allowed to fall back within the riser tube to the same level as the free surface of the metal in thereservoir 17. - As soon as the metal has fallen to clear the
conduit 340 themould 314 is lowered from contact with themould support 313 by lowering theclamping plate 373. The thus inverted mould can then be removed laterally by a suitable mechanical handling device. A head of metal is maintained by theenlarged header portion 342 of the ingate 349 in the mould itself so that a, reduced, pressure is maintained applied to the metal in themould cavity 315 and to feed thecavity 315 during solidification. A small residual volume of metal will not fully drain towards the reservoir adjacent to the ingate, when in the inverted position and, if this is not retained by its oxide film and surface tension, provision may be made to prevent it flowing from the mould by providing a gutter as shown at 378. - If desired, the embodiment shown in Figure 8 may be modified for use with a mould made of non-bonded sand using an in situ destroyable pattern simply by providing a suitable moulding box containing unbonded consolidated sand surrounding such a pattern in place of the
mould 314 described herein before. The expanded polystyrene pattern may provide the whole of themould cavity 315, ingate 349 andheader portion 342. Alternatively, if desired, theheader portion 342 and ingate 349 may be provided by a refractory shell. - In all the embodiments described hereinbefore a filter, such as the filter F shown in dotted line in Figure I may be placed in the path of flow of metal from the reservoir to the mould cavity to further control movement of contaminates to the mould cavity. The filter in the example illustrated is a disc of ceramic filter material located between the
first member 52 and therefractory mass 39 in place of the jointing gasket 39a. - Although in the examples described above the longitudinal axis of the openings for the passage of metal through the first and second members of the rotary joints have coincided with the axis of rotation of the mould cavity if desired, the or each of said longitudinal axes may be offset from the axis of rotation so as to perform a circular orbital motion around said axis. Moreover the mould cavity as a whole may be moved in a circular or other path, for example elliptical or an irregular path about a horizontal or substantially horizontal axis to change the orientation of the mould cavity relative to the force due to gravity. Any motion which results in a complete or partial inversion of the mould cavity is to be regarded as falling within the ambit of this invention and of the appended claims. Although in the above example the cavity has been fully inverted that is, rotated through 1800 from the position it occupies during filling, if desired, it may be only partially inverted, the angular disposition of the feeds from the primary source and from the secondary source being such as to prevent flow of metal from the cavity towards the primary source and to permit flow of metal from the secondary source to the cavity when the mould have been inverted to the desired extent. The term "inverted" is used in the claims hereof to refer to both such partial inversion as well as full inversion.
- Although in the above examples the metal is fed by being subjected to a pressure above atmospheric, if desired, the metal may be fed from the primary source into the mould cavity by imposing a pressure below atmospheric in the mould cavity and the metal in the primary source being subject to a higher pressure.
- In the above example the mould cavity has been completely filled with metal from the primary source prior to the commencement of changing the orientation of the mould cavity relative to the force due to gravity. However, if desired, the mould cavity may be only partially filled prior to the commencement of change in orientation, the "head" required for partial filling being maintained by the pump during change in orientation, the mould cavity then being further filled by virtue of flow of metal from the primary source.
- In all embodiments described hereinbefore the advantages accruing from bottom filling of the mould are attained and in addition the inversion of the mould and its removal from feeding relationship with the primary source
Claims (21)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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AT87301464T ATE48961T1 (en) | 1986-02-21 | 1987-02-20 | METHOD AND DEVICE FOR CASTING. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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GB8604385 | 1986-02-21 | ||
GB868604385A GB8604385D0 (en) | 1986-02-21 | 1986-02-21 | Casting |
Publications (2)
Publication Number | Publication Date |
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EP0234877A1 true EP0234877A1 (en) | 1987-09-02 |
EP0234877B1 EP0234877B1 (en) | 1989-12-27 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP87301464A Expired EP0234877B1 (en) | 1986-02-21 | 1987-02-20 | Method of and apparatus for casting |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0234877B1 (en) |
AT (1) | ATE48961T1 (en) |
DE (1) | DE3761246D1 (en) |
ES (1) | ES2012802B3 (en) |
GB (1) | GB8604385D0 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0599768A1 (en) * | 1992-11-20 | 1994-06-01 | Agustin Arana Erana | A machine for filling sand moulds with non-ferrous metals using a low pressure technique |
DE4304622A1 (en) * | 1993-02-16 | 1994-08-18 | Bruehl Aluminiumtechnik | Process for filling a mold |
DE4304621A1 (en) * | 1993-02-16 | 1994-08-18 | Bruehl Aluminiumtechnik | Pouring spout |
EP1072341A1 (en) * | 1999-07-29 | 2001-01-31 | Heinrich Wagner Sinto Maschinenfabrik GmbH | Casting device for a foundry moulding installation |
DE102006058145A1 (en) * | 2006-12-09 | 2008-06-12 | Ksm Castings Gmbh | Method for processing, in particular casting, a material, casting mold for carrying out the method and articles produced by the method or in the casting mold |
CZ303141B6 (en) * | 2000-04-19 | 2012-05-02 | Vaw Mandl & Berger Gmbh | Casting mold containing external parts of the mold and method of casting a melt therewith |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2225970A (en) * | 1988-07-04 | 1990-06-20 | Collins Motor Corp Ltd | Low pressure casting of metal |
JP3219778B2 (en) | 1997-06-26 | 2001-10-15 | ゲオルグ フィッチャー ディサ アクツイエセルスカプ | Method and apparatus for casting a metal object in a casting cavity adapted to be filled upward |
FR2775917B1 (en) * | 1998-03-10 | 2000-06-02 | Montupet Sa | LARGE SERIES MOLDING PROCESS FOR ALUMINUM ALLOY PARTS AND ASSOCIATED EQUIPMENT |
WO2004018131A1 (en) * | 2002-08-20 | 2004-03-04 | Loramendi, S.A. | Casting ladle |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3123877A (en) * | 1962-04-06 | 1964-03-10 | Apparatus for and method of casting metal members | |
FR1560465A (en) * | 1968-01-17 | 1969-03-21 | ||
FR2007747A1 (en) * | 1968-05-03 | 1970-01-09 | Sulzer Ag | |
FR2177466A1 (en) * | 1972-02-07 | 1973-11-09 | Alsacienne Atom | |
EP0152754A1 (en) * | 1984-02-15 | 1985-08-28 | Pont-A-Mousson S.A. | Foundry moulding process and mould for low-pressure precision casting with a gasifiable model and binderless sand mould |
-
1986
- 1986-02-21 GB GB868604385A patent/GB8604385D0/en active Pending
-
1987
- 1987-02-20 ES ES87301464T patent/ES2012802B3/en not_active Expired - Lifetime
- 1987-02-20 EP EP87301464A patent/EP0234877B1/en not_active Expired
- 1987-02-20 DE DE8787301464T patent/DE3761246D1/en not_active Expired - Lifetime
- 1987-02-20 AT AT87301464T patent/ATE48961T1/en not_active IP Right Cessation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3123877A (en) * | 1962-04-06 | 1964-03-10 | Apparatus for and method of casting metal members | |
FR1560465A (en) * | 1968-01-17 | 1969-03-21 | ||
FR2007747A1 (en) * | 1968-05-03 | 1970-01-09 | Sulzer Ag | |
FR2177466A1 (en) * | 1972-02-07 | 1973-11-09 | Alsacienne Atom | |
EP0152754A1 (en) * | 1984-02-15 | 1985-08-28 | Pont-A-Mousson S.A. | Foundry moulding process and mould for low-pressure precision casting with a gasifiable model and binderless sand mould |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0599768A1 (en) * | 1992-11-20 | 1994-06-01 | Agustin Arana Erana | A machine for filling sand moulds with non-ferrous metals using a low pressure technique |
ES2112686A1 (en) * | 1993-02-16 | 1998-04-01 | Bruehl Aluminiumtechnik | Rotary slide valve for metallurgical vessels |
DE4304621A1 (en) * | 1993-02-16 | 1994-08-18 | Bruehl Aluminiumtechnik | Pouring spout |
FR2701411A1 (en) * | 1993-02-16 | 1994-08-19 | Bruehl Aluminiumtechnik | Process for filling a casting mold and container for its implementation |
FR2701413A1 (en) * | 1993-02-16 | 1994-08-19 | Bruehl Aluminiumtechnik | Exit closure system. |
ES2109126A1 (en) * | 1993-02-16 | 1998-01-01 | Bruehl Aluminiuntechnik | Method of and vessel for filling a casting mold |
DE4304622A1 (en) * | 1993-02-16 | 1994-08-18 | Bruehl Aluminiumtechnik | Process for filling a mold |
AT404685B (en) * | 1993-02-16 | 1999-01-25 | Vaw Mandl & Berger Gmbh | Process for filling a mold |
EP1072341A1 (en) * | 1999-07-29 | 2001-01-31 | Heinrich Wagner Sinto Maschinenfabrik GmbH | Casting device for a foundry moulding installation |
TR200002194A3 (en) * | 1999-07-29 | 2001-03-21 | Heinrich Wagner Sinto Maschinenfabrik Gmbh | A casting device for the foundry molding system |
CZ303141B6 (en) * | 2000-04-19 | 2012-05-02 | Vaw Mandl & Berger Gmbh | Casting mold containing external parts of the mold and method of casting a melt therewith |
DE102006058145A1 (en) * | 2006-12-09 | 2008-06-12 | Ksm Castings Gmbh | Method for processing, in particular casting, a material, casting mold for carrying out the method and articles produced by the method or in the casting mold |
US8763677B2 (en) | 2006-12-09 | 2014-07-01 | Ksm Castings Group Gmbh | Method for processing, in particular casting, a material, casting mould for carrying out the method and articles produced by the method or in the casting mould |
Also Published As
Publication number | Publication date |
---|---|
ES2012802B3 (en) | 1990-04-16 |
EP0234877B1 (en) | 1989-12-27 |
DE3761246D1 (en) | 1990-02-01 |
GB8604385D0 (en) | 1986-03-26 |
ATE48961T1 (en) | 1990-01-15 |
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