CN1113733C

CN1113733C - Polymer cutting apparatus and method

Info

Publication number: CN1113733C
Application number: CN97182389A
Authority: CN
Inventors: M·R·萨米尔; M·G·瓦戈纳
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1997-09-29
Filing date: 1997-09-29
Publication date: 2003-07-09
Anticipated expiration: 2017-09-29
Also published as: CN1275942A

Abstract

The present invention relates to a polymer cutter with a rotary cutting disk. A cutting edge is positioned on the periphery of the cutting disk, and cutting edge takes shearing motion rather than cutting movement. The cutting edge angle of a cutter blade on the rotary disk is larger than 70 degrees. The polymer cutter is particularly suitable for cutting thermoplastics to manufacture polymer granules or polymer pellets.

Description

The cutter sweep of polymer and cutting method

Invention field

The present invention relates to cutting polymer especially cutting polymer bar etc. the rotation chopping disk and with the method for this chopping disk cutting polymer.

Technical background

The important commodity that the polymer amount of being is big are applied to various fields.During handling, process and reclaiming polymer, often polymer need be cut into different sizes and/or difform less sheets.For example when the molding thermoplastic plastics, polymerization need be cut into quite little sheet of size or particle, so that easily they are sent into forming machine for example injection molding machine or extruder.

The cutter of cutting polymer has multiple structure now.In a kind of ordinary construction, use a kind of rotating disc, this dish comprises many cuttves that are in substantially parallel relationship to pivot center, and when to the capstan head transferring polymer, these cuttves are cutting polymer facing to dead knife rotates, and this cutter is shown in Fig. 2.In these cutters, cutter is configured to cut with the action of section, cuts polymer with very thin anterior blade.Although this cutter is for many years popular, there are some shortcomings in they.One of them shortcoming is breaking of cutter and weares and teares, particularly when cutting very hard and/or abrasion polymerization.As everyone knows, when adopting the very sharp-pointed cutter of cutting edge angle, the little metal on blade will make blade become very fragile, be easy to make the blade fracture and/or make its wearing and tearing very soon.When fracture or excessive wear take place, just can produce bad influence, and must stop the cutter running, so that the blade that resharpen blade or replacement have been worn and torn or broken to cut quality.This shutdown causes very large economy loss, and the one, spent tangible maintenance cost, the 2nd, lost the production time.Therefore need a kind of cut quality that can cut at a high speed good, simultaneously downtime few again polymer cutter sweep.

Brief summary of the invention

The present invention relates to a kind of rotary cutter dish with a pivot center, this capstan head comprises one or more cuttves, each cutter has a blade on the outer peripheral edges of above-mentioned rotary cutter dish, the knife angle of each cutter is at+10 ° to-15 ° approximately approximately, its cutting edge angle is 70 ° or bigger, and condition is that no any point is than the above-mentioned pivot center of above-mentioned blade further from above-mentioned rotary cutter dish on the sword face of above-mentioned cutter.

A kind of rotary cutter that is used for cutting polymer has also been described in this article, comprise a dead knife, a rotary cutter dish and the device of polymer being sent into above-mentioned rotary cutter dish, wherein above-mentioned rotary cutter dish has a pivot center and one or more cutter, each cutter has a blade on the outer peripheral edges of above-mentioned rotary cutter dish, the knife angle of each cutter is at+10 ° to-15 ° approximately approximately, its cutting edge angle is 70 ° or bigger, and condition is that no any point is than the above-mentioned pivot center of above-mentioned blade further from above-mentioned rotary cutter dish on the sword face of above-mentioned cutter.

The invention still further relates to method with the rotary cutter cutting polymer, wherein improve and comprise that employing has the rotary cutter dish of a pivot center and one or more cuttves, each cutter has a blade on the outer peripheral edges of above-mentioned rolling disc, the knife angle of each cutter is at+10 ° to-15 ° approximately approximately, its cutting edge angle is 70 ° or bigger, and condition is that no any point is than the above-mentioned pivot center of above-mentioned blade further from above-mentioned rotating disc on the sword face of above-mentioned cutter.

Brief description of drawings

Fig. 1 is perpendicular to the cross-sectional view of pivot center, and the part that the present invention typically rotates chopping disk is shown, and the polymer beads of dead knife, polymer strip and cutting-out also is shown.

Fig. 2 is perpendicular to the cross-sectional view of pivot center, and the part of the rotation chopping disk of typical conventional design is shown, and the polymer beads of dead knife, polymer strip and cutting-out also is shown.

Fig. 3 is perpendicular to the cross-sectional view of pivot center, and the typical rotary cutter dish of the present invention is shown.

Fig. 4 schematically illustrates the vitals of the rotary cutter dish that the present invention determines.

Fig. 5 illustrates shown in this paper the dish body of used rotary cutter dish in the example, and dimensional units is cm.Fig. 5 a is the plane of dish body, and Fig. 5 b illustrates the dish body cross-sectional view perpendicular to pivot center.Fig. 5 c illustrates illustrated details among Fig. 5 b.

Fig. 6 illustrate be used in shown in wedge shape part and blade in the rotary cutter dish example, dimensional units is cm.Fig. 6 a is the plane and the sectional view of wedge shape part, and Fig. 6 b is the sectional view of blade.

The invention details

This paper the said polymer means the polymer itself that does not comprise additive and contains any additives that contains usually in the polymer or the polymer of additive agent mixture.This additive comprises for example TiO of pigment ₂, antioxidant, antiozonant, flexibilizer, fire retardant, lubricant, dyestuff, antistatic additive, anti-colouring agent and filler and reinforcing agent for example talcum powder, clay, carbon ink, levigate glass, glass fibre, carbon fiber and aramid fibre.Preferred polymer is plastics (relative resilient bodies), and thermoplastic plastic is particularly preferred.

Fig. 1 is total cross-sectional view, and a part of rotary cutter dish and other parts of cutter sweep of the present invention are shown.The parts of the rotary cutter dish that illustrates are: rotary cutter dish dish body 1, direction rotation shown in this dish body edge; Some cuttves 2; Two wedge shape parts 6, this wedge shape part make cutter be fixed in the position of dish on the body 1 (for example use bolt, bolt hole shown in the figure but not shown bolt).Static dead knife 3 also is shown among the figure, and not shown its installed, and polymer strip 4 and firm cut polymer beads 5 that just direction is being carried shown in the edge also are shown.

Fig. 2 illustrates the similar figure of traditional polymer cutter, and this cutter comprises rotary cutter main body 7, some cuttves 8 and makes the cutter fix in position and wedge shape part 9.The polymer beads 12 that dead knife 10, polymer strip 11 also is shown among the figure and downcuts.

Substantially comparison diagram 1 and Fig. 2 just as can be seen, the main difference between cutter of the present invention and the conventional tool is, the cutting mode of conventional tool is shaved except that beard the spitting image of shaver, and the operation of cutter of the present invention more similarly is to cut off polymer.In two kinds of cutters, the blade and the gap between the dead knife of each cutter are preferably tried one's best little and practical.This often can provide the most neat cutting, usually between 0.025-0.25mm, preferably about 0.050-0.12mm.

Generally say, in this cutter, polymer connected push rotating knife, through after the dead knife, make the cutter of each cutter skim over the blade of dead knife at the blade of each cutter.In other words, on cutter from the rotary cutter dish pivot center point farthest blade of cutter normally, all somes pivot center of then more close rotary cutter dish of comparing with blade on the sword face.In addition, if suitable, preferably also rotary cutter dish and the parts except that cutter thereof are designed to make the polymer feeding.Under the situation of Fig. 1, make the inclination of revolving part and wedge shape part leave the outer rim of capstan head, as shown in the figure.For realizing this point, it will be obvious to those skilled in the art that other design.

Cutter can be parts separately, and it can be unloaded down from the rotary cutter dish, so that it is sharpened or replaces, other structure also is possible, and this cutter can be with bolt or is fixed on the rotary cutter dish with the wedge shape part as shown in the figure.Perhaps the rotary cutter dish can make a whole sheet metal, has the blade of sclerosis.Can save the processing in wedge shape part shown in Figure 1, hole etc. like this.Not cracked or this is useful especially often need not sharpen the time at blade.

Fig. 3 is perpendicular to the cross-sectional view of pivot center, and the dish of rotary cutter completely of the present invention is shown.This dish has the cutter 26 that center of rotation 24, dish body 25 and the some wedge shape parts 27 of a lot of usefulness are fixed in the dish body.When operation, the rotation of direction shown in this rim.

Fig. 4 is a schematic diagram, and the vitals of rotary cutter dish of the present invention and their correlation are shown.For the purpose of complete, also comprise dead knife among the figure.The rotating disc cutter of Fig. 4 has pivot center 13.For ease of explanation, stretch out the position of dish body 17 from axis 13 to cutter and be decorated with dotted line 14 (being actually radius).Dead knife 16 with blade 15 also is shown at Fig. 4.What stretch out from rotary cutter dish dish body 17 is cutter 18 (certainly having more than one cutter), and this cutter has blade face 19 and blade 20.In addition, this cutter also has the front surface 23 and the knife angle 22 of cutting edge angle 21, cutter.This knife angle 22 measures from radius, and for example the radius 14 from the point that stretches out dish body 17 through cutter 18 measures.Fig. 3 illustrates the positive-angle and the negative angle of knife angle 22.

The position of dead knife 16 and dish body 17 normally makes blade 15 be in substantially parallel relationship to pivot center 13, and this position preferably makes the gap between blade 15 and the blade 20 reduce when the rotary cutter dish is operated as far as possible.

21 at least 70 ° of the cutting edge angles of cutter or bigger are preferably in about 80 ° or bigger.This angle is the angle between the front surface 23 of blade face 19 and cutter.As in blade face 19 and the front surface 23 one or two is curved surface, then blade angle 21 is desirable as the angle between the angle between the another side at tangent line and angle or two tangent lines, and this tangent line is the tangent line at (on one or two surface of blade face 19 and front surface 23) blade 20 places.The maximum of cutting edge angle 21 determined by knife angle 22 and condition, and this condition is that any part of blade face 19 all is not more than the distance of blade 20 apart from this axis apart from the distance of pivot center 13.Because cutting edge angle 21 is sizable angles, so particularly had a large amount of metals (or other cutter material) at the rear portion of blade 20 round this angle.As everyone knows, this material of close blade will make blade become very solid, and will be broken not too easily.Exist lot of materials to be considered to slow down wearing and tearing at blade 20 places, thereby reduced the frequency of necessary resharpen blade 20.

In addition, knife angle 22 is the angles between the front surface 23 (perhaps being cut in the tangent line on surface 23 at blade 20, if front surface 23 is curves) of the radius that stretches out from axis 13 and cutter, and numerical value is about+10 ° to-15 ° approximately, preferably arrive-5 ° approximately, be preferably in about 0 ° at about 0 °.If knife angle 22 is too just, then may damage the shear action of blade 20 with respect to blade 15, this causes cutting polymer well, and if feed mouth 22 is too negative, then it can not make cutting edge angle 21 do enough greatly.

On sword face 19 no any point than blade 20 further from axis 13.This can obviously find out from the following fact, and promptly people always like making the blade 20 close blade 15 in actual capabilities ground to the greatest extent usually when cutting polymer.If any part of blade face 19 surpasses the distance of blade 20 apart from this axis from the distance of axis 13, then rotate when moving, just people can not make blade 20 to the greatest extent preferably possibly near blades 15 and don't make sword face 19 run into blade 15 simply at dish body 17.Certainly, when blade was subjected to a certain degree wearing and tearing owing to cutting polymer, the fraction sword face 19 of next-door neighbour's blade 20 may be than the actual edge of blade 20 further from axis 13.This allows, but when blade 20 wearing and tearing too during severity, and resharpen again is to guarantee cutting polymer in high quality.

Though not necessarily; But preferably make some cuttves 18, all cuttves 18 are extended along the whole length of dish body 17.This point is shown in Fig. 5.

Across the length (perpendicular to cross-sectional view shown in Figure 3) of dish body 17, blade 20 can parallel to the axis 13 or form spiralitys around axis 13, and the whole length of blade 20 is constant apart from the distance of axis 13 basically.Preferred spiral angle with respect to axis 13 is about 0 °～3 °.When dish body when very long, in the time of for example can cutting many polymer strip,, then can reduce to act on the total pressure on arbitrary cutter if cutter sequentially contacts polymer strip, if blade forms spiralitys around axis 13, then can play this effect.

The present invention also comprises the device that is used for cutting polymer, and this device comprises above-mentioned rotary cutter dish, a dead knife and polymer pushed the device of rotary cutter dish.The normally actionless parts of dead knife, it is configured to make gap between the cutter 18 of rotary cutter dish can try one's best when the rotary cutter dish rotates reasonably to pass through near dead knife.About 90 ° usually of " blade " its angles of dead knife, this blade play a part to prevent the crooked or otherwise motion of polymer when cutter is run into polymer.Prevailing method is on the surface of dead knife polymer transport to be entered the rotary cutter dish, as depicted in figs. 1 and 2.

As depicted in figs. 1 and 2, polymer 4 or 11 is pushed into the cutter 2 of rotary cutter dish or 8 path usually continuously.This needs a kind of device of feeding polymer.If cutter sweep so disposes, then can utilize gravity to make polymer " fall into " the rotary cutter dish.Yet more common method is to utilize one or more pairs of transfer rollers or a pair of inlet conveyor feeding polymer.Transfer roller is meant a pair of roller that has roll gap therebetween.Polymer is sent into roll gap, drive this roller then, make polymer enter the rotary cutter dish through roll gap.Inlet conveyor also is similar, it is the device of similar conveyer, have two conveyer belts, polymer be clipped in be driven through between the band with polymer from mould extrude and by input mechanism with its move through with shift out mould to rotary cutter dish, transferring polymer easily.Also known other transfer approach.

The original meaning of above-mentioned discussion is the method for explanation with rotary cutter dish cutting polymer described herein.Can cut for example sheet material, web, band and tubing thick-walled pipe particularly of difform polymer.If the too thin for example small diameter fibers of polymer or the film of cutting, then polymer may be crooked, such polymer may can cut maybe and can not cut, but promptly can cut, the quality of section also is bad, promptly uneven, and produce fines (than requiring little particle), or can only cut partly or cursorily.The polymer minimum transverse cross-sectional dimension of cutting preferably is about 1mm or bigger, preferably about 2mm or bigger.The full-size that can cut depends on the polymer that will cut, the power of cutter arrangement and the mechanical stress that this cutter sweep can bear.

A kind of preferred form of polymer to be cut is one or more polymer strip.So-called bar is meant the continuous basically polymer of one section clavate, and this cross-sectional dimension is no more than 6 times to its minimum transverse cross-sectional dimension, and it is better not surpass 3 multiple proportions, preferably is no more than twice.Preferred bar cross section is for circular or square approximately, and circle is good especially.The cross-sectional dimension of bar is preferably in about 2-4mm preferably at about 1-8mm.Bar is cut into quite short sheet, and its length is about 1-8mm, or changes a kind of expression way, makes the length diameter ratio of section be about 1, so just can obtain the useful especially polymer form that is commonly referred to section or particle.This is the prevailing solid polymer shape of sending in the machines such as injection molding machine, extruder.

For example

The polymer strip that the 3508 type cutters that the Conair Corp. company in use U.S. Michigan Bay City city makes come the incising circular cross section.Used capstan head is shown in Fig. 5 and 6.The diameter that enters the bar of cutter is about 2.3mm, and the length that cuts out section is about 2.5mm.Polymer strip pushes out through nib, and its diameter is about 4.0-4.5mm, and this (in molten state) is drawn into the about 2.3mm of diameter by the conveying mechanism of cutter.Gap between rotating knife and the dead knife is nominally 0.076mm.

During routine operation, it is produced productive rate and on average is about 545kg/h, and the scope of productivity ratio is between about 455-635kg/h.This need carry 10-20 root polymer strip with the linear velocity of about 60-90m/min.Maximum rotative speed is 1800r/min.This adjustable-speed saves produces above-mentioned section.

During about 4 months (about 1005 actual hours), by the about 450000kg polymer of the total coprocessing of above-mentioned cutter.All these polymer are filled with glass fibre, and the amount of glass fibre accounts for the 13%-45% of weight.In some polymer, also there is for example carbon black of more a spot of other material.

Indivedual polymer in the different time cutting are polyethylene terephthalate, poly terephthalic acid fourth two fat,

nylon

6,6 and the polyamide that comprises aromatic series and two kinds of cycling elements of aliphatic.All these polymer are all well cut into slices in whole test, and for example, the particulate amount of producing from the on-test to the off-test for different polymer does not have very big difference.The result that the result adopts same cutter to obtain during also with the conventional type rotary cutter dish that uses as shown in Figure 2 is suitable.

Finish to current result of the test, the wear extent of blade is through being measured as 0.032mm.Be difficult to this wear extent wear extent of blade with conventional cutter the time is compared, because the geometry difference of blade, and this effect of attrition cut quality.

Claims

1. one kind is the device with rotary cutter dish of a pivot center, this capstan head comprises one or more cuttves, each cutter has a blade on the outer peripheral edges of above-mentioned rotary cutter dish, the knife angle of each cutter is at+10 ° to-15 ° approximately approximately, and its cutting edge angle is 70 ° or bigger, condition is that no any point is than the above-mentioned pivot center of above-mentioned blade further from above-mentioned rotary cutter dish on the sword face of above-mentioned cutter.

2. device that is used for cutting polymer, comprise a dead knife, a rotary cutter dish and be used for polymer is pushed the feed mechanism of above-mentioned rotary cutter dish, wherein above-mentioned rotary cutter dish has a pivot center and one or more cutter, each cutter has a blade on the outer peripheral edges of above-mentioned rotary cutter dish, the knife angle of each cutter is at+10 ° to-15 ° approximately approximately, and its cutting edge angle is 70 ° or bigger, condition is that no any point is than the above-mentioned pivot center of above-mentioned blade further from above-mentioned rotary cutter dish on the sword face of above-mentioned cutter.

3. device as claimed in claim 1 or 2 is characterized in that, above-mentioned cutting edge angle is about 80 ° or bigger.

4. device as claimed in claim 1 or 2 is characterized in that, above-mentioned knife angle is at about 0 ° to-5 ° approximately.

5. device as claimed in claim 2 is characterized in that, the distance between above-mentioned blade and the said fixing cutter is about 0.025 to about 0.25mm.

6. device as claimed in claim 1 or 2 is characterized in that, the helical angle between above-mentioned pivot center and the above-mentioned blade is at about 0 ° to about 3 °.

7. device as claimed in claim 1 is characterized in that, above-mentioned polymer is a solid.

8. method with the rotary cutter cutting polymer, wherein improve and comprise, application has the rotary cutter dish of a pivot center and one or more cuttves, each cutter has a blade on the outer peripheral edges of above-mentioned rotary cutter dish, the knife angle of each cutter is at+10 ° to-15 ° approximately approximately, and its cutting edge angle is 70 ° or bigger, condition be on the sword face of above-mentioned cutter no any point than the above-mentioned pivot center of above-mentioned blade further from above-mentioned rotary cutter dish.

9. method as claimed in claim 8 is characterized in that, above-mentioned cutting edge angle is about 80 ° or bigger.

10. method as claimed in claim 8 is characterized in that, above-mentioned knife angle is at about 0 ° to-5 ° approximately.

11. method as claimed in claim 8 is characterized in that, the distance between above-mentioned blade and the said fixing cutter is about 0.025 to about 0.25mm.

12. method as claimed in claim 8 is characterized in that, the helical angle between above-mentioned pivot center and the above-mentioned blade is at about 0 ° to about 3 °.

13. method as claimed in claim 8 is characterized in that, above-mentioned polymer is thermoplastic.

14. method as claimed in claim 13 is characterized in that, the original shape that is bar of above-mentioned polymer.

15. method as claimed in claim 13 is characterized in that, above-mentioned polymer is fed above-mentioned rotary cutter dish continuously.

16. method as claimed in claim 14 is characterized in that, the about 2mm of above-mentioned minimum transverse cross-sectional dimension.

17. method as claimed in claim 14 is characterized in that, above-mentioned has circle or square cross section.

18., it is characterized in that above-mentioned polymer comprises at least one filler or amplified medium as claim 8 or 14 described methods.

19. method as claimed in claim 8 is characterized in that, makes a section or a material of above-mentioned polymer.

20. method as claimed in claim 8 is characterized in that, above-mentioned polymer is a solid.