CN110802120A

CN110802120A - Drawing die and machining method for pipe with rectangular section and unequal wall thickness

Info

Publication number: CN110802120A
Application number: CN201911231535.9A
Authority: CN
Inventors: 钱小兵
Original assignee: Taizhou Zhicheng Cemented Carbide Mould Co Ltd
Current assignee: Taizhou Zhicheng Cemented Carbide Mould Co Ltd
Priority date: 2019-11-29
Filing date: 2019-12-05
Publication date: 2020-02-18

Abstract

The invention discloses a drawing die for a rectangular pipe with unequal wall thickness and a processing method thereof. In the process of controlling the stretching of the pipe, the drawn pipe is in close contact with the transition outer die, the inner wall of the forming outer die and the moving core print, so that the inner surface and the outer surface of the drawn pipe are clean and consistent, and the parameter values of the upper wall thickness, the lower wall thickness, the left wall thickness and the right wall thickness of the pipe and the R values of four right-angled fillets on the inner wall of the pipe can be adjusted according to the parameter setting on the moving core print.

Description

Drawing die and machining method for pipe with rectangular section and unequal wall thickness

Technical Field

The invention relates to the field of special-shaped copper pipe belt loose core disc drawing, in particular to a drawing die and a processing method for a copper pipe with a rectangular section and unequal wall thickness.

Background

In view of the fact that the rectangular copper pipe in China at present adopts two methods of straight pulling and air pulling (coil pulling). The straight pulling has the defects that the length of the copper pipe is limited to a certain extent (within 10 meters), the air pulling has the defects that the length problem is solved, but the size, the size and the wall thickness of an inner hole R cannot be controlled and stabilized, and the copper pipe with the same wall thickness as the air pulling can only be used for pulling the copper pipe with the same wall thickness and cannot be pulled with the copper pipe with the different wall thickness. The method provided by the patent of 'moving core ball stretching combined die (patent number: CN 201821036680.2)' effectively avoids the collapse and the concavity of the inner cavity of the copper pipe in the stretching process, ensures uniform transition deformation and consistent wall thickness and outer diameter change of the pipe, and theoretically realizes infinite length of the copper pipe stretched by the stretching combined die. However, the patent does not solve the processing problem of the pipe with the rectangular section with unequal wall thickness. (for example: two opposite sides of a rectangular copper tube have different wall thicknesses, the dimensions of the two opposite sides are respectively 1.8mm on one side and 1.0mm on the other side.)

In the refrigeration industry and the medical appliance industry at present, the requirements on the sizes of various copper pipes are higher and higher, and particularly in the medical appliance industry, the requirements on the copper pipes with different wall thicknesses are higher and higher, and the requirements on the size specifications are higher and higher.

The prior method for processing the copper pipe with the rectangular section and unequal wall thickness is usually formed by welding and combining two copper plates with different wall thicknesses. However, the above methods all stay in the state of manual operation, which not only wastes manpower resources seriously, but also can not ensure the precision and strength of the copper tube, and can not meet the requirements of the medical appliance industry for high quality and high performance. At present, most of domestic copper pipes are used by means of imports, so that the lack of high-quality and high-precision copper pipes with rectangular sections with unequal wall thicknesses is a common problem in the medical instrument industry in China.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art, and provide a drawing die for copper pipes with rectangular sections and unequal wall thicknesses, in order to solve the technical problem, the technical scheme adopted by the invention is as follows: the invention comprises a transition external mold, a forming external mold and a movable core head, wherein the center of the transition external mold is provided with a trapezoidal compression hole with an arc-shaped curved surface, the trapezoidal compression hole is connected with a rectangular compression hole 1, the center of the forming external mold is provided with a trapezoidal compression hole, the rectangular compression hole 2 is connected with the trapezoidal compression hole, the movable core head is arranged in the trapezoidal compression hole, the movable core head is divided into a transition end, an extrusion end and a forming end, the transition end and the forming end are cuboid, the extrusion end in the middle is trapezoidal, the trapezoidal shape of the extrusion end is gradually reduced towards the stretching direction, the included angle of two opposite sides of the trapezoidal compression hole of the forming external mold is 9-30 degrees, the included angle of one pair of inclined planes of the trapezoidal platforms of the extrusion end is larger than that of the other pair of inclined planes.

Furthermore, the included angle of one pair of inclined planes of the extrusion end step platforms is 0.5-5 degrees larger than that of the other pair of inclined planes.

Furthermore, the fillet is conical, and the radius gradually decreases towards the stretching direction.

Further, the molding outer die is multiple.

Further, a method for processing the pipe with the rectangular section and unequal wall thickness adopts a drawing die for the pipe with the rectangular section and unequal wall thickness, and comprises the following specific steps:

step 1: the basic forming of the pipe is controlled by pulling a raw circular pipe through a transition outer die disc, so that the pipe becomes a pipe with an approximate rectangular cross section.

Step 2: and (3) adjusting the size and the wall thickness of the rectangular section pipe by drawing the product obtained in the step (1) through a forming external die and a moving core head disc, so that the size of the rectangular section pipe is further close to the size of a finished product.

And step 3: and (3) repeating the method in the step (2), further adjusting and adjusting the size and the wall thickness of the rectangular section pipe, repeating the molding outer die for n-1 times, wherein the more the repetition times are, the higher the precision of the product is, and the higher the strength is.

The invention has the following beneficial effects:

1. the defects of the traditional straight pulling and the traditional coiling pulling are thoroughly overcome, and the requirements on various sizes of copper tube products with rectangular sections and unequal wall thicknesses are controlled by adjusting the angle matching of the outer die and the moving core head within a certain numerical range while the strength of the copper tube is ensured.

2. The copper pipe enterprise is helped to improve the working efficiency by about 80%.

3. The labor cost of the enterprise is reduced by 80-90%, and the profit of the copper pipe enterprise can be improved by 50-80%.

Drawings

FIG. 1 is a front view of a transition outer mold of the present invention;

FIG. 2 is a cross-sectional view of a transition outer mold of the present invention;

FIG. 3 is a front view of the inventive outer mold;

FIG. 4 is a cross-sectional view of the inventive outer mold;

FIG. 5 is a front elevational view of the floating core of the present invention;

FIG. 6 is a left side view of the floating core head of the present invention

FIG. 7 is a top view of a floating core of the present invention

FIG. 8 is an enlarged partial view of the floating core of the present invention;

FIG. 9 is a schematic diagram of the drawing die for copper tubes with rectangular cross sections and unequal wall thicknesses according to the present invention;

reference numbers in the figures: 1-transition external mold; 2-forming an external mold; 3-a traveling core print; 4-copper pipe; 11-trapezoidal compression holes with arc curved surfaces; 12-rectangular compression holes 1; 21-trapezoidal compression holes, 22-rectangular compression holes 2; 31-transition end; 32-extrusion end; 33-forming end; 34-round corner.

Detailed Description

For the purpose of facilitating an understanding and practicing the invention by those of ordinary skill in the art, the invention is described in further detail below with reference to the accompanying drawings and detailed description, for example: customers require to process rectangular special pipes with different wall thicknesses, wherein the length of a copper pipe is 200 meters, the inner hole R0.5mm, the outer circle R1.5mm, the left wall thickness and the right wall thickness are 1.8mm, and the upper wall thickness and the lower wall thickness are 1.0mm, and the embodiment adopts 4 procedures of forming the outer mold 2.

As shown in figures 1 to 8, the first process adopts a copper pipe 4 with the wall thickness of 1.4mm to control the basic forming of the copper pipe by the coiling and drawing of a transition external die 1, so that the copper pipe becomes a pipe with an approximate rectangular section.

As shown in figure 9, the copper tube 4 with approximate rectangular section is adopted in the second process, the size and the wall thickness of the tube with the rectangular section are adjusted by coiling and drawing the forming outer die 2 and the moving core head 3, the included angle of two opposite sides of the trapezoidal compression hole 21 of the forming outer die 2 is 9-30 degrees, the included angle of the upper and lower opposite sides of the trapezoidal shape of the extrusion end 32 of the moving core head 3 is 9-28 degrees, and the included angle of the left and right opposite sides is 12-30 degrees. The wall thickness of the copper tube 4 is 1.4mm, the wall thickness of the copper tube 4 is adjusted up, down, left and right through the size and angle of the moving core head and the radius R value of 4 edge fillets 34 of the extrusion end 32 step table, the wall thickness of the copper tube 4 is reduced to 1.35m, and the wall thickness of the copper tube 4 is increased by 0.04mm-0.06 mm.

And in the third procedure, the same method as in the second procedure is repeatedly adopted, the left and right wall thickness of the copper pipe 4 is increased by 0.05mm-0.08mm, and the upper and lower wall thickness of the copper pipe 4 is reduced to 1.2 m.

The fourth procedure adopts the same method of the third procedure repeatedly, the left and right wall thickness of the copper tube 4 is increased to 1.65mm, and the upper and lower wall thickness of the copper tube 4 is reduced to 1.1 mm.

The fifth procedure adopts the same method of the fourth procedure repeatedly, the left and right wall thickness of the copper tube 4 is increased to 1.78-1.82mm, and the upper and lower wall thickness of the copper tube 4 is reduced to 1.0-1.05 mm.

The more the number of repetitions, the higher the precision of the product and the greater the strength.

The moving core print 3 is made of hard alloy die steel.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the spirit of the present invention, and these modifications and decorations should also be regarded as being within the scope of the present invention.

Claims

1. A drawing die for a pipe with a rectangular cross section and unequal wall thickness comprises a transition outer die (1), a forming outer die (2) and a moving core head (3), wherein a trapezoidal compression hole (11) with an arc-shaped curved surface is formed in the center of the transition outer die (1) and connected with rectangular compression holes (1), (12), a trapezoidal compression hole (21) is formed in the center of the forming outer die (2) and connected with the rectangular compression holes (2), (22), the moving core head (3) is arranged inside the trapezoidal compression hole (21), the moving core head (3) is divided into a transition end (31), an extrusion end (32) and a forming end (33), the transition end (31) and the forming end (33) are cuboid, the middle extrusion end (32) is trapezoidal, and the trapezoidal shape of the extrusion end (32) is gradually reduced towards the drawing direction,

the method is characterized in that: the included angle of two opposite sides of the trapezoid-shaped compression hole (21) of the forming outer die (2) is 9-30 degrees, the included angle of one pair of inclined planes of the trapezoid of the extrusion end (32) is larger than that of the other pair of inclined planes, and 4 edges of the trapezoid of the extrusion end (32) are fillets (34).

2. The drawing die for the pipe with the rectangular section and the unequal wall thickness as claimed in claim 1, is characterized in that: the included angle of one pair of inclined planes of the extrusion end (32) step platforms is 0.5-5 degrees larger than that of the other pair of inclined planes.

3. The drawing die for the pipe with the rectangular section and the unequal wall thickness as claimed in claim 1, is characterized in that: the fillet (34) is conical and gradually reduces in radius in the drawing direction.

4. A drawing die for pipes with different wall thicknesses and rectangular sections as claimed in any one of claims 1 to 3, wherein: the molding outer die (2) is multiple.

5. A method for processing a pipe with a rectangular section and unequal wall thickness is characterized by comprising the following steps: the drawing die for the pipe with the rectangular section and unequal wall thickness, which is disclosed by claim 4, comprises the following specific steps:

step 1: the basic molding of the pipe is controlled by adopting a raw circular pipe and drawing the pipe through a transition external die (1) so that the pipe becomes a pipe with an approximate rectangular section.

Step 2: and (3) adopting the product obtained in the step (1) to adjust the wall thickness of the tubular product with the rectangular section by coiling and drawing the molding outer die (2) and the moving core head (3) so as to further approach the size of a finished product.

And step 3: and (3) repeating the method in the step (2), wherein n molding outer dies (2) are repeated for n-1 times, and the more the number of repetition is, the higher the precision of the product is and the higher the strength is.