JP2013163187A - Pressing die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressing die which controls cohesion without using a large amount of a cooling lubricant, and enables excellent molding.SOLUTION: A pressing die is provided with a punch part 2 and a die part 3, wherein the outer peripheral surface and the apical surface of the punch part and the inner circumferential surface of the die part are coated with a carbon film 4 with a surface roughness Ra of 0.05 μm or smaller, an in-punch refrigerant channel 5 where a refrigerant can circulate is formed in the punch part, an in-die refrigerant channel 6 where the refrigerant can circulate is formed in the die part, the punch part is formed into a columnar shape, and the in-punch refrigerant channel has a center channel part 5a formed on the central axis of the punch part and having its tip disposed at the tip part of the punch part, a plurality of radiation channel parts 5b connected with the tip of the center channel part and formed to extend radially at equal angular intervals with each other, and a plurality of periphery channel parts 5c connected with the tip of the radiation channel part at the base end and formed along the central axis in the vicinity of the outer peripheral surface of the punch part.

Description

  The present invention relates to a press working die suitable for a dry press working die for producing an aluminum alloy can body.

  Conventionally, dies with a carbon film such as diamond film or DLC (Diamond Like Carbon) film have a highly lubricated surface. It is attracting attention that it can be pressed. It is known that the carbon film has high slip characteristics with a non-carbon solid-soluble alloy due to termination of hydrogen on the surface and can suppress adhesion due to the alloy to be processed.

  These carbon films are produced by seeding a cemented carbide mainly composed of tungsten carbide and directly depositing a diamond or DLC film by vapor phase synthesis such as CVD (Patent Document). 1-3). For example, in Patent Document 1, in a drawing and ironing method in which ironing is performed after drawing a metal base plate, at least the final stage of the ironing pass in the ironing process is a side that contacts the metal base plate in the die base material. A drawing ironing method using a die having a surface roughness Ra of the DLC film of 0.05 μm or less on the surface is proposed.

Japanese Patent Laid-Open No. 10-137861 JP 09-314253 A JP-A-11-277160

The following problems remain in the conventional technology.
That is, in the technique described in the above-mentioned patent document, when an alloy is formed at a high processing rate, it must be at a high temperature (300 ° C. or more locally) between the mold and the alloy to be processed. Under such a high temperature condition, no matter how smooth the surface of the mold is, the dynamic friction coefficient of the carbon film becomes high, and adhesion and deposition of the alloy to be processed cannot be avoided. In particular, when the temperature is higher than 300 ° C., there is a problem that hydrogen is separated from the carbon film on the surface of the mold, the slip characteristics are deteriorated, and the adhesion tends to occur. For this reason, in general, in order to avoid this phenomenon, a cooling lubricant is interposed between the mold and the alloy to be processed by radiating a cooling lubricant during molding. Since a lubricant is required, there is a disadvantage that the manufacturing cost increases.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a press working mold capable of suppressing adhesion without using a large amount of cooling lubricant and capable of performing a favorable forming process. .

  The present invention employs the following configuration in order to solve the above problems. That is, the press working die according to the first invention is a press working die, and includes a punch portion and a die portion for forming a workpiece, and an outer peripheral surface and a front end surface of the punch portion. And a carbon film having a surface roughness Ra of 0.05 μm or less is coated on the inner peripheral surface of the die portion, and a coolant flow passage in the punch through which a cooling medium can flow is formed inside the punch portion. In addition, an in-die refrigerant flow path through which a cooling medium can flow is formed inside the die part, the punch part is formed in a columnar shape, and the in-punch refrigerant flow path is formed on the punch part. A central flow path portion formed on the central axis and having a distal end disposed at the distal end portion of the punch portion, and a proximal end connected to the distal end of the central flow path portion and extending radially at equal angular intervals. Before the base end is connected to the tip of these radiation flow path sections. Characterized in that it comprises a plurality of peripheral channels section formed along the central axis in the vicinity of the outer peripheral surface of the punch unit.

In this press working mold, a coolant flow channel in the punch through which the cooling medium can flow is formed inside the punch portion, and a coolant flow channel in the die through which the cooling medium can flow is formed inside the die portion. Therefore, the punch part and the die part can be efficiently cooled from the inside together with the carbon film on the surface by the cooling medium circulating inside without using a large amount of cooling lubricant. Therefore, the cooling medium flowing through the in-punch refrigerant flow path and the in-die refrigerant flow path can be easily circulated, and by preparing the necessary amount as a circulation medium for actively cooling the punch section and the die section. That's it. In addition, an active cooling system can be used, and by constantly monitoring the temperature of the circulating cooling medium, temperature management during molding can be performed more strictly than in the past. This makes it possible to eliminate manufacturing instability factors due to thermal expansion / contraction of the mold.
Note that the surface roughness Ra of the carbon film is set to 0.05 μm or less. If Ra exceeds 0.05 μm, sufficient slip characteristics cannot be obtained during processing, and adhesion and deposition of the alloy to be processed. This is because there is a risk of occurrence of the above.

  Further, in this press working mold, the coolant flow path in the punch has the central flow path section, the plurality of radiation flow path sections, and the plurality of outer peripheral flow path sections, so that the cooling medium First, after being supplied to the center of the punch portion by the central flow passage portion, it circulates radially through the plurality of radial flow passage portions on the tip side, and further flows in the vicinity of the outer periphery by the plurality of outer peripheral flow passage portions, The carbon film on the front end surface and the outer peripheral surface can be efficiently cooled. In addition, the punch part can be cooled symmetrically about the central axis, temperature uniformity can be obtained at the outermost periphery of the same cross section, and non-uniformity of mold shape due to thermal expansion / contraction can occur. It is possible to suppress the increase in resistance during processing, thereby preventing adhesion and deposition of the alloy to be processed.

According to a second aspect of the present invention, there is provided a press working mold according to the first aspect, wherein the die portion is formed in an annular shape, and the in-die refrigerant flow path is formed in an annular shape along a circumferential direction of the die portion. It is formed.
That is, in this press working mold, the die portion is formed in an annular shape, and the in-die refrigerant flow path is formed in an annular shape along the circumferential direction of the die portion. The carbon film formed on the substrate can be efficiently cooled.

A press working mold according to a third aspect of the present invention includes the refrigerant supply source for supplying the cooling medium into the in-punch refrigerant flow path and the in-die refrigerant flow path in the first or second invention. The coolant supply source circulates the cooling medium flowing in the in-punch coolant channel and the in-die coolant channel in a turbulent flow having a Reynolds number of 3000 or more.
That is, in this press working mold, the refrigerant supply source circulates the cooling medium flowing in the in-punch refrigerant channel and the in-die refrigerant channel in a turbulent flow having a Reynolds number of 3000 or more. Compared to the case, the temperature distribution in the flow path is less likely to occur, and uniform cooling can be achieved throughout the flow path.

The press working mold according to a fourth aspect of the present invention is the coolant supply for supplying the cooling medium into the coolant flow channel in the punch and the coolant flow channel in the die in any one of the first to third aspects of the invention. The refrigerant supply source controls the temperature of the carbon film to be less than 300 ° C. by circulating the cooling medium.
In other words, in this press working mold, the coolant supply source circulates the cooling medium and controls the temperature of the carbon film to less than 300 ° C., thus preventing the hydrogen from detaching from the carbon film, and stable and high slip characteristics. Can be maintained.

According to a fifth aspect of the present invention, there is provided a press working mold according to any one of the first to fourth aspects, wherein the punch portion is formed of a cemented carbide with the carbon film formed on the outer peripheral surface and the tip surface. A bottom cylindrical outer base body and an inner base body that is provided inside the outer base body and is formed of copper or a copper alloy in which the coolant flow path in the punch is formed. .
That is, in this press working mold, since it is provided inside the outer base body and the coolant passage in the punch is formed inside and includes the inner base body formed of copper or a copper alloy, it has a heat conductive property. Heat exchange with the cooling medium can be performed through the inner substrate of high copper or copper alloy, and the outer substrate and the carbon film can be efficiently cooled.

According to a sixth aspect of the present invention, there is provided a press working die according to any one of the first to fifth aspects, wherein the work material is an aluminum alloy thin plate, and a dry ironing process is performed on the aluminum alloy thin plate. It is a die for press working.
In other words, this press working mold is a dry press working mold that performs drawing and ironing (DI) on an aluminum alloy thin plate, so that the product quality is stable with low cost and low environmental load. An aluminum alloy can body can be produced.

The present invention has the following effects.
In other words, according to the press working mold according to the present invention, the die coolant passage in which the cooling medium can be circulated is formed in the punch portion, and the cooling medium in the punch is formed in the punch portion. Since the inner refrigerant flow path is formed, the punch portion and the die portion can be efficiently cooled from the inside together with the carbon film on the surface by the cooling medium circulating inside without using a large amount of cooling lubricant.
Therefore, the die for press working of the present invention can be applied to a die for dry pressing in the DI process of an aluminum can, and the product quality can be stabilized by suppressing adhesion. Therefore, it is possible to realize a resource saving / energy saving process at a low cost without using a large amount of cooling lubricant.

In one Embodiment of the metal mold | die for press work which concerns on this invention, it is sectional drawing which shows the metal mold | die at the time of a process. In this embodiment, it is sectional drawing in the radiation flow path part which shows a punch part. In this embodiment, it is sectional drawing in the refrigerant | coolant flow path in die | dye which shows the outer side ring part of die | dye part.

  Hereinafter, an embodiment of a press working mold according to the present invention will be described with reference to FIGS. 1 to 3. In each drawing used in the following description, there is a part where the scale is appropriately changed as necessary in order to make each part recognizable or easily recognizable.

As shown in FIGS. 1 to 3, the press working mold 1 according to the present embodiment uses an aluminum alloy thin plate as a workpiece W, and performs a DI working on the aluminum alloy thin plate. The die includes a punch portion 2 and a die portion 3 for forming the workpiece W, and the outer surface of the punch portion 2 and the tip surface thereof and the inner surface of the die portion 3 have a surface roughness Ra. A carbon film 4 having a thickness of 0.05 μm or less is coated.
Further, an in-punch refrigerant flow path 5 through which the cooling medium L can flow is formed inside the punch section 2, and an in-die refrigerant flow through which the cooling medium L can flow is formed inside the die section 3. A path 6 is formed.

  The punch portion 2 is formed in a columnar shape, and the in-punch refrigerant flow passage 5 is formed on the central axis of the punch portion 2, and a central flow passage portion 5 a having a distal end disposed at the distal end portion of the punch portion 2, A proximal end is connected to the distal end of the central flow path portion 5a and a plurality of radial flow path portions 5b formed radially extending at equal angular intervals from each other, and a proximal end is connected to the distal ends of these radial flow path portions 5b. A plurality of outer peripheral flow path portions 5 c formed along the central axis are provided in the vicinity of the outer peripheral surface of the punch portion 2.

  The punch portion 2 is provided with a bottomed cylindrical outer base body 7 formed of a cemented carbide with a carbon film 4 formed on the outer peripheral surface and the front end surface thereof, and is provided inside the outer base body 7 and also includes a refrigerant in the punch. A flow path 5 is formed inside and includes an inner base body 8 formed of copper or a copper alloy. That is, the carbon film 4 is formed on the outer peripheral surface and the front end surface of the outer base body 7 which are portions that directly contact the workpiece W during DI processing.

The die portion 3 is formed in an annular shape, and the in-die refrigerant flow path 6 is formed in an annular shape along the circumferential direction of the die portion 3.
The die portion 3 is provided with an annular inner ring portion 9 formed of a cemented carbide with a carbon film 4 formed on the inner peripheral surface, and provided on the outer periphery of the inner ring portion 9 and also has an in-die refrigerant. A flow path 6 is formed inside and includes an outer annular portion 10 made of an iron-based material such as stainless steel (SUS). That is, the carbon film 4 is formed on the inner peripheral surface of the inner annular portion 9 that is a portion that directly contacts the workpiece W during DI processing.

The press working mold 1 includes a refrigerant supply source 11 that supplies the cooling medium L into the in-punch refrigerant flow path 5 and the in-die refrigerant flow path 6.
The refrigerant supply source 11 has a function of controlling the flow velocity so that the cooling medium L flowing in the in-punch refrigerant flow path 5 and the in-die refrigerant flow path 6 flows in a turbulent flow having a Reynolds number of 3000 or more. ing. That is, the refrigerant supply source 11 sets the flow velocity of the cooling medium L to 0.5 m / s or more when the inner diameter of each refrigerant flow path is set to 5 mm, for example, and turbulent flow with a Reynolds number of 3000 or more. And In addition, the cooling medium L of this example employs 30 ° C. cooling water.

  Furthermore, the refrigerant supply source 11 also has a function of controlling the temperature of the carbon film 4 to less than 300 ° C. by circulating and circulating the cooling medium L. In other words, the refrigerant supply source 11 has a temperature detection function such as a temperature sensor that measures the temperature of the circulating cooling medium L, and the carbon that is constantly estimated by monitoring the temperature of the cooling medium L. A control mechanism for controlling the temperature and flow rate of the cooling medium L is provided so that the temperature at the film 4 does not exceed 300 ° C.

  As the cemented carbide, for example, tungsten carbide (WC) as a main material and a binder containing less than 10% of Co or the like or WC without a binder are adopted. In these cemented carbides, Co in the vicinity of the surface that lowers the adhesion strength of the carbon film 4 is removed by chemical treatment, and the carbon film 4 is formed thereon by vapor phase synthesis.

  The carbon film 4 is a DLC film or a polycrystalline diamond film, and a diamond film is employed in this embodiment. At the stage where these carbon films 4 are synthesized, the undulation on the outermost surface is about several μm in Ra. This is polished by using, for example, a pulsed laser beam having a wavelength of 360 nm or less so that Ra ≦ 0.05 μm. That is, the carbon film 4 is polished with laser light so that the surface roughness Ra is 0.05 μm or less.

  In this press working mold 1, as shown in FIG. 1, the punch part 2 is inserted into the cup-formed work material W and pushed into the die part 3, and the work material W is drawn and ironed. Processing is performed in a plurality of stages to produce a can body. At this time, the cooling refrigerant L is supplied from the refrigerant supply source 11 to each refrigerant flow path under the above conditions, and the carbon film 4 of the punch part 2 and the die part 3 is appropriately cooled.

  Thus, in the press working mold 1 of the present embodiment, the in-punch refrigerant flow path 5 through which the cooling medium L can flow is formed inside the punch part 2, and the cooling medium L is inside the die part 3. Is formed so that the punch part 2 and the die part 3 can be placed together with the carbon film 4 on the surface by the cooling medium L which circulates inside without using a large amount of cooling lubricant. Can be efficiently cooled. That is, by cooling the inside of the mold with water, the temperature rise of the carbon film 4 on the mold surface that occurs during processing can be prevented, and the sliding characteristics with the workpiece W can be maintained.

  The cooling medium L that circulates through the in-punch refrigerant flow path 5 and the in-die refrigerant flow path 6 can be easily circulated, and is provided as much as necessary as a circulation medium for actively cooling the punch section 2 and the die section 3. Just do it. Moreover, it can be set as an active cooling system, and by always monitoring the temperature of the circulating cooling medium L, temperature management at the time of molding can be performed more strictly than in the past. This makes it possible to eliminate manufacturing instability factors due to thermal expansion / contraction of the mold.

  Moreover, since the coolant flow channel 5 in the punch has the central flow channel portion 5a, the plurality of radiation flow channel portions 5b, and the plurality of outer peripheral flow channel portions 5c, the cooling medium L is After being supplied to the center of the punch portion 2 by the central flow passage portion 5a, it circulates radially through the plurality of radial flow passage portions 5b on the tip side, and further flows in the vicinity of the outer periphery by the plurality of outer peripheral flow passage portions 5c. The carbon film 4 on the front end surface and the outer peripheral surface can be efficiently cooled. In addition, the punch portion 2 can be cooled symmetrically about the central axis, temperature uniformity can be obtained at the outermost periphery of the same cross section, and non-uniformity of mold shape due to thermal expansion / contraction can occur. It is possible to suppress the increase in resistance during processing, thereby preventing adhesion and deposition of the alloy to be processed.

Furthermore, since the die part 3 is formed in an annular shape and the in-die refrigerant flow path 6 is formed in an annular shape along the circumferential direction of the die part 3, the die part 3 is formed on the inner peripheral surface of the die part 3. The carbon film 4 can be efficiently cooled.
Further, since the coolant supply source 11 circulates the cooling medium L flowing in the in-punch coolant channel 5 and the in-die coolant channel 6 in a turbulent flow having a Reynolds number of 3000 or more, compared to the case of laminar flow. It is difficult to create a temperature distribution in the flow path, and uniform cooling can be achieved throughout the flow path.

Moreover, since the coolant supply source 11 distribute | circulates the cooling medium L and controls the temperature of the carbon film 4 to less than 300 degreeC, it prevents that hydrogen detaches | leaves from the carbon film 4, and maintains the stable high slip characteristic. Can do.
Furthermore, since the inner base 8 is provided inside the outer base 7 and the coolant passage 5 in the punch is formed inside and formed of copper or copper alloy, the copper or copper alloy having high thermal conductivity is provided. The heat exchange with the cooling medium L is performed through the inner substrate 8, and the outer substrate 7 and the carbon film 4 can be efficiently cooled.

  Therefore, the press working mold 1 of the present embodiment is a dry press working mold that performs DI processing on an aluminum alloy thin plate, thereby producing a low-cost and stable product quality aluminum alloy can body. can do.

Next, the results of performing DI processing using the press working mold of the above embodiment and evaluating it will be described.
The press mold used is a cemented carbide containing 6% Co on the outer base of the punch part and the inner annular part of the die part, which are parts that directly act during processing, and is polycrystalline on it. Diamond was coated with carbon film by vapor phase synthesis.

The coated polycrystalline diamond carbon film was polished using a pulsed laser beam having a wavelength of 262 nm and 10 kHz to polish to Ra <0.03 μm.
In addition, the optical roughness, the electron microscope, and the laser microscope were used for the surface roughness (surface undulation) measurement of the carbon film. The structural evaluation of the carbon film was measured using Raman spectroscopy.

Furthermore, the diameter of each refrigerant flow path was 3 mm, the cooling medium was 25 ° C., and ironing was performed with an aluminum alloy processing rate of 40% while flowing in a turbulent flow state with a cross-sectional average speed of 1 m / s. For comparison, ironing was performed in the same manner even when the cooling medium was not circulated.
As a result, when the cooling medium was not circulated, adhesion and deposition of the aluminum alloy were confirmed in continuous ironing, but when the mold was cooled by circulating the cooling refrigerant, adhesion and deposition were observed. Neither could be confirmed.

  The technical scope of the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Die for press work, 2 ... Punch part, 3 ... Die part, 4 ... Carbon film, 5 ... Refrigerant flow path in punch, 5a ... Central flow path part, 5b ... Radiation flow path part, 5c ... Outer periphery flow path 6, refrigerant flow path in die, 7 outer side substrate, 8 inner substrate, 11 refrigerant supply source, L cooling medium, W work material

Claims (6)

A mold for press working,
It has a punch part and a die part that mold the workpiece,
The outer peripheral surface and tip surface of the punch portion and the inner peripheral surface of the die portion are coated with a carbon film whose surface roughness Ra is 0.05 μm or less,
A coolant flow path in the punch through which the cooling medium can flow is formed inside the punch section, and a coolant flow path in the die through which the cooling medium can flow is formed inside the die section,
The punch portion is formed in a columnar shape,
A central flow path portion in which the coolant flow path in the punch is formed on a central axis of the punch portion, and a tip is disposed at a tip portion of the punch portion;
A plurality of radiation flow path portions formed by extending proximally from each other at an equiangular interval with a base end connected to the distal end of the central flow path portion;
A press working characterized in that a base end is connected to the distal ends of these radiation flow path portions and a plurality of outer flow path portions formed along the central axis in the vicinity of the outer peripheral surface of the punch portion. Mold. The press working die according to claim 1,
The die part is formed in an annular shape,
The die for press working, wherein the in-die refrigerant flow path is formed in an annular shape along a circumferential direction of the die portion. The press working die according to claim 1 or 2,
A refrigerant supply source for supplying the cooling medium into the refrigerant flow path in the punch and the refrigerant flow path in the die;
The press working die, wherein the coolant supply source circulates the cooling medium flowing in the in-punch coolant channel and the in-die coolant channel in a turbulent flow having a Reynolds number of 3000 or more. In the metal mold | die for press work as described in any one of Claim 1 to 3,
A refrigerant supply source for supplying the cooling medium into the refrigerant flow path in the punch and the refrigerant flow path in the die;
The press working mold, wherein the coolant supply source controls the temperature of the carbon film to be less than 300 ° C. by circulating the cooling medium. In the metal mold | die for press work as described in any one of Claim 1 to 4,
The punched portion has a bottomed cylindrical outer base body formed of a cemented carbide with the carbon film formed on the outer peripheral surface and the tip surface;
A press working die, comprising: an inner base provided inside the outer base and having an in-punch coolant flow path formed therein and formed of copper or a copper alloy. In the metal mold | die for press work as described in any one of Claim 1 to 5,
The workpiece is an aluminum alloy thin plate,
A die for press working, which is a die for dry press working for drawing and ironing the aluminum alloy thin plate.

Images