JP4497289B2 - Stripping method for ironing molded parts - Google Patents

Description

  The present invention relates to a stripping method for an ironing-molded molded body for efficiently extracting a molded body that has been drawn and ironed into a cylindrical cup shape or the like from its punch.

  Conventionally, a blank workpiece called a blank is punched out from a metal plate, the blank is drawn to the iron punch diameter, and passed through a mold having a gap between the punch and the die smaller than the thickness of the workpiece, A drawing and ironing process for forming a cylindrical body having a thin side wall thickness with respect to the bottom thickness is well known. In addition to cans filled with beer, carbonated beverages, and the like, the molded body by such ironing processing includes a photosensitive drum substrate of a printer or a copier (in addition to the photosensitive drum substrate, a developing roll, a fixing roll, a transfer roll, There are some which require a long roundness with respect to the outer diameter and high roundness due to their properties, such as paper feed rolls and various rolls such as charging rolls).

When such a relatively long ironing molded body is removed from the punch after molding (stripping), a method is generally used in which a nail-like member called a finger is caught on the edge portion of the can body. It is.
Japanese Patent Application Laid-Open No. H10-228667 describes a product in which a molded body is extruded by incorporating a knockout device in a punch and expanding and contracting its tip.
Patent Document 2 discloses a method in which a pressurized fluid is sent to the operation surface of the ironing mandrel to separate the ironing sleeve having a large wall thick portion between the bottom and the opposite side from the ironing mandrel. A method is described in which pressurized fluid is discharged at the transition between the normal wall thickness and the large wall thickness of the sleeve.
Japanese Patent Publication No. 45-9878 Japanese Patent Publication No. 1-16573

However, the conventional technique has the following problems.
(A) In the conventional method in which the nail-shaped member is pulled by pulling on the edge portion of the can body after ironing, if the side wall of the molded body after ironing is thin, it is difficult to apply the nail, and adhesion to the punch When the force is large, there is a drawback that it cannot be pulled out due to buckling.
(B) When the knockout device is arranged in the punch as in Patent Document 1, the stroke of the knockout device requires the length of the can, and it is difficult to incorporate the device when the can is relatively long. is there.
(C) In the method of extruding the molded body by pressurizing the fluid from the inside of the punch as in Patent Document 2, if the side wall of the molded body is extremely thin, the can body is likely to burst before reaching the pressure required for extraction, The deformation due to the internal pressure at the bottom is also remarkable.
The present invention was made to solve the above-mentioned problems, and the side wall after ironing is thin, can be applied to a molded body that is relatively long and has no change in diameter (inner diameter) in the length direction, Stripping of ironing-molded compacts that can be efficiently extracted without causing damage such as buckling, deformation, or rupture even when the adhesion to the punch is large (especially in the case of punches with almost no taper) It aims to provide a method.

(1) The stripping method of the ironing molded article of the present invention is such that a cylindrical cup obtained by drawing a flat blank to a pan is punched with a punch having a smaller coefficient of thermal expansion than the cylindrical cup with respect to the thickness of the bottom. It is characterized by having a molded body heating step of drawing and squeezing a cylindrical molded body with a thin sidewall thickness and heating the cylindrical molded body with a heating means to relieve the adhesion between the cylindrical molded body and the punch.

(2) stripping method of ironing molding of the present invention, following the previous SL moldings heating step, the piston away to withdraw the molded body is advanced a piston provided on the tip portion of the punch from the punch It is characterized by having a mold process.

(3) The stripping method of the ironing-molded molded body according to the present invention includes, in the pressurized fluid flow path formed between the front of the piston and the bottom of the molded body, following the piston release step of claim 2. It is characterized by having a fluid injection process for injecting a pressure fluid.

(1) According to the stripping method of the ironing molded article of the present invention, the molded article covered with a punch having a thermal expansion coefficient smaller than that of the blank is heated, and a difference between the thermal expansion and the molded article is utilized. Since the adhesion between the punches is relaxed, it can be easily removed from the punch without causing mechanical damage to a particularly thin and long molded body, thereby improving work efficiency and yield. In addition, since the number of mechanically movable parts can be reduced, it is excellent in maintainability.

(2) According to the stripping method of the ironing molded article of the present invention, since the molded article is released from the punch by projecting the piston provided at the tip of the punch, molding with reduced adhesion by heating. The body can be pulled out of the punch smoothly, and its reliability and reliability are excellent.

(3) According to the stripping method of the ironing processed molded body of the present invention, since the pressure fluid is injected into the molded body from the front periphery of the punch following the piston releasing step of claim 2 , the molded body is punched. It is possible to reduce the stroke width of the piston, etc. required to completely pull out from the cylinder, or to eliminate the need for mechanical movable devices such as the piston, so that the device can be configured compactly, and the space is limited. It can be applied under location conditions and has excellent versatility.

(4) According to the stripping process of ironing molding of the present invention, since the heating means is a high frequency induction heating equipment, which is arranged around the shaped body, that is excellent in temperature controllability and maintainability . Moreover, it is excellent in the responsiveness and thermal efficiency at the time of heating a long molded object.

Hereinafter, a preferred embodiment of a stripping method for an ironing formed article of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a cross-sectional view of an essential part of an ironing apparatus to which a stripping method for ironing molded articles according to Embodiment 1 of the present invention is applied.
In FIG. 1, 10 is an ironing apparatus, 11 is a punch on which a molded body S after drawing and ironing is crowned, 12 is a coil of a high-frequency induction heating device disposed around the molded body S, and 13 is in the punch 11. It is a pressurized fluid channel arranged in.
The formed body S is formed into a cylindrical cup from a substantially flat blank made of carbon steel such as nickel, nickel alloy, iron alloy, steel, copper alloy, aluminum alloy, and the like. It is held in the crowned state.
The molded body S has, for example, a cup shape having an inner diameter of about 30 to 45 mm, a length of about 300 to 400 mm, and a wall thickness of about 0.01 to 1 mm, and its length (H) and inner diameter (D) The ratio (H / D) is formed to be about 3 to 30, and is applied to the case where the body length with respect to the outer diameter is long and high roundness is required, such as various rolls of printers and copiers, It can also be used for containers and the like.

The ironing device 10 is a processing device having an outer die (die) and a movable inner die (punch), wherein the outer die has a drawing portion, and the inner die is an inner die. Between the one inclined surface and the inner second inclined surface, there is an inner ironing portion formed of an inner flat surface, and a movable punch 11 is provided at an end, and the drawing portion is more than the inner ironing portion. Is also configured to be located upstream in the direction of movement of the workpiece.
The blank to be processed is drawn to the outer diameter of the punch 11 and formed between the inner mold and the outer mold positioned at predetermined positions while being pressed by the punch 11 after being formed into a cylindrical cup. Thus, ironing is performed by the inner flat surface. In this way, by performing drawing and ironing step by step in one mold, the blank is sequentially brought closer to the target shape to obtain a bottomed cylindrical molded body with high dimensional accuracy. be able to.

It is preferable that the punch 11 is formed in a columnar shape having almost no punch taper, and the ratio (H / D) of the length (H) to the diameter (D) is in the range of 3 to 30. The punch 11 is made of a blank material such as nickel, nickel alloy, iron alloy, copper alloy, aluminum alloy or the like having a thermal expansion coefficient smaller than that, for example, periodic table IVa, Va, VIa group metal carbides Fe, Co It is made of a metal material such as cemented carbide sintered with an iron-based metal such as Ni, or a ceramic material such as alumina or zirconia. For example, when the blank is nickel or a nickel alloy having a thermal expansion coefficient of 13 to 17 × 10 ⁻⁶ / ° C., the punch 11 is made of cemented carbide having a thermal expansion coefficient of about 4 × 10 ⁻⁶ / ° C. As a result, by heating the compact S, it is possible to effectively relieve the adhesive force between the compact S and the punch 11 induced by the interference fit of ironing.

The pressurized fluid flow path 13 is built in the punch 11, and high pressure water (fluid) supplied from a fluid pressurizing device such as a pump (not shown) is supplied from the discharge port 13 a at the punch tip to a predetermined pressure, for example, 1.96 × 10. ^A predetermined amount is discharged at a pressure of ⁶ Pascals (about 20 kgf / cm ² ) so that the bottom surface of the molded body S can be pressed.

  The high-frequency induction heating device induces an eddy current in a conductor by flowing a high-frequency current through the coil 12 disposed around the object to be heated, and the Joule heat of the eddy current. It is a device that generates heat. The heating value of the molded body S or punch 11 itself to be heated can be adjusted by the load power, frequency, coil shape, material, etc., and rapid heating is easy with an electric control circuit, so the controllability is good. Also suitable for automated lines.

The stripping method of the ironing process compact | molding | casting applied to the ironing apparatus 10 comprised as mentioned above is demonstrated.
In the drawing and ironing step, a nickel alloy blank having a thermal expansion coefficient of 16.2 × 10 ⁻⁶ / ° C. is drawn into a cylindrical cup, and the thermal expansion coefficient is, for example, 4. in the die hole in which the cylindrical cup is disposed. A molded body S is formed by press-fitting a punch 11 made of a cemented carbide of 0 × 10 ⁻⁶ / ° C. and the like and drawing and squeezing it into a cylindrical molded body.

In the next molded body heating step, the molded body S is heated to a temperature of about 60 to 100 ° C. by the coil 13 of the high-frequency induction heating device that is a heating means. As a result, the molded body S is thermally expanded larger than the punch 11, and the adhesion between the molded body S and the punch 11 is relaxed.
Here, it is desirable to set the thermal expansion coefficient P of the punch material at the heating temperature in a range in which the ratio (P / B) is, for example, 1/4 or less with respect to the thermal expansion coefficient B of the blank material. This is because when the ratio (P / B) is greater than 1/4, the effect of releasing the molded body that is in close contact with the punch due to the difference in thermal expansion is extremely reduced.

  In the final fluid injection step, high pressure water of a predetermined pressure is supplied from a pump or the like to the pressurized fluid flow path 13 provided in the punch 11 following the molded body heating step, and is discharged from the discharge port 13a at the tip thereof. A predetermined amount of high-pressure water is jetted to the bottom of the molded body S. As a result, the compact S is extracted by pushing the compact S forward of the punch 11 with the pressure of high-pressure water.

FIG. 2A is a graph showing the relationship between the liquid pressure of high-pressure water and the amount of movement of taking out the molded body (can). As shown in the figure, the liquid pressure becomes maximum immediately after the molded body S is detached from the punch 11 and may exceed the breaking pressure value of the molded body S. However, after that, the pressure gradually decreases to almost 0.98. × 10 ⁶ Pascal (10 kgf / cm ² )
When such a thin cylindrical cup-shaped compact is subjected to internal pressure, the cylindrical stress (σ2) of the thin cylinder subjected to internal pressure is twice the axial stress (σ1). Therefore, when the molded body is ruptured by internal pressure, it is not torn circumferentially, but always torn axially along the circumferential generatrix as shown in FIG. Therefore, it is preferable to start extracting the entire molded body with a mechanical knockout mechanism in which only the axial force acts, and to inject the liquid after the frictional force is lowered to a low level to extract the molded body.

  Since the stripping method of the ironing processed molded body of the first embodiment is configured as described above, the thickness of the molded body is thin and the ratio between the length and the diameter (H / D) enables the extraction work to be efficiently performed with a high yield without causing damage such as buckling, deformation, or rupture to the molded body S even if it is long and long.

(Embodiment 2)
FIG. 3 is an explanatory view of the stripping method for the ironing formed article according to Embodiment 2 of the present invention.
In FIG. 3, reference numeral 20 denotes a punch portion of the ironing device, 21 denotes a punch covered with the compact S after drawing ironing, and 22 denotes a piston. It advances by being pressurized by a pressure fluid such as high-pressure water supplied from the fluid flow path 22a. Reference numeral 22b denotes a pressurized fluid flow path, which is formed around the inner wall of the punch 21 and the side wall of the piston 22. 22 c is a pressurized fluid flow path formed by the front and bottom of the piston 22.

  The punch unit 20 is a part of an ironing device (not shown). The molded body S formed into a cylindrical cup shape from a flat blank can be obtained by performing a known drawing process or a redrawing process one or more times after performing this known drawing process. The punch 21 is made of a metal material or a ceramic material having a smaller coefficient of thermal expansion than a metal material such as a nickel alloy used as a blank. As a result, the effect of relaxing the adhesion between the molded body and the punch by the heating means is made more effective.

  The punch 21 has a built-in piston 22, and is supplied with high pressure water to the pressurized fluid flow path 22a via a pump or the like to advance the piston 22 forward by a predetermined distance. However, a small amount of the molded body S that has been relaxed by heating means such as an infrared heater is extruded and released.

When the molded body S is extracted from the punch 21, first, the pressurized fluid flow path 22a at the rear of the piston 22 is filled with fluid and the piston 22 is mechanically advanced, so that the bottom of the molded body S is slightly pushed to the bottom. By applying pressure evenly to prevent the bottom from overhanging and preventing the bottom from becoming spherical, the molded body S is prevented from coming into close contact with the punch 21 and becoming difficult to come off. When the bottom of the piston 22 moves away from the punch bottom and the position of the piston 22 advances to the position shown in FIG. 3B, an opening 22b1 of the pressurized fluid flow path 22b newly appears at the rear of the piston 22. The pressurized fluid channel 22a and the pressurized fluid channel 22b communicate with each other, and the pressurized fluid passes through the pressurized fluid channel 22b and then reaches the bottom portion and the front portion of the piston 22 as indicated by an arrow. It is supplied to the pressurized fluid flow path 22c to be formed.
Furthermore, when the pressurized fluid is continuously supplied to the pressurized fluid channel 22c, the volume of the pressurized fluid channel 22c increases and the molded body S can be extracted from the punch 21.
The advancement of the piston 22 is stopped when the pressurized fluid passes through the pressurized fluid channel 22b. That is, the piston position in FIG. 3B is the same as the piston position in FIG.

In the punching unit 20 of the ironing apparatus, a liquid ejecting device, an infrared heater, and the like (not shown) are arranged as heating means for heating the molded body S in close contact with the punch 21 from its periphery.
Examples of the liquid ejecting apparatus include a spray device for spraying hot water of about 60 to 100 ° C. or the like on the molded body S and heating the molded body S to a predetermined temperature.
Examples of the infrared heater include a heating device that includes a curved reflector and the like, and can irradiate the surface of the cylindrical molded body S with infrared rays having a wavelength of about 0.8 to 5 μm.

Next, a stripping method for the ironing molded article applied to the ironing machine configured as described above will be described with reference to FIG.
In the squeezing and ironing process, a thin plate blank made of nickel having a thermal expansion coefficient of 13.4 × 10 ⁻⁶ / ° C. is drawn into a cylindrical cup, and, for example, thermal expansion is performed in a die hole in which the cylindrical cup is disposed. A punch 21 made of a cemented carbide such as tungsten carbide having a rate of 4.0 × 10 ⁻⁶ / ° C. is press-fitted into the bottomed cylindrical cup-shaped formed body S for ironing.

In the molded body heating step, the molded body S is heated to a temperature of about 60 to 100 ° C. by infrared irradiation by an infrared heater disposed around it or high temperature water injection by a liquid ejecting apparatus. Thereby, the molded body S is thermally expanded more than the punch 11 so that the adhesion between the molded body S and the punch 11 is relaxed.
As a heating means, in addition to an infrared heater that heats the molded body from the outer periphery of the punch 21 and a liquid ejecting apparatus, a liquid heated at a high temperature is circulated and heated in a liquid flow path provided in the punch. A device that heats the punch portion 20 to a predetermined temperature using a high-temperature liquid circulation device, an electric heater built in the punch, or the like can be applied. When circulating a high-temperature liquid, factory waste heat can be effectively used as a heat source, and heat loss is small, energy saving is excellent, and temperature controllability is excellent.

  In the subsequent piston releasing step, as shown in FIG. 3 (b), the piston 22 provided at the tip of the punch 21 is supplied with high-pressure water to the pressurized fluid flow path 22a, so that a predetermined distance is obtained. For example, the molded body S is protruded from the tip of the punch 21 by projecting about 5 to 50 mm, and is initially moved. At this time, since the adhesion of the molded body S to the punch 21 is relaxed in the molded body heating process, even if the H / D ratio of the molded body S is large and long, sliding friction with the punch 21 is achieved. Since the resistance is reduced and the bottom is uniformly initially pressurized by the piston 22, it is possible to effectively suppress the occurrence of deformation and damage of the molded body accompanying the extrusion operation.

  In the fluid injection process, as shown in FIG. 3C, high pressure water is supplied from the pressurized fluid flow path 22a communicating with the opening 22b1 of the pressurized fluid flow path 22b following the piston release process. The piston 22 stops at a position where it has moved a predetermined distance (initial movement). After that, the pressurized fluid channel 22c formed on the front surface of the piston 22 is filled with high-pressure water in the flow as indicated by the arrow X.

Since the stripping method of the ironing formed article of the second embodiment is configured as described above, it has the following effects.
(A) Since the adhesive force between the molded body and the punch is relieved by utilizing the difference in thermal expansion between the punch and the molded body, it is possible to easily remove the molded body from the punch without damaging it. Yield can be improved.
(B) Since the high pressure water is supplied to the pressurized fluid flow path 22a and the piston 22 provided at the tip of the punch is advanced to release the molded body S, the molded body after the adhesion force relaxation by heating is smoothly punched. 21, and it is excellent in further certainty and reliability in its operation.
(C) In the initial stage of extraction, pressure is applied evenly to the bottom of the molded body S by the advancing operation of the piston 22, and the molded body S comes into close contact with the punch 21 due to overhanging the bottom, making it difficult to separate the mold. Preventing it from happening, once the bottom is removed from the bottom of the punch, and then a smaller fluid pressure is applied to the bottom, the long molded body S can be easily pulled out. Yield can be improved.
(D) Since the molded body is extracted by the pressure fluid, the stroke width of the piston 22 necessary for mechanically pulling out the molded body from the punch 21 can be reduced, and the entire apparatus can be configured compactly.
(E) The heating means can be appropriately selected inside and outside the punch, and when the liquid ejecting apparatus heats the punch portion from the surroundings, hot water heated by factory waste heat or the like can be applied. It is excellent in energy saving and economical efficiency. When a high-temperature liquid circulation device or an electric heater is used as the heating means, the temperature controllability is excellent, and the molded body can be heated from within the punch, so that heat loss is small and energy saving is particularly excellent.

  The present invention is widely applied to a method of extracting a molded body that has been drawn and ironed into a cylindrical cup shape from a punch, and in particular, buckled, deformed, or ruptured into a long and thin cylindrical shaped body after ironing. This makes it possible to extract efficiently without causing any damage.

It is principal part sectional drawing of the ironing apparatus with which the stripping method of the ironing process molded object which concerns on Embodiment 1 is applied. It is the graph which showed the relationship between the liquid pressure of high-pressure water and a molded object (can) taking-out movement amount, and explanatory drawing of the fracture | rupture form by the internal pressure load. It is explanatory drawing of the stripping method of the ironing process molded object which concerns on Embodiment 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ironing apparatus of Embodiment 1 11 Punch 12 Coil of high frequency induction heating apparatus 13 Pressurized fluid flow path 13a Discharge port 20 Punch part of ironing apparatus of Embodiment 2 21 Punch 22 Pistons 22a-22c Pressurized fluid flow Road S compact

Claims (3)

A cylindrical molded body drawn and ironed with a punch having a smaller coefficient of thermal expansion than a cylindrical cup formed by drawing a flat blank is heated by a heating means to cause the cylindrical molding due to a difference in thermal expansion between the cylindrical molded body and the punch. A stripping method of a ironing processed molded body having a molded body heating step for relaxing the adhesion between the body and the punch,
The heating means is a high-frequency induction heating device disposed around the molded body;
Heat the shaped body covered with a punch,
A stripping method for an ironing-molded molded body, wherein the drawn and ironed cylindrical molded body is extracted from a punch. 2. The ironing process molding according to claim 1, further comprising a piston mold releasing step of pulling out the molded body from the punch by advancing a piston provided at a tip portion of the punch subsequent to the molded body heating step. Body stripping method. 3. An ironing process comprising a step of injecting a pressure fluid into a pressurized fluid passage formed between the front of the piston and the bottom of the molded body, following the piston releasing step of claim 2. Stripping method for processed molded body.