Elastic body molding method and elastic body molding device

Abstract

Provided is a method for molding an elastic body, in which liquid silicone rubber (50) having fluidity is supplied in a raised manner from a movable supply nozzle (6) at the tip of an LSR supply device to the upper surface (11a) of a mold (14) attached to a press, the supply nozzle (6) is moved and avoided, the press (10) is closed, a cavity (15) of the mold (14) is filled with the liquid silicone rubber (50), and the upper surface (11a) of the mold (14) is pressed by the upper surface (11a) of the mold (14). A molded article is molded by simultaneously pressurizing and heating. As a result, an elastomer molded article having good quality can be easily molded without performing a pre-molding.

Description

Technical Field

[0001] The invention relates to a forming method of elastic bodies such as silicone rubber and an elastic body forming device. Background Art

[0002] Conventionally, there is known a method for molding an elastic body, in which an elastic body is formed from silicone rubber by compression molding.

[0003] Compression molding has the following problems:

[0004] Since pre-forming is required and the pre-forming process cannot be omitted, the preparation time is long and time-consuming.

[0005] Since the material used needs to be preformed, it has a higher viscosity and poorer fluidity than the material used in injection molding, so it is difficult to evenly distribute the material in the mold.

[0006] The quality of molded products is affected by the thickness accuracy of the preform and the position of the mold.

[0007] In contrast, for example, as disclosed in Patent Document 1, there is known a method for manufacturing a liquid injection device, wherein the injection device includes a valve mechanism including a valve seat forming a flow path and an elastic body that opens and closes the flow path by contacting and separating relative to the valve seat, wherein the elastic body is formed by injection molding.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2019-198999 Summary of the invention

[0011] Problem that the invention aims to solve

[0012] However, there are the following problems with injection molding:

[0013] It is difficult to inject a large amount of material into a mold in a short time (a few seconds).

[0014] It is necessary to set up multiple gates (many gates) for material injection, and the gate design (number and position) is difficult.

[0015] Compared with compression molding, high injection pressure is required and the equipment cost is high.

[0016] Generally speaking, the structure of an injection molding mold is more complex than that of a compression molding mold, and the mold manufacturing cost is high.

[0017] The present invention has been made in view of this point, and an object of the present invention is to facilitate molding of a molded product of good quality without performing pre-molding.

[0018] Solutions for solving problems

[0019] In order to achieve the above object, in the present invention, a material to be formed having fluidity is supplied to the upper surface of a die mounted on a press machine without performing preforming.

[0020] Specifically, in the first invention, a structure is set as follows: a fluid material to be formed is supplied from a movable supply nozzle at the front end of a material to be formed supply device to an upper surface of a die mounted on a press machine in a raised manner,

[0021] The supply nozzle is moved to avoid the problem.

[0022] The punching machine is molded, the mold cavity of the mold is filled with the material to be formed, and pressurized and heated at the same time to form a molded product.

[0023] According to the above structure, since the material to be formed having fluidity is supplied to the upper surface of the mold mounted on the punching machine, the pre-forming process can be omitted, and a compression mold with a simple structure without an injection gate can be used, so the manufacturing cost can be reduced. Moreover, compared with general injection molding, molding can be performed at a low temperature, so the shrinkage rate is small, and a molded product with high precision can be obtained.

[0024] In the second invention, based on the first invention, the following structure is adopted:

[0025] The mold includes an upper mold, a lower mold, and a core sandwiched by the upper mold and the lower mold to form the cavity, and a fluid molding material is supplied to the upper surface of the core in a bulging manner.

[0026] According to the above configuration, since the core is used, a molded product having a complicated shape including an under shape can be easily molded.

[0027] In the third invention, based on the first or second invention, the following structure is adopted:

[0028] The supply nozzle is rotated to avoid the mold.

[0029] According to the above configuration, the supply nozzle can be retracted and the mold can be closed with a simple configuration, so molding is easy.

[0030] In the fourth invention, in addition to any one of the first to third inventions,

[0031] The molded material is liquid silicone rubber, which is thermally cured by being pressurized and heated by the press machine.

[0032] Liquid silicone rubber (LSR) has been conventionally molded by injection molding, but according to the above structure, molding can be performed at a lower temperature than injection molding, so that variations in outer dimensions can be suppressed and a silicone rubber molded body with high precision can be obtained.

[0033] In the fifth invention, based on the fourth invention,

[0034] The material to be formed is a material obtained by mixing two or more liquid silicone rubbers, and is heat-cured by applying pressure and heating by the press machine.

[0035] In the sixth invention, in addition to any one of the first to fifth inventions,

[0036] When the material to be formed is supplied from the supply nozzle, the supply nozzle is raised as the material to be formed rises.

[0037] According to the above structure, even if a large amount of the material to be formed is supplied at a high speed, the supply nozzle will not be buried in the bulging material to be formed, and air can be prevented from being drawn in.

[0038] In the seventh invention, in addition to any one of the first to sixth inventions,

[0039] The method further includes a cutting step of cutting a connection portion between the supply nozzle and the material to be formed after the supply of the material to be formed from the supply nozzle is completed.

[0040] According to the above structure, the material to be formed is reliably prevented from dripping from the supply nozzle, thereby preventing the surroundings from being contaminated.

[0041] In the eighth invention, there are:

[0042] A forming material supply device that mixes two or more liquid silicone rubbers to supply a liquid forming material;

[0043] a supply nozzle capable of changing a supply position of the material to be formed supplied from the material to be formed supply device by moving; and

[0044] A punching machine houses the supply nozzle between dies installed on the punching machine, wherein the fluid material to be formed supplied from the supply nozzle is supplied to the upper surface of the die in a raised manner, the die is closed while the supply nozzle is moved to avoid the material, the cavity of the die is filled with the material to be formed, and pressurization and heating are performed simultaneously to form a molded product.

[0045] According to the above structure, since the material to be formed with fluidity is supplied to the upper surface of the die of the punching machine, the pre-forming process can be omitted, and a compression mold with a simple structure without a gate for injection molding can be used. Therefore, the mold cost can be suppressed, and the maintenance and management of the mold also become easy, thereby suppressing the maintenance cost. In addition, compared with injection molding, it can be formed at a low temperature, so the shrinkage rate is small, and thus a molded product with high precision can be obtained. Moreover, it is possible to use a punching machine with a relatively simple structure, without using an injection molding machine that becomes a large-scale equipment.

[0046] Liquid silicone rubber has been conventionally molded by injection molding, but according to the above-mentioned structure, molding can be performed at a lower temperature than injection molding, so that variations in outer dimensions can be suppressed and a silicone rubber molded body with high precision can be obtained.

[0047] Effects of the Invention

[0048] As described above, according to the present invention, each of the problems of injection molding and compression molding is solved, and the elastic body can be molded at low cost and with high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a plan view schematically showing a standby posture of the elastic body molding device according to the embodiment of the present invention.

[0050] Figure 2 This is a plan view schematically showing the supply posture of the elastic body molding device according to the embodiment of the present invention.

[0051] Figure 3A This is an enlarged side view showing the supply nozzle and its surroundings in the supply posture.

[0052] Figure 3B This is an enlarged side view showing the supply nozzle and its surroundings in a state after supply.

[0053] Figure 3C This is an enlarged side view showing the supply nozzle and its surroundings in transition from the retracted posture to the mold closing process.

[0054] Figure 4A is the equivalent of Figure 3A Side view of.

[0055] Figure 4B is the equivalent of Figure 3B Side view of.

[0056] Figure 4C is the equivalent of Figure 3C Side view of.

[0057] Figure 5A This is a front view schematically showing the outer shape of the silicone rubber molded body.

[0058] Figure 5B It is a cross-sectional view showing a silicone rubber molded body.

[0059] Figure 6 1 is a flowchart showing a method for molding a silicone rubber molded body according to an embodiment of the present invention. DETAILED DESCRIPTION

[0060] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0061] Figure 1 and Figure 2 The schematic diagram of a silicone rubber molded body manufacturing device 1 according to an embodiment of the present invention is shown. The silicone rubber molded body manufacturing device 1 is provided with an LSR supply device 2 as a material supply device to be formed, and the LSR supply device 2 mixes two liquid silicone rubbers (liquid A and liquid B) and supplies liquid silicone rubber (LSR) as a liquid material to be formed. The LSR supply device 2 is a well-known device, so detailed description is omitted, and it is provided with a barrel pump 3 for extracting liquid materials. The LSR supply device 2 has a pump syringe that feeds the two extracted liquid materials in an appropriate ratio and a static mixer 4 that mixes the two liquids, and a nozzle rotation mechanism 5 is provided on the front end side of the static mixer 4. The viscosity of the two liquid liquid silicone rubber materials is about 500 to 1000 pas. For example, the A agent and the B agent are based on silicon, and a crosslinking agent and a platinum catalyst are added separately to any one of them. For example, specifically, the A agent contains a vinyl-containing silicone polymer, a platinum catalyst, a filler and a curing inhibitor, and the B agent contains a vinyl-containing silicone polymer, a Si-H-containing silicone polymer (crosslinking agent), a filler, and a curing inhibitor.

[0062] In the drawing, the control unit (controller) 7 composed of a microcomputer or the like is configured to control the entire silicone rubber molded product manufacturing apparatus 1, but the LSR supply device 2 and the press machine 10 may be controlled by different control units.

[0063] like Figure 2 and Figure 3C As shown in FIG. 1 , the nozzle rotating mechanism 5 can rotate the base end side around the rotating shaft 5a by an electric motor, manual operation, etc., and can eject the liquid silicone rubber supplied from the static mixer 4 from the supply nozzle 6 provided on the front end side. The nozzle rotating mechanism 5 can be, for example, in a retreat position away from the punching machine 10 (such as Figure 1 ) and the supply position approximately directly above the core 11 of the punching machine 10 described later (as shown in Figure 2 The supply nozzle 6 may be rotated by about 90° between the supply nozzle 6 and the supply nozzle 6. The supply nozzle 6 may have a diameter of, for example, 10 mm to 15 mm, and a flow rate of about 60 g / sec (53 cc / sec). Alternatively, the supply nozzle 6 may be moved to the retreat position by sliding by translation or the like instead of rotating.

[0064] Also like Figure 3A to Figure 3C As shown, the punching machine 10 has a lower die 13 and an upper die 12 (in Figure 3A and Figure 3B Although not shown in detail, a core 11 composed of a plurality of parts is provided between the lower mold 13 and the upper mold 12 to form a cavity 15 for forming a silicone rubber molded body 15. The supply nozzle 6 can be accommodated between the upper mold 12 and the lower mold 13 and the core 11 in the open mold state. In this embodiment, for example, a film covering a wafer suction portion of a semiconductor manufacturing device, that is, a silicone rubber molded body 51 as an elastic body is used as a molding object. The silicone rubber molded body 51 is Figure 5A The thin disk-shaped body with sidewall 52 shown in the figure is actually Figure 5B As shown, a complex shape having many ribs 53 on the inner side is also possible. The lower mold 13, the core 11, and the upper mold 12 are set to a vulcanization temperature of about 110 to 130°C, for example.

[0065] like Figure 3B As shown in FIG. 1 , the liquid silicone rubber having fluidity supplied from the supply nozzle 6 is supplied to the upper surface 11a of the lower mold 11 in a bulging manner. Then, as shown in FIG. Figure 3C As shown, the press machine 10 is configured to close the mold while rotating the supply nozzle 6 to avoid it, fill the cavity 15 (details not shown) of the lower mold 11 and the upper mold 12 with liquid silicone rubber, and simultaneously pressurize and heat it to form a molded product.

[0066] - Method for forming a silicone rubber molded body -

[0067] Next, use Figure 6 A method for molding the silicone rubber molded body 51 according to the present embodiment will be described.

[0068] First, in the silicone rubber molded body manufacturing apparatus 1 in the standby state (evacuation state), as shown in FIG. Figure 1 As shown, the nozzle rotating mechanism 5 is located at a position retracted from the punching machine 10 .

[0069] Then, when manufacturing starts, in step S01, the supply nozzle 6 is rotated by about 90° using the nozzle rotating mechanism 5, as shown in FIG. Figure 2 As shown in FIG. 1 , the supply nozzle 6 is disposed above the upper surface 11a of the lower mold 11. Figure 3A As shown, the supply nozzle 6 is positioned approximately at the center of the mold (lower mold 11 ) and at a height H of about 100 mm above the upper surface 11 a of the lower mold 11 .

[0070] Next, in step S02, a supply button (not shown) of the LSR supply device 2 (control unit) is pressed.

[0071] Next, in step S03, Figure 3B As shown, the liquid silicone rubber 50 mixed by the static mixer 4 is supplied to the upper surface 11a of the lower mold 11. The supplied liquid silicone rubber 50 is raised in a spiral manner like ice cream. As for the supply speed, it is advantageous to have a speed as fast as possible, for example, about 53cc / second as described above.

[0072] Next, in step S04 , when the material supply is completed, in a cutting process, the material is cut at the tip of the nozzle using, for example, a resin spoon. Figure 3B In the state where the supply of the liquid silicone rubber 50 is stopped, the coiled liquid silicone rubber 50 is connected to the front end of the supply nozzle 6 to a certain extent by the liquid silicone rubber 50, so that the liquid silicone rubber 50 is reliably cut off in the cutting process, and the liquid silicone rubber 50 will not be scattered to the punching machine 10 and its surroundings.

[0073] Next, in step S05, the supply nozzle 6 is rotated 90° to return to Figure 1 Standby position shown.

[0074] Next, in step S06 , a press start button (not shown) of the control unit 7 is pressed.

[0075] Next, in step S07, Figure 3C As shown, the upper mold 12 is closed, and while the upper mold 12 and the lower mold 11 are being pulled in, at the moment when the pulling-in completion position is reached, the lower mold 11 gradually rises, and the stamping pressure rises to a specified pressure, and the molding begins. That is, the liquid silicone rubber 50 is filled into the cavity 15 of the lower mold 11 and the upper mold 12, and is pressurized and heated at the same time to form the silicone rubber molded body 51. The punching machine 10 is opened, the molded silicone rubber molded body 51 is taken out, and the burrs are removed to obtain the final product.

[0076] On the other hand, in step S08, in the LSR supply device 2, material is supplied from the barrel pump 3 to the pump syringe of the LSR supply device 2 in a specified amount, and the supply of material for the next injection amount is completed, and the LSR supply device 2 and the barrel pump 3 stop the supply action and return to step S01.

[0077] Hereinafter, the operations from step S01 to step S08 are repeated.

[0078] In this embodiment, since the liquid silicone rubber 50 having fluidity is supplied to the upper surface 11a of the lower mold 11 of the punching machine 10, the pre-molding process can be omitted, and a compression mold with a simple structure without an injection gate can be used, so the manufacturing cost can be reduced. When the compression mold with a simple structure is used, the maintenance management of the mold becomes easy, and the maintenance cost is suppressed.

[0079] Furthermore, the structure can be formed by using a press machine 10 having a relatively simple structure, without using an injection molding machine which is a large-scale equipment.

[0080] Furthermore, since the molding can be performed at a low temperature compared to general compression molding, the shrinkage rate is small, so a molded product with high precision can be obtained. For example, in a silicone rubber molded body 51 with a diameter of 300 mm, molding with an outer diameter accuracy of ±0.3 mm or less can be achieved. In addition, the yield rate can also be achieved above 95%.

[0081] Although liquid silicone rubber is conventionally molded by injection molding, in this embodiment, since liquid silicone rubber is used in compression molding using a compression mold with low manufacturing cost, molding can be performed at a low temperature. Therefore, the deviation of the outer dimensions is suppressed, and a high-precision silicone rubber molded body 51 can be obtained.

[0082] - Modifications -

[0083] In this variation, if Figure 4A to Figure 4C As shown, when the liquid silicone rubber 50 is supplied from the supply nozzle 6 ′, the supply nozzle 6 ′ can be raised as the liquid silicone rubber 50 rises.

[0084] Specifically, in this modification, a lifting unit 7' for lifting and lowering the supply nozzle 6' is provided at the front end of the nozzle rotating mechanism 5'. The actuator is not particularly limited, and may be an air cylinder or an electric motor.

[0085] For example, Figure 4A As shown in FIG. 1 , the initial height H0 when rotating from the escape position to the supply position is set to, for example, H0 = 100 mm.

[0086] Then, if Figure 4B As shown, the supply nozzle 6' is lowered to a height of H1 = 50 mm before starting the supply. By lowering the height as much as possible, it is possible to prevent air from being drawn in when supplying the material.

[0087] Furthermore, if Figure 4C As shown, the supply nozzle 6' is raised to a height of H2 as the material is supplied. H2 is set to 100 mm, for example.

[0088] Therefore, in this modification, even if a large amount of liquid silicone rubber 50 is supplied at a high speed, the supply nozzle 6 ′ does not get buried in the bulging liquid silicone rubber 50 , and air can be prevented from being drawn in.

[0089] Therefore, according to the elastic body molding method of the present embodiment, the problems of injection molding and compression molding are solved, and the silicone rubber molded body 51 can be molded at low cost and with high precision.

[0090] (Other embodiments)

[0091] Regarding the above-mentioned embodiment, the present invention may also be configured as follows.

[0092] That is, in the above embodiment, the molding material is liquid silicone rubber, but it is not limited to this, and may be other thermosetting or thermoplastic molding materials that can be supplied at high speed and have an appropriate viscosity to flow into every corner of the cavity 15.

[0093] In the above embodiment, the elastic body is a disk-shaped thin-walled silicone rubber molded body 51, but it may be a molded body of other uses, other shapes, or other materials. Even a molded body of a particularly complex shape can be molded at high speed and at low cost.

[0094] In the above embodiment, a microcomputer is described as an example of a control unit (controller). However, the control unit can be physically constructed in any way as long as it is a device that controls the silicone rubber molded body manufacturing device 1. For example, the control unit can also be a device that uses software (program) such as a microcomputer or a programmable logic controller (PLC). Alternatively, the control unit can also be implemented by combining hardware (circuit components).

[0095] In addition, the above embodiments are merely preferred examples in nature and are not intended to limit the scope of the invention, its applications, or uses.

[0096] Description of Reference Numerals

[0097] 1: Silicone rubber molded body manufacturing device

[0098] 2: LSR supply device

[0099] 3: Barrel pump

[0100] 4: Static mixer

[0101] 5, 5': Nozzle rotation mechanism

[0102] 5a: Rotation axis

[0103] 6, 6': Supply nozzle

[0104] 7: Control Department

[0105] 7': Lifting section

[0106] 10: Punching machine

[0107] 11: Core

[0108] 11a: Upper surface

[0109] 12: Upper mold

[0110] 13: Lower die

[0111] 14: Mould

[0112] 15: Cavity

[0113] 50: Liquid silicone rubber

[0114] 51: Silicone rubber molded body (elastomer)

[0115] 52: Sidewall

[0116] 53: Ribs.

Claims

1. A method for forming an elastomer, characterized in that: The material to be formed is supplied in a convex manner from a movable supply nozzle at the front end of the material to be formed supply device to the upper surface of the die mounted on the press machine. The supply nozzle is moved to avoid the problem. The punching machine is molded, the mold cavity of the mold is filled with the material to be formed, and pressurized and heated at the same time to form a molded product.

2. The method for forming an elastic body according to claim 1, characterized in that: The mold includes an upper mold, a lower mold, and a core sandwiched by the upper mold and the lower mold to form the cavity, and a fluid molding material is supplied to the upper surface of the core in a bulging manner.

3. The method for forming an elastic body according to claim 1 or 2, characterized in that: The supply nozzle is rotated to avoid the mold.

4. The method for forming an elastic body according to claim 1 or 2, characterized in that: The molded material is liquid silicone rubber, which is thermally cured by being pressurized and heated by the press machine.

5. The method for forming an elastic body according to claim 4, characterized in that: The material to be formed is a material obtained by mixing two or more liquid silicone rubbers, and is heat-cured by applying pressure and heating by the press machine.

6. The method for forming an elastic body according to claim 1 or 2, characterized in that: When the material to be formed is supplied from the supply nozzle, the supply nozzle is raised as the material to be formed rises.

7. The method for forming an elastic body according to claim 1 or 2, characterized in that: The method further includes a cutting step of cutting a connection portion between the supply nozzle and the material to be formed after the supply of the material to be formed from the supply nozzle is completed.

8. An elastic body forming device, characterized in that: have: A forming material supply device that mixes two or more liquid silicone rubbers to supply a liquid forming material; a supply nozzle capable of changing a supply position of the material to be formed supplied from the material to be formed supply device by moving; as well as A punching machine houses the supply nozzle between dies installed on the punching machine, wherein the fluid material to be formed supplied from the supply nozzle is supplied to the upper surface of the die in a raised manner, the die is closed while the supply nozzle is moved to avoid the material, the cavity of the die is filled with the material to be formed, and pressurization and heating are performed simultaneously to form a molded product.

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