Method for forming an elastic body and apparatus for forming an elastic body

Abstract

Fluid liquid silicone rubber (50) is supplied, so as to bulge, 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 machine; moving the nozzle (6) out of the way, the press machine (10) is clamped and the liquid silicone rubber (50) is pressurized and heated while being filled into the cavity (15) of the mold (14) to mold a molded article. An elastic molded article of good quality is molded easily in this way, even without pre-molding.

Description

Technical Field

[0001] The present invention relates to a method for molding an elastomer such as silicone rubber and an elastomer molding apparatus.

Background Art

[0002] Conventionally, an elastomer molding method for forming an elastomer using compression molding (compression molding) with silicone rubber is known.

[0003] Compression molding · Requires preforming and the preforming process cannot be omitted, resulting in a long lead time and high labor costs · The material used requires preforming, so it has a higher viscosity and poorer fluidity compared to the material used in injection molding, making it difficult for the material to evenly spread in the mold · The quality of the molded product depends on the thickness accuracy of the preform and the setting position on the mold There are such problems.

[0004] On the other hand, for example, as in Patent Document 1, a method for manufacturing a liquid injection device including a valve seat formed with a flow path and an elastomer that opens and closes the flow path by contacting and separating from this valve seat, and a method for manufacturing a liquid injection device in which this elastomer is formed by injection molding is known.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, regarding this injection molding, · It is difficult to inject a large amount of material into the mold in a short time (several seconds) • Multiple material injection gates are required (multiple gates), making gate design (number and location) difficult. Compared to compression molding, it requires higher injection pressure and has higher equipment costs. Generally, injection molding dies have a more complex structure than compression molding dies, and the cost of manufacturing the molds is higher. This presents a problem.

[0007] This invention has been made in view of the above, and its purpose is to easily form high-quality molded products without the need for pre-molding. [Means for solving the problem]

[0008] To achieve the above objective, this invention provides a mechanism for supplying a fluid material to be molded to the upper surface of a die attached to a press machine without pre-molding.

[0009] Specifically, in the first invention, a fluid material to be molded is supplied from a movable supply nozzle at the tip of the material to be molded device to the upper surface of a mold attached to a press machine in such a way that it is raised. The supply nozzle is moved to avoid this, The configuration involves clamping the press machine and filling the mold cavity with the material to be molded, while simultaneously applying pressure and heating to form the molded product.

[0010] According to the above configuration, since the fluid material to be molded is supplied to the upper surface of the mold attached to the press machine, the pre-molding process can be eliminated, and a simple compression mold without an injection gate can be used, thus reducing manufacturing costs. Moreover, since molding can be performed at a lower temperature compared to conventional injection molding, the shrinkage rate is small, resulting in molded products with high precision.

[0011] In the second invention, in the first invention, The mold comprises an upper mold, a lower mold, and a core sandwiched between the upper and lower molds to form the cavity, and is configured to supply a fluid material to be molded so as to create a raised surface on the upper surface of the core.

[0012] According to the above configuration, since a core is used, molded products with complex shapes, including an under-shape, can be easily formed.

[0013] In the third invention, in the first or second invention, The supply nozzle is configured to rotate to avoid the mold.

[0014] According to the above configuration, the mold clamping can be performed with a simple structure while avoiding the supply nozzle, making molding easier.

[0015] In the fourth invention, in any one of the first to third inventions, The material to be molded is liquid silicone rubber, which is heat-cured by applying pressure and heating in the press machine.

[0016] Liquid silicone rubber (LSR) has traditionally been molded by injection molding, but with the above configuration, molding can be performed at lower temperatures compared to injection molding, thus reducing variations in external dimensions and resulting in high-precision silicone rubber molded products.

[0017] In the fifth invention, in the fourth invention, The material to be molded is a mixture of two or more liquid silicone rubbers, which is heat-cured by applying pressure and heating in the press machine.

[0018] In the sixth invention, in any one of the first to fifth inventions, When supplying the material to be molded from the supply nozzle, the supply nozzle is raised in accordance with the rise of the material to be molded.

[0019] According to the above configuration, even when a large amount of the molding material is supplied at high speed, the supply nozzle will not be buried in the raised molding material, and air entrainment is also prevented.

[0020] In the seventh invention, in any one of the first to sixth inventions, after the supply of the molding material from the supply nozzle is completed, a cutting step of cutting the connection portion between the supply nozzle and the molding material is further included.

[0021] [[ID=z9]] According to the above configuration, by surely preventing the dripping of the molding material from the supply nozzle, the surroundings are not soiled.

[0022] In the eighth invention, a molding material supply device that mixes two or more liquid silicone rubbers to supply a liquid molding material, a supply nozzle that can change the supply position for supplying the molding material supplied from the molding material supply device by moving, receives the supply nozzle between the molds attached to a press machine, and supplies the fluid molding material supplied from the supply nozzle so as to bulge on the upper surface of the mold, and the mold is clamped in a state where the supply nozzle is moved and avoided, and the molding material is filled into the cavity of the mold while pressurizing and heating to form a molded product. It has a press machine.

[0023] According to the above configuration, since the fluid molding material is supplied to the upper surface of the lower mold of the press machine, the preliminary molding process can be omitted and a compression mold with a simple structure without an injection gate can be used. For this reason, the mold cost can be suppressed, the maintenance and management of the mold are facilitated, and the maintenance cost is suppressed. In addition, since it can be molded at a lower temperature than injection molding, the shrinkage rate is small, so a molded product with good accuracy can be obtained. Furthermore, it can be configured with a press machine having a relatively simple structure without using a large-scale injection molding machine.

[0024] Liquid silicone rubber has traditionally been molded by injection molding, but with the above configuration, molding can be performed at lower temperatures compared to injection molding, thus reducing variations in external dimensions and resulting in high-precision silicone rubber molded products. [Effects of the Invention]

[0025] As described above, the present invention overcomes the problems of both injection molding and compression molding, enabling the inexpensive and highly accurate molding of elastic bodies. [Brief explanation of the drawing]

[0026] [Figure 1] This is a plan view showing an overview of the standby position of an elastic body molding apparatus according to an embodiment of the present invention. [Figure 2] This is a plan view showing an overview of the supply position of an elastic body molding apparatus according to an embodiment of the present invention. [Figure 3A] This is a side view showing a magnified view of the supply nozzle and its surroundings in the supply position. [Figure 3B] This is a side view showing a magnified view of the supply nozzle and its surroundings after supply has been completed. [Figure 3C] This is a side view showing a magnified view of the supply nozzle and its surroundings during the transition from the retracted position to the mold clamping process. [Figure 4A] This is a modified example, a side view equivalent to Figure 3A. [Figure 4B] This is a modified example, a side view equivalent to Figure 3B. [Figure 4C] This is a modified example, a side view equivalent to Figure 3C. [Figure 5A] This is a front view showing the general outline of the silicone rubber molded body. [Figure 5B] This is a cross-sectional view showing a silicone rubber molded body. [Figure 6] This flowchart shows a method for molding a silicone rubber molded article according to an embodiment of the present invention. [Modes for carrying out the invention]

[0027] Embodiments of the present invention will be described below with reference to the drawings.

[0028] Figures 1 and 2 show a schematic of a silicone rubber molded article manufacturing apparatus 1 according to an embodiment of the present invention. The silicone rubber molded article manufacturing apparatus 1 includes an LSR supply device 2, which is a material supply device for molding that supplies liquid silicone rubber (LSR) as a liquid material to be molded by mixing two liquid silicone rubbers (liquid A and liquid B). Since the LSR supply device 2 is a known device, a detailed explanation will be omitted, but it is equipped with a pail pump 3 for drawing up the liquid material. The LSR supply device 2 has a pump syringe for supplying the two drawn-up liquid materials in an appropriate ratio, and a static mixer 4 for mixing the two liquids, and a nozzle rotation mechanism 5 is provided on the tip side of the static mixer 4. The viscosity of the two liquid silicone rubber materials is about 500 to 1000 pas. For example, agents A and B are silicone-based, with a crosslinking agent and a platinum catalyst added to one of them. For example, specifically, Agent A comprises a vinyl gas-containing silicone polymer, a platinum catalyst, a filler, and a curing inhibitor, while Agent B comprises a vinyl gas-containing silicone polymer, a Si-H group-containing silicone polymer (crosslinking agent), a filler, and a curing inhibitor.

[0029] In the drawing, the control unit (controller) 7, which consists 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 separate control units.

[0030] As shown in Figures 2 and 3C, the nozzle rotation mechanism 5 is rotatable at its base end around a pivot axis 5a by an electric motor, manual operation, etc., and is capable of discharging liquid silicone rubber supplied from the static mixer 4 from the supply nozzle 6 located at its tip end. The nozzle rotation mechanism 5 can rotate approximately 90° between, for example, a retracted position away from the press machine 10 (shown in Figure 1) and a supply position almost directly above the core 11 of the press machine 10 (shown in Figure 2), which will be described later. The diameter of the supply nozzle 6 is, for example, 10 mm to 15 mm, and the flow rate is approximately 60 g / second (53 cc / second). Note that instead of rotating the supply nozzle 6, it may be moved to the retracted position by sliding it horizontally or by other means.

[0031] As shown in Figures 3A to 3C, the press machine 10 has a lower die 13 and an upper die 12 (omitted in Figures 3A and 3B), which are openable and closable molds 1. Although not shown in detail, a core 11 consisting of multiple parts is provided between the lower die 13 and the upper die 12, thereby forming a cavity 15 for molding a silicone rubber molded body 15. A supply nozzle 6 can be received between the upper die 12 in the open state and the lower die 13 and core 11. In this embodiment, for example, the target of molding is a silicone rubber molded body 51 as an elastic body, which is a membrane covering the wafer suction part of a semiconductor manufacturing apparatus. This silicone rubber molded body 51 is a thin disc shape with side walls 52, as shown in Figure 5A, but in reality, as shown in Figure 5B, it may have a complex shape with many ribs 53 on the back side. The lower die 13, core 11, and upper die 12 are set to a vulcanization temperature of, for example, 110 to 130°C.

[0032] The fluid liquid silicone rubber supplied from the supply nozzle 6 is as shown in Figure 3B, Core The liquid silicone rubber is supplied so as to form a bulge on the upper surface 11a of 11. Then, as shown in Figure 3C, the press machine 10 rotates the supply nozzle 6 to avoid the bulge and clamps the mold, and the liquid silicone rubber is placed in the lower mold. 13 The system is configured to form a molded product by filling the cavity 15 (details not shown) of the upper mold 12 with pressure and heat.

[0033] -Method for molding silicone rubber products- Next, the molding method for the silicone rubber molded body 51 according to this embodiment will be explained with reference to Figure 6.

[0034] First, in the standby (retracted) state of the silicone rubber molded product manufacturing apparatus 1, as shown in Figure 1, the nozzle rotation mechanism 5 is in a position retracted from the press machine 10.

[0035] Then, when manufacturing begins, in step S01, the nozzle rotation mechanism 5 rotates the supply nozzle 6 by approximately 90°, and as shown in Figure 2, the supply nozzle 6 Core Set it above the upper surface 11a of 11. As shown in Figure 3A, the position of the supply nozzle 6 is the mold ( Core 11) Approximately at the center, the height H is Core It is located approximately 100 mm above the upper surface 11a of 11.

[0036] Next, in step S02, press the supply button (not shown) of the LSR supply device 2 (control unit).

[0037] Next, in step S03, as shown in Figure 3B, the liquid silicone rubber 50 mixed in the static mixer 4 Core It is supplied onto the upper surface 11a of 11. The supplied liquid silicone rubber 50 rises up in a coiled shape, like soft-serve ice cream. The supply speed should be as fast as possible, but for example, as mentioned above, it is about 53 cc / second.

[0038] Next, in step S04, once the material supply is complete, in the cutting process, the material is cut at the nozzle tip using, for example, a resin spoon. Figure 3B shows the state after this cutting process. With the supply of liquid silicone rubber 50 stopped, the coiled liquid silicone rubber 50 and the tip of the supply nozzle 6 are connected to some extent by the liquid silicone rubber 50. Therefore, by reliably cutting the liquid silicone rubber 50 in this cutting process, the liquid silicone rubber 50 does not splatter onto the press machine 10 and its surroundings.

[0039] Next, in step S05, the supply nozzle 6 is rotated 90° to return to the standby position shown in Figure 1.

[0040] Next, in step S06, the press start button (not shown) of the control unit 7 is pressed.

[0041] Next, in step S07, as shown in Figure 3C, the upper mold 12 closes, and the upper mold 12 and the lower mold 13 As it is retracted, and once it has finished moving to the retraction completion position, the lower mold 13 The mold rises, the press pressure increases to the predetermined pressure, and molding begins. In other words, the liquid silicone rubber 50 is in the lower mold. 13 The silicone rubber molded body 51 is formed by filling the cavity 15 of the upper mold 12 with the material, pressurizing and heating it, and then removing the excess material. The molded silicone rubber molded body 51 is removed by opening the mold in the press machine 10, and any burrs or other debris are removed to become the final product.

[0042] Meanwhile, in step S08, the LSR supply device 2 supplies material from the pail pump 3 to the pump syringe of the LSR supply device 2. Once a predetermined amount is supplied and the supply of material for the next shot is complete, the LSR supply device 2 and the pail pump 3 stop their supply operations, and the process returns to step S01.

[0043] The operations from step S01 to step S08 are repeated below.

[0044] In this embodiment, a fluid liquid silicone rubber 50 is used in a press machine 10. Core Since the material is supplied to the upper surface 11a of 11, the pre-molding process can be omitted, and a simple compression mold without an injection gate can be used, thus reducing manufacturing costs. A simple compression mold structure makes mold maintenance easier and reduces maintenance costs.

[0045] Furthermore, it can be constructed using a relatively simple press machine 10 without requiring a large injection molding machine.

[0046] Furthermore, because molding can be performed at lower temperatures compared to conventional compression molding, the shrinkage rate is smaller, resulting in high-precision molded products. For example, a 300mm diameter silicone rubber molded body 51 could be molded with an outer diameter accuracy of ±0.3mm or less. In addition, a yield of over 95% was achieved.

[0047] While liquid silicone rubber has conventionally been molded by injection molding, this embodiment uses compression molding with a compression mold, which has lower manufacturing costs, allowing molding to be performed at low temperatures. As a result, variations in external dimensions are suppressed, and a highly accurate silicone rubber molded body 51 can be obtained.

[0048] -Variations- In this modified example, as shown in Figures 4A to 4C, the supply nozzle 6' is configured to be raised in accordance with the rise of the liquid silicone rubber 50 when the liquid silicone rubber 50 is supplied from the supply nozzle 6'.

[0049] Specifically, in this modified example, a lifting mechanism 7' for raising and lowering the supply nozzle 6' is provided at the tip of the nozzle rotation mechanism 5'. The actuator is not particularly limited, but may be an air cylinder or an electric motor.

[0050] For example, as shown in Figure 4A, the initial height H0 when rotated from the avoidance position to the supply position is, for example, H0 = 100 mm.

[0051] Then, as shown in Figure 4B, the supply nozzle 6' is lowered to a height of H1 = 50 mm before supplying begins. Lowering it as low as possible prevents air from being drawn in during material supply.

[0052] Furthermore, as shown in Figure 4C, the supply nozzle 6' is raised to a height of H2 in accordance with the material supply. H2 is, for example, 100 mm.

[0053] Therefore, in this modified example, even when a large amount of liquid silicone rubber 50 is supplied at high speed, the supply nozzle 6' does not become buried in the raised liquid silicone rubber 50, and air entrapment is also prevented.

[0054] Therefore, according to the method for molding an elastic body according to this embodiment, the problems of both injection molding and compression molding are resolved, and an inexpensive and highly accurate silicone rubber molded body 51 can be molded.

[0055] (Other embodiments) The present invention may also have the following configuration in the above embodiment.

[0056] In other words, although the material to be molded in the above embodiment was liquid silicone rubber, it is not limited to this, and other thermosetting or thermoplastic molding materials that can be supplied at high speed and have a suitable viscosity to flow into every corner of the cavity 15 may also be used.

[0057] In the above embodiment, the elastic body was a disc-shaped, thin-walled silicone rubber molded body 51, but it may be of other use, shape, or material, and even complex shapes can be molded quickly and inexpensively.

[0058] In the above embodiment, a microcomputer was described as an example of a control unit (controller). However, the control unit can be physically configured in any way as long as it controls the silicone rubber molded product manufacturing apparatus 1. For example, the control unit may utilize software (programs), such as a microcomputer or a programmable logic controller (PLC). Alternatively, the control unit may be implemented by combining hardware (circuit components).

[0059] The embodiments described above are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses. [Explanation of Symbols]

[0060] 1. Silicone rubber molded product manufacturing apparatus 2 LSR supply device 3. Pail pump 4 Static Mixer 5.5' Nozzle Rotation Mechanism 5a Rotary shaft 6,6' supply nozzle 7 Control Unit 7' Lifting section 10 Press machine 11 Core 11a Top side 12 Upper mold 13 Lower mold 14 molds 15 Cavity 50 Liquid silicone rubber 51. Silicone rubber molded body (elastic body) 52 Side wall 53 Ribs

Claims

1. The movable supply nozzle at the tip of the material supply device supplies fluid material to be molded in a raised manner onto the upper surface of the die attached to the press machine. The supply nozzle is moved to avoid this, The process includes clamping the press machine and filling the molded material into the cavity of the mold while applying pressure and heating to form a molded product. The mold comprises an upper mold, a lower mold, and a core sandwiched between the upper and lower molds to form the cavity, and a fluid material to be molded is supplied to the upper surface of the core in such a way that it forms a raised mound. A method for forming an elastic body, characterized by the features described above.

2. A movable supply nozzle at the tip of the material to be molded supply device supplies a fluid material to be molded in such a manner that it rises on the upper surface of a die attached to a press machine, The supply nozzle is moved to avoid this, The process includes clamping the press machine and filling the molded material into the cavity of the mold while applying pressure and heating to form a molded product. When supplying the material to be molded from the supply nozzle, the supply nozzle is raised in accordance with the rise of the material to be molded. A method for forming an elastic body, characterized by the features described above.

3. The core consists of a plurality of parts, and the material to be molded is filled into the cavities between the plurality of parts to form a disc-shaped membrane having ribs on the back side. The method for molding an elastic body according to feature 1.

4. The supply nozzle is rotated to avoid the mold. A method for molding an elastic body according to feature 1 or 2.

5. After the supply of the material to be molded from the supply nozzle is completed, the process further includes a cutting step of cutting the connecting portion between the supply nozzle and the material to be molded. A method for molding an elastic body according to feature 1 or 2.

6. A material supply device that supplies a liquid material to be molded by mixing two or more liquid silicone rubber components, A supply nozzle that can change the supply position for supplying the material to be molded from the material supply device by moving, The press machine comprises a press that receives the supply nozzle between the molds attached to the press, supplies the fluid material to be molded from the supply nozzle so as to rise on the upper surface of the mold, and clamps the mold while filling the cavity of the mold with the material to be molded, thereby forming a molded product. The mold comprises an upper mold, a lower mold, and a core that is sandwiched between the upper mold and the lower mold to form the cavity. A fluid material to be molded is supplied to the upper surface of the core in such a way that it forms a raised bump. An elastic body molding apparatus characterized by the following:

7. A material supply device for supplying a liquid material to be molded by mixing two or more liquid silicone rubbers, A supply nozzle that can change the supply position for supplying the material to be molded from the material supply device by moving, The press machine comprises a press that receives the supply nozzle between the molds attached to the press, supplies the fluid material to be molded from the supply nozzle so as to rise on the upper surface of the mold, and clamps the mold while filling the cavity of the mold with the material to be molded, thereby forming a molded product. When supplying the material to be molded from the supply nozzle, the supply nozzle is raised in accordance with the rise of the material to be molded. An elastic body molding apparatus characterized by the following:

8. The core consists of a plurality of parts, and the material to be molded is filled into the cavities between the plurality of parts to form a disc-shaped membrane having ribs on the back side. The elastic body molding apparatus according to feature 6.

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