Resin parts molding method
The resin part molding method addresses air bubble accumulation in narrow grooves by aligning the groove cross-section with gravity, preventing defects and ensuring strong adhesion of the resin part tip, thus improving the quality and performance of molded resin parts.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-12-03
- Publication Date
- 2026-06-15
AI Technical Summary
The accumulation of air bubbles in narrow grooves during resin part molding leads to defects such as voids and reduced adhesion when forming resin parts with protruding tips, as the air bubbles float and accumulate in the narrow parts of the groove, affecting the quality of the resin parts.
A resin part molding method where the groove cross-section narrows vertically from the opening to the depth, aligning with the direction of gravity, ensuring air bubbles float upwards and are prevented from accumulating in narrow areas, using molds with a specific groove shape and resin flow direction opposite to gravity.
Prevents air bubble accumulation in narrow grooves, thereby avoiding defects and ensuring strong adhesion of the resin part tip, enhancing the quality and performance of the molded resin parts.
Smart Images
Figure 2026096244000001_ABST
Abstract
Description
【Technical Field】 【0001】 The present invention relates to a method for molding resin parts from a curable liquid resin. 【Background Art】 【0002】 As a technology with a similar content to this type, for example, Patent Document 1 describes a technology for filling a container with a liquid resin that is a viscous fluid. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2005-239235 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 However, when applying the technology described in Patent Document 1 to the molding technology of resin parts, that is, when filling the liquid resin into a molding space formed by clamping an upper mold and a lower mold and including the wall surface of the groove instead of the above-mentioned container, there is a risk that the performance of the resin part formed by curing the liquid resin will deteriorate. Specifically, when the groove is formed in the upper mold and the cross section of the groove has a shape in which the groove width becomes narrower as it progresses in the direction from the lower mold to the upper mold, the air bubbles contained in the liquid resin filled in the molding space will densely accumulate in the narrow part of the groove width. This is because the specific gravity of the air bubbles is smaller than that of the liquid resin, and the air bubbles float in the liquid resin. 【0005】 After that, when the liquid resin is cured, a resin part having a shape with a protruding tip is formed. However, due to the air bubbles densely accumulated in the narrow part of the groove width, there is a risk that defects such as voids will occur in the tip part of the formed resin part. As a result, for example, when the tip part of the resin part is adhered to the surface of another part, the adhesion of the resin part will decrease. 【0006】 The present invention has been made in view of these points, and its objective is to provide a resin part molding method that can suppress the accumulation of air bubbles contained in the liquid resin in areas where the groove width is narrow when filling a molding space including a groove, which is formed by clamping an upper mold and a lower mold, with liquid resin. [Means for solving the problem] 【0007】 In view of the above problems, the present invention provides a resin part molding method for molding a resin part having a protruding tip from a curable liquid resin, wherein the resin part molding method comprises: a mold clamping step of clamping an upper mold and a lower mold having a groove formed thereon; a filling step of filling a molding space formed by clamping the upper mold and the lower mold, which includes at least the groove, with the liquid resin; a molding step of curing the liquid resin filled in the molding space and molding the resin part; and a removal step of opening the upper mold and the lower mold and removing the resin part, wherein the cross-section of the groove has a shape in which the groove width narrows according to the protruding shape of the resin part as it progresses in the vertical direction, which is the depth direction of the groove, from the opening of the groove. [Effects of the Invention] 【0008】 According to the present invention, an upper mold and a lower mold with a groove formed therein are clamped together, and the space formed by the clamping of the upper and lower molds, which includes at least the groove, is used as the molding space. Furthermore, the cross-section of the groove has a shape in which the groove width narrows as it progresses vertically from the groove opening to the groove depth direction. That is, the groove width narrows as it progresses in the direction of gravity, which is from the upper mold to the lower mold. Also, when liquid resin is filled into the molding space, since the specific gravity of air bubbles is lower than that of the liquid resin, the air bubbles contained in the liquid resin float upward in the opposite direction to gravity due to buoyancy. This prevents air bubbles from accumulating densely in areas where the groove width is narrow. As a result, defects such as voids caused by air bubbles can be prevented from occurring at the tip of the resin part molded by curing the liquid resin, and a decrease in the adhesion of the resin part when the tip of the resin part is brought into close contact with the surface of other parts can be prevented. [Brief explanation of the drawing] 【0009】 [Figure 1] This is a schematic diagram of an apparatus used in a resin parts molding method according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view relating to XX in Figure 1(C). [Figure 3] This is a flowchart of a resin part molding method according to an embodiment of the present invention. [Modes for carrying out the invention] 【0010】 The resin parts molding method according to the present invention will be described in detail below with reference to Figures 1 to 3. Note that the embodiments shown below are only one aspect of the present invention and do not limit the technical scope of the present invention. 【0011】 <Structure> Figure 1(A) is a schematic diagram of the entire molding apparatus 10 used in a resin part molding method according to an embodiment of the present invention. The resin part 3 molded by the molding apparatus 10 is a part that is molded integrally with the insert 2. The resin part 3 is a part with an endless series of convex ridges that are continuous and circumferential around the center of the surface of the insert 2. For example, the insert 2 can be a separator that constitutes a single cell of a fuel cell, and the resin part 3 can be a gasket that seals the fluid flowing on the surface of the separator. Such a resin part 3 is molded by the molding apparatus 10 described below. The molding apparatus 10 includes an upper mold 41 and a lower mold 42 that can be clamped and opened. During molding, the insert 2 is sandwiched between the clamped upper mold 41 and the lower mold 42, and the insert 2 and the lower mold 42 form a molding space S for molding the resin part 3. In this embodiment, a resin part 3 molded integrally with the insert 2 is shown as an example; however, the resin part 3 may not be molded integrally with the insert 2, but may be molded as a separate component. By molding the resin part 3 integrally with the insert 2, the work of attaching the resin part 3 to the insert 2 afterwards can be eliminated. 【0012】 The upper mold 41 is positioned above the lower mold 42 so as to face the lower mold 42. As shown in the plan view of the upper mold 41 in Figure 1(B), the opposing surface 41a of the upper mold 41 that faces the lower mold 42 is provided with a plurality of (for example, four) claws 7 for fixing the insert 2 to the upper mold 41. The plurality of claws 7 have claw tips 7a that engage with the outer edge 2a of the insert 2 when it is fixed to the upper mold 41. The protruding portion 7b of each claw 7 that protrudes from the opposing surface of the upper mold 41 toward the lower mold 42 is accommodated in a recess 71 formed on the opposing surface 42c of the lower mold 42 (second lower mold portion 42b), which will be described later, when the mold is clamped. 【0013】 In this embodiment, as shown in Figure 1(A), the lower mold 42 has a first resin channel 51 connected to the dispenser 5 and extending horizontally, and a second resin channel 6 that is continuous with the first resin channel 51 and extending vertically. A gate 61 connected to the molding space S is formed at the tip of the second resin channel 6. Here, the dispenser 5 is a device that dispenses a fixed amount of liquid resin 1, and the dispenser 5 stores the liquid resin 1 for molding the resin part 3. 【0014】 The lower mold 42 comprises a first lower mold section 42a and a second lower mold section 42b. The first lower mold section 42a has a first resin channel 51 and a part (upstream portion) of the second resin channel 6 formed therein. The second lower mold section 42b has a part (downstream portion) of the second resin channel 6 formed therein. By using the first lower mold section 42a and the second lower mold section 42b together, a continuous second resin channel 6 is formed along the vertical direction. 【0015】 The second lower mold portion 42b has a groove 420 and a plurality of (for example, four) recesses 71 formed on the opposing surface 42c (the surface facing the insert 2 during molding) that faces the upper mold 41. The groove 420 has a groove shape corresponding to the shape of the resin part 3. As shown in the plan view of the lower mold 42 in Figure 1(C), the groove 420 is an endless groove continuously formed to circle the center of the opposing surface 42c of the second lower mold portion 42b. The groove 420 communicates with a part (downstream portion) of the second resin flow path 6 via the gate 61. 【0016】 Figure 2 is a cross-sectional view relating to XX in Figure 1(C). The cross-section of the groove 420 (groove cross-section) has a cross-sectional shape in which the groove width narrows as it progresses from the opening of the groove 420 in the vertical direction, which is the depth direction of the groove 420 (corresponding to the direction of gravity in Figure 2). The groove 420 has a groove shape that corresponds to the cross-sectional shape of the resin part 3, and the shape of the deepest part of the groove 420 and the surrounding area including it corresponds to the protruding shape of the tip part 31 of the resin part 3. Specifically, in the groove cross-section, the groove 420 is formed by a pair of opposing groove wall surfaces 421, 421 with a virtual line along the vertical direction passing through the deepest part in between, and a gate 61 is formed on one of them. The groove 420 is composed of a wide groove and a narrow groove formed on the bottom surface of the wide groove, from the opening in the depth direction. In the groove cross-section, a step is formed in the groove wall surface 421 at the center in the depth direction, thereby forming a narrow groove from the center to the deepest part. The portion of the resin part 3 formed by the narrow groove corresponds to the tip portion 31 of the resin part 3. 【0017】 In this embodiment, the second resin channel 6 is formed such that the liquid resin 1 flows through it in the opposite direction to gravity. This prevents air bubbles 8 accumulated in the second resin channel 6 from agglomerating and entering the molding space S. However, if this phenomenon can be suppressed, the second resin channel 6 may, for example, communicate with the groove 420 along the horizontal direction. 【0018】 Here, when the liquid resin 1 is an ultraviolet curable resin, the entire lower mold 42 or the second lower mold part 42b is made of a material having translucency. On the other hand, when the liquid resin 1 is a thermosetting resin, a heater (not shown) is provided on either one or both of the upper mold 41 and the lower mold 42. 【0019】 <Flow Chart> Hereinafter, the flow of the resin part molding method according to the embodiment will be described with reference to FIG. 3. The resin part molding method according to the embodiment is a method of curing a curable liquid resin 1 to mold a resin part 3 having a shape in which the tip portion 31 protrudes. In the flow chart shown in FIG. 3, first, in step S1, the upper mold 41 and the lower mold 42 are clamped in a state where the insert 2 covers the opening of the groove 420 formed in the second lower mold part 42b. Here, step S1 corresponds to the clamping step in the present invention. 【0020】 Next, in step S2, the liquid resin 1 stored in the dispenser 5 is quantitatively filled into the molding space S formed by the groove wall surface 421 of the groove 420 and the surface of the insert 2 by clamping the upper mold 41 and the lower mold 42. At this time, since the specific gravity of the bubbles 8 is smaller than that of the liquid resin 1, as shown in FIG. 2, the bubbles 8 contained in the liquid resin 1 filled in the molding space S float in the direction opposite to the gravitational direction in the liquid resin 1. The floating bubbles 8 flow out of the liquid resin 1. As a result, the bubbles 8 accumulate at a position close to the surface of the insert 2, and it is possible to prevent the bubbles 8 from densely accumulating in the narrow groove. Further, when the resin part 3 is particularly a gasket, the tip portion 31 of the resin part 3 is elastically deformed, so that the tip portion 31 of the resin part 3 easily adheres to the surface of another part. Therefore, as a result of suppressing the dense accumulation of the bubbles 8 in the narrow groove, it is possible to prevent the elasticity of the tip portion 31 from decreasing. 【0021】 As shown in FIG. 1(C), since the groove 420 is continuously formed so as to surround the center of the opposing surface 42c of the second lower mold part 42b, the resin part 3 is also continuously formed in an annular shape. Therefore, for example, by bringing the tip portion 31 into close contact with the surface of another part so that the resin part 3 surrounds the flow path of the liquid resin formed on the surface of another part, it is possible to prevent the liquid resin from leaking from the gap between the surface of the insert 2 and the surface of another part. Here, step S2 corresponds to the filling step in the present invention. 【0022】 Next, in step S3, the liquid resin 1 filled in the molding space S is cured, and the resin part 3 is integrally molded on the insert 2. As described above, since the insert 2 covers the opening of the groove 420, the liquid resin 1 filled in the molding space S contacts the surface of the insert 2. Therefore, when this liquid resin 1 is cured, the resin part 3 is integrally molded on the insert 2. The liquid resin 1 is cured, for example, by irradiating UV when it has photocurability, or by heating with a heater or the like when it has thermosetting properties. When the liquid resin 1 has photocurability, the entire lower mold 42 or the second lower mold part 42b is made of a transparent material so as to have translucency to UV. When the liquid resin 1 has thermosetting properties, since the liquid resin 1 is heated in the clamped state, the upper mold 41 and the lower mold 42 have heat resistance. Here, step S3 corresponds to the molding step in the present invention. Finally, in step S4, the upper mold 41 and the lower mold 42 are opened, and the resin part 3 is taken out together with the insert 2. Here, step S4 corresponds to the taking-out step in the present invention. 【Explanation of Reference Numerals】 【0023】 1: Liquid resin, 2: Insert, 3: Resin part, 31: Tip portion, 41: Upper mold, 42: Lower mold, 420: Groove, S: Molding space
Claims
[Claim 1] A resin part molding method for forming a resin part having a protruding tip from a liquid resin that has curing properties, The aforementioned resin part molding method is A mold clamping process in which the upper mold and the lower mold with grooves formed on it are clamped together, A filling step of filling the molding space, which includes at least the groove formed by clamping the upper mold and the lower mold, with the liquid resin, A molding step in which the liquid resin filled in the molding space is cured and the resin part is formed, The process includes a removal step of opening the upper mold and the lower mold to remove the resin part, A method for molding a resin part, characterized in that the cross-section of the groove has a shape in which the groove width narrows as it progresses in the vertical direction, which is the depth direction of the groove, from the opening of the groove, according to the protruding shape of the resin part.