TWI652159B - Injection molding method - Google Patents

Abstract

An injection molding method comprising the steps of: providing a mold set, comprising a first mold, and a second mold, the first mold having a first joint surface and a first forming structure, the second mold having a facing surface a second joint surface of a joint surface and a second forming structure; combining the first mold and the second mold, and providing an elastic film between the first mold and the second mold, so that the film is at least at first The first bonding structure and the second molding structure together define a molding cavity; and the molding material is injection molded The cavity is injection molded into a molded article.

Description

Injection molding method

The present invention relates to a molding method, and more particularly to an injection molding method.

The injection molding uses a first mold and a second mold corresponding to the shape of the first mold, and after the two molds are closed, the molding material is injected into the cavity of the two molds, and is heated. Pressing or the like causes the molding material to be shot and formed into a finished product according to the shape of the cavity. However, due to the better fluidity of some molding materials, such as the thermosetting materials used in the Reaction Injection Molding (RIM) method, the molding material may penetrate into the gap between the first mold and the second mold joint surface, resulting in The finished product after injection molding has a burr.

In order to avoid the generation of burrs, U.S. Patent No. 5,543, 159 discloses a reactive injection molding method in which a layer of thermosetting resin is applied around the periphery of a first mold or a second parting line, thus being first After the mold is combined with the second mold, the thermosetting resin is interposed on the joint surface of the first mold and the second mold to prevent the occurrence of burrs in the formed article. But the main problem with this method is that the first mold and When the second mold is combined, the resin at the periphery of the parting line is squeezed and partially overflows into the cavity, and the overflow portion must be additionally removed to avoid affecting the molding of the injection material in the cavity.

In addition, when a fragile embedded member such as glass is placed in a mold and integrally molded with a plastic material by using insert molding, the fragile embedded member is easily broken by the die extrusion, or because the mold surface is The presence of minute projections and dents on the surface of the frangible embedded member reduces the strength of the fragile embedded member, which is also a problem to be solved.

Accordingly, it is an object of the present invention to provide an injection molding method for preventing burrs from being formed on a molded article.

Another object of the present invention is to provide an injection molding method that reduces the risk of breakage of the frangible embedded member.

Therefore, in one embodiment, the injection molding method of the present invention comprises the steps of: providing a mold set including a first mold and a second mold, the first mold having a first joint surface and a first molding Structure, the second mold has a second joint surface facing the first joint surface and a second molding structure; a film is disposed between the first mold and the second mold; the first mold and the first mold The second mold is combined, and in the combined state, the film is at least between the first joint surface and the second joint surface and is sandwiched by the first joint surface and the second joint surface, and the The first molding structure and the second molding structure collectively define a molding cavity; and injecting a molding material into the molding cavity to inject and shape a molded article.

In another embodiment of the present invention, the injection molding method is a package The method includes the following steps: providing a mold set including a first mold and a second mold, the first mold having a first joint surface, the second mold having a second joint surface facing the first joint surface; Disposing an elastic film on at least the second joint surface of the second mold; closing the first mold and the second mold, so that the film is at least sandwiched between the first joint surface of the first mold and the second mold Between the second joint faces; and injecting a molding material into a molding cavity defined by the first mold and the second mold together to form a molded article.

In another embodiment, the injection molding method of the present invention comprises the steps of: providing a mold set comprising a first mold and a second mold, the first mold having a first joint surface, the second mold having a second bonding surface of the first bonding surface and a second molding structure located inside the second bonding surface; an elastic film is disposed on the second bonding surface of the second mold and the second molding structure; Closing the first mold and the second mold such that the film is sandwiched between the first joint surface of the first mold and the second joint surface of the second mold; and injecting the molding material into the first mold and the first mold A molding cavity commonly defined inside the two molds is formed by injection molding a molded product.

The present invention at least has the effect of being closely interposed between the first joint surface and the second joint surface through the elastic film to avoid generation of burrs of the molded article. Moreover, when embedded in the molding, it can be sandwiched between the mold and the substrate by the elastic film, and the risk of breakage or strength reduction of the fragile substrate can be reduced.

101‧‧‧Steps

102‧‧‧Steps

103‧‧‧Steps

104‧‧‧Steps

201‧‧‧Steps

202‧‧‧Steps

203‧‧‧Steps

204‧‧‧Steps

205‧‧‧Steps

206‧‧‧Steps

301‧‧‧Steps

302‧‧‧Steps

303‧‧ steps

304‧‧‧Steps

305‧‧‧Steps

306‧‧‧Steps

1‧‧‧Mold group

11‧‧‧First mould

111‧‧‧First joint

112‧‧‧First forming structure

12‧‧‧Second mold

121‧‧‧Second joint

122‧‧‧Second forming structure

123‧‧‧Second hole

13‧‧‧Molding cavity

14‧‧‧Pole

2‧‧‧film

21‧‧‧First hole

3‧‧‧Molded goods

4‧‧‧ release ink layer

5‧‧‧Substrate

Other features and effects of the present invention will be described with reference to the drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the detailed description, FIG. 1 is a flow block diagram illustrating the main steps of the first embodiment of the injection molding method of the present invention; FIGS. 2, 3 and 5 are diagrams illustrating the implementation steps of the first embodiment. FIG. 4 is a cross-sectional view showing a film and a molding cavity of the first embodiment; FIG. 6 is a perspective view showing a molded article of the first embodiment; FIG. 7 is a flow block diagram. The main steps of the second embodiment of the injection molding method of the present invention are illustrated; FIG. 8 to FIG. 10 are schematic flow charts illustrating the implementation steps of the second embodiment; FIG. 11 is a schematic diagram illustrating another implementation of the second embodiment. Figure 12 is a schematic view showing a release oil film layer of the embodiment separated from the molded article; Figure 13 is a flow block diagram showing the main steps of the third embodiment of the injection molding method of the present invention; 14 to FIG. 16 are schematic flow charts for explaining the implementation steps of the third embodiment; FIG. 17 is a cross-sectional view showing another embodiment of the third embodiment; FIG. 18 is a cross-sectional view showing the embodiment. a pole Into the molding cavity; 19 and 20 are cross-sectional views showing the steps of the fourth embodiment of the injection molding method of the present invention; and Fig. 21 is a cross-sectional view showing the steps of the fifth embodiment of the injection molding method of the present invention.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

1 is a block diagram of a main implementation step of a first embodiment of an injection molding method according to the present invention. The main steps of the first embodiment include: step 101, providing a mold set including a first mold, and a first a second mold; step 102, an elastic film is disposed between a first joint surface of the first mold and a second joint surface of the second mold; and step 103, the first mold and the second mold are combined to make The film is sandwiched between the first bonding surface and the second bonding surface; in step 104, a molding material is injected into the molding cavity to inject and form a molded article.

The implementation steps of the first embodiment will be specifically described below with reference to FIGS. 2 to 6.

Referring to FIG. 2, step 101 provides a mold set 1 including a first mold 11 and a second mold 12 on the lower side of the first mold 11, wherein the first mold 11 has a first joint surface 111 and a The first molding structure 112. The second mold 12 has a second connection facing the first joint surface 111 The first molding structure 112 and the second molding structure 122 are used to define a molding cavity 13 when the first mold 11 and the second mold 12 are combined (shown in FIG. 5). ).

Referring to FIGS. 3, 4, and 5, step 102 is to provide an elastic film 2 between the first joint surface 111 of the first mold 11 and the second joint surface 121 of the second mold 12, that is, the film 2 has elasticity and can be molded by the mold. The film is pressed and adhered to the surface of the mold, and in the present embodiment, the annular film 2 is placed on the second joint surface 121 of the second mold 12. Following the step 103, the first mold 11 and the second mold 12 are combined, wherein after the first mold 11 and the second mold 12 are combined, the film 2 is tightly clamped to the first Between the joint surface 111 and the second joint surface 121 (see FIG. 5), and together with the first molding structure 112 and the second molding structure 122, the aforementioned molding cavity 13 is defined, and the film 2 is the boundary of the molding cavity 13. Part of it. As shown in FIG. 5, in the present embodiment, the second joint surface 121 is wider than the first joint surface 111, the width of the film 2 is the same as the width of the first joint surface 111, and the film 2 is aligned with the first joint surface 111. After the first mold 11 and the second mold 12 are combined, the film 2 does not protrude inwardly to the molding cavity 13, and the film 2 has elasticity, and when the film 2 is sandwiched between the first joint surface 111 and the second joint surface 121 The two sides of the film 2 are respectively in close contact with the first joint surface 111 and the second joint surface 121, and the first joint surface 111 and the second joint surface 121 are adjacent to the molding cavity. There are no gaps in 13 places. Further, in the present embodiment, the film 2 is annular and disposed along the second joint surface 121 (see Fig. 4), and the film 2 has a thickness ranging from 0.05 mm to 0.075 mm. Film 2 can be ethylene-vinyl acetate copolymer (Ethylene-Vinyl) Acetate copolymer (EVA), polyimide (PI), polycarbonate (Polycarbonate, PC) or polyethylene terephthalate (PET). In other embodiments, the film 2 can also be disposed along the first bonding surface 111, and the thickness of the film 2 and the material of the film 2 can also be changed according to the needs of the user or the needs of the process. Not limited to what is disclosed here.

Referring to FIGS. 5 and 6, in step 104, the molding material is injected into the molding cavity 13 through a gate (not shown) that is inserted through the first mold 11 to inject a molded article 3. In the process of injection molding, the molding material has fluidity, so that if any gap exists in the molding cavity 13 during the injection molding material into the molding cavity 13 and has not been solidified, the molding material will flow into the gap and cause the molding material to flow into the gap. The production of the edging of the molded product 3. However, since the film 2 is tightly sandwiched between the first joint surface 111 and the second joint surface 121, the first joint surface 111 and the second joint surface 121 are adjacent to each other at the molding cavity 13 without gaps. The molding material is prevented from flowing into the gap between the first joint surface 111 and the second joint surface 121, thereby preventing the generation of the burrs of the molded article 3. In addition, since the film 2 is not disposed between the first bonding surface 111 and the second bonding surface 121 by, for example, spraying, the thickness of the film 2 is relatively uniform between the first bonding surface 111 and the second bonding surface 121. In this way, the problem of the adhesion of the molding cavity 13 due to the uneven thickness of the film 2 can be avoided. On the other hand, when the film 2 is tightly interposed between the first bonding surface 111 and the second bonding surface 121, The film 2 does not extend into the molding cavity 13 due to being tightly held, so that it is not necessary to use a computer numerical control (CNC) to cut the film 2 into the film. A portion of the molding cavity 13. In this embodiment, the molding material is a thermosetting material, and the molded product 3 is injection-molded by a Reactive Injection Molding (RIM) process. However, in other embodiments, the molding material is selected or injected. The selection of the molding process can be changed according to the needs of the user or the considerations in the process, and is not limited to the contents disclosed herein.

Referring to FIG. 7 and FIG. 8, the main steps included in the second embodiment of the injection molding method of the present invention, wherein steps 201-204 are substantially the same as the first embodiment, except that in step 202 of the embodiment, the film 2 is also covered. The second molding structure 122.

The specific implementation steps of the second embodiment are explained as follows. Referring to FIG. 8, step 202 is to provide an elastic film 2 between the first joint surface 111 of the first mold 11 and the second joint surface 121 of the second mold 12. In the present embodiment, the film 2 is not only closely interposed between the first joint surface 111 and the second joint surface 121, but also covers the surface of the second molding structure 122 (see FIG. 3), in other words, the film 2 A curved arc segment on the surface of the second molding structure 122 and a horizontal segment on the second bonding surface 121 are formed on the second mold 12. Step 203 combines both the first mold 11 and the second mold 12. Therefore, in step 204, after the molding material is injected into the molding cavity 13, the molded article 3 is formed in the molding cavity 13 and located on the film 2, and the film 2 also prevents the molding material from flowing into the first bonding surface 111 and the second bonding surface. In the gap between 121, the generation of burrs is prevented. Referring to Figures 8, 9, and 10, the step of demolding in the embodiment is further illustrated. In step 205, the molded article 3 is taken out from the molding cavity 13 together with the film 2. Finally, in step 206, the film 2 is separated from the molded article 3 to obtain a molded article 3 which is formed without burrs. On the other hand, although in the present embodiment, the film 2 covers the second molding structure 122, the user can cover the film 2 on the first bonding surface 111 and the first molding structure 112 according to the requirements of its use (see Figure 3) is not limited to what is disclosed herein. Further, the film 2 can also be rolled to a roll process or the entire film 2 can be directly disposed between the first mold 11 and the second mold 12. And if necessary in the process, the formed film 2 may be first shot by injection molding, and then the film 2 is disposed between the first mold 11 and the second mold 12.

Referring to Figures 11 and 12, in another embodiment, in order to make the film 2 easier to separate from the molded article 3, the film 2 may have a release ink layer 4. The release ink layer 4 is disposed facing the molded article 3 and is located between the film 2 and the molded article 3. By the release ink layer 4, the user can easily separate the molded article 3 from the film 2, and the damage caused by the film 2 to the molded article 3 during the process of separating the molded article 3 from the film 2 can be reduced.

Referring to Figures 13 and 14, the third embodiment of the injection molding method of the present invention comprises the main steps, wherein steps 301-304 are substantially the same as the first embodiment, except in step 302, except in the first mold 11 and An elastic film 2 is disposed between the two molds 12, and a substrate 5 is disposed between the first mold 11 and the second mold 12, that is, insert molding.

The specific implementation steps of the third embodiment are as follows: Referring to FIGS. 14 and 15, step 302 is to provide a film 2 and a substrate 5 between the first mold 11 and the second mold 12. Step 303 will be the first The first joint surface 111 of one mold 11 is combined with the second joint surface 121 of the second mold 12. In the present embodiment, the film 2 is entirely covered on the surfaces of the second joint surface 121 and the second molding structure 122, and the substrate 5 is disposed on the film 2. In addition, the substrate 5 can be formed by injection molding or other molding methods, and the material of the substrate 5 can be, for example, polycarbonate, polycarbonate, and Acrylonitrile Butadiene Styrene (ABS). Copolymer, polyamine (Nylon) or fiberglass board. Referring to FIG. 15, after the molding material is injected into the molding cavity 13 in step 304, the molded article 3 is formed in the molding cavity 13 and combined with the substrate 5, and the film 2 also prevents the molding material from flowing into the first bonding surface 111 and the first In the gap between the two joint faces 121, the generation of burrs is further avoided. Referring to FIG. 16, the step of demolding the embodiment is further illustrated. In step 305, the substrate 5, the molded article 3 and the film 2 are taken out together from the molding cavity 13; finally, the film 2 and the substrate are further processed in step 306. 5 Separation was carried out to obtain a molded article 3 which was formed without burrs and combined with the substrate 5. In addition, in order to allow the user to easily separate the substrate 5 from the film 2, a release ink layer 4 may be disposed between the substrate 5 and the film 2 as in the embodiment of the second embodiment described above ( See Figure 11) to make film 2 easier to separate from substrate 5.

Referring to FIG. 17, in another embodiment, the film 2 has a first hole 21 in a region covering the second molding structure 122, and the second mold 12 is formed with a second hole 123 communicating with the first hole 21. Further, the mold set 1 further includes a ram 14 movably disposed in the second hole 123 and projecting into the molding cavity 13. Therefore, referring to FIG. 18, after the injection molding process is completed, it is only necessary to project the ejector 14 into the molding cavity 13, At this time, the plunger 14 can lift the substrate 5 and separate from the film 2. Further, since the film 2 is still left on the second molding structure 122 and the second bonding surface 121, the film 2 can be reused to reduce the manufacturing cost. In other implementations, the number of the ejector pins 14, the first holes 21 and the second holes 123 may be two or more, and the second holes 123 may also be formed in the first mold 11 (see FIG. 17). That is, the number of the ejector pins 14, the first holes 21 and the second holes 123, and the position of the second holes 123 can be changed according to the needs of the user in use or in the process, and the contents disclosed herein are not limit.

Referring to FIG. 19 and FIG. 20, the fourth embodiment of the injection molding method of the present invention is substantially the same as the third embodiment, except that another elastic film 2 is disposed between the first mold 11 and the second mold 12, and The substrate 5 is provided as a fragile material such as glass. The details are as follows: one of the films 2 covers the first bonding surface 111 and the first molding structure 112, and the other film 2 covers the second bonding surface 121 and the second molding structure 122, and the substrate 5 is disposed on two The films 2 are located between the molding chambers 13. After the molding material is injected into the molding cavity 13, the molded article 3 is formed in the molding cavity 13 and combined with the substrate 5, and in the present embodiment, the molded article 3 is bonded only to the periphery of the substrate 5 to make the substrate 5 Most areas are exposed. During the formation of the molded article 3, the two films 2 are interposed between the substrate 5 and the first mold 11 and the second mold 12, respectively, so that the surface of the substrate 5 is not directly in contact with the first mold 11 and the second mold 12. That is, when the first mold 11 and the second mold 12 sandwich the substrate 5, the film 2 is pressed against the surface of the substrate 5. Since the film 2 has elasticity, the surface of the film 2 is relatively soft When the surface of the film 2 is in contact with the surface of the substrate 5 and is pressed against the surface of the substrate 5, no damage is caused to the surface of the substrate 5, for example, pits are formed, thereby preventing the substrate 5 from being broken or having a reduced strength. Furthermore, since the surfaces of the two films 2 are respectively adhered to the surfaces of the first mold 11, the second mold 12, and the substrate 5, and are closely sandwiched between the first joint surface 111 and the second joint surface 121, not only The first joint surface 111 and the second joint surface 121 are in close contact with each other, so that it can be avoided between the substrate 5 and the first mold 11 and the second mold 12 and between the first mold 11 and the second mold 12 The occurrence of the slit can also prevent the molded article 3 from being burred. In addition, in the embodiment, since the two films 2 cover the first molding structure 112 and the second molding structure 122 respectively, a runner (not shown) and a corresponding gate may be opened in the second mold 12 near the molding cavity 13 (Fig. Not shown, and a perforation (not shown) is formed in the film 2 covering the second molding structure 122 corresponding to the gate of the second mold 12, so that the molding material passes through the runner, the gate and the film of the second mold 12. 2 corresponding to the perforation injection molding cavity 13.

At the time of demolding, the base material 5, the molded product 3, and the film 2 are taken out together from the molding cavity 13, and the film 2 is separated from the substrate 5 to obtain a molded article 3 which is formed without burrs and bonded to the substrate 5.

Referring to FIG. 21, the fifth embodiment of the injection molding method of the present invention is substantially the same as the fourth embodiment. However, in the embodiment, only one film 2 covers the first bonding surface 111 and the first molding structure 112, and The two joint faces 121 and the second forming structure 122 do not cover the film. When the first mold 11 and the second mold 12 are closed, the substrate 5 is located in the molding cavity 13 and the outer surface of the substrate 5 is in close contact with the film 2, and the film 2 is closely sandwiched between the first bonding surface 111 and the second Between the joint faces 121. After the molding material is injected into the molding cavity 13, The product 3 is formed in the molding cavity 13 and combined with the substrate 5, and by the adhesion of the film 2 to the outer surface of the substrate 5, the boundary between the molded article 3 and the substrate 5 can be prevented from being on the substrate 5. The outer surface is burred, and the film 2 is tightly sandwiched between the first joint surface 111 and the second joint surface 121, so that the outer periphery of the molded article 3 can be prevented from being burred. Therefore, as long as a film 2 is provided, it is possible to prevent the occurrence of burrs. By providing the film 2 between the first mold 11 and the outer surface of the substrate 5, the risk of cracking or strength reduction of the substrate 5 can also be reduced.

As described above, the elastic film 2 is tightly interposed between at least the first joint surface 111 and the second joint surface 121, and the generation of the burrs of the molded product 3 can be prevented. Further, at the time of embedding molding, the elastic film 2 can be interposed between the molds 11, 12 and the substrate 5, and the risk of breakage or strength reduction of the fragile substrate 5 can be reduced.

However, the above is only the embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and the patent specification of the present invention are still It is within the scope of the patent of the present invention.

Claims (5)

An injection molding method comprising the steps of: providing a mold set comprising a first mold and a second mold, the first mold having a first joint surface and a first forming structure, the second mold having a facing a second joint surface of the first joint surface and a second forming structure, the second joint surface being wider than the first joint surface; only the second joint of the first joint surface of the first mold and the second mold An elastic film is disposed between the faces, the film has the same width as the first joint surface, and the film is aligned with the first joint surface; the first mold and the second mold are combined, and the film, The first molding structure and the second molding structure collectively define a molding cavity, the film is a part of a boundary of the molding cavity, and in the combined state, the film is only located on the first bonding surface and the first Between the two joint faces and sandwiched by the first joint surface and the second joint surface, the first joint surface and the second joint surface are adjacent to each other at the molding cavity; and the molding material is injected into the molding The cavity is injection molded into a molded article. The injection molding method of claim 1, the method further comprising: disposing a substrate, the substrate is placed in the molding cavity after the first mold and the second mold are combined, and the molding material is injected into the molding After the cavity, the molded article is combined with the substrate. The injection molding method according to claim 1, wherein the film has a thickness ranging from 0.05 mm to 0.075 mm. The injection molding method according to claim 1, wherein the film is made of ethylene-vinyl acetate copolymer, polyamidamine, polycarbonate, or polyparaphenylene Made of acid glycol. An injection molding method comprising the steps of: providing a mold set comprising a first mold and a second mold, the first mold having a first joint surface, the second mold having a side facing the first joint surface a second joint surface, the second joint surface being wider than the first joint surface; an elastic film disposed only on the second joint surface of the second mold, the film having the same width as the first joint surface and the film Aligning with the first joint surface; closing the first mold and the second mold such that the film is only sandwiched between the first joint surface of the first mold and the second joint surface of the second mold; A molding material is injected into the film, a molding cavity defined by the first mold and the second mold, to form a molded article, which is a part of the boundary of the molding cavity.