Molding apparatus

Abstract

To apply marking such as a letter or an illustration onto a resin molded article without labor or cost.SOLUTION: A molding apparatus 1 has a core 2 provided with an ejector 3, and a cavity 4. Between the core 2 and the cavity 4, a heated resin is filled from a resin injection port. After completion of the resin filling, a resin molded article 5 having a predetermined shape is molded by supplementing pressure and cooling. A mold release resistance force of the ejector 3 is adjusted within a predetermined range. At the time of mold release of the resin molded article 5 by the ejector 3, marking due to whitening is applied by the ejector 3 to the resin molded article 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a molding device for applying marking to a resin molded product. [Background technology]

[0002] Conventionally, resin molded products have been marked with letters or illustrations by metal engraving, printed directly with letters or illustrations, or affixed with printed stickers. However, these processes require additional effort and cost beyond the molding process, such as engraving, printing, and sticker affixing, and there has been a demand for reducing these costs as much as possible.

[0003] On the other hand, in resin molding, when a molded product with poor mold releasability is ejected, the resin in the ejector portion undergoes plastic deformation, causing whitening.

[0004] Patent Document 1 discloses a technology relating to an injection molding apparatus that uses an ejector pin that protrudes from a mold to release a molded product from the mold after injection molding a product using the mold. In order to prevent whitening, this injection molding apparatus is equipped with a detection means that detects the mold release resistance force of the molded product acting on the ejector pin when releasing the molded product, a vibration device that can vibrate the ejector pin in the protruding direction, and a control means that controls the vibration device in accordance with the mold release resistance force detected by the detection means. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-170314 Summary of the Invention [Problem to be solved by the invention]

[0006] However, instead of preventing the whitening phenomenon as in the technique described in Patent Document 1, it is conceivable to perform marking by utilizing this phenomenon.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a molding apparatus capable of performing markings such as characters and illustrations on a resin molded product without spending time and cost.

Means for Solving the Problems

[0008] In order to achieve the above object, the molding apparatus according to the present invention is characterized in that it is a molding apparatus having a core provided with an ejector and a cavity, the demolding resistance of the ejector is adjusted within a predetermined range, when the resin molded product is demolded by the ejector, markings due to whitening are applied to the resin molded product by the ejector.

Effects of the Invention

[0009] According to the characteristics of the molding apparatus according to the present invention, markings such as characters and illustrations can be made on a resin molded product without spending time and cost.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or equivalent parts and components are denoted by the same or equivalent reference numerals throughout the drawings. However, it should be noted that the drawings are schematic and different from the actual ones. Also, there are portions where the dimensional relationships and ratios are different between the drawings.

[0012] In addition, the following embodiments exemplify devices and the like for embodying the technical idea of the present invention, and the technical idea of the present invention does not specify the arrangement of each component and the like as follows. The technical idea of the present invention can be variously modified within the scope of the claims.

[0013] (Example 1) Hereinafter, Example 1 of the molding apparatus 1 according to the present invention will be described in detail with reference to the accompanying drawings.

[0014] FIG. 1 is a schematic configuration diagram of a molding apparatus 1 according to Example 1 of the present invention.

[0015] As shown in FIG. 1, the molding apparatus 1 includes a core 2 and a cavity 4.

[0016] Between the core 2 and the cavity 4, resin heated from a resin inlet (not shown) is filled, and a resin molded product 5 is molded.

[0017] The core 2 is provided with an ejector 3 that projects the resin molded product 5 from the core 2.

[0018] As a molding procedure of the resin molded product 5, first, resin heated from a resin inlet (not shown) is filled. After the filling of the resin is completed, a resin molded product 5 having a predetermined shape is molded by performing pressure compensation and cooling.

[0019] Thereafter, the cavity 4 is removed from the core 2 and the resin molded product 5. At this time, for example, the cavity 4 is gripped from the vertical direction and pulled backward, so that the cavity 4 is removed from the core 2 and the resin molded product 5.

[0020] Next, the ejector 3 slides backward with respect to the main body of the core 2, so that the resin molded product 5 is projected from the core 2.

[0021] When the ejector 3 ejects the resin molded product 5 from the core 2, the resin at the portion of the resin molded product 5 that contacts the tip surface 3a of the ejector 3 undergoes plastic deformation and turns white.

[0022] Specifically, in advance, the release resistance between the ejector 3 and the resin molded product 5 when the resin molded product 5 is ejected from the core 2 is adjusted within a predetermined range. If the release resistance is too high, the resin molded product 5 may be deformed. If the release resistance is too low, whitening may not occur, or the contrast between the whitened portion and the non-whitened portion may deteriorate. Therefore, the release resistance is adjusted in advance so that the resin molded product 5 is not deformed and the contrast is good.

[0023] As a result, without deforming the resin molded product 5, the resin at the portion of the resin molded product 5 that contacts the tip surface 3a of the ejector 3 is whitened in a state with high contrast and good visibility, so that marking can be performed.

[0024] (Example 2) In Example 2 of the present invention, the release resistance is adjusted.

[0025] FIG. 2 is a schematic configuration diagram of a molding apparatus 1A according to Example 2 of the present invention.

[0026] As shown in FIG. 2, the molding apparatus 1A according to Example 2 of the present invention includes, in addition to the configuration of the molding apparatus 1 according to Example 1 of the present invention, a release resistance measuring means 31 and recessed portions 21a, 21b.

[0027] The release resistance measuring means 31 is composed of, for example, a pressure sensor, and measures the release resistance between the ejector 3 and the resin molded product 5.

[0028] The recessed portions 21a, 21b are provided to adjust the release resistance between the ejector 3 and the resin molded product 5.

[0029] The recessed portions 21a and 21b are minute recesses provided on the surface of the core 2, and are provided such that the amount of the recesses, that is, the amount of undercut, is variable. When the amount of undercut of the recessed portions 21a and 21b is large, the mold release resistance increases, and when the amount of undercut of the recessed portions 21a and 21b is small, the mold release resistance decreases. Here, the adjustment of the amount of undercut of the recessed portions 21a and 21b is performed by changing the discharge and suction force of air or by changing the magnetic attraction force with the insert fitting or the like.

[0030] Then, the measured value of the mold release resistance by the mold release resistance measuring means 31 is adjusted to a range in which the ejector 3 causes whitening on the resin molded product 5 when the resin molded product 5 is released from the mold and does not cause damage to the released resin molded product 5.

[0031] As described above, according to the molding apparatus 1A according to the second embodiment of the present invention, the mold release resistance measuring means 31 is provided, and the mold release resistance is adjusted by adjusting the amount of undercut formed by forming minute recesses on the core side. The measured value of the mold release resistance by the mold release resistance measuring means 31 is adjusted to a range in which the ejector 3 causes whitening on the resin molded product 5 when the resin molded product 5 is released from the mold and does not cause damage to the released resin molded product 5.

[0032] Therefore, since the mold release resistance can be adjusted to an appropriate value, the resin at the portion where the tip surface 3a of the ejector 3 contacts in the resin molded product 5 is whitened in a state with high contrast and good visibility without damaging the resin molded product 5.

[0033] (Embodiment 3) In the third embodiment of the present invention, characters, figures, and the like are formed by whitening.

[0034] FIG. 3 and FIG. 4 are schematic configuration diagrams of a molding apparatus 1B according to the third embodiment of the present invention.

[0035] The molding apparatus 1B according to the third embodiment of the present invention is different from the molding apparatus 1A according to the second embodiment of the present invention in the shape of the tip surface of the ejector 3. Since the other configurations are the same, the description thereof is omitted.

[0036] As shown in FIGS. 3 and 4, the molding device 1B includes an ejector 3B.

[0037] On the tip surface of the ejector 3B, shapes such as characters and figures are formed. In the example shown in FIG. 3, the ejector 3B has tip surfaces 3b, 3c, and 3d, and the shape of this tip surface is configured to represent characters, figures, etc.

[0038] Specifically, when the ejector 3B slides backward with respect to the main body of the core 2, the resin molded product 5 is pushed out from the core 2. When the ejector 3B pushes out the resin molded product 5 from the core 2, the resin at the portions where the tip surfaces 3b, 3c, and 3d of the ejector 3 contact the resin molded product 5 undergoes plastic deformation and turns white. The tip surfaces 3b, 3c, and 3d are molded so that this whitened shape represents a specific character or figure.

[0039] As described above, according to the molding device 1B according to the second embodiment of the present invention, since shapes such as characters and figures are formed on the tip surfaces 3b, 3c, and 3d of the ejector 3B that pushes out the resin molded product 5, by making the shapes of the tip surfaces 3b, 3c, and 3d into various characters and figures that are desired to be whitened, desired characters and figures can be marked on the resin molded product 5.

[0040] (Appendix) This application discloses the following invention.

[0041] (Appendix 1) A molding device having a core provided with an ejector and a cavity, wherein the mold release resistance of the ejector is adjusted within a predetermined range, and when the resin molded product is released by the ejector, the resin molded product is marked by whitening by the ejector. A molding device characterized by the above.

[0042] As a result, without deforming the resin molded product, the resin at the location where the tip surface of the ejector contacts the resin molded product is marked by whitening in a state with high contrast and good visibility, so that markings such as characters and illustrations can be made on the resin molded product without spending time and cost.

Explanation of Reference Signs

[0043] 1, 1A, 1B Molding device 2 Core 3, 3B Ejector 3a to 3d Tip surface 4 Cavity 5 Resin molded product 21a, 21b Depressed portion 31 Release resistance measuring means

Claims

【Claim 1】 A molding apparatus having a core provided with an ejector and a cavity, wherein the mold release resistance of the ejector is adjusted within a predetermined range, and when the resin molded product is released by the ejector, the ejector marks the resin molded product by whitening. A molding apparatus characterized by the above.

Images