Nested mold

Abstract

To propose an insert mold with excellent wear resistance without losing the thermal conductivity of conventional (beryllium copper alloy (BeCu)).MEANS FOR SOLVING THE PROBLEM: An insert mold 20 is incorporated into a mold for injection molding. The insert mold 20 has a hard member portion 40, which is a steel material, and a high thermal conductivity member portion 50, which is a copper material attached to a cavity 44 formed in the hard member portion 40, and the gap between the hard member portion 40 and the high thermal conductivity member portion 50 is filled with a filling member 70 that has thermal conductivity.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an insert mold incorporated in a mold for injection molding of synthetic resin.

Background Art

[0002] When manufacturing a mold, for example, when there is a slightly convex shape in the mold shape, if this convex shape is machined integrally, the material extraction efficiency is poor and it is difficult to perform cutting machining at once. Therefore, in such cases, by making the convex shape into a separate part, the yield and workability can be improved. This separate part (mold) is called an "insert (insert mold)".

[0003] As a mold material for synthetic resin molding, generally, high-strength, various types, and inexpensive steel materials are used. However, in a mold, thermal conductivity is also an important essential element. Although steel materials are higher in strength than non-ferrous metal molds, their thermal conductivity is significantly inferior. Regarding the mold body, it is possible to form a cooling channel through which water flows in the mold to cool the mold. However, in the case of an insert mold, it is often difficult to form the above cooling channel. Therefore, in an insert mold, beryllium copper alloy (BeCu) having a thermal conductivity 3 to 7 times that of steel has come to be widely used.

[0004] Regarding the injection molding of resin using an insert mold, for example, Patent Document 1 discloses the following technology. Patent Document 1 relates to a manufacturing apparatus and a manufacturing method for manufacturing an intake manifold of an automobile, which is a hollow molded body made of synthetic resin shown in FIG. 1. Note that Patent Document 1 does not describe the material constituting the insert mold.

[0005] This intake manifold 30 is configured to include a pair of first half members 31, a second half member 32, and a box-shaped third half member 33 provided at an end of the second half member 32, and each abutting portion 31a, 32a, 33a is joined and manufactured.

[0006] As shown in FIG. 2, the injection molding apparatus 1 includes a fixed mold 2 (first mold) and a movable mold 3 (second mold). The fixed mold 2 has a female mold part 4 for molding the first half member 31, a male mold part 5 for molding the second half member 32, and a male mold part 6 for molding the third half member 33. These female mold part 4, male mold part 5, and male mold part 6 are arranged along a direction (vertical direction in the figure) orthogonal to the mold opening and closing direction P. Further, the fixed mold 2 side is provided with a primary injection nozzle 7 and a secondary injection nozzle 8 capable of injecting molten resin.

[0007] The movable mold 3 includes a movable mold body 10 capable of traveling in the mold opening and closing direction P by a traveling means (not shown), and a protruding mechanism A, a turning mechanism B, and a slide mechanism C provided on the movable mold body 10. The slide mechanism C has a slide member 11 slidably supported in a direction (vertical direction in the figure) orthogonal to the mold opening and closing direction P on the movable mold body 10, and a drive cylinder 12 for sliding the slide member 11.

[0008] The nested mold 20 is incorporated in a rotor 22 placed on a turning plate 15 of the turning mechanism B of the movable mold 3. Further, the nested mold 20 abuts against the male mold part 5 of the opposing fixed mold 2 in the state of FIG. 2 with the mold clamped.

[0009] In the mold clamping state during primary injection, a cavity for the first half member 31 is formed between the female mold part 4 of the fixed mold 2 and the male mold part 17 of the slide member 11. Also, a cavity for the second half member 32 is formed between the male mold part 5 of the fixed mold 2, the female mold part 18 of the protruding plate 13, and the nested mold 20 of the rotor 22. Further, a cavity for the third half member 33 is formed between the male mold part 6 of the fixed mold 2 and the female mold part 19 of the rotor 23. In this state, the molten resin injected from the primary injection nozzle 7 is supplied to each of the above cavities via the runner 9a, and the first half member 31, the second half member 32, and the third half member 33 are injection molded.

[0010] When the mold is opened, the first split member 31 is held by the female mold part 4 of the fixed mold 2, the second split member 32 is held by the female mold part 18 of the protruding plate 13 and the nested mold 20 of the rotor 22, and further, the third split member 33 is held by the female mold part 19 of the rotor 23.

[0011] After that, by the action of the drive motor 16, the swivel plate 15 is swiveled by a predetermined angle (for example, 180 degrees), the third split member 33 held by the female mold part 19 of the rotor 23 is opposed to the lower end part of the second split member 32 in the mold opening and closing direction P, and further, when the slide member 11 is moved upward by the action of the drive cylinder 12, the first split member 31, the second split member 32, and the third split member 33 will oppose in the mold opening and closing direction P.

[0012] Then, as shown in FIG. 3, when the mold is closed again to perform the secondary injection molding, the butting parts 31a, 32a, and 33a of the first split member 31, the second split member 32, and the third split member 33 are butted, and the molten resin injected from the secondary injection nozzle 8 is supplied between the butting parts 31a, 32a, and 33a via the runner 9b, and the butting parts 31a, 32a, and 33a of the first split member 31, the second split member 32, and the third split member 33 are joined to form the intake manifold 30 of FIG. 1.

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0014] By the way, although beryllium copper alloy (BeCu) has good thermal conductivity compared to steel materials, it is inferior in terms of strength, so the wear during injection molding is larger compared to the case of using steel materials. In particular, when the nested mold abuts against the opposing mold in the mold-clamped state as in Patent Document 1, the degree of wear increases with the abutment.

[0015] For example, in the above-mentioned Patent Document 1, in the nested mold 20, the progress of wear at the contact portion with the opposing mold surface appears as burrs that become obstacles to the air flow path of the intake manifold 30. Therefore, it is necessary to perform regular welding repairs, replacements, etc. as measures against wear of the nested mold 20.

Means for Solving the Problems

[0016] The present invention proposes a nested mold that does not impair the thermal conductivity of the conventional (beryllium copper alloy (BeCu)) and has excellent wear resistance. The present invention according to claim 1 is a nested mold incorporated in a mold for injection molding, and the nested mold has a hard member part and a high thermal conductivity member part mounted in a cavity formed in the hard member part. Moreover, the gap between the rigid member portion and the high heat conductivity member portion is filled with a heat-conductive filling member. It is a nested mold characterized by the above.

[0017] In the present invention according to claim 1, since the nested mold has a hard member part and a high thermal conductivity member part mounted in a cavity formed in the hard member part, wear is suppressed by the hard member part, and cooling can be quickly performed by mounting the high thermal conductivity member part in the cavity formed in the hard member part. As a result, a nested mold that does not impair the thermal conductivity and has excellent wear resistance can be manufactured. Furthermore, since the gap between the rigid member portion and the high heat conductivity member portion is filled with a heat-conductive filling member, the gap between the rigid member portion and the high heat conductivity member portion can be connected by the heat-conductive filling member, and heat can be smoothly transferred from the rigid member portion to the high heat conductivity member portion. As a result, an insert mold excellent in wear resistance can be manufactured without impairing heat conductivity.

[0018] Here, the hard member part refers to a part formed of a member having a higher hardness than the high thermal conductivity member part, and the high thermal conductivity member part refers to a part formed of a member having better thermal conductivity than the hard member part.

[0019] The present invention according to claim 2 is a nested mold in which, in the invention according to claim 1, the hard member part is a steel material and the high thermal conductivity member part is a copper material.

[0020] In the present invention according to claim 2, since the hard member part is a steel material, it has high strength and is inexpensive. Also, since the high thermal conductivity member part is a copper material, it has a high thermal conductivity and extremely good thermal conductivity. As a result, a nested mold that does not impair the thermal conductivity and has excellent wear resistance can be manufactured.

[0023] Claim 3 In the present invention of Claim 1 or Claim 2 the insert mold, which is the heat dissipation grease, is the nested mold.

[0024] Claim 3 In the present invention of Claim

[0025] since the insert mold, which is the heat dissipation grease, can fill the gap between the hard member part and the high heat conduction member part according to the shapes of the hard member part and the high heat conduction member part, the heat connection between the hard member part and the high heat conduction member part can be surely performed. As a result, a nested mold excellent in wear resistance can be manufactured without impairing the heat conductivity. 4 3 In the present invention of Claim

[0026] 4 the insert mold, which is the silicone containing the heat conductive particles or powder, is the nested mold. In the present invention of Claim

[0027] 5 since the insert mold, which is the silicone containing the heat conductive particles or powder, can surely perform the heat conduction between the hard member part and the high heat conduction member part by the heat conductive particles or powder, and the silicone has high heat resistance and is hardly deteriorated even at the temperature during the injection molding of the synthetic resin. As a result, a nested mold excellent in wear resistance can be manufactured without impairing the heat conductivity. An insert mold incorporated in an injection molding die, the insert mold having a rigid member portion and a high heat conductivity member portion mounted in a cavity formed in the rigid member portion. The present invention of Claim characterized in that is the nested mold in which the high heat conduction member part is the discharge master made of the copper material for electrical discharge machining used for forming the cavity part of the hard member part.

[0028] ​​There is electrical discharge machining as a method of machining a mold. Electrical discharge machining is a technique for cutting a mold by bringing an electrode close to a mold part and generating a spark, and it is a machining technique capable of finishing the mold into the shape of the electrode (discharge master). Also, copper material is used for the electrode. This is because the consumption rate is as low as 0.001% and the electrical conductivity is excellent, so it can be machined efficiently. Note that the electrode after machining is generally discarded.

[0029] Claim 5 In the present invention of An insert mold incorporated in an injection molding die, the insert mold having a rigid member portion and a high heat conductivity member portion mounted in a cavity formed in the rigid member portion. Since the high heat conduction member part is an electrode (discharge master) made of copper material used for forming the cavity part of the hard member part, the cavity part of the hard member part can be accurately machined into the shape of the high heat conduction member part, and by mounting the discharge master in the cavity part, heat conduction from the hard member part to the high heat conduction member part can be efficiently performed.

[0030] Also, even when using heat dissipation grease, the amount used can be reduced. Furthermore, the electrode (discharge master) can be effectively utilized. Therefore, an inexpensive nested mold excellent in cooling efficiency and durability can be manufactured.

Effect of the Invention

[0031] A nested mold incorporated in a mold for injection molding, the nested mold having a hard member part and a high heat conduction member part mounted in a cavity formed in the hard member part, so that wear is suppressed by the hard member part, and cooling can be quickly performed by mounting the high heat conduction member part in the cavity formed in the hard member part. As a result, a nested mold excellent in wear resistance without impairing the thermal conductivity can be manufactured.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0033] Embodiments of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is a perspective view of the intake manifold 30. The intake manifold 30 is configured to include a pair of first half members 31, a second half member 32, and a box-shaped third half member 33 provided at the end of the second half member 32. The resin material used is polyamide (PA) resin. Note that glass fiber-reinforced PA may be used, or other materials may be used. Note that the intake manifold is not limited to the shape of FIG. 1.

[0034] FIG. 2 is a side sectional view showing the mold clamping state at the time of primary injection of the injection molding apparatus 1, and FIG. 3 is a side sectional view showing the mold clamping state at the time of secondary injection of the injection molding apparatus 1. The molding method of the intake manifold 30 using the injection molding apparatus 1 is as described in the background art.

[0035] FIG. 4 is a top view of the nested mold 20 of the embodiment of the present invention, and FIG. 5 is a sectional view taken along the line A-A of FIG. 4. As shown in FIGS. 4 to 6, the nested mold 20 is composed of a hard member part 40, a high heat conduction member part 50, and a filling member 70 that fills the space between the hard member part 40 and the high heat conduction member part 50.

[0036] The hard member part 40 is composed of a main body part 41 formed with a convex part 43 protruding in a columnar shape on a flat upper surface, and an attachment part 42 for attaching to the rotor 22 of the swivel plate 15 of the injection molding apparatus 1 using bolts (not shown). In the attachment part 42, hole parts 45, 46 having a two-step diameter with a larger diameter on the convex part 43 side are formed.

[0037] Further, in the main body part 41, a cavity part 44 (FIG. 6(b)) having an opening part 47 is formed on the lower surface opposite to the convex part 43. The method of forming the cavity part 44 will be described in detail later.

[0038] The convex part 43 abuts against the male mold part 5 of the fixed mold 2 facing during the primary injection molding, and the molten resin is supplied from the primary injection nozzle 7 between the female mold part 4 and the male mold part 5 of the fixed mold 2, and the second half member 32 having a flange part 34 having a cylindrical air flow path is molded.

[0039] The hard member part 40 of the nested mold 20 is made of steel material. In this embodiment, DHA-Thermo manufactured by Daido Steel Co., Ltd., which has a high thermal conductivity among steel materials, is used. Note that other steel materials may be used.

[0040] Next, the high thermal conductivity member part 50 and the method of forming the cavity part 44 of the hard member part 40 will be described with reference to FIG. 6. The cavity part 44 of the hard member part 40 is formed by electrical discharge machining. As described above, electrical discharge machining is a technique for cutting a mold by bringing an electrode close to the mold part and generating a spark, and it is a machining technique capable of finishing the mold into the shape of the electrode (discharge master).

[0041] First, using DHA-Thermo as the material, the outer shape of the hard member part 40 is produced by cutting or grinding. Thereafter, hole parts 45, 46 having a two-step diameter with a larger diameter on the convex part 43 side are formed in the attachment part 42.

[0042] Next, an electrode 60, which is a discharge master for forming a cavity 44 in the hard member part 40, is made of tough pitch copper (JIS alloy number C1100) by cutting or grinding the above material. Here, tough pitch copper is refined by electrolysis of blister copper produced from copper ore. Note that this electrode 60 becomes the high heat conduction member part 50 later.

[0043] Next, as shown in Fig. 6(a), the electrode 60 is opposed to the opening 47 side of the hard member part 40, and a voltage is applied between the facing hard member part 40 and the electrode 60 in a liquid such as water or oil, and sparks are intermittently discharged to machine the shape of the electrode 60 into the hard member part 40 in a non-contact state, that is, perform profile electric discharge machining.

[0044] As a result, after the electric discharge machining, as shown in Fig. 6(b), the shape of the electrode 60 is formed as the cavity 44 of the hard member part 40. Due to the nature of the electric discharge machining, the cavity 44 of the hard member part 40 is formed about 0.1 mm larger than the electrode 60. Also, in Fig. 6(b), the thickness t of the main body part 41 after the electric discharge machining is 3 mm. By setting the thickness of the main body part 41 to about 3 mm, the strength of the hard member part 40 can be ensured and the decrease in heat conduction can be suppressed.

[0045] Next, after applying a filling member 70 to the surface of the high heat conduction member part 50 (electrode 60), the high heat conduction member part 50 is inserted and mounted in the cavity 44 of the hard member part 40, and a hole 61 having the same diameter as the hole 46 is formed in the high heat conduction member part 50 (Fig. 6(c)). Thereby, the nested mold 20 is completed. In this embodiment, as the filling member 70, G-779 manufactured by Shin-Etsu Chemical Co., Ltd., which is in the form of grease containing alumina powder with good thermal conductivity blended with silicone oil as the base oil, is used. Note that it is not limited to the above material.

[0046] Then, when the nested mold 20 is attached to the rotor 22 using bolts (not shown) and primary injection molding is performed, the convex part 43 abuts against the fixed mold 2, and the second half member 32 having a flange part 34 with a cylindrical air flow path is molded.

[0047] FIG. 7 is a graph showing the relationship between the number of moldings of the intake manifold 30 for explaining the effects of the present invention and the surface temperature of the nested mold 20. The measurement point is the part X near the convex part 43 in FIG. 4. The temperature was measured before the mold clamping in the primary injection molding. In FIG. 7, 〇 and the solid line indicate the present embodiment, ▲ and the broken line indicate the conventional case using beryllium copper alloy (BeCu), and ■ and the one-dot chain line indicate the case where, as a comparative example, the nested mold 20 uses the same DHA-Thermo as the main body part 41 and several rectangular recesses are formed as heat radiating parts on the surface opposite to the convex part 43.

[0048] As is clear from FIG. 7, in the case (■) where the nested mold 20 is manufactured using the same DHA-Thermo as the main body part 41, the temperature did not sufficiently decrease after the first molding, and in the third molding, poor solidification occurred in the synthetic resin after molding. On the other hand, in the case of the present embodiment (〇), it has a cooling effect better than the conventional case (▲).

[0049] Therefore, it is possible to manufacture the nested mold 20 that has excellent wear resistance without impairing the thermal conductivity, so that the number of maintenance times such as welding repair and replacement of the nested mold 20 and the associated costs can be significantly reduced. In addition, since the electrode 60 (discharge master) can be effectively utilized, the nested mold 20 can be manufactured at low cost.

[0050] In practicing the present invention, it is not limited to the above-described embodiment, and various modifications are possible without departing from the object of the present invention.

[0051] For example, in the above-described embodiment, the injection molding in which the nested mold abuts against the opposing mold during mold clamping has been described, but the present invention can also be applied to a nested mold that does not abut against the opposing mold during mold clamping.

[0052] For example, in the above embodiment, the injection molded body is described as an intake manifold of a vehicle, and the injection molding apparatus is described as the same apparatus as in the background art. However, the present invention can also be applied to injection molded bodies other than the intake manifold of a vehicle, and further, it can also be applied to injection molding apparatuses other than the form shown in FIG. 2.

[0053] For example, in the above embodiment, tough pitch copper is used as the electrode 60. However, other copper materials such as free-cutting copper (JIS alloy number C1450) in which tellurium (Te) is added to improve machinability, or oxygen-free copper (JIS alloy number C1020) in which the residual oxygen content is reduced by vacuum fusion casting may be used.

[0054] For example, in the above embodiment, the space between the hard member portion 40 and the high heat conduction member portion 50 is filled with the filling member 70. However, the filling member 70 may not be used. However, when the filling member 70 is not used, a very thin air layer is formed between the hard member portion 40 and the high heat conduction member portion 50, so the cooling efficiency is slightly reduced compared to the case where the filling member 70 is used.

[0055] For example, in the above embodiment, the electrode which is the discharge master used during electrical discharge machining is attached to the cavity portion 44 formed in the hard member portion 40 to form the high heat conduction member portion 50. However, instead of the electrode 60, a separately processed high heat conduction member portion may be attached to fabricate the nested mold 20.

Explanation of Reference Numerals

[0056] 1 Injection molding apparatus 20 Nested mold 30 Intake manifold 34 Flange 40 Hard member portion 41 Main body portion 42 Mounting portion 43 Protrusion 44 Cavity portion 47 Opening 50 High heat conduction member portion 60 Electrode (discharge master) 61 Hole portion 70 Filling member

Claims

1. A nested mold incorporated in a mold for injection molding, The nested mold has a hard member part and, a high heat conduction member part mounted in a cavity formed in the hard member part, and a filling member having heat conductivity is filled in a gap between the hard member part and the high heat conduction member part. The nested mold is characterized by this.

2. The nested mold according to claim 1, wherein the hard member part is made of steel and the high heat conduction member part is made of copper.

3. The nested mold according to claim 1 or claim 2, wherein the filling member is heat dissipation grease.

4. The nested mold according to claim 3, wherein the heat dissipation grease is silicone containing heat conductive particles or powder.

5. A nested mold incorporated in a mold for injection molding, The nested mold has a hard member part and, a high heat conduction member part mounted in a cavity formed in the hard member part, and the high heat conduction member part is a discharge master made of copper material for electrical discharge machining used to form the cavity of the hard member part. The nested mold is characterized by this.

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