JPH0470964B2 - - Google Patents

Description

[Detailed description of the invention] Purpose of the invention (industrial application field) The present invention is applicable to vacuum forming, injection molding, blow molding,
This invention relates to electroforming molds used for various synthetic resin moldings such as rim urethane molding.

(Prior Art) In a mold used for vacuum molding of synthetic resin, etc., a large number of through holes must be formed in order to vacuum the molded object and bring it into close contact with the inside of the mold.

Traditionally, this type of mold has been formed by using a thermal spraying method to form the mold and making it porous at the same time, or by mixing water with synthetic resin to form the mold and then dehydrating it to make it porous. However, there were problems in that the holes were too small and were difficult to penetrate.

Therefore, in recent years, electroforming molds have appeared in which a thin and solid mold is formed by electroforming, and then through holes are formed by machining such as drilling or laser processing.

In addition, the present applicant has previously patented an invention for an electroforming mold, which is an epoch-making electroforming mold that replaces the conventional type, and in which the electroforming mold body having a large number of through holes is formed by electroforming. An application has been filed and the application has already been published (Japanese Patent Application Laid-open No. 152692/1983).

However, during molding such as vacuum forming, if the temperature of the electroforming mold body is out of the appropriate range, there is a problem that the quality of the molded product deteriorates or the moldability deteriorates.

Therefore, conventionally, a temperature control tube is connected to the back side of the electroforming mold body, and a temperature control medium such as oil is circulated through the temperature control tube to keep the temperature of the electroforming mold body always within the appropriate range. I'm trying to maintain it.

Here, since the electroforming mold body and the temperature control tube need to be thermally tightly coupled, conventionally, silver solder welding, soldering, or heat-resistant resin bonding has been employed as a means for joining the two.

(Problems to be Solved by the Invention) By the way, with any of the above-mentioned joining means, among the through holes formed in the electroforming mold body, those in the joint part with the temperature control tube are filled with silver solder, It will be covered with solder or heat-resistant resin. Therefore,
There was an unavoidable problem in that the vacuum suction ability was reduced at the portion where the through hole was blocked.

Structure of the Invention (Means for Solving the Problems) Therefore, in order to solve these problems, the present invention provides a method in which a metal flocculent body is placed on the back side of an electroforming mold body having a large number of through holes. A technical measure was taken to press a temperature control tube against the cotton-like body.

(Function) When the object to be molded is placed in the electroforming mold body and the vacuum pump is operated, air from the molding surface side is sucked through the through holes to the back surface side.

At this time, the cotton-like body hardly obstructs ventilation. Even in the cotton-like material compressed between the temperature control tube and the electroforming mold body, its breathability deteriorates only in a very small part of the center; There are almost no

Therefore, the high vacuum suction ability of the electroforming mold body is maintained over the entire surface, so the entire object to be molded is reliably vacuum suctioned to the electroforming mold body and formed into the desired shape of the lid. .

Further, since the electroforming mold body and the temperature control tube are thermally closely coupled by the cotton-like body, the temperature of the electroforming mold body can always be maintained within an appropriate range.

(First Embodiment) Hereinafter, a first embodiment in which the present invention is embodied in an electroforming mold used for vacuum forming the skin of the lid of an automobile console box will be described with reference to FIGS. 1 to 4. .

The electroforming mold 1 of this embodiment is configured such that an electroforming mold main body 2 having a large number of through holes and its accessories are detachably attached to a reinforcing mold 3.

That is, the electroforming mold main body 2 is constructed by integrally forming a reference part 4 with a flat edge and a gently recessed molding part 5 in the center by nickel electroforming, and the entire body is made of nickel electroforming. It is formed to a thickness of approximately 3 mm.

A large number of through holes 6 are formed in almost the entire electroforming mold body 2 by the electroforming, and each of the through holes 6 gradually widens from the molding surface 7 side of the electroforming mold body 2 to the back surface 8 side. It penetrates while expanding its diameter. The diameter of this through hole 6 is 50 to 500 μm on the molding surface 7 of the electroforming mold body 2, and 100 to 2000 μm on the back surface 8.
The distribution density of the through holes 6 is preferably within the range of 5 to 1000 per 10 cm ² .

On the other hand, solid non-perforated parts 9 without the through holes 6 are formed at important points in the electroforming mold body 2, and bolts 10 are stud-welded at the tops of the back surfaces of each non-perforated parts 9. ing. Note that since the non-perforated portion 9 has an area only about the size of the head of the bolt 10, it hardly affects the vacuum suction ability of the electroforming mold body 2.

A metal temperature control tube 11 is installed on the back side of the electroforming mold body 2.
is disposed therein, and a temperature regulating medium such as oil is circulated therein, so that the temperature of the electroforming mold body 2 is always maintained within an appropriate range.

Furthermore, a cotton-like body 12 made of stainless steel (SUS304) is disposed on the back surface of the electroforming mold body 2 so as to surround the temperature control tube 11 as well. This cotton-like body 12 not only has excellent air permeability because it has many gaps, but also has excellent thermal conductivity and corrosion resistance because it is made of stainless steel.

Further, a metal net-like body 13 is disposed below the cotton-like body 12 so as to pass through each of the bolts 10, and is tightened upward by a first nut 14 screwed into the bolt 10. ing.

By tightening the net-like body 13 with the first nut 14, movement and falling of the cotton-like body 12 are prevented, and as shown in FIG.
The temperature control tube 11 connects to the cotton body 12 on the back side of the electroforming mold body 2 via the cotton body 12a compressed between
Furthermore, due to the cotton body 12b compressed between the temperature control tube 11 and the electroforming mold body 2, these temperature control tubes 11 and the electroforming mold body 2 are thermally sealed. is combined with

Note that even with the tightening described above, the breathability of most of the cotton-like body 12 is maintained.

Next, as shown in Fig. 4, the reinforcing mold 3 is
A rectangular frame-shaped frame 15 and a frame 1 each made of metal.
Reinforcement ribs 1 installed inside 5 and extending vertically and horizontally
6, and a bottom plate 17 detachably attached to the bottom of the frame 15.

Brackets 18 are attached to key points of the reinforcing ribs 16. The bolts 10 are inserted into these brackets 18 and tightened with the second nuts 19, and the edge of the reference part 4 of the electroforming mold body 2 is fixed to the upper end of the frame 15 with flat head screws 20. The electroforming mold body 2 and the like are detachably attached to the reinforcing mold 3.

Further, the bottom plate 17 is removably attached to an angle 31 attached to the inside of the frame body 15 with bolts 32 in a sealed state.

Note that a suction tube 33 for vacuum suction is formed on the side of the frame 15.

Next, a method for manufacturing the electroforming mold body 2 will be briefly explained.

First, a mandrel (not shown) having the same shape as the lid of an automobile console box is formed. This mandrel can be formed directly by cutting wood, or by pasting real leather for grain patterns on a wooden mold to form a master model, and then copying the shape of this master model onto a female mold. It can also be formed by injecting an epoxy resin mold into a female mold.

Next, a conductive coating is formed on the surface of this mandrel. This conductive coating consists of paste-like silver lacquer,
It can be formed by spraying a mixture of a butyl acetate solution and a vinyl chloride lacquer, or by a silver mirror reaction.

Subsequently, the mandrel was immersed as a cathode in a plating solution (not shown) which mainly consists of nickel sulfamate and boric acid and does not contain a surfactant to suppress the formation of pinholes. Apply electricity to perform electroforming.

As described above, the entire electroforming mold body 2 is electroformed to a thickness of about 3 mm, and the through holes 6 are formed. This through hole 6 is formed during electroforming due to factors such as the fact that the conductive film does not contain vinyl chloride, the plating solution does not contain a surfactant, and the current during electroforming is large. They are formed at the same time.

Therefore, by changing these factors, the through hole 6
Not only can the diameter and number of holes be freely controlled, but there is no need to machine holes after electroforming, so a high-quality electroforming mold body 2 can be manufactured easily and at low cost.

Regarding the electroforming mold 1 configured as above,
Next, how to use it will be explained.

First, as shown in FIG. 2, the electroforming mold 1 in which the electroforming mold body 2 and the like are attached to the reinforcing mold 3 is set in a vacuum forming apparatus (not shown), and the suction pipe 3
A vacuum pump 22 is connected to.

Next, a vinyl chloride resin sheet 23, which will become the skin of the lid of the automobile console box, is placed on the electroforming mold body 2, and when the vacuum pump 22 is activated, the pressure inside the reinforcing mold 3 is reduced, so that the molding surface Air on the 7 side is sucked through the through hole 6 to the rear surface 8 side.

At this time, the cotton-like body 12 hardly obstructs ventilation. Even in the flocculent body 12b compressed between the temperature control tube 11 and the electroforming mold body 2, the air permeability deteriorates only in a very small part of the center. There is almost no blockage.

Therefore, the high vacuum suction ability of the electroforming mold body 2 is maintained over the entire surface, so the entire vinyl chloride resin sheet 23 is reliably vacuum suctioned to the molding surface 7 and shaped into the desired shape of the lid. be done.

Further, during the vacuum forming described above, the temperature of the electroforming mold body 2 tends to change due to resin heat and the like.

However, according to this embodiment, the electroforming mold body 2 and the temperature control tube 11 are thermally tightly coupled by the compressed cotton-like body 12b, and the temperature control tube 11 contains oil, etc. Since the temperature control medium flows, the temperature of the electroforming mold body 2 can always be maintained within an appropriate range.

In addition, if the through hole 6 becomes clogged with dust etc. as the vacuum forming process continues,
It is necessary to clean the electroforming mold body 2 to eliminate clogging. As mentioned above, the electroforming mold 1 of this example is made entirely of metal and does not use any resin (solvents cannot be used for resin), so it can be cleaned using the following three methods. be able to.

First, by immersing the entire electroforming mold 1 in a solvent and cleaning it while the electroforming mold body 2 and other parts are still attached to the reinforcing mold 3, dust etc. that have clogged the through holes 6 can be dissolved. You can take it.

Second, the electroforming mold body 2 and the like are once removed from the reinforcing mold 3, and the electroforming mold body 2 is immersed in a solvent with the mesh body 13, the cotton body 12, and the temperature control tube 11 still attached. By cleaning the hole 6
It can dissolve dust, etc. stuck in the water.

Thirdly, after removing the electroforming mold body 2 etc. from the reinforcing mold 3, and further removing the mesh body 13, cotton body 12 and temperature control tube 11, only the electroforming mold body 2 is immersed in a solvent. By washing, it is possible to dissolve dust and the like that are clogged in the through holes 6.

In particular, according to the second and third methods described above, since the solvent effectively spreads over both the molding surface 7 and the back surface 8 of the electroforming mold body 2, clogging can be effectively eliminated.

Furthermore, according to the third method, the electroforming mold body 2
After immersing in a solvent to liberate and dissolve dust, etc., the dust can be blown off by blowing air onto both the molding surface 7 and the back surface 8, so clogging can be almost completely eliminated. can.

(Second Embodiment) In the second embodiment, as shown in FIG.
is formed into a block shape from aluminum etc.
The bolt 10 is attached to the back side of the reinforcing mold 3 with the second nut 1.
9, and the temperature control tube 11 is supported in the recess 24 provided on the upper surface of the reinforcing mold 3 via the cotton body 12, and the only difference from the first embodiment is that the mesh body 13 is omitted. are doing.

Therefore, this embodiment also provides substantially the same effects as the first embodiment, and has the advantage of being even more robust. However, the first embodiment is superior in terms of ease of manufacture.

It should be noted that the present invention is not limited to the configuration of the above-mentioned embodiments, and may be modified and embodied as desired without departing from the spirit of the invention, for example, as described below.

(1) The through holes 6 of the electroforming mold body 2 are not limited to those formed by electroforming, but may be formed by machining such as drilling or laser processing after forming a thin and solid electroforming mold body. It may be formed by.

(2) As long as the cotton-like body 12 is made of metal, there are no limitations on the type of metal or the thickness of the fibers.
For example, materials made of copper, iron, nickel, aluminum, etc. can be used. however,
In terms of corrosion resistance, the material made of stainless steel is preferable.

(3) The method of joining the bolt 10 to the non-perforated portion 9 is not limited to stud welding, but may also be silver solder welding, adhesive bonding, or the like.

(4) The non-perforated portion 9 may be formed by performing preliminary treatment before electroforming (increasing the conductivity of the conductive film, etc.) so that no through holes 6 are formed, or by filling the through holes 6 after electroforming. I can do it.

(5) The electroforming mold of the present invention can be used not only for vacuum forming but also for
It can be used for various synthetic resin moldings such as injection molding, blow molding, and rim urethane molding. For example, if this electroforming mold is used for blow molding, it is possible to vividly transfer grain patterns, etc., which are difficult to achieve with blow pressure alone, using vacuum suction.

Effects of the Invention As detailed above, the present invention can maintain the high vacuum suction ability of the electroforming mold body over its entire surface, and can reliably shape the entire object by vacuum suction. In addition, the electroforming mold body and the temperature control tube are thermally closely coupled, and the temperature of the electroforming mold body can always be maintained within an appropriate range, which is an excellent effect.

[Brief explanation of drawings]

1 to 4 show a first embodiment embodying the present invention, FIG. 1 is a sectional view of the main part, FIG. 2 is a sectional view of the electroforming mold body attached to the reinforcing mold, and FIG. 3 is a sectional view of the main part of the electroforming mold. is a cross-sectional view of the electroforming mold body removed from the reinforcing mold,
FIG. 4 is a perspective view of the reinforced type, and FIG. 5 is a partial sectional view of the second embodiment. 1... Electroforming mold, 2... Electroforming mold body, 6...
Through hole, 11...temperature control tube, 12...cotton-like body.

Claims (1)

[Claims] 1. A metal cotton body 12 is disposed on the back side of an electroforming mold body 2 having a large number of through holes 6.
An electroforming mold characterized in that a temperature control tube 11 is pressed against. 2. The electroforming mold according to claim 1, wherein the through hole 6 is formed by electroforming. 3. The electroforming mold according to claim 1, wherein the through hole 6 is formed by machining. 4. The electroforming mold according to claim 1, wherein the cotton body 12 is made of stainless steel.