JPH02139205A - Molding core - Google Patents

Abstract

PURPOSE:To remarkably reduce the volume to be melted in a molding core and its melting time without impairing the processability for the under-cut of a molded item by a method wherein a molding core is produced by integrally covering the outer surface of a flexible inserted body by a meltable covering body. CONSTITUTION:The molding core concerned consists of a continuous body 12 as a flexible insert 12, which consists of a high thermally conductive metal such as copper and has an articulated structure, and a meltable covering body 13 as a meltable covering body, which is provided so as to integrally cover the outer surface of the continuous body and made of alloy melting at comparatively low temperature such as tin- bithmuth alloy melting at 140-160 deg.. The continuous body 12 is produced by connecting cylindrical bodies 14 and spherical bodies 15, which are arranged alternately, with each other by a connecting wire 16. After molding, only the meltable covering body of a molding core, which is made integrally onto the outer surface of the continuous body, is melted out from a molded item by means of heating or is eluted in water. The insert is pulled out by flexing when necessary. Since the meltable covering body only occupies the outer surface part of the molding core and its volume is few, the elution is done quickly.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to a molding core used for molding synthetic resin molded products, etc. Regarding the molding core to be removed.

(Prior art) Conventionally, in order to manufacture synthetic resin molded products with undercut shapes such as bent pipes, for example, Japanese Patent Laid-Open No. 60-9432
As described in Publication No. 3, after molding is performed using a molding core made of a low melting point alloy such as tin or bismuth, the molding core is melted and removed from the molded product. There is.

However, since the synthetic resin molded product is integrally molded on the outer surface of the molding core made of the above-mentioned alloy, the alloy must be heated through the synthetic resin layer, and it takes time for the alloy to dissolve.
Poor energy efficiency.

As a method to solve these drawbacks, there are methods of inserting a heater into the molding core and induction heating. but,? ! If a heater is inserted into an irregularly shaped molding core, the heater is likely to break due to repeated use. In addition, ml heating requires special coils that match the shape of each product, making it unsuitable for production of a wide variety of products.In addition, the induction heating equipment is expensive, so it has the disadvantage of increasing equipment costs. . Furthermore, even if these methods are used, the inherent properties of the above alloys, such as low specific heat and low heat conductivity, cannot be overcome, and are rather disadvantageous in terms of energy costs.

Furthermore, as described in JP-A-56-104014, a method of using a water-soluble organic salt, such as a urea salt, in the molding core is also being explored. However, since only the parts of this molding core that come into contact with water begin to deliquesce, for example, the internal structure? ! In the case of a 2M vibrator-shaped molded product, it takes a long time for the deliquescence to progress to the inside of the vibrator. That is, it takes a long time to remove the urea salt, and the productivity is very low. In addition, water containing large amounts of urea salts must be treated as wastewater. However, the cost of sewage treatment is much higher than the cost of urea salt itself.

Therefore, reducing wastewater treatment costs becomes an essential task to reduce overall production costs.

(Problem II to be Solved by the Invention) As mentioned above, in the conventional soluble molding core, the entire core was made of a soluble substance such as a low melting point alloy or urea salt, which increased the material cost and elution cost. There were problems such as poor production efficiency and increased equipment costs.

The present invention aims to solve these problems, and proposes a molding core that can reduce material costs and elution costs, reduce installation costs, and improve production efficiency1). ', the purpose is to

[Structure of the invention]

(Means for Solving the Problem) The present invention provides a molding core that is installed in a mold, covers the outer surface, and is removed from the molded product after the molded product is integrally molded. The outer surface of the notebook is integrally covered with a soluble coating such as a low melting point alloy or a water-soluble organic salt. .

(Function) In the present invention, only the soluble coating of the molding core, which is integrally formed on the outer surface of the molded product, is eluted from the molded product by means such as heating or water dissolution, and the insert body is bent as necessary. While drawing wide.

At this time, the in-sheet body is pulled out at an appropriate time before elution, during elution, or after elution, depending on the material r1 of the soluble coating. In any case, only the outer surface of the molding core is covered with soluble material, and since the amount thereof is small, elution occurs quickly.

(Example) Hereinafter, one example of the molding core of the present invention is shown in Figs. 1 and 2.
This will be explained based on the diagram.

FIG. 1 shows a molding core 11, and this molding core 1
1 is a continuous body 12 made of a metal with good thermal conductivity and conductivity, such as copper, and serving as a bendable insert body having a joint structure.
and an alloy that melts at a relatively low temperature, for example, 140° to 160°, which is provided integrally covering the outer surface of the continuum 12.
Tin and screws that melt at °? The meltable coating 13 is a soluble coating made of a stainless steel alloy. The continuous body 12 is made up of cylindrical bodies 14 and spherical bodies 15 arranged alternately and connected by a connecting line 16.

That is, a part of the adjacent spherical body 15 is slidably fitted into a spherical recess 17 formed on the end surface of the cylindrical body 14, and a pair of cones formed within this spherical body 15 The connecting wire 16 is inserted through the shaped through hole 18 and the inside of the cylindrical body 14, and the end of the connecting wire 1G is
It is fixed to the open end surface of the cylindrical body 14 at the end of the continuous body 12. Further, the tip side of the cylindrical body 14 at this end protrudes from the end surface of the covering body 13.

In FIG. 2, reference numeral 21 indicates a V-shaped crossover pipe which is an intake pipe for an automobile engine as a molded product made of synthetic resin. They are integrally connected by a connecting portion 24 so as to avoid crossing each other.

The continuous body 12 has an outer diameter smaller than the inner diameter of the tube portion 23, and can be freely inserted into and taken out of the tube portion 23 by being bent.

In manufacturing the molding core 11, the continuous body 12 is installed in a VI mold (not shown) having a longer cavity with the same shape as the inner shape of the tube portion 23, and the molten tin-bissinus alloy is poured into the cavity. injected into the continuum 12
The covering body 13 is cast integrally with the mold.

Then, in forming the V-shaped crossover tube 21, first,
The molding core 11 is placed in a cavity of a synthetic resin mold (not shown). Then, a resin fluid, e.g.
A thermoplastic resin such as polyamide containing glass fiber chips, a thermosetting resin such as unsaturated polyester, or a reactive resin such as polyurethane is introduced into the cavity, and the V-shaped intersecting tube 21 is formed so as to cover the outer surface of the molding core 11. to form.

However, the ends of the molding core 11 are exposed from the V-shaped crossover tube 21.

Next, as shown in FIG. 2, a heater 26 is directly connected to the continuum 12 at the exposed end of the molding core 11, and the stomach temperature is adjusted to the melting point of the tin-bismuth alloy, for example, 170°C. Oil 2 in oil Wg28 with heated heater 21
A V-shaped crossover tube 21 in which a molding core 11 is embedded is inserted into the tube 9. Then, the continuum 12 is directly heated by the heater 26 and its temperature increases rapidly.

In this way, the continuous body 12 mediates heat conduction, and the covering body 13 made of a tin-bismuth alloy is melted. At that time, since the continuum 12 itself does not melt, there is no need for latent heat of fusion, that is, thermal energy required for the state change from solid to liquid, which is more necessary for melting than when the entire molding core is made of a tin-bismuth alloy. The thermal energy required is small.

As the heating progresses, the continuum 12 completely melts the covering 13 surrounding the continuum 12, and the continuum 12 becomes a ■-shaped intersecting tube 2.
It becomes possible to move it inside 1. Here, continuum 1
2 is connected to an ultrasound imager (not shown), the continuum 1
2 and the molten tin-bismuth alloy around it were photographed,
Tin-bismuth alloy in an unmolten state and ■-shaped crossover tube 21
Excite vibrations at the boundary between the In this way, heat can be transferred more effectively in a narrow space. @Afterwards, continuum 1
VA 2! When the cross tube 21 is pulled out from the tube section 23, the oil 29 at about 170.degree. C. flows through the tube section 23, and the molten alloy flows out from the tube section 23. Here, the continuous body 12 can be freely bent and moved in the hot oil 29.

The continuous body 12 taken out from the oil tank 28 is again placed in the casting mold and used to form the molding core 11.

According to the above configuration, it is only necessary to melt the covering 13 of the molding core 11, so that the elution can be performed quickly.
Elution costs can also be reduced and production efficiency can be improved. Moreover,
Since the continuous body 12 covered with the covering body 13 can be used as a heat conduction medium, elution can be performed more quickly. Since the continuum 12 is bendable, the above V
It is also possible to mold a molded product having a relatively complicated bent undercut shape, such as the mold crossover tube 21. Also, continuum 1
Since the parts 2 and the like can be easily reused, material costs can be reduced, and since the continuous body 12 has a strong structure, it is highly durable and can be used repeatedly without any problem. Furthermore, unlike cases where induction heating is performed, expensive equipment is not required, and equipment costs can be reduced.

In the above embodiment, the molded product was the ■-shaped cross tube 21, but of course it can also be used to mold other things, especially the pipes of the gods. For example, it can be used to mold a branch pipe 31, which is a synthetic resin intake pipe for an engine, as shown in FIG. This branch pipe 31 extends from the base pipe part 32 to the first
The branch pipe section 33 is branched into two, and these first branch pipe sections 3
The second branch pipe portions 34 are branched into two from the tips of 3, and the tips of these second branch pipe portions 34 are connected to the 7 flange portions 35.
However, at the branching part of each tube part 32, 33, 34 where the molding core 11 is embedded, the tip of the other molding core 11 is inserted into the middle part of one molding core 11. All you have to do is join them. It can also be used to mold an intake compressor tree housing 3G for an engine supercharger as shown in FIG. This housing 36 has a woodwind section 37.
The molding core 11 is formed by bending the continuous body 12 according to the shape of the turbo scroll tube 38.

In this way, even if the continuous body 12 is inside the annularly bent tube portion 38, the continuous body 12 can be easily pulled out later.

Furthermore, since the same continuous body 12 can be used in common for various molded products as described above, and the versatility is high, it is suitable for the production of a wide variety of products.

In the above embodiment, the fusible covering 13 is made of a tin-bismuth alloy, but it may be made of other materials. For example, tin, bismuth, antimony, cadmium,
It may be formed from an alloy containing one or more of lead and zinc as main components.

In addition, the material of the continuum 12 which is the insert body is as follows.
In addition to copper, brass, iron, nickel, etc. can also be used.

In addition, the materials of the molded product that is integrally molded with the molding core 11 include thermoplastic resins, thermosetting resins, resins made by reacting one or more resin components, and plastic inorganic materials. It may be.

Further, the structure of the continuum is not limited to that of the above embodiment. For example, as shown in FIGS. 5 and 6, the continuous body 41 as an insert body may be one in which a plurality of rotary bodies 42 are connected to each other so as to be able to alternately bend or rotate freely. That is, the shaft portions 45 which are provided protrudingly from the outer peripheral surface of the substantially C-shaped main body portions 43 of the adjacent rotary bodies 42 and have the circular 7 flange portions 44 at their tips are connected to the hole portions 47 of the same shape formed in the connecting joint 46. The two rotary bodies 42 are rotatably connected coaxially and rotatably therein, and the two rotary bodies 42 are rotatably connected in the direction indicated by arrow A. Note that the connecting joint 46 is divided into left and right halves. Further, for example, a shaft portion 49 is rotatably supported by a pair of disc-shaped portions 48 fixed to both end surfaces of one main body portion 43 of the adjacent rotary bodies 42, The inner circumferential surface of the one main body 43 is slidably abutted, and the inner circumferential surface of the main body 43 of the other rotating body 42 is fixed, so that both the rotating bodies 42 move in the direction indicated by arrow B. It is rotatably supported.

Next, still other embodiments of the present invention are shown in FIGS. 7 to 9.
This will be explained based on the diagram.

The molding core 51 in this embodiment includes a bundle 52 as a bendable metal insert body, and a soluble coating made of a water-soluble urea salt provided integrally covering the outer surface of the bundle 52. It is composed of a water-soluble covering body 53 as a body. The bundle 52 further includes an outer bundle 52a and an inner bundle 52b. Each of these bundles 52a and 52b is made of a bendable metal wire 54a such as a steel wire.

54b are bundled, and one end of the metal wires 54a, 54b is attached to a fixed body 55a made of metal such as lead or zinc.
It is solidified with 55b. Note that the metal wire 54a
, 54b are not fixed. The inner bundle 52b is located inside the outer bundle 52a, and can be freely opened and pulled out through a through hole 56 formed in the fixed body 55a of the outer bundle 52a. Incidentally, screw holes 57a and 57b for connecting a drawer are formed in each of the fixed bodies 55a and 55b, respectively. Further, the outer fixed body 55a protrudes from the end face of the covering body 53, and the outer fixed body 55a protrudes from the end face of the covering body 53.
The fixed body 55b on the inner side of the end face of 5a projects.

FIG. 8 shows an intake pipe for an engine as a molded product, and this intake pipe 61 is made up of a plurality of bent pipe parts 62 arranged in parallel and connected together by a flange part 63.

The bundle 52 has an outer diameter smaller than the inner diameter of the tube section 62, and an overall length longer than the tube section 62.

In molding the molding core 51, as shown in FIG. 7, the bundle 52 is installed in a two-part core mold 67 having a longer cavity 66 with the same shape as the inner shape of the tube portion 62. , the heated and melted urea salt 68 was added to the V-savity 66 described above.
Then, the covering body 53 is formed integrally with the bundle body 52.

To mold the intake pipe 61, first, the molding core 51 is placed in the cavity of a synthetic resin mold (not shown), a resin fluid is introduced, and as shown in FIG. As shown in FIG. 9(2), the intake pipe 61 is molded so as to surround the molding core 11. However, the end of the molding core 51 is exposed from the intake pipe 61.

Note that as the material of the intake pipe 61, the same material as in the previous embodiment can be used.

Next, as shown in FIG. 9(C), the fixed body 55b of the inner bundle 52b is pulled, and the inner bundle 52b is pulled out while being bent from the outer bundle 52a. (As shown in Q, the outer bundle body', +28 fixed body 55a
is pulled, and the outer bundle 52a is bent and pulled away from the covering 53. At this time, the inner bundle 52b slides with respect to the outer bundle 52a, and after pulling the inner bundle 52b, the bundle of metal wires 54a of the outer bundle 52a is reduced in diameter and easily removed from the covering 53. Since it is peeled off, the bundle 52 can be easily pulled out by pulling it out in two stages as described above. The molded core 51 from which the bundle 52 has been removed is placed inside the intake pipe 61 by a coating 53 made of a single urea salt material.
It becomes a hollow core consisting of chisel.

Next, water heated to a temperature of about 30° C. is circulated through the hollow portion 69 within the covering 53 to elute the covering 53 from the inside of the pipe portion 62 of the intake pipe 61. The circulation tank (not shown) is a dip type or a flow tank type, and is a combination of one or two or more tanks to send water in which urea salts have been dissolved to the wastewater treatment process, and to pass the water through a semipermeable membrane or the like. Perform concentration treatment, neutralization treatment, etc.

According to the above configuration, the amount of urea salt treated by the volume of the bundle 52 is reduced, so the time and cost required for wastewater treatment can be reduced, and running costs can be reduced. In addition to the fact that the amount of urea salt to be dissolved is small, since water flows into the hollow urea salt covering 53, the contact area between the covering 53 and drought water increases dramatically. This can significantly shorten the elution time of urea salts. Furthermore, the ability to process relatively complex undercut shapes and the ability to reuse the bundle 52 is similar to the previous embodiment. of course,
It can also be used for molding other than the intake pipe 61.

In the above embodiment, the bundle 52 has a double structure including the outer bundle 52a and the inner bundle 52b, but it may be composed of only one bundle, or three or more can be separated. It may be made up of several parts.

Furthermore, as the material for the covering body 53, water-soluble organic salts or inorganic salts other than urea salts can also be used. Also,
It may also be a substance that dissolves in liquids other than water.

〔Effect of the invention〕

According to the present invention, since the molding core is constructed by integrally covering the outer surface of the bendable insert body with the soluble coating, the volume of the portion of the molding core to be melted is significantly reduced.
Elution time can be significantly shortened without compromising processability for undercut shapes of molded products, improving production efficiency and reducing material and elution costs. Since no equipment is required, equipment costs can also be reduced.

[Brief Description of the Drawings] Fig. 1 is a sectional view showing one embodiment of the molding core of the present invention, and Fig. 2 is a perspective view showing the elution process of the molding core from a V-shaped crossover tube as a molded product. Figure 3 is a perspective view of a branch pipe as a molded product integrally molded with the molding core, and Figure 4 is an intake compressor housing as a molded product integrally molded with the molding core. 5 is a perspective view of an insert body showing another embodiment of the present invention, FIG. 6 is a sectional view thereof, and FIG. 7 is a manufacturing core showing a further embodiment of the present invention. A perspective view with a part of the process cut away, Figure 8 is a perspective view of the intake pipe as a molded product integrally molded with the molding core, and Figure 9 is a diagram showing the handling of the insert body of the molding core. FIG. 11... Molding core, 12... Continuous body as insert body, 13... Fusible coating body as soluble coating body, 21
...■-type crossover pipe as a molded product, 31...Branch pipe as a molded product, 3G...Intake air ventricular housing as a molded product, 41...Continuum as an insert body, 5
1. Molding core, 52. Bundle as an insert body,
53...Water-soluble coating as a soluble coating, 61...
Intake pipe, as a molded product. -View/II- Thickness - ζ Multi-stage (C)

Claims (1)

[Claims] (1) In a molding core that is installed in a mold, covers the outer surface, and is removed from the molded product after the molded product is integrally molded, the outer surface of the bendable insert body is integrally covered with a soluble coating. A molding core characterized by being covered with.