JPH0459125B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Objective) The present invention relates to an apparatus for molding synthetic resin parts. It is an object of the present invention to provide a simple molding device suitable for multi-purpose molding applications, which forms a mold and easily molds synthetic resin parts by various molding methods according to molding conditions using this simple mold.

(Prior art) In recent years, the development of synthetic resin materials has progressed rapidly, and synthetic resin parts have come to be used in large quantities in various fields. There is also a growing tendency for molding to shift from the traditional high-volume production of small products to high-mix low-volume production.

In recent years, competition in the development of new products has become fierce, resulting in frequent product model changes, and there has been a strong demand for faster prototyping and lower prototyping costs associated with new product development.

Under these circumstances, if conventional molds made by cutting metal are used to manufacture prototypes for high-mix, low-volume production or new product development, the manufacturing period for the molds will be long and the manufacturing costs will be high. Because they are expensive, they lead to longer prototyping periods and higher prototyping costs and product unit prices.

Therefore, in the molding of synthetic resin parts, there is currently a strong demand for the establishment of a rapid and inexpensive mold making method and for the establishment of an efficient molding method using this mold.

For this reason, at present, as molds for molding synthetic resin parts, simple molds are used in which liquid synthetic resin for molding mixed with metal powder or molten low-melting point alloy is injected into the mold housing the master mold, solidified, and then molded. Various uses have been considered, but there has not been much progress in putting it into practical use.

This is because when creating a simple mold using existing various equipment, the work is not smooth and it is not necessarily easy to manufacture it, and when the created mold is attached to an existing molding machine for molding. Since the strength of the mold is extremely low compared to the mold, the mold is easily deformed or destroyed.

Therefore, in order to solve the above-mentioned problems and put a simple mold into practical use, it was necessary to develop a dedicated simple mold making device and a molding device using this simple mold.

In view of the above-mentioned current situation, the present invention has focused on the development of a device that can smoothly mold a simple mold for molding synthetic resin parts and mold synthetic resin parts using this molded simple mold. It was created as a result of repeated efforts.

(Structure) That is, the present invention comprises: a fixed plate horizontally fixed to the upper end of a support rod erected on a base; a drive transmission rod vertically slidably inserted through the fixed plate; A drive transmission plate horizontally fixed to the upper end of the drive transmission rod, and a movable plate drive cylinder mounted on the fixed plate and equipped with a plunger whose upper end surface is in contact with the lower surface of the drive transmission plate so as to be movable up and down. a vacuum device formed by fixing the device horizontally to the lower end of the drive transmission rod and having a stepped hole with a removable sealing lid; A multi-purpose molding device characterized by comprising a chamber, a vacuum exhaust device connected to the vacuum chamber via an exhaust pipe, and a mold mounting jig installed in a stepped hole provided in the movable platen. .

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, in which a fixed platen 1 is provided which is held horizontally by a support rod 5 erected on a base plate 4. Below, a movable platen 2 is held horizontally at the lower end of a drive transmission rod 15 inserted vertically into the fixed platen 1.
A vacuum chamber 3 having a top plate connected to a vacuum exhaust device 12 via an exhaust pipe 13 is provided.

A movable plate drive cylinder device 6 is placed on the fixed plate 1 with the upper end surface of the plunger 6' in contact with the lower surface of the drive transmission plate 9 held horizontally by the upper end of the drive transmission rod 15. Pressure generated by a pressure generator 7 is transmitted to the movable platen driving cylinder device 6 via a pressure regulator 8 by a medium such as oil or air flowing in a transfer pipe 18.

The plunger 6' of the movable plate drive cylinder device 6 moves up and down by adjusting the pressure by the pressure regulator 8.
The accompanying vertical movement of the drive transmission plate 9 also causes the drive transmission rod 15 to move up and down, and the vacuum chamber 3 whose top plate is the movable plate 2 held horizontally at the lower end of the drive transmission rod 15 is directed toward the fixed plate 1. It moves up and down.

The vacuum chamber 3 is provided with a door 16 that can be opened and closed, and a protruding rod 10 that stands up on the base plate 4 is inserted through the bottom plate of the vacuum chamber 3. is sealed with a seal 11, and the movable platen 2, which also serves as the top plate of the vacuum chamber 3, is equipped with a mounting jig as shown in Fig. 2 in order to removably attach a mounting jig for mounting a mold. A stepped hole 17 is provided with a removable sealing lid 19.

Further, the vacuum chamber 3 is connected to a vacuum evacuation device 12 via a telescoping pipe 14 and an exhaust pipe 13 so as to be able to move up and down while performing evacuation.

Next, a method of using the apparatus having the above-mentioned structure will be explained. First, a case in which a simple mold is molded using a liquid mold resin will be explained based on FIG.

Simple mold molding using liquid resin for molds involves mixing metal powder, inorganic powder, etc. into a two-component liquid resin such as epoxy resin, polyester resin, or polyurethane resin. This is a method of injecting it into a mold, letting it harden, and then cutting out the surface shape of the original to form a mold.

At this time, in order to obtain a good mold, it is necessary to prevent air bubbles from entering the resin, and also to spread the resin liquid to every detail on the surface of the mold and perform detailed molding. It is preferable to work below.

For this reason, when molding a simple mold using liquid mold resin, a lid 1 is inserted into a stepped hole 17 provided in a movable platen 2.
9 is fitted and sealed, the container 21 containing the mold liquid resin 22 is placed on the pedestal 20 and stored inside the vacuum chamber 3, and the door 16 is closed. After sealing, the vacuum evacuation device 12 is operated to remove air in the mold liquid resin 22 by vacuum defoaming.

Subsequently, the mold 23 containing the master mold 24 is stored in the vacuum chamber 3 which has been returned to atmospheric pressure after the vacuum degassing operation of the liquid resin for the mold has been completed, and the vacuum degassed mold is placed inside the mold 23. Inject liquid resin 22 for door 16
After closing and sealing, the vacuum chamber 3 is kept in a reduced pressure state for a predetermined period of time by operating the vacuum evacuation device 12 again, and the mold liquid resin 22 is vacuum degassed to completely remove the mixed air and the details of the surface of the master mold 24 are removed. The inflow of

After the above-mentioned mold-making operation is completed, the inside of the vacuum chamber 3 is returned to atmospheric pressure, and the mold frame 23 is left as it is or taken out from the vacuum chamber 3 to allow the liquid mold resin 22 to harden. After the resin has hardened, remove the mold 23 and remove the mold 2.
4 is separated to obtain a simplified type.

In general, liquid resin for molds has a high viscosity, so it is difficult to remove air mixed in the resin liquid, and air pockets occur in the details of the mold, which tends to hinder the inflow of resin liquid.
If the work is carried out using a mold, there will be no formation of cavities due to the mixing of air, and therefore a simple mold with high strength and a fine mold of the original mold can be obtained.

Furthermore, similar to the simple molding using the liquid mold resin described above, synthetic resin parts can also be molded by casting using the vacuum chamber 3.

To form synthetic resin parts by casting, two-component polyester resin, epoxy resin, acrylic resin,
This is a method of injecting a casting resin such as polyurethane resin and curing it to obtain a molded product.

The silicone rubber mold used for casting is created in exactly the same way as the simple mold described above.
The only difference is that a silicone rubber liquid for molds is used instead of liquid resin for molds.

The method of obtaining a cast part using a silicone rubber mold is the same as the method of forming a mold. First, the casting resin is vacuum defoamed using the vacuum chamber 3, and then this vacuum defoaming is performed. After injecting the molding resin into a silicone rubber mold, the pressure is maintained for a predetermined period of time to ensure that air mixed in the injected resin liquid is completely removed and that it flows into the details of the rubber mold, and then the resin liquid is cured at atmospheric pressure. Wait and get the molded parts.

As mentioned above, when casting is performed under reduced pressure using the vacuum chamber 3, even when the casting resin has a high viscosity, there is no formation of cavities due to air intrusion, and even the details of the mold can be faithfully reproduced. It is possible to obtain extremely good molded parts.

Next, to explain the method of forming a simple mold using a low melting point alloy based on Fig. 3, the vacuum chamber 3
A stepped hole 17 provided in the movable platen 2 as a top plate of
A mold installation board as a mold installation jig fitted into the 2
3 is a formwork around which a band heater 28 is wound;
24 is a master mold made of hard material such as gypsum or metal; 25 is a piston fixed to the lower surface of the stationary plate 1;
7 is injected, the band heater 28 is energized to keep it warm for a predetermined period of time, the energization is stopped, and the low melting point alloy 2 is injected.
When the movable platen 7 cools down to a semi-solidified state, the movable platen drive cylinder device 6 is activated to move the movable platen 2 toward the fixed platen 1.

When the piston 25 fits into the formwork 23 and presses the low melting point alloy 27 with an appropriate pressure, the operation of the movable plate drive cylinder device 6 is stopped, and complete solidification is waited for while the piston 25 is pressed at a predetermined pressure.

After the low melting point alloy 27 is completely solidified, the movable plate drive cylinder device 6 is activated to lower the movable plate 2, and when the piston 25 comes out of the formwork 23, the operation is stopped and the formwork 23 is disassembled. Together with prototype 24
A simple mold made of a low melting point alloy is obtained.

When a simple mold is formed using a low-melting point alloy using the method described above, the low-melting point alloy is appropriately pressed toward the master mold during solidification, so the surface of the master mold is faithfully reproduced, and the strength is increased without the occurrence of cavities. A very good mold with a large size can be obtained.

Next, a case in which vacuum forming is performed using the apparatus of the present invention will be explained based on FIG. 4.

A mold mounting jig in which a heating plate 29 and a presser foot 30 are attached to the lower surface of the fixed platen 1, and an exhaust port 35 with a solenoid valve 36 is provided in a stepped hole 17 on the movable platen 2 as the top plate of the vacuum chamber 3. After mounting the flange 34 as the flange 34, the vacuum forming mold 32 provided with the suction holes 33 is housed in the frame 31 and mounted.

A resin plate 37 for molding is placed on the vacuum mold 32 while being held by the frame 31, and after the resin plate 37 is heated by the hot plate 29, the movable platen drive cylinder device 6
Due to the operation of the vacuum chamber 3, the movable platen 2 as a top plate is held down and the resin plate 3 is attached to the lower end surface of the
The resin plate 37 is raised until the surfaces of the molds 7 come into contact with each other, and the vacuum evacuation device 12 is operated, and the solenoid valve 36 is opened to adsorb the resin plate 37 softened by heating to the surface of the vacuum mold 32 to perform vacuum forming.

Next, the case of performing vacuum transfer molding will be explained based on FIG.

38 is a piston mounted on the lower surface of the fixed plate 2;
Reference numeral 40 denotes a pot with a heater 39 wound around its outer periphery and containing resin 48, and this pot 40 is connected to the stepped hole 17 of the movable platen 2 serving as the top plate of the vacuum chamber 3.
The piston 38 is mounted on a mold mounting board 41 as a mold mounting jig mounted on the mold mounting plate 41, facing the piston 38.

Reference numeral 42 denotes a simple mold for molding, which has a cavity 43 connected to the resin discharge port of the pot 40 and a suction hole 44 for exhaustion connected to the cavity 43. The mold is mounted on a mold mounting board 41 as a mold mounting jig mounted on the board 2 while being clamped by a mold clamping device 46 via a mold clamping plate 45 provided with an exhaust port 47 .

Therefore, the simple mold 42 is connected to the mold clamping device 4.
After setting it on movable plate 2 using 6, turn pot 40.
Put a predetermined amount of resin 48 into the heater 3.
When the resin 48 is melted by the heating by the movable platen 2, the vacuum evacuation device 12 is activated and the movable platen driving cylinder device 6 is activated.
, and eventually the pot 40 containing the resin 48
The piston 38 is fitted into the resin 48, and the resin 48 is extruded into the cavity 43 of the simple mold 42 to perform vacuum transfer molding.

Since the above-described molding method uses a vacuum, molding can be performed at lower pressure than normal transfer molding.

Therefore, even if a simple mold made of synthetic resin or low melting point alloy is used based on the above explanation, the mold will not be deformed or destroyed, the mold life will be extended, and a good molded product can be obtained. can be obtained.

Next, the case of vacuum injection molding will be explained based on FIG. 6. 49 is a pressure regulator, 50 is an injection plunger drive cylinder device, 51 is an injection plunger, 52 is an injection cylinder, 53 is a heater, 54 is a hopper, 55 is a simple type, 56 is a die set, 57 is a cavity, and 58 is a movable platen 2.
59 is a protruding pin plate, 60 is a protruding pin, 61 is a knock bar, 62 is an intake pipe, 63
is an intake port, 64 is an intake slit, 65 is an intake reservoir,
66 is resin.

The cavity 55-a of the simple mold 55 accommodated in the die sets 56-a and 56-b is mounted on the fixed platen 1,
The core mold 55-b is fixed to a mold mounting plate 58 as a mold mounting jig fitted into the stepped hole 17 of the movable platen 2,
The movable platen drive shilander device 6 is operated to raise the movable platen 2 and the mold is clamped, and then the vacuum evacuation device 12 is operated to evacuate the cavity 56 while the injection plunger drive cylinder device 50 is operated to perform injection. The plunger 51 supplies the resin 66 from the hopper 54 to the injection shilander 52 and injects the heated and melted resin 66 into the cavity 56.

After the injection molding is completed, the operation of the vacuum exhaust device 12 is stopped, and the movable plate drive cylinder device 6 is activated again to lower the movable plate 2 to open the mold, but at this time, the protruding pin plate 59 and the knock bar 61 collide. The ejector pin 60 then ejects the injection molded part.

According to this type of vacuum injection molding, molding can be performed at extremely low pressure as in the case of the vacuum transfer molding described above. Even if a simple mold formed using this method is used, the mold will not be deformed or destroyed, the mold life will be extended, and a good molded product can be obtained.

The main uses of the device of the present invention have been explained above, but in addition to this, it can also be used to remove ears caused by compression molding or vacuum compression molding or molding of resin powder, metal powder, ceramic powder, mixed powder of these, etc. It is also possible to do trimming work, etc., and its uses are extremely wide-ranging.

(Effects) As is clear from the above explanation, the present invention makes it possible to extremely efficiently mold a simple mold for molding synthetic resin parts, and the molded simple mold is free from cavities due to the inclusion of air bubbles. It is a good product with no generation and the surface of the original mold is minutely molded.

Further, the present invention uses a simple mold made of synthetic resin or a low melting point alloy and molded by the apparatus of the present invention,
By low-pressure molding under reduced pressure such as vacuum transfer molding and vacuum injection molding, it is also possible to mold extremely good synthetic resin parts without causing deformation or destruction of the mold.

Further, the present invention can be used for various purposes such as casting, vacuum forming, compression molding, vacuum compression forming, trimming, etc., and the structure of the apparatus is extremely simple and easy to operate.

Therefore, the present invention makes it possible to mold prototype parts quickly and at low cost when developing a new product, and also makes it possible to reduce the cost of high-mix, low-volume production, thereby reducing the burden on research and development and production departments. It greatly contributes to rationalization.

[Brief explanation of the drawing]

Fig. 1 is a front view with a partially cutaway cross section showing an embodiment of the present invention, Figs. 2 and 3 are a simplified molding state, Fig. 4 is a vacuum forming state, and Fig. 5 is a vacuum transfer state. FIG. 6 is a diagram showing the vacuum injection molding state, where 1 is a fixed plate, 2 is a movable plate, and 3 is a diagram showing a vacuum injection molding state.
is a vacuum chamber, 4 is a base plate, 5 is a support rod, 12
is a vacuum evacuation device.

Claims (1)

[Claims] 1. A fixed plate fixed flat to the upper end of a support rod erected on a base plate, a drive transmission rod inserted vertically and slidably through the fixed plate, and a drive transmission rod attached to the upper end of the drive transmission rod. a drive transmission plate fixed horizontally, a movable plate drive cylinder device mounted on the fixed plate and equipped with a plunger whose upper end surface is in contact with the lower surface of the drive transmission plate so as to be movable up and down, and the drive transmission cylinder device mounted on the fixed plate; A movable platen having a stepped hole with a removable sealing lid fixed horizontally to the lower end of the rod, a vacuum chamber formed by fixing side plates and bottom plates to each other with the movable platen as a top plate, and the vacuum chamber. A multi-purpose molding device comprising: a vacuum evacuation device connected to a chamber via an exhaust pipe; and a mold mounting jig attached to a stepped hole provided in the movable platen.