JPH018340Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a pot-type mold for a transfer molding machine that performs transfer molding of rubber.

Conventionally, when molding a rubber molded product by transfer molding, a transfer molding machine used for transfer molding of thermosetting resin is used. However, in this type of pot type mold, the pot is fixed directly to the upper mold, a sprue gate is installed there, the material is press-fitted into the cavity formed by the upper mold and the lower mold, and the mold is heated by a hot platen. Since the structure is such that the rubber is vulcanized and molded within the mold, this heat is transmitted from the upper mold to the pot, and the remaining rubber material in the pot is vulcanized, so this leftover material is discarded as scrap during the next molding. I had to.

Therefore, a heat insulating board made of resin-impregnated asbestos material is installed at the bottom of the pot, that is, the point of contact with the upper mold, to block the heat of the upper mold and prevent the residual rubber inside the pot from being vulcanized. A pot-type mold for a transfer molding machine for rubber molding has been developed, which can be used to eliminate the waste of residual material.

However, the sprue gate is directly drilled into the insulation board attached to the bottom of the pot of the above pot-type mold, and since this is made of a brittle material, the insulation board may be damaged during press-fitting, the shape of the gate portion may be deformed, and the sprue gate may be damaged during press-fitting. Since the rubber in these parts was not vulcanized, the remaining gate material was difficult to release from the mold, resulting in poor workability.

This idea was made to eliminate the above-mentioned drawbacks, and it prevents damage to the insulation board and deformation of the gate shape, and also makes it easier to process the gate and release the remaining material from the gate. An object of the present invention is to provide a pot-type mold for a transfer molding machine that can improve properties.

To this end, the present invention provides a pot-type mold for a transfer molding machine in which a heat insulating board is attached to the bottom of the pot in contact with the upper mold, and the heat insulating board has a seal plate at the top and a metal part at the bottom. The main feature is that a sprue gate made of fluorine resin is attached with a reinforcing member, and a sprue gate is bored through the seal plate, the reinforcing member, and the sprue gate.

Hereinafter, embodiments of this invention will be described based on the drawings.

FIG. 1 is a sectional view of a transfer molding machine when the mold is opened, and FIG. 2 is a sectional view of a heat insulating plate attached to the bottom of a pot of a pot type mold of the same molding machine.
Reference numeral 1 denotes a movable surface plate attached to the tip of the ram 2, and a lower mold 4 is attached thereon via a heating plate 3. In this embodiment, in order to mold a basket-shaped rubber product, a core 5 and a sliding mold 6a are placed in the recess of the lower mold 4.
6b is fitted. That is, a core 5 is fitted into the center of the lower mold 4 so as to be slidable up and down, and sliding molds 6a and 6b are fitted into the recessed portions so as to slide toward the core 5 from both sides. It is connected to the tip of the piston rod, etc. of the sliding cylinder. 7 is the lower mold 4
The upper mold is located above the gates 7a, and has a plurality of gates 7a.
When the lower mold rises, the upper mold 7 is pushed up and comes into contact with the heat insulating plate 9 at the bottom of the pot 8 located above.
When the upper mold 7 rises, the upper mold 7 is pushed up and raised to fit into the upper plunger 15.

A heat insulating board 9 as shown in FIG. 2 is attached to the bottom of the pot 8 in order to prevent the residual rubber in the pot 8 from being affected by the vulcanization heat transmitted from the mold. Heat insulation board 9
The base material 10 is made of asbestos material or the like impregnated with resin, a sprue gate part 11 made of fluororesin is provided at the upper center of the base material 10, and a reinforcing member 12 made of metal is attached to the lower side of the sprue gate part 11. Further, a seal plate 13 is fixed on the sprue gate portion 11. Then, a plurality of sprue gates 14 are drilled through the seal plate 13, the sprue gate portion 11, and the reinforcing member 12 at positions corresponding to the gates 7a of the upper mold. In addition, 1
Reference numeral 6 designates a gasket fitted into the outer circumferential portion of the heat insulating board 9 so as to protrude downward, and reference numeral 17 represents an air passage for suction inside the cavity.

In the transfer molding machine configured in this way, in the mold opening state shown in FIG. 1, all the members on the movable surface plate 1 rise as the ram 2 rises.
The upper mold 7 and the lower mold 4 are matched together with the core 5, and the sliding molds 6a and 6b are further pushed out to the center to complete mold clamping. Further, as the movable surface plate 1 rises, the pot 8 is pushed up via the upper die 7, and the plunger 15 enters the pot 8, so that the rubber material in the pot 8 is released as shown in FIG. The rubber is pressurized, passes through the sprue gate 14 of the heat insulating plate 9, passes through the gate 7a of the upper mold 7, and is injected into the cavity. In this state, the rubber in the cavity is vulcanized by the heat from the hot platen 3, and the mold is opened after a predetermined period of time. At this time, since the metal reinforcing member 12 is provided at the bottom of the sprue gate 14 of the heat insulating board 9, vulcanization is promoted at this point, the rubber residue in the gate hardens, and the gate residue is transferred from the sprue gate 14. can be easily taken out.

As explained above, according to the pot-type mold of the transfer molding machine of this invention, a metal reinforcing material is provided at the bottom of the sprue gate provided in the heat insulation board, so that the rubber remaining at the bottom of the sprue gate is processed. By curing with sulfur, the remaining gate material can be easily released from the mold, improving workability. Furthermore, compared to conventional heat insulating panels that use only heat insulating materials such as resin-impregnated asbestos material, damage and wear at the sprue portion can be reduced, and the sprue gate can be easily processed.

[Brief explanation of the drawing]

The figures show an embodiment of this invention; Fig. 1 is a cross-sectional view of the transfer molding machine in the mold open state, Fig. 2 is an enlarged cross-sectional view of the heat insulation plate, and Fig. 3 is a cross-section of the transfer molding machine during injection. It is a diagram. 7...Upper mold, 8...Pot, 9...Insulation board, 1
1... Sprue gate part, 12... Reinforcement member, 13
...Seal plate, 14...Sprue gate.

Claims (1)

[Scope of utility model registration request] In a pot type mold for a transfer molding machine, in which a heat insulating board is attached to the bottom of the pot that contacts the upper mold, and a sprue gate part is provided on the heat insulating board, the sprue gate part of the heat insulating board is formed of fluororesin,
A seal plate is attached above the sprue gate portion, a metal reinforcing member is attached below the sprue gate portion, the seal plate, the sprue gate portion,
and a pot-type mold for a transfer molding machine, characterized in that a sprue gate is bored through the reinforcing member.