JPH0512134B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a material supply method and apparatus for a molding machine used when injection molding rubber or a material with properties similar to rubber.

[Conventional technology]

In general, unlike plastic materials, rubber materials do not have fluidity at room temperature, so they cannot be supplied from the hopper to the material supply opening of the injection cylinder by utilizing natural fall. Therefore, as a normal means of supplying rubber material to a molding machine, the rubber material is processed into a ribbon shape by another molding machine, taking into account the biting of the screw in the injection cylinder, and this is sequentially fed into the material supply port. I'm putting it in. However, ribbon-like materials are viscous and can be stored and
If the materials overlap during transportation, they will stick to each other and become difficult to handle, so the surface of the ribbon-shaped materials is sprinkled with talc as an anti-stick agent. This talc easily scatters and pollutes the surrounding area, making the work environment worse.Furthermore, since talc is mixed into the rubber material, it has a negative effect on the quality of molded products. As a means to solve these problems, a molding machine is known from Utility Model Publication No. 56013/1983, in which a hopper is provided with a material molding function to streamline material supply. The raw material supply device of this molding machine has an extrusion device with a plunger connected to the hopper provided at the material supply port of the injection cylinder, and has a plunger that heats and fluidizes the rubber material in the hopper from the outside of the hopper. Furthermore, the material is formed into a ribbon shape by a flat constriction section provided below the hopper together with a cooling means, and then extruded to a material supply section.

[Problem to be solved by the invention]

In the conventional device described above, the rubber material is heated by a heater installed outside the hopper, so a temperature difference occurs between the outer peripheral part near the heater and the central part far from the heater. 180
To heat the whole thing evenly so that it does not reach ℃,
Special temperature control is required. In addition, in order to form into a ribbon shape, the material, which is close to a molten state, is rapidly cooled in a constriction section close to the raw material supply port, so fluidity is suppressed at the constriction section.
This acts as a resistance to extrusion by the plunger, resulting in poor supply efficiency. This invention was devised to solve the above-mentioned conventional problems, and its purpose is to uniformly heat and soften rubber or similar materials in a hopper, and to sequentially soften each softened material. The object of the present invention is to provide a new material supply method and device that can extrude and supply material to a material supply port of a molding machine.

[Means to solve the problem]

The invention according to the above object partitions the inside of the bottom of the hopper provided at the material supply port of the injection cylinder by a temperature control plate having a large number of material passage holes, and uses the plunger of the extrusion device disposed above the hopper to The above-mentioned problem is solved by pressing the material in the hopper onto a temperature control plate to soften it by heating, and by force-feeding the softened material from the material through hole to the material supply port. The hopper also has a temperature control plate provided to partition the inside of the bottom, and the temperature control plate includes a plurality of heat medium passages penetrated through the plate at regular intervals, and a plate between the heat medium passages. It is equipped with a large number of material holes drilled in the surface and a large number of convex portions protruding from the top surface for increasing the heat transfer area, thereby allowing the plunger to heat and soften the material in the hopper and extrude it. It becomes.

[Effect]

In the above configuration, when the plunger presses the rubber material in the hopper, the material in the portion pressed against the temperature control plate heated to a predetermined temperature is heated and softened. This softened material is further pushed out from the material passage hole to the material supply port below the temperature control plate by the pressure of the plunger, and flows into the injection cylinder.

【Example】

In the figure, reference numeral 1 denotes an injection cylinder which has a screw 2 for injection molding inside. Further, the upper rear portion of the injection cylinder 1 serves as a material supply port 3. A frame 4 and a cylindrical hopper 5 within the frame are vertically provided in the material supply port 3, and a hydraulically operated extrusion device 6 is mounted and fixed on the frame. At the tip of the downward piston rod 7 of this extrusion device 6, a plunger 8 is attached which has an outer diameter matching the inner diameter of the hopper and which moves in and out of the hopper. The inner bottom surface 9 of the hopper 5 is formed in the shape of a funnel, and a temperature control plate 10 is provided on the upper part of the inner bottom surface 9 so as to divide the bottom part into upper and lower parts. A plurality of heat medium passages 11, 11 penetrate through the plate of the temperature control plate 10, and a large number of material holes 1 of a required diameter are formed on the plate surface between the heat medium passages.
2 and 12 are bored at regular intervals. Further, on the upper surface, a large number of convex portions 13, 13 for increasing the heat transfer area are provided to protrude alternately with the material through holes 12,12. Note that 14 is a heat medium pipe. To feed materials using the above device, first heat the temperature control plate 10 with a heat medium to adjust the temperature to a range of 80 to 100°C, then put the rubber material 15 into the hopper 5 and extrude it. The device 6 is actuated to extend and move the piston rod 7. As a result, the plunger 8
is inserted into the hopper, and the rubber material 15 is placed on the temperature control plate 1.
Press the top surface of 0. The material in the area pressed against the temperature control plate 10 is heated and softened and becomes fluid, and the material directly flows through the material through hole 1 due to the pressing force.
2 to the inner bottom surface 9, and further to the material supply port 3.
being pushed towards. Since this heat softening is caused by pressing the material with the plunger 8, the amount of material supplied to the material supply port 3 can be adjusted by adjusting the pressing time. In addition, the heating softening of the material is limited to the material near the temperature control plate, and the influence of heating on other parts is extremely small, and the temperature at the temperature control plate 10 is controlled to be significantly lower than the vulcanization hardening temperature. Ru. Although the illustrated molding machine is of an in-line screw type, it can also be applied to a plunger type in the same way as in the embodiments, so the present invention is not particularly limited to the molding machine described in the embodiments. do not have.

【Effect of the invention】

As described above, this invention uses a plunger to press a rubber material or the like against a temperature control plate having a material passage provided in a hopper, thereby partially heating and softening the material, so that a constant amount of the material is always kept. Since the material is supplied, there is no vulcanization hardening due to heating, the thermal history of the material to be molded is always constant, and the quality of the molded product is guaranteed. In addition, since the heated and softened material is extruded through the material before melting, there is no loss of pressing force unlike when pressing a material that has been cooled and molded through the molten material.
Pressure supply can be performed efficiently. Furthermore, since the material is supplied in a heated and softened state, the melting distance of the material in the injection cylinder is shortened, and the screw length is also shortened, thereby reducing the cost of the molding machine and the material supplying device itself. It is simple because it is only necessary to provide a temperature control plate having heat medium passages, material holes, etc. on the inner bottom of a hopper equipped with an extrusion device, and the cost is not particularly high compared to conventional devices.

[Brief explanation of the drawing]

The drawings schematically show one embodiment of a material supply device capable of carrying out the material supply method for a rubber molding machine or the like according to the present invention. The figure is a plan view of the temperature control plate, and FIG. 4 is a longitudinal sectional view thereof. DESCRIPTION OF SYMBOLS 1...Injection tube, 3...Material supply port part, 4...Frame, 5...Hopper, 6...Extrusion device, 8...
Plunger, 9... Inner bottom surface, 10... Temperature control plate, 1
1...Heating medium passage, 12...Material hole, 13...
Convex portion for increasing heat transfer area, 15...Rubber material.

Claims (1)

[Claims] 1. A hopper is provided at the material supply port of the injection cylinder, and a material extrusion device equipped with a plunger is disposed above the hopper, and the rubber or similar material in the hopper is
In a molding machine for extruding rubber or the like into an injection cylinder using the plunger, the inside of the bottom of the hopper is divided by a temperature control plate having a large number of material passage holes, and the material in the hopper is transferred onto the temperature control plate by the plunger. A material supply method for a rubber molding machine or the like, characterized in that the material is pressed, heated and softened, and the softened material is fed under pressure from a material through hole to the material supply port. 2. A hopper is provided at the material supply opening of the injection cylinder, and a material extrusion device equipped with a plunger is disposed above the hopper, and the rubber or similar material in the hopper is
In the molding machine for rubber, etc., which is extruded and supplied into the injection cylinder by the plunger, the hopper has a temperature control plate in the bottom, and the temperature control plate has a plurality of heating mediums inserted through the plate at regular intervals. A material supply device for a rubber molding machine, etc., comprising a passage and a large number of material holes bored in a plate surface between heat medium passages, and provided to partition the inside of a hopper bottom. . 3. The material supply device for a rubber molding machine or the like according to item 2, wherein the temperature control plate has a large number of convex portions for increasing the heat transfer area on its upper surface.