JPS60122124A - Resin injection apparatus - Google Patents

Abstract

PURPOSE:To eliminate waste of material while enabling the replacement for a short time in the alteration of material by branching a material supply vertical hole of a piston into a plurality of subholes near the center to heat in the vicinity of the branch point. CONSTITUTION:A vertical hole 14 of a piston 13 sliding within a cylinder 8 is branched into a plurality of subholes 15 and heated at the branch point 16 with an internal heater 17 buried in the piston 13. Therefore, a filamentous resin material 19 fed to the vertical hole 14 is heated and melted with a band heater 12 and an internal heater 17 at the branch point 16 and flows down shunted into the subholes 15. The melted resin passing through the subholes 15 flows down into a lower space 21 formed with the cylinder 8 and the piston 13 kept hot. Thus, as the resin is melted by internal heating of the cylinder, a higher heat efficiency is made possible to reduce the heat source of the equipment down to a small capacity while achieving a quick rising with a quick rise in the temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to an improvement in a resin injection device used when molding a synthetic resin material. When molding resin materials, it is common to keep the resin material in a fluid state and seal it in a mold under pressure.There are several methods such as injection molding, transfer molding, and compression molding. The most commonly used method is injection molding. FIG. 1 shows a screw-type resin injection device in a conventional resin injection molding device. 3 is a nozzle hole provided at the tip of a cylinder 2. FIG.

4 is a band heater, sfi, that heats the cylinder 2;

A resin material supply port 6 provided in the cylinder 2 is a hopper for storing pellet-shaped resin material.

The pellet-shaped resin material enters the screw n7 from the supply port 5, and is sent to the nozzle hole 3 in front of the screw 1 by rotation of the screw 1. Since the screw groove 7 becomes shallower in the direction of the tip of the cylinder 2, the pellet-shaped resin material is compressed, and the shearing force due to the rotation of the screw 1 and the band -
It is melted by heating in the tank 4.

However, the conventional resin injection apparatus described above has the following drawbacks. (1) To change the material, remove the material remaining in the screw groove 7 and insert the new material into the screw groove 7.
- Supply new materials one after another to fill groove 7;
Must be replaced gradually. This does not waste a lot of material, and it takes a long time to replace it. (
2) The screw and cylinder are long, making the device large and, as a result, requiring a large space for installation. (3
) At the start of molding, it is necessary to heat the cylinder and screw to the same temperature in order to raise the temperature until the resin in the screw groove melts.

Therefore, the heat capacity becomes large and the time required to start molding is long. (4) The screen, cylinder, and cylinder require high-precision machining, making the equipment expensive. SUMMARY OF THE INVENTION An object of the present invention is to provide a resin injection device that eliminates the drawbacks of the conventional devices mentioned above.

[Structure of the Invention] The resin injection device of the present invention comprises a cylinder having a nozzle hole at the lower end, a piston slidably inserted into the cylinder, and the piston supplies linear resin material in the axial direction. The vertical hole branches into a plurality of support holes near the center of the piston, and the support hole opens into a lower space formed between the tip of the piston and the cylinder. The piston is characterized in that it has an internal heater therein that heats the vicinity of the branch point and melts the linear resin material.

An embodiment of the invention will be described with reference to FIG.

Reference numeral 8 denotes a metal cylinder, which has a nozzle hole 9 at its lower end and a stopper hole 11 for fixing at its upper flange 10.
is the provision. 12 is a band heater that heats the cylinder 8. 15 is a metal piston that slides inside the cylinder 8, and has a vertical hole 14 passing through in the axial direction. The vertical hole 14 branches into a plurality of support holes 15 in the middle, and the branch point 16 is heated by an internal heater 17 embedded inside the piston 13. Reference numeral 18 denotes a sphere (check valve') for preventing backflow provided inside the branch hole 15. 19 is a linear resin material supplied to the vertical hole 14; 20 is a resin melted by heating by the band heater 12 and the internal heater 17; 21 is a resin material melted in the lower space formed between the cylinder 8 and the piston 16; Store resin.

Reference numeral 22 denotes a recess formed in the sliding movement of the cylinder 8 and piston 13, which functions to smooth the sliding movement between the two and to retain resin leaking out along the sliding movement.

Next, its effect will be explained. When the linear resin material 19 supplied to the vertical hole 14 reaches the branch point 16, it is heated by the band heater 12 and the internal heater 17 and melted. The molten resin flows into the branch hole 15 and descends. When the pressure on the resin supply side is high, the sphere 18 for preventing backflow provided in the branch hole 15 descends downward to open the valve seat and allow the resin to flow down, but when the resin pressure in the lower space 21 is higher than the pressure on the supply side. When the pressure rises, it is pushed upward and closes the valve seat, preventing resin from flowing backward.

The molten resin that has passed through the support hole 15 flows into the lower space 2 formed by the cylinder 8 and the piston 13 which are kept warm.
Flows down into 1. When the nozzle hole 9 of the cylinder 8 is closed, the piston 13 is pushed up by the pressure of the resin flowing into the lower space 21, expanding the lower space 21 and storing the molten resin. When the storage amount reaches a predetermined value, the supply of resin material is stopped. When injecting molten resin, use nozzle hole 9.
is opened and the piston 13 is driven to compress the molten resin.

At this time, the sphere 18 closes the valve seat to prevent the molten resin from flowing back.

FIG. 3 shows an embodiment of a resin injection molding apparatus using the resin injection apparatus shown in FIG. The flange 10 of the resin injection device is fixed to a fixed platen 24 via a spacer 25. While supporting the 25Vi fixed platen 24, the movable platen 2
6 is fixed upright to the base 28 with a tie bar that holds it movably up and down. 27 is a fixing nut. 2
9 is a mold opening/closing cylinder rotatably attached to the base 28, 30 is a toggle bin, and 31 is a toggle arm.

32 is an injection cylinder attached to the upper part of the base 2B. 36 connects its base to the rod 55 of the injection cylinder 32 at rg11! The actuating lever is freely attached to the IJJ, and is supported in the middle by a fulcrum 34, and its tip is positioned at the top so as to drive the piston 13 of the resin injection device. The 561Ii pinch roller functions to feed out the linear resin material 19. This is a winding frame (stock device) for 37Fi linear resin material 19. 38 is an upper mold attached below the fixed platen 24, and 59d is a resin injection hole. 40 is a lower mold attached to the movable platen 26.

Next, its operation will be explained. The mold opening/closing cylinder 29 pushes up the movable platen 26 to create the lower mold 40 and the upper mold! 18, the injection cylinder 32 is operated to push down the resin injection device cylinder 13 through the operating lever 33, and the resin injection device injects the molten resin stored in the lower space 21 by the aforementioned operation. From the hole 59, the mold (39, 40
). When injection is completed, injection cylinder 3
2 to pull up the piston 15 and remove the linear resin material 1.
9 is supplied to the resin injection device. The resin injection device melts the supplied linear resin material 19 by the above-described operation and stores it in the lower space 21 thereof. During this time, the cooled and solidified resin molded product is taken out and subjected to the next injection molding.

[Effects of the Invention] Since the present invention has the above structure and operation, it has the following effects.

(1) Thermal efficiency is high because the resin is melted by internal heating of the cylinder, and the heat source of the device can be made small in capacity.
In addition, since the temperature rises quickly and the start-up time is quick, productivity is high.

(2) Since almost all of the molten resin inside the cylinder is extruded in one extrusion, there is no waste of material when changing the resin material, and replacement can be performed in a short time.

(6) Since the device is vertical, it does not require a large space for installation unlike the screen type shown in FIG.

(4) It has a simple structure and does not require high-precision assembly technology, so it can be provided at low cost.

[Brief explanation of the drawing]

Figure 1: Conventional Scrier Mold 4 (Cross-sectional view of a resin injection device. Figure 2. Cross-sectional view of an embodiment of the resin injection device of the present invention. Figure 3N: Resin injection molding using the resin injection device of the present invention. FIG. 8 showing an embodiment of the device: cylinder, 9: nozzle hole, 10: flange, 11: stopper hole, 12: band heater, 1
3... Piston, 14... Vertical hole, 15... Support hole,
16... Branch point, 17... Internal heater, 1B...
Sphere (check valve) 19... Linear resin material, 20... Melted resin, 21... Lower space, 22... Concavity Fig. 1

Claims (1)

[Claims] (1) A cylinder having a nozzle hole at the lower end, and a piston slidably inserted into the cylinder, the piston having a vertical hole through which a linear resin material is supplied in the axial direction,
The vertical hole branches into a plurality of supporting holes near the center of the piston, the supporting holes open a lower space formed between the tip of the piston and the cylinder, and the piston is connected to the branching point. A resin injection device (2) characterized in that it has an internal heater therein that heats the vicinity and melts the linear resin material; A resin injection device according to claim 1ffi(1), characterized in that a stop valve is provided.