CN111452318A

CN111452318A - Internal heating type hot runner plastic injection molding machine

Info

Publication number: CN111452318A
Application number: CN201910450625.0A
Authority: CN
Inventors: 陈星昊
Original assignee: NINGBO SURELY MEH CO Ltd
Current assignee: NINGBO SURELY MEH CO Ltd
Priority date: 2019-05-20
Filing date: 2019-05-20
Publication date: 2020-07-28
Anticipated expiration: 2039-05-20
Also published as: CN111452318B

Abstract

An internal heating type hot runner plastic injection forming machine, a toggle rod hinged plate is hinged with a charging barrel fixing plate through a double-swing rod mechanism, an injection plunger piston capable of reciprocating is arranged in the injection charging barrel, a mixing cone is arranged in the mixing charging barrel, a spiral heating ring is assembled in a central hole of the mixing cone, a temperature sensor is inserted into an inner hole of a conical tip of the mixing cone, a plurality of left-handed and right-handed spiral grooves are alternately arranged on an outer cylindrical surface of the mixing cone, the rotating directions of adjacent spiral grooves are opposite, one ends of all the spiral grooves are communicated with the inner hole of the injection charging barrel, the other ends of the spiral grooves are communicated with the conical tip of the mixing cone, the conical tip of the mixing cone extends into the position near a fixed template point sprue of a mold, and molten plastic is extruded by the. The invention has the advantages of high temperature control precision, low mold cost, good mixing effect, low labor cost, less raw material waste and the like for the injection molding processing of small-sized precision plastic products.

Description

Internal heating type hot runner plastic injection molding machine

Technical Field

The invention relates to a thermoplastic plastic injection molding processing machine, in particular to a small injection molding machine which heats thermoplastic plastic and enters a mold through injection by a hot runner and a static mixer.

Background

The existing plastic injection molding machine melts plastic and enters a mold through a hole with a diameter of a few millimeters of a nozzle, and the mold is provided with a pouring runner, namely a cold runner mold. The production of small products is often that the product is only a few tenths of grams, and the pouring runner is up to the weight of several grams, so that the waste of raw materials is large, and the demoulding of plastics in the pouring runner is difficult, thus being not beneficial to full-automatic unmanned production. The prior small-sized plastic injection molding machine has small diameter of a charging barrel, cannot adopt an injection device in a reciprocating screw rod mode, but adopts an injection device in a reciprocating plunger mode, so that the prior small-sized plastic injection molding machine has no screw rod rotation action, can not dynamically stir and mix plastics, and has low product quality. The existing heating method of the charging barrel of the plastic injection molding machine adopts external heating type heating, namely an electric heating ring is sleeved on the outer cylindrical surface of the charging barrel or electric induction heating is adopted, the plastic in the inner hole of the charging barrel is heated in a single direction, the plastic contacting with the inner wall is melted and overheated, but the plastic at the central part is still solid. The sensor that its temperature control system is used for detecting the temperature also installs at the outer wall, can't detect the actual temperature of plastics. Thus affecting product quality.

Disclosure of Invention

The invention aims to make up the defects and discloses an internally heated hot runner plastic injection molding machine which has the advantages of uniform heating temperature, high temperature control precision, no need of a pouring runner for a mold, a static mixer and convenience for unmanned operation and automatic cycle production.

The technical scheme adopted by the invention for solving the technical problems is as follows:

an internal heating type hot runner plastic injection molding machine is characterized in that a toggle rod hinged plate, a charging barrel fixing plate, a fixed plate and a movable plate are sleeved on a large pull rod in sequence, the toggle rod hinged plate is fixed with the large pull rod, the movable plate is fixed with the large pull rod through threads, the large pull rod is in clearance fit with the fixed plate and sliding bearings in the charging barrel fixing plate, the large pull rod can axially slide relative to the fixed plate and the charging barrel fixing plate, the toggle rod hinged plate is hinged with the charging barrel fixing plate through a double-swing-rod mechanism, a mixing charging barrel is tightly pressed and fixed with the injection charging barrel fixing plate through a nut, the injection charging barrel is fixed with the mixing charging barrel in an interference fit manner, an injection plunger capable of reciprocating motion is arranged in the injection charging barrel, the upper end of the injection plunger is fixed with a plunger pull plate, the two ends of the plunger pull plate are fixed with piston rods of two symmetrically arranged injection cylinders, end covers, the mixing barrel in be equipped with mixing awl, mixing awl mesopore assembly spiral heating coil, temperature sensor inserts mixing awl point head hole, mixing awl is compressed tightly fixedly with mixing barrel by screw thread pressure sleeve, mixing awl outer cylindrical surface sets up a plurality of left and right handed helicla flute at intervals, the direction of rotation of adjacent helicla flute is opposite, all helicla flutes intersect with the helicla flute of incorgruous direction of rotation, all helicla flutes one end communicates with each other with injection barrel hole, the other end communicates with each other with mixing awl point head, near mixing awl point head stretches into mould fixed die plate point gate, the outer cylindrical surface helix flute of accessible mixing awl flows to mixing awl point head through injection plunger extrusion, in the die cavity of mould fixed die plate centre aperture entering mould lower mould.

In the double-swing-rod mechanism with the toggle rod hinged plate connected with the material cylinder fixing plate, a hinged hole in the middle of an L-type toggle rod is hinged with a two-force rod, the other two hinged holes are respectively hinged with the material cylinder fixing plate and a piston rod of a die cylinder, a piston rod-free end cover of the die cylinder is hinged with a rack, the other end of the two-force rod is hinged with the toggle rod hinged plate, the toggle rod hinged plate is in clearance fit with a slide rod through a sliding bearing, one end of the slide rod is inserted into the material cylinder fixing plate and fixed, the other end of the slide rod is fixed with a support on the rack, and the toggle rod hinged plate can move.

Drawings

FIG. 1 is a schematic front view of a cross-section taken from a horizontal perspective

FIG. 2 is a partially cut-away, top schematic view of the injection cartridge of FIG. 1 with the chassis removed

FIG. 3 is a schematic left side view of the injection cartridge portion of FIG. 1 rotated 45 counterclockwise

FIG. 4 is a schematic view of the mold clamping cylinder of FIG. 1 in a retracted position with the movable platen in an open position

Detailed Description

The names of the reference symbols in the drawings are as follows:

the device comprises a frame 1, a clamping cylinder 2, an L type toggle rod 3, a slide rod 4, a toggle rod hinged plate 5, an injection cylinder 6, an injection charging barrel 7, an injection cylinder fixing plate 8, an injection plunger 9, a plunger pull plate 10, a two-force rod 11, a charging barrel fixing plate 12, a threaded pressing sleeve 13, a temperature sensor 14, a mixing charging barrel 15, a mixing cone 16, a spiral heating ring 17, a fixed plate 18, a mould fixed plate 19, a mould lower mould 20, a movable plate 21 and a large pull rod 22.

An internal heating type hot runner plastic injection molding machine, a toggle rod hinged plate 5, a charging barrel fixing plate 12, a fixed plate 18 and a movable plate 21 are sleeved on a large pull rod 22 in order, the toggle rod hinged plate 5 is fixed with the large pull rod 22, the movable plate 21 is fixed with the large pull rod 22 by screw threads, the large pull rod 22 is in clearance fit with sliding bearings in the fixed plate 18 and the charging barrel fixing plate 12, the large pull rod 22 can axially slide relative to the fixed plate 18 and the charging barrel fixing plate 12, the toggle rod hinged plate 5 is hinged with the charging barrel fixing plate 12 by a double-swing rod mechanism, a mixing charging barrel 15 is tightly pressed and fixed with the charging barrel fixing plate 12 by a screw cap, the injection charging barrel 7 is fixed with the mixing charging barrel 15 in interference fit, an injection plunger 9 capable of reciprocating motion is arranged in the injection charging barrel 7, the upper end of the injection plunger 9 is fixed with a plunger pull plate 10, two ends of the plunger pull plate 10 are fixed with piston rods of two symmetrically arranged injection, the center of an injection cylinder fixing plate 8 and an injection charging barrel 7 are pressed and fixed by a screw cap, a mixing cone 16 is arranged in a mixing charging barrel 15, a spiral heating ring 17 is assembled in a central hole of the mixing cone 16, a temperature sensor 14 is inserted into an inner hole at the tip of the mixing cone 16, the mixing cone 16 is pressed and fixed with the mixing charging barrel 15 by a thread pressing sleeve 13, a plurality of left mixing cones 16 are arranged on the outer cylindrical surface at intervals, the spiral grooves of the right-handed screw are opposite in the rotating direction of the adjacent spiral grooves, all the spiral grooves are intersected with the spiral grooves with different rotating directions, one end of each spiral groove is communicated with an inner hole of the injection charging barrel 7, the other end of each spiral groove is communicated with the tip of the mixing cone 16, the tip of the mixing cone 16 extends into the position close to a point gate of the fixed die plate 19 of the die, and molten plastic is extruded by the injection plunger 9, flows to the tip of the mixing cone 16 through the spiral grooves on the outer cylindrical surface of the mixing cone 16 and enters the die cavity of the lower die 20 of the die.

In the double-swing-rod mechanism with the toggle rod hinged plate 5 connected with the material cylinder fixing plate 12, a hinged hole in the middle of an L-type toggle rod 3 is hinged with a two-force rod 11, the other two hinged holes are respectively hinged with the material cylinder fixing plate 12 and a piston rod of a die cylinder 2, a piston rod-free side end cover of the die cylinder 2 is hinged with a frame 1, the other end of the two-force rod 11 is hinged with the toggle rod hinged plate 5, the toggle rod hinged plate 5 is in clearance fit with a sliding rod 4 through a sliding bearing, one end of the sliding rod 4 is inserted into the material cylinder fixing plate 12 for fixing, the other end of the sliding rod 4 is fixed with a support on the frame 1, and the toggle rod hinged plate 5 can move on.

The internal heating type hot runner injection molding machine comprises the following working steps:

in the first step, a piston rod of a mold clamping cylinder pushes L toggle rods, L toggle rods move anticlockwise, the toggle rod hinged plates are driven by the two vertical rods, the large pull rod, the movable plate and the lower mold of the mold are driven to move rightwards, and the lower mold is tightly pressed with the fixed plate of the mold.

The second step is that: the injection cylinder drives the plunger pulling plate to be pulled down, the plunger pulling plate drives the injection plunger to be pressed down, molten plastic in the externally heated injection charging barrel enters the mixing charging barrel under the extrusion of the injection plunger, moves to the cone tip part along the spiral groove on the outer cylindrical surface of the mixing cone, and enters the mold cavity through the point gate at the center of the mold fixed plate to form a product.

And thirdly, pushing up the injection cylinder, moving the injection plunger upwards, pulling back the mold clamping cylinder, rotating the L toggle rods clockwise, pulling the toggle rod hinge plate to move leftwards through the two upright rods, moving the large pull rod fixed with the toggle rod hinge plate to move leftwards to drive the movable plate and the lower mold of the mold to move leftwards, continuously moving the lower mold of the mold to the right after the mechanical ejector rod contacts the mold ejection mechanism, ejecting the plastic product by the mold ejection mechanism, and finishing one working process.

Has the advantages of

The existing plastic injection molding mold has two types, namely a cold runner mold and a hot runner mold, wherein plastic in a pouring runner communicating a machine nozzle with a mold cavity is discarded along with a product after being cooled. For small products, the weight of the plastic in the pouring runner is 5 to 20 times of the weight of the product, which is quite wasteful. The hot runner mold is characterized in that a heating device is arranged in a pouring runner of the hot runner mold, plastic in the pouring runner is always in a heating fluid state, during injection, the heated plastic enters a mold cavity through the heating pouring runner through a point pouring gate, no runner waste is generated in the production process, and the hot runner mold has the advantages of being less in material waste, suitable for multiple cavities of one mold, high in production efficiency, convenient for full-automatic unmanned operation production, complex in mold structure, high in cost, large in axial and radial sizes of a hot runner system, and not suitable for production of precise small products. The cold runner mold has the defects of large raw material waste, unsuitability for clamping by a manipulator, incapability of full-automatic unmanned production and high labor cost; by adopting the hot runner mold, not only the mold cost is high, but also the axial size of the mold is large, and the mold cannot be installed on a small-specification machine. The large-size machine is selected, which is not only power-consuming, but also not suitable for the production of small precision products. According to the problems existing in the precise small plastic injection molding production process, the invention discloses an internal heating type hot runner injection molding machine which is suitable for the injection molding process of small precise plastic products. The basic principle is to move the hot runner system in the mold to the mixing barrel of the machine. The mould need not to set up hot runner system, reduces mould cost by a wide margin. Meanwhile, the full-automatic unmanned operation production is facilitated, and the labor cost is reduced. In order to improve the temperature control precision, the invention adopts an internal heating type hot runner structure, and a temperature sensor is placed near an injection nozzle of a hot runner system, so that the temperature control precision is greatly improved. In order to fully mix the plastics, a plurality of spiral grooves are arranged on the outer cylindrical surface of the mixing cone, the rotating directions of the adjacent spiral grooves are opposite, and all the spiral grooves are intersected with the spiral grooves with the different rotating directions. The static mixer is composed of the spiral grooves, plastics flowing through each groove are intersected with the reverse rotating groove for n times, the mixing degree is n times of 2, and the mixing effect is excellent. By adopting the technical schemes, the invention has the advantages of high temperature control precision, low mould cost, good mixing effect, low labor cost, less raw material waste and the like for the injection molding processing of small-sized precise plastic products. According to the 24-hour production calculation of the manpower and raw material cost at the present stage, the manpower and raw material cost saved in one year is 5 to 10 times of the machine cost.

Claims

1. An internal heating type hot runner plastic injection molding machine is characterized in that a toggle rod hinged plate (5), a charging barrel fixing plate (12), a fixed plate (18) and a movable plate (21) are sleeved on a large pull rod (22) according to the sequence, the toggle rod hinged plate (5) is fixed with the large pull rod (22), the movable plate (21) is fixed with the large pull rod (22) through threads, the large pull rod (22) is in clearance fit with sliding bearings in the fixed plate (18) and the charging barrel fixing plate (12), the large pull rod (22) can axially slide relative to the fixed plate (18) and the charging barrel fixing plate (12), the fixed plate (18) and the charging barrel fixing plate (12) are fixed through screws, the toggle rod hinged plate (5) is hinged with the charging barrel fixing plate (12) through a double-swing rod mechanism, a mixing charging barrel (15) is tightly pressed and fixed with the charging barrel fixing plate (12) through a nut, an injection charging barrel (7) is fixed with the mixing charging barrel (15), and an injection plunger (9, the upper end and the plunger arm-tie (10) of injection plunger (9) are fixed, and the both ends of plunger arm-tie (10) are fixed with the piston rod of two injection jar (6) of symmetrical arrangement, and the piston rod side end cover of injection jar (6) is fixed with injection jar fixed plate (8), and injection jar fixed plate (8) center and injection feed cylinder (7) are compressed tightly fixedly with the nut, its characterized in that: a mixing cone (16) is arranged in the mixing barrel (15), a spiral heating ring (17) is assembled in the middle hole of the mixing cone (16), a temperature sensor (14) in the spiral heating ring (17) is inserted into an inner hole at the tip of the mixing cone (16), the mixing cone (16) is pressed and fixed with the mixing barrel (15) by a thread pressing sleeve (13), a plurality of left mixing cones (16) are arranged at intervals on the outer cylindrical surface, the spiral grooves of the right-handed screw are opposite in rotation direction, all the spiral grooves are intersected with the spiral grooves with different rotation directions, one end of each spiral groove is communicated with an inner hole of the injection charging barrel (7), the other end of each spiral groove is communicated with the tip of the mixing cone (16), the tip of the mixing cone (16) extends into the position close to a point gate of the fixed die plate (19) of the die, and molten plastic is extruded by the injection plunger (9) and can flow to the tip of the mixing cone (16) through the spiral grooves on the outer cylindrical surface of the mixing cone (16) and enter the die cavity of the lower die (20) of the die through the central small hole of the fixed die.

2. The internal heating type hot runner plastic injection molding machine according to the claim one, characterized in that in the double-swing link mechanism that the toggle link hinged plate (5) is connected with the material cylinder fixing plate, the middle hinged hole of the L type toggle link (3) is hinged with the two-force rod (11), the other two hinged holes are respectively hinged with the material cylinder fixing plate (12) and the piston rod of the mold clamping cylinder (2), the side end cover without the piston rod of the mold clamping cylinder (2) is hinged with the frame (1), the other end of the two-force rod (11) is hinged with the toggle link hinged plate (5), the toggle link hinged plate (5) is in clearance fit with the slide rod (4) through a sliding bearing, one end of the slide rod (4) is inserted into the material cylinder fixing plate (12) for fixation, the other end is fixed with the bracket on the frame (1), and the toggle link hinged plate (5) can move on the slide rod (4) along the axial direction of the slide rod.