TW201908098A - Plastic injection molding method for thick products and mold thereof capable of greatly reducing pressure holding and cooling time during injection molding to greatly reduce manufacturing cost and enhance productivity - Google Patents

Abstract

The present invention relates to a plastic injection molding method for thick products and mold thereof, which is mainly used for forming plastic products with thickness greater than 4 mm, wherein the forming mold is constructed with at least one blank cavity and one product cavity and the thickness of the blank cavity must be less than the thickness of the product. After opening of the forming mold, the blank must be moved from the blank cavity into the product cavity; then, performing the enclosing injection and injection molding simultaneously for the blank in the product cavity and the blank cavity; and, after mold clamping, pressure holding and cooling, the blank and the product may be produced at the same time. By the injection molding method, the present invention may greatly reduce the pressure holding and cooling time during injection molding, so as to greatly reduce the manufacturing cost and enhance the productivity.

Description

Thick plastic injection molding method and mold thereof

The invention relates to the technical field of optical plastic molding, in particular to an injection molding method and a mold of a plastic part exceeding a thickness of 4 mm.

According to the general plastic injection molding, a pair of molding holes are sprayed with at least one cavity, a first-class channel and an injection port, and after the granular plastic material is heated to become a fluid, the fluid plastic is injected into the spiral mechanism. In the molding die, the fluid plastic passes through the injection port and the flow channel, and finally reaches and fills the cavity, and then a cooling water path provided in the molding die is used to cool the fluid in the cavity. The plastic, after the final formation of the fluid plastic into a solid, is a finished plastic part after demolding, thus completing a cycle of plastic injection molding.

In addition, generally for the plastic injection molding of thick parts, a set of molds is used in combination with one injection machine. The injection molding is used for one-stage injection, pressure is maintained to prevent shrinkage, and after cooling and solidification, the mold is taken out, which must be used due to the thickness of the finished product. Long-term holding time and cooling curing time, in order to avoid "shrink marks" on the surface of the product, so the entire injection molding cycle time is long, making the process cost of producing thick parts high, the production volume is also low, making thick plastic parts The unit price of the finished product is high.

In view of the above problems of the plastic injection molding method of the above-mentioned general thick parts, the present inventors have exhausted the development of the thick plastic injection molding method and the mold thereof of the present invention, and the main purpose of the present invention is to provide a plastic molding product for thick parts. The same injection molding machine and a set of innovative structure of the mold design, in order to achieve rapid production to reduce the cost of the process and its mold; the second objective of the present invention is: a fully automatic or semi-automatic thick plastic Injection molding method and mold thereof.

In order to achieve the above object, the present invention uses the following technical means for the thick plastic injection molding method and the mold thereof:

The invention relates to a thick plastic injection molding method, which comprises the following steps: a cavity forming step, which is to construct at least one initial embryo cavity and a finished mold cavity in a molding die, wherein the initial embryo cavity The thickness of the finished part must be less than the thickness of the finished part; in the first molding step, the original embryo mold hole and the finished mold cavity are simultaneously injected with the rubber material, and at least one original blank piece and one finished product part are formed; a step of inserting the original blank from the priming cavity into the finished cavity after the molding die is opened, and the finished component is detached from the molding die; and a second injection molding step, The first blank member and the primordial mold cavity in the finished mold cavity are simultaneously subjected to injection coating and injection molding, and after the mold clamping and cooling, the original blank member and the finished product are simultaneously produced; The step can greatly shorten the pressure holding and cooling time during injection molding, thereby greatly reducing production costs and increasing productivity.

The manner of moving the ejector piece in the step of moving the priming piece into the finished cavity step is set to be manual or automated.

The invention relates to a thick plastic injection mold, which comprises: a molding die comprising a movable mold side and a static mold side, and a groove is arranged on the movable mold side, and an initial portion is arranged at the bottom of the concave mold. a mold cavity, a finished mold cavity, a first-class track between the two mold holes and a positioning cone; and a moving positioning mechanism, comprising a carrier plate and two positioning holes, wherein the carrier plate sinks into the In the groove on the movable mold side, one of the positioning holes is sleeved in the positioning cone in the groove, and the supporting plate is provided with two supporting holes corresponding to the initial embryo cavity and the finished mold cavity.

The priming piece and the finished part may be made of thermoplastic engineering plastic, and the polycarbonate (PC), polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer (ABS), poly Propylene (PP), polyethylene terephthalate (PET), high density polyethylene (HDPE), low density polyethylene (LHPE), thermoplastic rubber (TPE), thermoplastic polyurethane (TPU) , polycarbonate + acrylonitrile-butadiene-styrene copolymer (PC/ABS), industrial liquid crystal polymer (LCP), polystyrene (PS), polyetheretherketone (PEEK) or polyether oxime (PES) The plastic material; in addition, the minimum thickness of the finished part is set to at least 4 mm.

One side of the groove on the side of the movable mold is an initial embryo cavity, and the other side is a finished cavity which can be embedded in the initial embryo.

The flow channel is configured as a cold runner, and includes a vertical runner and a transverse flow passage, wherein the transverse flow passage is configured to flow into the initial embryo cavity while the other side flows into the finished mold cavity, and flows to the The first flow regulating device is arranged on the cross flow channel of the primordial cavity, and the second flow regulating device is also disposed on the lateral flow path of the finished mold cavity.

The flow channel is set as a hot runner, and includes a hot runner and a lateral heat splitter. The lateral heat splitter plate flows into the direction of the initial embryo cavity and then is connected to the hot runner. The road is injected into the initial mold cavity, and the other side flows into the direction of the finished mold cavity, and then the hot runner is connected to inject the finished mold cavity.

The automatic device is disposed on the movable mold side, and the automatic device includes a driving device and a rotating shaft, wherein the driving device drives the rotating shaft, and the rotating shaft is connected to the inner plate of the groove. Support between the holes.

The above-mentioned driving device is preferably provided with an electric motor, a rotary cylinder, a gear and a rack set or a gear and a chain set to drive the rotating shaft and the carrier.

A closed circulating cooling water passage is disposed in the movable mold side and the static mold side, and each closed circulating cooling water passage cools the initial embryo mold hole, the finished mold cavity and the periphery thereof.

The thick plastic injection molding method and the mold thereof use the following technical means: 1. The invention uses the same injection molding machine with a new mold design device to split the thickness of the original design into an original blank and A finished part, and then the initial embryo cavity and the finished mold cavity are simultaneously designed on the same set of molds, and the injection molding of the initial embryo and the finished product can be simultaneously performed, and the thickness of the initial embryo is smaller than the thickness of the original design finished product, so that the initial embryo is formed in the injection molding. The pressure holding and cooling time can be greatly shortened, so that the injection molding production cost of "thick plastic parts" can be greatly reduced, and the production capacity can be increased, and at the same time, the surface of the finished product can be prevented from having "shrinkage marks" to improve product quality and Its yield. 2. The invention adopts one of the plate holes to support the first blank member after the first injection molding and solidification, and after the mold is opened, the carrier plate is ejected and rotated by manual or automatic means. Then, the original blank member is moved into the finished mold cavity, and a second injection molding is performed to cover the original blank member in the finished mold cavity to complete a finished product.

First, please refer to FIG. 1 and FIG. 2, which are related to a thick plastic injection molding method and a mold thereof, and embodiments thereof include:

In the present invention, an optical finished part 8 is produced, as shown in Fig. 3, which can be separated into an original blank 7 and a finished part 8 containing the original blank 7. The molding die 1 of the present invention is set as a group, wherein one side is set to a static mold side 3 (also referred to as a female mold), and the other side is set to a movable mold side 2 (also referred to as a male mold), and the static mold side is 3 is provided with an initial embryo mold hole 31 corresponding to an initial embryo mold hole 21 provided on the movable mold side 2, and a finished mold cavity 32 provided on the static mold side 3 is provided corresponding to the movable mold side 2 A finished mold cavity 22.

Further, a three-plate mold cold runner 5 provided on the static mold side 3 of the molding die 1 of the present invention comprises a vertical runner 51, and then a side branch from the vertical runner 51 is provided to flow to the initial embryo cavity. The cross flow passage 52 of 31 has a first flow regulating device 53 on the cross flow passage 52 of the ejector cavity 31, and the lateral flow passage 52 to the finished mold cavity 32 on the other side, and the cross flow of the finished mold cavity 32 A second flow regulating device 54 is provided on the track 52. In particular, the flow path can be designed for the three-plate cold runner 5 (Fig. 5) and the second plate cold runner 50 (Fig. 6) or The hot runner 500 system runner design using a hot runner (Figure 7).

Please refer to FIG. 8 and FIG. 9 , and a moving positioning mechanism 4 is disposed on the movable mold side 2 of the mold. The moving positioning mechanism 4 includes a receiving plate 41 and an automatic device 42 , and the automatic device 42 is connected. The driving device 41 further includes a driving device 421 and a rotating shaft 422, and the power source of the driving device 421 can be set as "electric motor", "hydraulic hydraulic cylinder", "pneumatic cylinder drive" The gear and chain set, the "gear and belt set" or the "electric motor" rotate directly. In particular, as shown in FIG. 9, the carrier 41 and its rotating shaft 422 are connected by a rotary cylinder 423.

If the original blank member 7 is to be rotated, the carrier plate 41 is used. The carrier plate 41 carries the injection molded initial blank member 7 to avoid falling off, and then first rotates out of the groove 20 and then rotates 180 degrees to the At the finished mold cavity 22 of the movable mold side 2, the support plate 41 is retracted into the recess 20, that is, the original blank member 7 is inserted into the finished mold cavity 22 of the movable mold side 2; A positioning cone 24 is disposed in the vicinity of the ejector cavity 21 of the movable mold side 2, and a positioning hole 411 is formed in the carrier plate 41 for positioning to avoid misalignment of the carrier plate 41 and the finished mold cavity 22 of the movable mold side 2. . The circular actuation mechanism of the carrier plate 41 from the groove 20, the rotation of the 180 degree, the retraction into the groove 20, and the like may be performed by the above-mentioned automatic device 42, but the automatic device 42 may not be limited, and may be artificial. After the insulated glove is placed, the carrier 41 is rotated 180 degrees by hand, and the original blank 7 is placed in the finished cavity 22 of the movable mold side 2.

Therefore, the molding die 1 of the present invention can be simultaneously formed into a general single-shot injection molding machine to simultaneously form the primary blank member 7 and the finished component 8. The actuation mode is as follows with reference to FIG. 2, FIG. 4 and FIG.

Action 1: Close the mold. The carrier plate 41 of the movable mold side 2 is reset against the ejector die 21 and the finished cavity 22 of the movable mold side 2, and the movable mold side 2 of the molding die 1 is moved to the static mold side 3 and clamped tightly. By clamping.

Action 2: Injection molding. The plastic is melted by a screw rotating friction heated by the injection molding machine tube, and the molten plastic is quantitatively injected through the tube screw extrusion, and the molten plastic flows through the vertical runner 51 of the static mold side 3 and is bifurcated through the cross flow. The passage 52 flows into the priming cavity 31 and the finished cavity 32, respectively, and the first flow regulating device 53 on the transverse flow path 52 of the priming cavity 31 can be traversed with the finished cavity 32 during the initial injection molding. The second flow regulating device 54 on the track 52 adjusts its flow balance accordingly.

Action 3: Keep pressure and cool. The machine screw of the injection molding machine maintains a certain pressure to maintain the cooling and shrinkage of the plastic material until the molten plastic cools and solidifies. That is, a closed circulating cooling water passage 6 is disposed in the movable mold side 2 and the static mold side 3, and each closed circulating cooling water passage 6 is accelerated to cool the initial embryo mold hole, the finished mold cavity and its surroundings.

Action 4: Open the mold to take out the finished part 8. When the movable mold side 2 is opened away from the static mold 3 side to be opened, it will be stopped after being returned to the original position. If the flow path of the static mold side 3 is designed as a three-plate mold cold flow path 5, the three-plate mold cold flow path 5 It will be pulled off and separated from the original blank 7 and the finished part 8. That is, after the movable mold side 2 is retracted to the original position, the carrier plate 41 of the movable mold side 2 is actuated by the automatic molding device 42 to actuate the groove 20 or manually removed from the groove 20 by the injection molding machine. The finished product 8 finished product and the three-plate cold cooling flow path 5 can be gripped by a robot on an injection molding machine or a human work take-out action.

Thereafter, the carrier 41 of the movable mold side 2 is rotated 180 degrees via the automation device 42 on the molding die 1, for example, using a rotary cylinder 423, an electric motor or a manual, via the positioning cone 24 and positioning. The hole 411 is positioned to engage the priming member 7 into the finished mold cavity 22 of the movable mold side 2. Thereafter, the carrier 41 of the movable mold side 2 is brought into close contact with the ejector cavity 21 and the finished cavity 22 of the movable mold side 2 via the automatic device 42 of the injection molding machine, the electric motor or the manual resetting action. And then return to the initial position of action one.

According to the above action one to action four, the cycle action can be continuously repeated to achieve the purpose of mass production.

Please refer to FIG. 3, because the thickness T0 of the finished part 8 to be manufactured is too thick, in order to obtain a perfect finished surface, the surface shrinkage trace is reduced as much as possible, so that the maximum production time of the thick plastic injection molding product is In the action three holding pressure and cooling stroke, but the molding die 1 of the present invention is designed to disassemble the minimum thickness T0 of the manufactured finished part 8 into the initial thickness of the initial blank 7 of the initial blank, and the finished part 8 The finished mold cavity of the thickness T2 is coated, and the coating thickness T2 is equal to the thickness T21 plus the thickness of the T22. Therefore, the minimum thickness T0 of the finished product 8 is equal to the sum of T1 and T2, so that the two different molding molds 1 of the present invention are different. The cavity can be cooled at the same time, so the time of the three pressure and cooling of the action can be greatly reduced, thereby reducing the cycle time of the entire injection molding, reducing the production cost of the thick plastic product and increasing the productivity of the machine.

In particular, in the foregoing embodiments, the thick plastic injection molding plastic material substrate can be a general thermoplastic engineering plastic, and can be set as polycarbonate (PC), polymethyl methacrylate (PMMA), acrylonitrile-butyl Alkene-styrene copolymer (ABS), polypropylene (PP), polyethylene terephthalate (PET), high density polyethylene (HDPE), low density polyethylene (LHPE), thermoplastic rubber (TPE) , thermoplastic polyurethane (TPU), polycarbonate + acrylonitrile-butadiene-styrene copolymer (PC/ABS), industrial liquid crystal polymer (LCP), polystyrene (PS), polyether Plastic raw materials such as ether ketone (PEEK) or polyether oxime (PES).

Therefore, the advantages and effects of the present invention can be summarized as follows: [1] The injection molding method of the thick plastic product splits the original design finished product into the initial embryo pattern and the finished product pattern, thereby reducing the forming thickness of the injection molding, thereby reducing The pressure holding and cooling time can greatly reduce the cost of injection molding process and increase production capacity. [2] The injection molding tool device of the thick product can design the initial embryo pattern and the finished product pattern in the same set of molds at the same time. The mold can simultaneously project the shaped embryo and the finished plastic piece containing the initial embryo. The mold can be matched with a single piece. The injection molding machine or the two-shot injection molding machine can be produced.

In view of the above embodiments, the present invention relates to a thick plastic injection molding method and a mold thereof, and the constituent elements thereof have not been seen in various books or publicly used, and are in conformity with the patent application requirements, and are requested to be clarified by the bureau. To grant a patent, to express a prayer; to be clear, the above is the specific embodiment of the patent application and the technical principles applied. If the change is made according to the concept of this patent application, the function produced by it The role shall not be exceeded by the spirit of the specification and the drawings, and shall be combined with Chen Ming within the scope of this patent application.

A‧‧‧ Thick plastic injection molding method

B‧‧‧Thick plastic injection mould

1‧‧‧Molding mould

2‧‧‧Move side

20‧‧‧ Groove

21‧‧‧Earth embryo cavity

22‧‧‧ finished mold cavity

24‧‧‧ positioning cone

3‧‧‧Static side

31‧‧‧Earth embryo cavity

32‧‧‧ finished mold cavity

4‧‧‧Mobile positioning mechanism

41‧‧‧ board

411‧‧‧Positioning holes

42‧‧‧Automation

421‧‧‧ drive

422‧‧‧ shaft

423‧‧‧Rotary cylinder

5‧‧‧Three-plate cold runner

50‧‧‧Two-plate cold runner

500‧‧‧hot runner

51‧‧‧Inverted runner

52‧‧‧ cross flow

53‧‧‧First flow regulating device

54‧‧‧Second flow regulating device

6‧‧‧Closed circulation cooling waterway

7‧‧‧First blank

8‧‧‧Finished parts

Minimum thickness of T0‧‧‧ finished parts

Minimum thickness of T1‧‧‧ initial blank

T21, T22‧‧‧ coating thickness

Figure 1 is a clamping state diagram of a thick plastic injection molding die of the present invention. Fig. 2 is a view showing the mold opening state of the thick plastic injection molding mold of the present invention. Figure 3: A cross-sectional view of the appearance of the original blank, the finished part, and the finished part. Figure 4 is a flow chart of the method for injection molding of a thick piece of plastic according to the present invention. Fig. 5 is a schematic view showing the three-plate cold flow passage of the thick plastic injection molding mold of the present invention. Figure 6 is a schematic view showing the cold flow path of the second plate mold of the thick plastic injection molding die of the present invention. Figure 7 is a schematic view showing the flow path of the hot runner system of the thick plastic injection molding die of the present invention. Figure 8 is a schematic view of the automatic device of the thick plastic injection molding die of the present invention. Figure 9 is a schematic view of another automated device of the thick plastic injection molding die of the present invention.

Claims (10)

A thick plastic injection molding method comprises the following steps: a mold cavity construction step is to construct at least one initial embryo mold hole and a finished mold cavity at a molding die, wherein the thickness of the preliminary embryo mold cavity It must be smaller than the thickness of the finished part; a first molding step is to simultaneously inject the rubber material into the initial embryo mold hole and the finished mold cavity, and form at least one original blank piece and a finished product part; After the mold is opened, the original blank is moved from the initial mold cavity into the finished mold cavity, and the finished product is separated from the molding die; and a second injection molding step is performed. The priming piece and the priming cavity in the finished mold cavity are simultaneously subjected to injection coating and injection molding, and after the mold is held and cooled, the primordial piece and the finished part are simultaneously produced; by the above steps, The pressure holding and cooling time during injection molding can be greatly shortened, so that the production cost can be greatly reduced, the productivity can be increased, and the surface of the finished product can be prevented from shrinking. The thick plastic injection molding method according to claim 1, wherein the initial movement of the original blank into the finished cavity step is set to be manual or automated. A thick plastic injection mold comprises: a molding die comprising a movable mold side and a static mold side, and a groove is arranged on the movable mold side, and an initial embryo mold is arranged on the bottom portion of the concave mold. a hole, a finished mold hole, a first-class track between the two mold holes and a positioning cone; and a moving positioning mechanism, comprising a carrier plate and two positioning holes, wherein the carrier plate sinks into the movable mold In the side groove, one of the positioning holes is sleeved in the positioning cone in the groove, and the carrier plate is provided with two supporting holes corresponding to the initial embryo cavity and the finished mold hole; The hole can support the preformed solidified piece, and after the mold is opened, the plate is ejected and rotated by the manual or automatic device, and the other positioning hole is inserted into the positioning cone, and then The priming piece is moved into the finished mold cavity and is again injection molded, thereby covering the priming piece in the finished mold cavity to complete a finished part; by the above steps, the injection molding can be greatly shortened Pressure and cooling time, which can significantly reduce production costs, increase production capacity, and avoid The finished surface having a glycidyl marks. The thick plastic injection mold according to claim 3, wherein the original blank and the finished product are set as thermoplastic engineering plastics, which can be set as polycarbonate (PC), polymethyl methacrylate (PMMA), acrylonitrile. - Butadiene-styrene copolymer (ABS), polypropylene (PP), polyethylene terephthalate (PET), high density polyethylene (HDPE), low density polyethylene (LHPE), thermoplastic rubber (TPE), thermoplastic polyurethane (TPU), polycarbonate + acrylonitrile-butadiene-styrene copolymer (PC/ABS), industrial liquid crystal polymer (LCP), polystyrene (PS) The plastic material of polyetheretherketone (PEEK) or polyether oxime (PES); in addition, the minimum thickness of the finished part is set to at least 4 mm. The thick plastic injection mold of claim 3, wherein one side of the groove on the movable mold side is an initial embryo mold hole, and the other side is a finished mold cavity which can be embedded in the initial embryo. The thick plastic injection mold of claim 3, wherein the flow passage is a cold flow passage, and includes a vertical runner and a transverse flow passage, wherein the horizontal flow passage is configured to flow into the initial embryo cavity while the other side Then flowing into the finished mold cavity, and a first flow regulating device on the transverse flow path to the initial embryo cavity, and a second flow regulating device on the other side flowing to the transverse flow channel of the finished mold cavity. The thick plastic injection mold of claim 3, wherein the flow channel is a hot runner, comprising a hot runner and a transverse heat splitter plate, and the lateral heat splitter plate flows into the direction of the initial embryo cavity Then, the hot runner is connected to the initial mold cavity, and the other side flows into the direction of the finished mold cavity, and then the hot runner is connected to inject the finished mold cavity. The thick plastic injection mold of claim 3, wherein the automatic device is provided in the movable mold side, and the automatic device comprises a driving device and a rotating shaft, wherein the driving device drives the rotating shaft, and the rotating shaft has Connected between the two supporting holes provided in the groove in the groove. The thick plastic injection mold of claim 8, wherein the driving device is configured to be an electric motor, a rotary cylinder, a gear and rack set or a gear and chain set to drive the rotating shaft and the carrier. The thick plastic injection mold of claim 3, wherein a closed circulation cooling water path is arranged on the movable mold side and the static mold side, and each closed circulation cooling water passage is cooled by the initial embryo mold hole, the finished mold cavity and the surrounding thereof. .