CA2475758A1 - Method and apparatus for injection molding - Google Patents
Method and apparatus for injection molding Download PDFInfo
- Publication number
- CA2475758A1 CA2475758A1 CA 2475758 CA2475758A CA2475758A1 CA 2475758 A1 CA2475758 A1 CA 2475758A1 CA 2475758 CA2475758 CA 2475758 CA 2475758 A CA2475758 A CA 2475758A CA 2475758 A1 CA2475758 A1 CA 2475758A1
- Authority
- CA
- Canada
- Prior art keywords
- assembly
- injection
- plasticization
- synthetic resinous
- resinous material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
- B29C45/53—Means for plasticising or homogenising the moulding material or forcing it into the mould using injection ram or piston
- B29C45/54—Means for plasticising or homogenising the moulding material or forcing it into the mould using injection ram or piston and plasticising screw
- B29C45/542—Means for plasticising or homogenising the moulding material or forcing it into the mould using injection ram or piston and plasticising screw using an accumulator between plasticising and injection unit, e.g. for a continuously operating plasticising screw
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
A method and apparatus are disclosed for the production of injection molded products from a wide variety of synthetic resinous materials, without predrying. The apparatus includes a plasticization assembly in proximity to, and interconnected with, a melt reservoir and an injection assembly, wherein, the injection assembly alternatively accepts plasticated and masticated synthetic resinous material from the melt reservoir or expels said material into the molding assembly, and the melt reservoir accepts plasticated and masticated synthetic resinous material from the plasticization assembly and transfers said material into the injection cylinder. An interconnecting assembly is used for providing communication between the plasticization assembly, the injection assembly, and the melt reservoir.
Description
TITLE: METHOD AND APPARATUS FOR INJECTION MOLDING
I. BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates generally to methods and apparatus for injection molding. More particularly, this invention concerns a method and apparatus for injection molding for use for articles made from synthetic hygroscopic synthetic resinous materials.
I. BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates generally to methods and apparatus for injection molding. More particularly, this invention concerns a method and apparatus for injection molding for use for articles made from synthetic hygroscopic synthetic resinous materials.
2. Description of prior art As is know in the field of injection molding, the injection molding machine typically receives synthetic resinous material as a particulate feedstock, heats, plasticates and masticates the synthetic resinous material to a moldable consistency and forces the plasticated synthetic resinous material into a molding assembly. When dealing with hygroscopic synthetic resinous materials in common commercial practice, the synthetic resinous materials, in particulate form, are passed through a separate pre-drying apparatus before entering molding apparatus. In the pre-drying apparatus the particulate synthetic resinous material is exposed to dry heat for a predetermined period of time at a temperature below the synthetic resinous material melting temperature. This pre-drying has been necessary since water, present in the particulate synthetic resinous material, vaporizes during the material plasticization and generates pockets of water vapour. The provision of separate drying apparatus includes an additional capital expense, which detracts from profitability of the injection molding apparatus Many defects are attributed to the evolution of gaseous pockets containing water vapour or volatilized substances. For example, defects such as polymer degradation and diminished physical material properties in a molded product have been associated with gaseous pockets. Moreover, surface defects, such as loss of gloss and voids, sometimes occur in the molded product as a result of gaseous pockets. These latter defects are sometimes merely cosmetic but do, on occasion, substantially affect physical properties of the molded product.
In fashioning articles of indeterminate length from synthetic resinous materials, vented extruders allow removal of volatiles as well as moisture from feedstock.
Extruders, however, operate with essentially steady synthetic resinous material flow into the machine, essentially steady or continuous flow of product out of the machine, and essentially steady flow of synthetic resinous material through a vent section of the extruder machine. As a result of the essentially steady operation of the vented extruders, only small perturbations of flow conditions inside the barrel at a vent port exhaust device opening typically occur.
A typical injection molding machine, by contrast, operates in a three-part cycle, a plasticizing portion during which feedstock is heated, plasticated, and masticated to a moldable consistency, an injection portion during which the plasticizied synthetic resinous material is injected into a molding assembly, and a holding portion during which synthetic resinous material in the mold is permitted to solidify. A variation of this method is in a two-stage injection molding process where in the masticated and plasticated synthetic resinous material is transferred from the plasticizing assembly into the injection assembly. The synthetic resinous material is then expelled from the injection assembly into a molding assembly under high injection pressure. In both cases, a plasticizing screw is typically impulsively stroked forward through a distance of several inches to transfer a charge of plasticized synthetic resinous material, either into a molding assembly or into the injection assembly.
In an effort to overcome some of the disadvantages associated with the production of molded objects from hygroscopic synthetic resinous materials, the use of vented injection molding machines, allowing gaseous volatiles to escape, has been suggested.
However, the cyclical operation of injection molding machines causes unsteady flow conditions to prevail inside these molding machines. This in turn contributes to a particularly undesirable result, wherein plasticized synthetic resinous materials are discharged or bleed from the vent port exhaust device. As a result, the masticated and plasticated synthetic resinous material has a tendency to pass outwardly of the barrel through the vent port exhaust device openings, through which water vapour and volatile gases are intended to be exhausted. When this unfavourable result occurs, the masticated and plasticated synthetic resinous material may solidify in the vent port exhaust device opening, thereby blocking the opening and severely inhibiting, if not actually preventing the subsequent release of volatilized material from the vent port exhaust device opening.
For example, United States Patent No. 6,187,229, granted Feb. 13, 2001, to Kiyoto et al.
for a "Process for Molding Information Recording Disks" discloses a molding process, wherein plasticization, injection and filing of synthetic resinous materials are carried out in separate cylinders. A synthetic resinous material, such as polycarbonate, is supplied, with out pre-drying, to an injection molding machine, for molding. The synthetic resinous material is masticated and plasticated by the machine, while volatile components are heated, vaporized and exhausted through a vent port exhaust device.
A main disadvantage is present in the above-summarized process. The synthetic resinous material is extruded into an injection cylinder and then transferred, under high pressure, to a mold, while the screw remains stationary during the holding portion of the molding cycle, thus allowing a pooling of melted synthetic resinous material. When the screw resumes its rotation, the pool of melted synthetic resinous material is conveyed, at a relatively high speed, along the screw. Thus, a surge, which normally causes vent port exhaust device bleed and the associated problems stated above, is formed.
United States Patent No. 6,234,659 granted May 22, 2001, to Takashima et al., for a "Surge Suppressor for Vented Injection Molding Machine Screw" describes a plasticizing apparatus installed in a vented injection molding machine which operates without pre-drying. The vented injection molding machine includes a two-stage screw, rotatably and reciprocably mounted within a barrel. A surge suppressor is provided between the first and second stages and comprises an integral protrusion of the screw root and a deep channel section immediately following the protrusion. The surge suppressor prevents the surge of molten synthetic resinous material into the vent area, following the holding portion of an injection molding cycle, thereby allowing faster recovery and preventing bleeding of plasticized synthetic resinous material from the vent port exhaust device opening. The main disadvantage of the above surge suppressor, used with a molding machine screw, resides in the following: this design requires a support for the increased length of the two-stage cantilevered screw, so as to obtain an appropriate seal in the second stage of the screw. Furthermore, the reciprocating nature of the screw, within the barrel, limits the range of shot size. Also, the surge suppressor required to be adapted to the viscosity of the melted synthetic resinous material.
Examples of particular synthetic resinous materials for which venting is desirable during injection molding are as follows: polyesters, polycarbonates, nylons, acrylics, ABS, styrenic polymers, acetal polymers, polyphenylene oxides, polyethylene terephthalate (PET) and barrier resins.
II. SUMMARY OF THE INVENTION
Accordingly, it is seen that a need continues to exist for a truly effective method and apparatus for vented injection molding.
It is a first objective of the present invention to elaborate a method and design an apparatus that allows the use of non pre-dried synthetic resinous material.
It is a second objective of the present invention to develop, based on a new method, a simple to operate, reliable, injection molding machine which is not prone to polymer oxidation.
It is a third objective of the present invention to obtain a wide range of shot sizes, while preventing vent port exhaust device bleed.
Generally stating, the injection molding machine, according to the present invention, comprises the following main assemblies:
- a plasticization assembly adapted to receive, masticate and plasticate a pre-established quantity of synthetic resinous material, the plasticization assembly being in proximity to, and interconnected with, - a melt reservoir assembly and an injection assembly, so that while the melt reservoir assembly communicates with the plasticization assembly, the injection assembly forcibly expels said. synthetic resinous material, already masticated and plasticated, into a molding assembly, successively, the melt reservoir assembly is in communication with the injection assembly such that the pre-established quantity of synthetic resinous material is transferred to the injection assembly;
- an interconnecting assembly for providing - a communication between the plasticization assembly and th.e melt reservoir assembly, and between the injection assembly and molding assembly, successively, and - a communication between the melt reservoir assembly and the injection assembly, allowing the transfer of the pre-established quantity of synthetic resinous material;
- a common base incorporating a lower stationary base and an upper moving base, the latter being used - to support and - alternatively translate the plasticization assembly, melt reservoir assembly, and the injection assemblies on the lower stationary base; and - a translating assembly for alternatively translating the upper moving base with respect to the lower stationary base and the molding assembly.
In one aspect of this invention, the plasticization assembly comprises a cylindrical-housing subassembly incorporating a feed end in proximity to the electrical motor-mechanical transmission unit; a discharge at the distal end of the cylindrical housing; and a vent port exhaust device positioned at a mid point. The plasticizing assembly further comprises band-heaters, mounted around the cylindrical-housing subassembly, respectively its external surface; a hopper connected to the feed port of the cylindrical-housing subassembly, wherein synthetic resinous material is discharged; an inlet for introducing an inert gas into the cylindrical-housing subassembly communicating with the feed port; a vent port exhaust device connecting the interior of the cylindrical-housing subassembly with the environment; and the electrical motor- mechanical transmission unit being coupled to the two stage plasticizing screw. The two stage plasticizing screw is constituted by, a thread having a constant external diameter, commensurate to cooperate with an internal diameter of the cylindrical-housing subassembly, and a variable root diameter. In order to accomplish a two stage plasticizing operation, the variable root diameter basically increases from a minimum to a maximum along a first stage, starting from one extremity, proximate to a drive end to an end of this stage. Along a second stage the root diameter basically replicates the first stage by increasing .from the minimum to the maximum diameter, terminating with a check valve assembly.
In yet another aspect of the present invention, the melt reservoir assembly comprises a cylindrical-housing subassembly that incorporates a reservoir cylinder, coaxial with an actuating cylinder. The reservoir cylinder has a diameter relatively smaller than the diameter of the actuating cylinder, and is usually provided with heating elements. A
plunger is located within the reservoir cylinder, while a piston is located in the actuating cylinder. A rod conveniently interconnects the plunger with the piston, and under the pressure of a fluid, the piston is displaced towards the injection cylinder.
In another aspect of the present invention, the injection assembly comprises a stepped cylindrical-housing subassembly that incorporates an injection cylinder, coaxial with an actuating cylinder. The injection cylinder has a diameter relatively smaller than the diameter of the actuating cylinder, and is usually provided with heating elements. A
plunger is located within the injection cylinder, while a piston is located in the actuating cylinder. A rod conveniently interconnects the plunger with the piston, and under the pressure of a fluid, the piston is displaced towards the injection cylinder.
In yet another aspect of this invention, the interconnecting assembly comprises a manifold, being heated by conventional heating elements, having located at one end, a two position - three port valve. The manifold is connected, at one extremity, to;
- the plasticization assembly and, at its other extremity, to;
- an injection assembly; while at its mid point - to a melt reservoir assembly; the two position - three port valve having a) a first port connected to the melt channel connecting the plasticizing assembly and the melt reservoir assembly;
b) a second port connected to the injection assembly; and c) a fourth port connected, via a nozzle, to a molding assembly.
'The method for injection molding, adapted for use with the above described machine, comprising masticating and plasticati.ng a pre-established quantity of the synthetic resinous material, generally provided with hygroscopic properties, in the a plasticization assembly;
- expelling the synthetic resinous material, already masticated and plasticated, from the plasticization assembly, into the melt reservoir assembly, while - forcibly expelling the synthetic resinous material, already masticated and plasticated, from the injection assembly into a molding assembly, then - transferring the pre-established quantity of the synthetic resinous material, already masticated and plasticated, from the melt reservoir assembly to the injection cylinder upon the completion of the hold portion of the molding cycle, whereby a) masticating and plasticating a pre-established quantity of the synthetic resinous material, generally provided with hygroscopic properties, in the a plasticization assembly;
b) expelling the synthetic resinous material, already masticated and plasticated, from the plasticization assembly, into the melt reservoir assembly, while c) forcibly expelling the synthetic resinous material, already masticated and plasticated, from the injection assembly into a molding assembly, then d) transferring the pre-established quantity of the synthetic resinous material, already masticated and plasticated, from the melt reservoir assembly to the injection cylinder upon the completion of the hold portion of the molding cycle, whereby forgoing steps a, b and c are performed simultaneously and in series with step d, successively, as a continuous process.
III. BREIF DESCRIPTION OF THE DRAWINGS
Although the characteristic features of the invention will be particularly pointed out in the claims, the invention itself and the manner in which it may be made and used may be better understood by referring to the following description and accompanying drawings.
Like reference numerals refer to like parts throughout the several views of the drawings in which:
Figure 1 is a perspective view of the injection molding machine according to the present invention;
Figure 2 is a vertical cross-section along the plasticization assembly;
Figure 3 is an enlarged view of Detail A of Fig. 2; and Figure 4 is an enlarged view of Detail B of Fig. 2 IV. DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1- 4 illustrate an injection molding machine 100 incorporating the following main assemblies:
- a plasticization assembly 200 adapted to receive, masticate and plasticate a pre-established quantity of synthetic resinous material, the plasticization assembly 200 being in proximity to and interconnected with - a melt reservoir assembly 300 and an injection assembly 400, so that while the melt reservoir assembly 300 communicates with the plasticization assembly 200, the injection assembly 400 forcibly expels the synthetic resinous material, already masticated and plasticated, into a molding assembly (not shown), successively, the melt reservoir assembly 300 communicates with the injection assembly 400 such that the pre-established quantity of synthetic resinous material is transfer to the injection assembly 400;
- an interconnecting assembly 500 for providing - a communication between the plasticization assembly 200 and the melt reservoir assembly 300, and between the injection assembly 400 and molding assembly (not shown), successively, and - a communication between the melt reservoir assembly 300 and the injection assembly 400, when the hold portion of the injection cycle is complete;
- a common base 600 incorporating a lower stationary base 610 and an upper moving base 620, the latter being used - to support and - alternatively translate the plasticization assembly 200, melt reservoir assembly 300, and the injection assembly 400 on the lower stationary base 610; and - a translating assembly 650 for alternatively translating the upper moving base 620 with respect to the lower stationary base 610 and a molding assembly (not shown).
In one aspect of this invention, the plasticization assembly 200 comprises a cylindrical-housing subassembly 210 / constituted of several components /, incorporating a feed port 220 in proximity to the electrical motor- mechanical transmission unit 230; a discharge 240 at the distal end of the cylindrical housing subassembly 210; and a vent port exhaust device 250, connecting the interior of the cylindrical-housing subassembly with the environment, positioned at a mid point. The plasticizing assembly 200, further comprises band-heaters 260, mounted around the cylindrical-housing subassembly 210, respectively its external surface; a hopper 270 connected to the feed port 220 of the cylindrical-housing subassembly 210, wherein synthetic resinous material is discharged; an inlet 280 for introducing an inert gas into the cylindrical-housing subassembly 210 communicating with the feed port 220; and an electrical motor- mechanical transmission unit 230 being coupled to the two stage plasticizing screw 290. The two stage plasticizing screw290 is constituted by, a thread 291 having a constant external diameter 292, commensurate to cooperate with an internal diameter 293 of the cylindrical-housing subassembly 210, and a variable root diameter 294. In order to accomplish a two stage plasticizing operation, the variable root diameter 294 basically increases from a minimum to a maximum along a first stage, starting from one extremity, proximate to a drive end to an end of this stage.
Along a second stage the root diameter basically replicates the first stage by increasing from the minimum to the maximum diameter, terminating with a check valve assembly (not shown).
In yet another aspect of the present invention, the melt reservoir assembly 300 comprises a cylindrical-housing subassembly 310 / constituted of several components/, that incorporates a reservoir cylinder 320, coaxial with an actuating cylinder 330.
The reservoir cylinder 320 has a diameter relatively smaller than the diameter of the actuating cylinder 330, and is usually provided with heating elements 340. A plunger 350 is located within the reservoir cylinder 320, while a piston 360 is located in the actuating cylinder 330. A rod 370 conveniently interconnects the plunger 350 with the piston 360, and under the pressure of a fluid, the piston is displaced towards the reservoir cylinder 320.
In another aspect of the present invention, the inj ection assembly 400 comprises a stepped cylindrical-housing subassembly 410 / constituted of several components/, that incorporates an injection cylinder 420, coaxial with an actuating cylinder 430. The injection cylinder 420 has a diameter relatively smaller than the diameter of the actuating cylinder 430, and is usually provided with heating elements 440. A plunger 450 is located within the injection cylinder 420, while a piston 460 is located in the actuating cylinder 430. A rod 470 conveniently interconnects the plunger 450 with the piston 460, and under the pressure of a fluid, the piston 460 is displaced towards the injection cylinder 420.
In yet another aspect of this invention, the interconnecting assembly 500 comprises a manifold 510, being heated by conventional heating elements (not shown), having located at one end, a two position - three port valve 520. The manifold .'i 10 is connected, at one extremity, to;
- the cylindrical-housing subassembly 210 and, at its other extremity, to;
- an injection cylinder 420; while at its mid point - to a melt reservoir cylinder 320; the two position - three port valve 520 having a) a first port 522 connected to the melt channel connecting the cylindrical-housing subassembly 210 and the reservoir cylinder 320;
b) a second port 524 connected to the injection cylinder 420; and c) a third port 526 connected, via a nozzle 700, to a molding assembly (not shown).
Two position - three port valve 520 is operated as follows:
in a first position, first port 524 communicates with second port 526, so synthetic resinous material is forcible expelled from the injection cylinder 420 via manifold 510 and through nozzle 700 to the molding assembly, simultaneously, the synthetic resinous material, already masticated and plasticated, is extruded from cylindrical housing 210 of plasticization assembly 200, into the melt reservoir cylinder 320, via manifold 510; in a second position, first port 524 communicates with third port 522, so that the synthetic resinous material, already masticated and plasticated, is transferred from the melt reservoir cylinder 320, into the injection cylinder 420, via manifold 510;
The method for injection molding, adapted for use with the above described machine, comprising - masticating and plasticating a pre-established quantity of the synthetic resinous material, generally provided with hygroscopic properties, in the a plasticization assembly 200;
- expelling the synthetic resinous material, already masticated and plasticated, from the plasticization assembly 200, into the melt reservoir assembly 300, while - forcibly expelling the synthetic resinous material, already masticated and plasticated, from the injection assembly 400 into a molding assembly, then - transferring the pre-established quantity of the synthetic resinous material, already masticated and plasticated, from the melt reservoir assembly 300, to the injection cylinder 400, upon the completion of the packing portion of the molding cycle, whereby a) masticating and plasticating a pre-established quantity of the synthetic resinous material, generally provided with hygroscopic properties, in the a plasticization assembly 200;
b) expelling the synthetic resinous material, already masticated and plasticated, from the plasticization assembly 200, into the melt reservoir assembly 300, while c) forcibly expelling the synthetic resinous material, already masticated and plasticated, from the injection assembly 400 into a molding assembly (not shown), then d) transfernng the pre-established quantity of the synthetic resinous material, already masticated and plasticated, from the melt reservoir assembly 300, to the injection cylinder 400, upon the completion of the packing portion of the molding cycle, whereby forgoing steps a, b and c are performed simultaneously and in se~~ies with step d, successively, as a continuous process.
In fashioning articles of indeterminate length from synthetic resinous materials, vented extruders allow removal of volatiles as well as moisture from feedstock.
Extruders, however, operate with essentially steady synthetic resinous material flow into the machine, essentially steady or continuous flow of product out of the machine, and essentially steady flow of synthetic resinous material through a vent section of the extruder machine. As a result of the essentially steady operation of the vented extruders, only small perturbations of flow conditions inside the barrel at a vent port exhaust device opening typically occur.
A typical injection molding machine, by contrast, operates in a three-part cycle, a plasticizing portion during which feedstock is heated, plasticated, and masticated to a moldable consistency, an injection portion during which the plasticizied synthetic resinous material is injected into a molding assembly, and a holding portion during which synthetic resinous material in the mold is permitted to solidify. A variation of this method is in a two-stage injection molding process where in the masticated and plasticated synthetic resinous material is transferred from the plasticizing assembly into the injection assembly. The synthetic resinous material is then expelled from the injection assembly into a molding assembly under high injection pressure. In both cases, a plasticizing screw is typically impulsively stroked forward through a distance of several inches to transfer a charge of plasticized synthetic resinous material, either into a molding assembly or into the injection assembly.
In an effort to overcome some of the disadvantages associated with the production of molded objects from hygroscopic synthetic resinous materials, the use of vented injection molding machines, allowing gaseous volatiles to escape, has been suggested.
However, the cyclical operation of injection molding machines causes unsteady flow conditions to prevail inside these molding machines. This in turn contributes to a particularly undesirable result, wherein plasticized synthetic resinous materials are discharged or bleed from the vent port exhaust device. As a result, the masticated and plasticated synthetic resinous material has a tendency to pass outwardly of the barrel through the vent port exhaust device openings, through which water vapour and volatile gases are intended to be exhausted. When this unfavourable result occurs, the masticated and plasticated synthetic resinous material may solidify in the vent port exhaust device opening, thereby blocking the opening and severely inhibiting, if not actually preventing the subsequent release of volatilized material from the vent port exhaust device opening.
For example, United States Patent No. 6,187,229, granted Feb. 13, 2001, to Kiyoto et al.
for a "Process for Molding Information Recording Disks" discloses a molding process, wherein plasticization, injection and filing of synthetic resinous materials are carried out in separate cylinders. A synthetic resinous material, such as polycarbonate, is supplied, with out pre-drying, to an injection molding machine, for molding. The synthetic resinous material is masticated and plasticated by the machine, while volatile components are heated, vaporized and exhausted through a vent port exhaust device.
A main disadvantage is present in the above-summarized process. The synthetic resinous material is extruded into an injection cylinder and then transferred, under high pressure, to a mold, while the screw remains stationary during the holding portion of the molding cycle, thus allowing a pooling of melted synthetic resinous material. When the screw resumes its rotation, the pool of melted synthetic resinous material is conveyed, at a relatively high speed, along the screw. Thus, a surge, which normally causes vent port exhaust device bleed and the associated problems stated above, is formed.
United States Patent No. 6,234,659 granted May 22, 2001, to Takashima et al., for a "Surge Suppressor for Vented Injection Molding Machine Screw" describes a plasticizing apparatus installed in a vented injection molding machine which operates without pre-drying. The vented injection molding machine includes a two-stage screw, rotatably and reciprocably mounted within a barrel. A surge suppressor is provided between the first and second stages and comprises an integral protrusion of the screw root and a deep channel section immediately following the protrusion. The surge suppressor prevents the surge of molten synthetic resinous material into the vent area, following the holding portion of an injection molding cycle, thereby allowing faster recovery and preventing bleeding of plasticized synthetic resinous material from the vent port exhaust device opening. The main disadvantage of the above surge suppressor, used with a molding machine screw, resides in the following: this design requires a support for the increased length of the two-stage cantilevered screw, so as to obtain an appropriate seal in the second stage of the screw. Furthermore, the reciprocating nature of the screw, within the barrel, limits the range of shot size. Also, the surge suppressor required to be adapted to the viscosity of the melted synthetic resinous material.
Examples of particular synthetic resinous materials for which venting is desirable during injection molding are as follows: polyesters, polycarbonates, nylons, acrylics, ABS, styrenic polymers, acetal polymers, polyphenylene oxides, polyethylene terephthalate (PET) and barrier resins.
II. SUMMARY OF THE INVENTION
Accordingly, it is seen that a need continues to exist for a truly effective method and apparatus for vented injection molding.
It is a first objective of the present invention to elaborate a method and design an apparatus that allows the use of non pre-dried synthetic resinous material.
It is a second objective of the present invention to develop, based on a new method, a simple to operate, reliable, injection molding machine which is not prone to polymer oxidation.
It is a third objective of the present invention to obtain a wide range of shot sizes, while preventing vent port exhaust device bleed.
Generally stating, the injection molding machine, according to the present invention, comprises the following main assemblies:
- a plasticization assembly adapted to receive, masticate and plasticate a pre-established quantity of synthetic resinous material, the plasticization assembly being in proximity to, and interconnected with, - a melt reservoir assembly and an injection assembly, so that while the melt reservoir assembly communicates with the plasticization assembly, the injection assembly forcibly expels said. synthetic resinous material, already masticated and plasticated, into a molding assembly, successively, the melt reservoir assembly is in communication with the injection assembly such that the pre-established quantity of synthetic resinous material is transferred to the injection assembly;
- an interconnecting assembly for providing - a communication between the plasticization assembly and th.e melt reservoir assembly, and between the injection assembly and molding assembly, successively, and - a communication between the melt reservoir assembly and the injection assembly, allowing the transfer of the pre-established quantity of synthetic resinous material;
- a common base incorporating a lower stationary base and an upper moving base, the latter being used - to support and - alternatively translate the plasticization assembly, melt reservoir assembly, and the injection assemblies on the lower stationary base; and - a translating assembly for alternatively translating the upper moving base with respect to the lower stationary base and the molding assembly.
In one aspect of this invention, the plasticization assembly comprises a cylindrical-housing subassembly incorporating a feed end in proximity to the electrical motor-mechanical transmission unit; a discharge at the distal end of the cylindrical housing; and a vent port exhaust device positioned at a mid point. The plasticizing assembly further comprises band-heaters, mounted around the cylindrical-housing subassembly, respectively its external surface; a hopper connected to the feed port of the cylindrical-housing subassembly, wherein synthetic resinous material is discharged; an inlet for introducing an inert gas into the cylindrical-housing subassembly communicating with the feed port; a vent port exhaust device connecting the interior of the cylindrical-housing subassembly with the environment; and the electrical motor- mechanical transmission unit being coupled to the two stage plasticizing screw. The two stage plasticizing screw is constituted by, a thread having a constant external diameter, commensurate to cooperate with an internal diameter of the cylindrical-housing subassembly, and a variable root diameter. In order to accomplish a two stage plasticizing operation, the variable root diameter basically increases from a minimum to a maximum along a first stage, starting from one extremity, proximate to a drive end to an end of this stage. Along a second stage the root diameter basically replicates the first stage by increasing .from the minimum to the maximum diameter, terminating with a check valve assembly.
In yet another aspect of the present invention, the melt reservoir assembly comprises a cylindrical-housing subassembly that incorporates a reservoir cylinder, coaxial with an actuating cylinder. The reservoir cylinder has a diameter relatively smaller than the diameter of the actuating cylinder, and is usually provided with heating elements. A
plunger is located within the reservoir cylinder, while a piston is located in the actuating cylinder. A rod conveniently interconnects the plunger with the piston, and under the pressure of a fluid, the piston is displaced towards the injection cylinder.
In another aspect of the present invention, the injection assembly comprises a stepped cylindrical-housing subassembly that incorporates an injection cylinder, coaxial with an actuating cylinder. The injection cylinder has a diameter relatively smaller than the diameter of the actuating cylinder, and is usually provided with heating elements. A
plunger is located within the injection cylinder, while a piston is located in the actuating cylinder. A rod conveniently interconnects the plunger with the piston, and under the pressure of a fluid, the piston is displaced towards the injection cylinder.
In yet another aspect of this invention, the interconnecting assembly comprises a manifold, being heated by conventional heating elements, having located at one end, a two position - three port valve. The manifold is connected, at one extremity, to;
- the plasticization assembly and, at its other extremity, to;
- an injection assembly; while at its mid point - to a melt reservoir assembly; the two position - three port valve having a) a first port connected to the melt channel connecting the plasticizing assembly and the melt reservoir assembly;
b) a second port connected to the injection assembly; and c) a fourth port connected, via a nozzle, to a molding assembly.
'The method for injection molding, adapted for use with the above described machine, comprising masticating and plasticati.ng a pre-established quantity of the synthetic resinous material, generally provided with hygroscopic properties, in the a plasticization assembly;
- expelling the synthetic resinous material, already masticated and plasticated, from the plasticization assembly, into the melt reservoir assembly, while - forcibly expelling the synthetic resinous material, already masticated and plasticated, from the injection assembly into a molding assembly, then - transferring the pre-established quantity of the synthetic resinous material, already masticated and plasticated, from the melt reservoir assembly to the injection cylinder upon the completion of the hold portion of the molding cycle, whereby a) masticating and plasticating a pre-established quantity of the synthetic resinous material, generally provided with hygroscopic properties, in the a plasticization assembly;
b) expelling the synthetic resinous material, already masticated and plasticated, from the plasticization assembly, into the melt reservoir assembly, while c) forcibly expelling the synthetic resinous material, already masticated and plasticated, from the injection assembly into a molding assembly, then d) transferring the pre-established quantity of the synthetic resinous material, already masticated and plasticated, from the melt reservoir assembly to the injection cylinder upon the completion of the hold portion of the molding cycle, whereby forgoing steps a, b and c are performed simultaneously and in series with step d, successively, as a continuous process.
III. BREIF DESCRIPTION OF THE DRAWINGS
Although the characteristic features of the invention will be particularly pointed out in the claims, the invention itself and the manner in which it may be made and used may be better understood by referring to the following description and accompanying drawings.
Like reference numerals refer to like parts throughout the several views of the drawings in which:
Figure 1 is a perspective view of the injection molding machine according to the present invention;
Figure 2 is a vertical cross-section along the plasticization assembly;
Figure 3 is an enlarged view of Detail A of Fig. 2; and Figure 4 is an enlarged view of Detail B of Fig. 2 IV. DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1- 4 illustrate an injection molding machine 100 incorporating the following main assemblies:
- a plasticization assembly 200 adapted to receive, masticate and plasticate a pre-established quantity of synthetic resinous material, the plasticization assembly 200 being in proximity to and interconnected with - a melt reservoir assembly 300 and an injection assembly 400, so that while the melt reservoir assembly 300 communicates with the plasticization assembly 200, the injection assembly 400 forcibly expels the synthetic resinous material, already masticated and plasticated, into a molding assembly (not shown), successively, the melt reservoir assembly 300 communicates with the injection assembly 400 such that the pre-established quantity of synthetic resinous material is transfer to the injection assembly 400;
- an interconnecting assembly 500 for providing - a communication between the plasticization assembly 200 and the melt reservoir assembly 300, and between the injection assembly 400 and molding assembly (not shown), successively, and - a communication between the melt reservoir assembly 300 and the injection assembly 400, when the hold portion of the injection cycle is complete;
- a common base 600 incorporating a lower stationary base 610 and an upper moving base 620, the latter being used - to support and - alternatively translate the plasticization assembly 200, melt reservoir assembly 300, and the injection assembly 400 on the lower stationary base 610; and - a translating assembly 650 for alternatively translating the upper moving base 620 with respect to the lower stationary base 610 and a molding assembly (not shown).
In one aspect of this invention, the plasticization assembly 200 comprises a cylindrical-housing subassembly 210 / constituted of several components /, incorporating a feed port 220 in proximity to the electrical motor- mechanical transmission unit 230; a discharge 240 at the distal end of the cylindrical housing subassembly 210; and a vent port exhaust device 250, connecting the interior of the cylindrical-housing subassembly with the environment, positioned at a mid point. The plasticizing assembly 200, further comprises band-heaters 260, mounted around the cylindrical-housing subassembly 210, respectively its external surface; a hopper 270 connected to the feed port 220 of the cylindrical-housing subassembly 210, wherein synthetic resinous material is discharged; an inlet 280 for introducing an inert gas into the cylindrical-housing subassembly 210 communicating with the feed port 220; and an electrical motor- mechanical transmission unit 230 being coupled to the two stage plasticizing screw 290. The two stage plasticizing screw290 is constituted by, a thread 291 having a constant external diameter 292, commensurate to cooperate with an internal diameter 293 of the cylindrical-housing subassembly 210, and a variable root diameter 294. In order to accomplish a two stage plasticizing operation, the variable root diameter 294 basically increases from a minimum to a maximum along a first stage, starting from one extremity, proximate to a drive end to an end of this stage.
Along a second stage the root diameter basically replicates the first stage by increasing from the minimum to the maximum diameter, terminating with a check valve assembly (not shown).
In yet another aspect of the present invention, the melt reservoir assembly 300 comprises a cylindrical-housing subassembly 310 / constituted of several components/, that incorporates a reservoir cylinder 320, coaxial with an actuating cylinder 330.
The reservoir cylinder 320 has a diameter relatively smaller than the diameter of the actuating cylinder 330, and is usually provided with heating elements 340. A plunger 350 is located within the reservoir cylinder 320, while a piston 360 is located in the actuating cylinder 330. A rod 370 conveniently interconnects the plunger 350 with the piston 360, and under the pressure of a fluid, the piston is displaced towards the reservoir cylinder 320.
In another aspect of the present invention, the inj ection assembly 400 comprises a stepped cylindrical-housing subassembly 410 / constituted of several components/, that incorporates an injection cylinder 420, coaxial with an actuating cylinder 430. The injection cylinder 420 has a diameter relatively smaller than the diameter of the actuating cylinder 430, and is usually provided with heating elements 440. A plunger 450 is located within the injection cylinder 420, while a piston 460 is located in the actuating cylinder 430. A rod 470 conveniently interconnects the plunger 450 with the piston 460, and under the pressure of a fluid, the piston 460 is displaced towards the injection cylinder 420.
In yet another aspect of this invention, the interconnecting assembly 500 comprises a manifold 510, being heated by conventional heating elements (not shown), having located at one end, a two position - three port valve 520. The manifold .'i 10 is connected, at one extremity, to;
- the cylindrical-housing subassembly 210 and, at its other extremity, to;
- an injection cylinder 420; while at its mid point - to a melt reservoir cylinder 320; the two position - three port valve 520 having a) a first port 522 connected to the melt channel connecting the cylindrical-housing subassembly 210 and the reservoir cylinder 320;
b) a second port 524 connected to the injection cylinder 420; and c) a third port 526 connected, via a nozzle 700, to a molding assembly (not shown).
Two position - three port valve 520 is operated as follows:
in a first position, first port 524 communicates with second port 526, so synthetic resinous material is forcible expelled from the injection cylinder 420 via manifold 510 and through nozzle 700 to the molding assembly, simultaneously, the synthetic resinous material, already masticated and plasticated, is extruded from cylindrical housing 210 of plasticization assembly 200, into the melt reservoir cylinder 320, via manifold 510; in a second position, first port 524 communicates with third port 522, so that the synthetic resinous material, already masticated and plasticated, is transferred from the melt reservoir cylinder 320, into the injection cylinder 420, via manifold 510;
The method for injection molding, adapted for use with the above described machine, comprising - masticating and plasticating a pre-established quantity of the synthetic resinous material, generally provided with hygroscopic properties, in the a plasticization assembly 200;
- expelling the synthetic resinous material, already masticated and plasticated, from the plasticization assembly 200, into the melt reservoir assembly 300, while - forcibly expelling the synthetic resinous material, already masticated and plasticated, from the injection assembly 400 into a molding assembly, then - transferring the pre-established quantity of the synthetic resinous material, already masticated and plasticated, from the melt reservoir assembly 300, to the injection cylinder 400, upon the completion of the packing portion of the molding cycle, whereby a) masticating and plasticating a pre-established quantity of the synthetic resinous material, generally provided with hygroscopic properties, in the a plasticization assembly 200;
b) expelling the synthetic resinous material, already masticated and plasticated, from the plasticization assembly 200, into the melt reservoir assembly 300, while c) forcibly expelling the synthetic resinous material, already masticated and plasticated, from the injection assembly 400 into a molding assembly (not shown), then d) transfernng the pre-established quantity of the synthetic resinous material, already masticated and plasticated, from the melt reservoir assembly 300, to the injection cylinder 400, upon the completion of the packing portion of the molding cycle, whereby forgoing steps a, b and c are performed simultaneously and in se~~ies with step d, successively, as a continuous process.
Claims (6)
1. An injection molding machine incorporating the following main assemblies:
- a plasticization assembly adapted to receive, masticate and plasticate a pre-established quantity of synthetic resinous material, said plasticization assembly being in proximity to and interconnected with - a melt reservoir assembly and an injection assembly, so that while said melt reservoir assembly communicates with said plasticization assembly, said injection assembly forcibly expels said synthetic resinous material, already masticated and plasticated, into a molding assembly, successively, said melt reservoir assembly being in communication with said injection assembly such that said pre-established quantity of synthetic resinous material is transferred to said injection assembly;
- an interconnecting assembly for providing - a communication between said plasticization assembly and said melt reservoir assembly, and between said injection assembly and said molding assembly, successively, and - a communication between said melt reservoir assembly and said injection assembly, when the hold portion of the injection cycle is complete;
- a common base incorporating a lower stationary base and an upper moving base, the latter being used - to support and - alternatively translate said plasticization assembly, said melt reservoir assembly, and said injection assemblies on said lower stationary base; and - a translating assembly for alternatively translating said upper moving base with respect to said lower stationary base and said molding assembly.
- a plasticization assembly adapted to receive, masticate and plasticate a pre-established quantity of synthetic resinous material, said plasticization assembly being in proximity to and interconnected with - a melt reservoir assembly and an injection assembly, so that while said melt reservoir assembly communicates with said plasticization assembly, said injection assembly forcibly expels said synthetic resinous material, already masticated and plasticated, into a molding assembly, successively, said melt reservoir assembly being in communication with said injection assembly such that said pre-established quantity of synthetic resinous material is transferred to said injection assembly;
- an interconnecting assembly for providing - a communication between said plasticization assembly and said melt reservoir assembly, and between said injection assembly and said molding assembly, successively, and - a communication between said melt reservoir assembly and said injection assembly, when the hold portion of the injection cycle is complete;
- a common base incorporating a lower stationary base and an upper moving base, the latter being used - to support and - alternatively translate said plasticization assembly, said melt reservoir assembly, and said injection assemblies on said lower stationary base; and - a translating assembly for alternatively translating said upper moving base with respect to said lower stationary base and said molding assembly.
2. The injection molding machine, as defined in claim 1, wherein said plasticization assembly comprises a cylindrical-housing subassembly incorporating a feed end in proximity to the electrical motor- mechanical transmission unit; a discharge at the distal end of said cylindrical housing; and a vent port exhaust device positioned at a mid point, said plasticizing assembly further comprising band-heaters, mounted around said cylindrical-housing subassembly, respectively its external surface; a hopper connected to said feed port of said cylindrical-housing subassembly, wherein said synthetic resinous material is discharged; an inlet for introducing an inert gas into said cylindrical-housing subassembly communicating with said feed port; said vent port exhaust device connecting the interior of said cylindrical-housing subassembly with the environment;
and said electrical motor- mechanical transmission unit being coupled to a two stage plasticizing screw; said two stage plasticizing screw, rotating about its longitudinal axis of symmetry, without any rectilinear displacement, being constituted by a thread having a constant external diameter, commensurate to cooperate with an internal diameter of said cylindrical-housing subassembly and a variable root diameter, and in order to accomplish a two stage plasticizing operation, said variable root diameter basically increases from a minimum to a maximum along a first stage, starting from one extremity, proximate to said drive end to an end of said stage, and along a second stage said root diameter basically replicates said first stage by increasing from said minimum to said maximum diameter and terminating with a check valve assembly.
and said electrical motor- mechanical transmission unit being coupled to a two stage plasticizing screw; said two stage plasticizing screw, rotating about its longitudinal axis of symmetry, without any rectilinear displacement, being constituted by a thread having a constant external diameter, commensurate to cooperate with an internal diameter of said cylindrical-housing subassembly and a variable root diameter, and in order to accomplish a two stage plasticizing operation, said variable root diameter basically increases from a minimum to a maximum along a first stage, starting from one extremity, proximate to said drive end to an end of said stage, and along a second stage said root diameter basically replicates said first stage by increasing from said minimum to said maximum diameter and terminating with a check valve assembly.
3. The injection machine, as defined in claim 1 or 2, wherein said melt reservoir assembly comprises a cylindrical-housing subassembly incorporating a reservoir cylinder, coaxial with an actuating cylinder, said reservoir cylinder having a diameter relatively smaller than the diameter of said actuating cylinder, and being usually provided with heating elements; a plunger being located within said reservoir cylinder, while a piston is located in said actuating cylinder, a rod conveniently interconnecting said plunger with said piston, and, under the pressure of a fluid, said piston being displaced towards said injection cylinder.
4. The injection molding machine, as defined in claim 1 or 2, wherein, said injection assembly comprises a stepped cylindrical-housing subassembly that incorporates an injection cylinder, coaxial with an actuating cylinder, said injection cylinder having a diameter relatively smaller than said diameter of the actuating cylinder, and being usually provided with heating elements; a plunger being located within said injection cylinder, while a piston is located in said actuating cylinder and a rod conveniently interconnects said plunger with said piston, and under the pressure of a fluid, said piston is displaced towards said injection cylinder.
5. The injection machine, as defined in claim 1 or 2, wherein the interconnecting assembly comprises a manifold, heated by conventional heating elements, and having at one end, a two position - three port valve, said manifold being connected, at one extremity, to;
- said plasticization assembly and, at its other extremity, to;
- said injection assembly; while at its mid point being connected to;
- said melt reservoir assembly;
- said two position - three port valve having - a first port connected to said melt channel for interconnecting said cylindrical-housing subassembly and said melt reservoir cylinder;
- a second port connected to said injection cylinder; and - a third port connected, via a nozzle, to said molding assembly.
- said plasticization assembly and, at its other extremity, to;
- said injection assembly; while at its mid point being connected to;
- said melt reservoir assembly;
- said two position - three port valve having - a first port connected to said melt channel for interconnecting said cylindrical-housing subassembly and said melt reservoir cylinder;
- a second port connected to said injection cylinder; and - a third port connected, via a nozzle, to said molding assembly.
6. A method for injection molding, adapted for use with an injection molding machine, said injection molding machine incorporating the following main assemblies:
- a plasticization assembly adapted to receive, masticate and plasticate a pre-established quantity of synthetic resinous material, said plasticization assembly being in proximity to and interconnected with - a melt reservoir assembly and an injection assembly, so that while said melt reservoir assembly communicates with said plasticization assembly, said injection assembly forcibly expels said synthetic resinous material, already masticated and plasticated, into a molding assembly, successively, said melt reservoir assembly being in communication with said injection assembly, such that said pre-established quantity of synthetic resinous material is transfer to said injection assembly;
- an interconnecting assembly for providing - a communication between said plasticization assembly and said melt reservoir assembly, and between said injection assembly and said molding assembly, successively, and - a communication between said melt reservoir assembly and said injection assembly, when the hold portion of the injection cycle is complete;
- a common base incorporating a lower stationary base and an upper moving base, the latter being used - to support and - alternatively translate said plasticization assembly, said melt reservoir assembly, and said injection assemblies on said lower stationary base;
and - a translating assembly for alternatively translating said upper moving base with respect to said lower stationary base and said molding assembly, said method for injection molding comprising a) masticating and plasticating a pre-established quantity of said synthetic resinous material, generally provided with hygroscopic properties, in said plasticization assembly;
b) expelling said synthetic resinous material, already masticated and plasticated, from said plasticization assembly, into said melt reservoir assembly, while c) forcibly expelling said synthetic resinous material, already masticated and plasticated, from said injection assembly into said molding assembly, then d) transferring the pre-established quantity of said synthetic resinous material, already masticated and plasticated, from said melt reservoir assembly, into said injection cylinder, upon the completion of the holding portion of the molding cycle, whereby forgoing steps a, b and c are performed simultaneously, followed by step d, successively, as a continuous process.
- a plasticization assembly adapted to receive, masticate and plasticate a pre-established quantity of synthetic resinous material, said plasticization assembly being in proximity to and interconnected with - a melt reservoir assembly and an injection assembly, so that while said melt reservoir assembly communicates with said plasticization assembly, said injection assembly forcibly expels said synthetic resinous material, already masticated and plasticated, into a molding assembly, successively, said melt reservoir assembly being in communication with said injection assembly, such that said pre-established quantity of synthetic resinous material is transfer to said injection assembly;
- an interconnecting assembly for providing - a communication between said plasticization assembly and said melt reservoir assembly, and between said injection assembly and said molding assembly, successively, and - a communication between said melt reservoir assembly and said injection assembly, when the hold portion of the injection cycle is complete;
- a common base incorporating a lower stationary base and an upper moving base, the latter being used - to support and - alternatively translate said plasticization assembly, said melt reservoir assembly, and said injection assemblies on said lower stationary base;
and - a translating assembly for alternatively translating said upper moving base with respect to said lower stationary base and said molding assembly, said method for injection molding comprising a) masticating and plasticating a pre-established quantity of said synthetic resinous material, generally provided with hygroscopic properties, in said plasticization assembly;
b) expelling said synthetic resinous material, already masticated and plasticated, from said plasticization assembly, into said melt reservoir assembly, while c) forcibly expelling said synthetic resinous material, already masticated and plasticated, from said injection assembly into said molding assembly, then d) transferring the pre-established quantity of said synthetic resinous material, already masticated and plasticated, from said melt reservoir assembly, into said injection cylinder, upon the completion of the holding portion of the molding cycle, whereby forgoing steps a, b and c are performed simultaneously, followed by step d, successively, as a continuous process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2475758 CA2475758A1 (en) | 2004-08-16 | 2004-08-16 | Method and apparatus for injection molding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2475758 CA2475758A1 (en) | 2004-08-16 | 2004-08-16 | Method and apparatus for injection molding |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2475758A1 true CA2475758A1 (en) | 2006-02-16 |
Family
ID=35852026
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2475758 Abandoned CA2475758A1 (en) | 2004-08-16 | 2004-08-16 | Method and apparatus for injection molding |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2475758A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3944948A1 (en) * | 2020-07-31 | 2022-02-02 | Sumitomo Heavy Industries, Ltd. | Injection molding machine |
-
2004
- 2004-08-16 CA CA 2475758 patent/CA2475758A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3944948A1 (en) * | 2020-07-31 | 2022-02-02 | Sumitomo Heavy Industries, Ltd. | Injection molding machine |
| CN114055736A (en) * | 2020-07-31 | 2022-02-18 | 住友重机械工业株式会社 | Injection molding machine |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1444082B1 (en) | Apparatus for injection molding multilayered articles | |
| US3826477A (en) | Injection molding machine with a venting device | |
| CN100503200C (en) | Rubber injection molding device and rubber product manufacturing method | |
| CA1097471A (en) | Vented injection molding machine | |
| CN1555972A (en) | Polymer material extrusion injection shaping method and its device | |
| US5447425A (en) | Injection molding assembly for forming foam products | |
| MX2007012845A (en) | Apparatus for transferring doses and dose. | |
| CA2476712A1 (en) | Method for injection molding and injection molding machine therefor | |
| CA2475758A1 (en) | Method and apparatus for injection molding | |
| US20130112782A1 (en) | Injection assembly | |
| CA2063924C (en) | Improvements in plasticising units for screw injection moulding machines | |
| KR20000068492A (en) | Production of moulded articles and apparatus for producing moulded articles | |
| JP5246934B2 (en) | Injection molding machine | |
| CA1279455C (en) | Injection molding press | |
| CA1098673A (en) | Parison extrusion head | |
| JP2004322438A (en) | Method for plasticizating resin material and plasticization apparatus for method | |
| US6293690B1 (en) | Vented single stage barrier screw with a gas vent hole and axial bore in the screw for venting gases | |
| US6234659B1 (en) | Surge suppressor for vented injection molding machine screw | |
| US20060099299A1 (en) | Plasticizing unit for micro injection molding machine | |
| KR100346098B1 (en) | Information recording disk injection molding method | |
| US3954362A (en) | Transfer molding thermosetting polymeric material | |
| CN212242008U (en) | Novel double-screw exhaust type injection molding machine | |
| CN220390230U (en) | Anti-overflow injection molding machine extrusion device | |
| US20030026869A1 (en) | Direct transfer conveying mechanism | |
| JP3025775B1 (en) | Screw type plastic injection machine |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |