TWI581941B - Method of external vacuum injection molding of eva - Google Patents

Description

EVA external vacuum injection molding method

The invention relates to an injection molding method, in particular to an EVA external vacuum injection molding method.

According to the molding technology of the sole, it can be roughly divided into two methods: injection and hot pressing. In either way, during the molding process, the cavity is vacuumed, and the air in the cavity is discharged, thereby obtaining Good quality molded products. In practice, the vacuuming technique can be divided into an external vacuum and an in-mold vacuum. The following two parts are explained.

As shown in FIG. 1 , it is a schematic diagram of vacuum pumping in a conventional mold, which mainly comprises the ability to relatively engage the upper mold 1 and the lower mold 2, and a mold hole 3 between the upper mold 1 and the lower mold 2, which is to be used by an injection machine 4. The mixture is injected into it for foam molding. However, the vacuuming means is carried out through a vacuum extraction device 5 connected to the cavity 3 at the same time as the shot or after the shot to discharge the air in the cavity 3; however, under long-term operation, part The remaining materials and impurities will be blocked in the air passage 6 between the cavity 3 and the vacuum extraction device 5 along with the exhaust gas, and are not easily found by the staff, resulting in air traps or yellowing after a large number of molded articles are produced. It will be discovered. Although it can be cleaned up, it is usually produced at the time of discovery, resulting in waste of cost. In addition, it is necessary to stop the machine when it is cleared, resulting in inconvenience in work.

Another example is the first and second figures of Taiwan Patent M360124, which discloses a hot press forming machine with a vacuum cover device, wherein the lower mold base 10 and the upper mold base 20 are respectively driven by a hydraulic cylinder, and can be produced. Lifting action, and can cause the upper cover 24 to combine with the moving cover 262 to form a closed environment and begin vacuuming operation, however, the lower die holder 10 and the upper die holder 20 are respectively movable, so that The parting line will change with the thickness of the mold base, and it cannot be used with the injection machine at the fixed point, making the manufacturing inconvenient.

Therefore, the present invention is intended to solve the aforementioned problems and disadvantages, and thereby improve the molding process of the sole.

In order to solve the above problems, the present invention discloses an EVA external vacuum injection molding method, which is to apply an external vacuum step before the molten material is injected into the cavity, so that the invention has both injection molding and vacuum evacuation. The double advantage is to improve the processing skills of the sole and avoid cost waste.

In order to achieve the above object, the present invention provides an EVA external vacuum injection molding method, which comprises the following steps: a mold forming step of providing a first mold base and a second mold base, and the second mold base is opposite to the first mold base. Engaging so as to have a parting line between the first mold base and the second mold base; the sealing step is to provide a sealing device disposed on the periphery of the first mold base for making the second mold base and the first mold base After the die holder is joined, a closed space is formed between the two; the vacuum evacuation step is performed to extract the air between the sealed space and the first die base and the second die base; and the projecting step provides an injection device. Having an injection hole, the injection device extends through the sealed space such that the central axis of the injection hole is at the same level as the parting line to inject a molten material between the first mold base and the second mold base; a step of heating and heating the first mold base and the second mold base, and continuing to make a molten material to form a molding material after a ripening time; and removing the second mold base to take out Molded material.

Therefore, the present invention utilizes the injection method to perform EVA molding, and performs vacuuming in cooperation with the cavity, so that the present invention has the dual advantages of injection molding and vacuum evacuation, and is relatively convenient in manufacturing, and does not There is a problem that a vacuum in the mold of the conventional technique produces a large number of defective products, effectively avoiding cost waste.

Furthermore, the first mold base of the present invention has a first mold and is fixed, and the second mold base has a second mold. Thus, as the processed product is different, only the first change is required. The two molds can be used, so that the parting line of the two mold bases is always at a fixed level, so that the injection machine can be injected into the molten material along the parting line, so that the processing is quite convenient and industrially usable.

Further, the present invention can be applied to the manufacture of a double material sole. Therefore, the present invention provides another EVA external vacuum injection molding method, which comprises the following steps: a molding step, providing a first mold base and a relative first mold a second mold base joined by the seat, a middle mold between the first mold base and the second mold base, the second mold base is engaged with the first mold base, so that there is a first mold base and the middle mold a first parting line, a second parting line between the second mold base and the middle mold; and a sealing step for providing a sealing device disposed between the circumferences of the first mold base for the first mold base After the second mold base is joined, a sealed space is formed between the two mold bases; the first vacuum evacuation step is performed to extract the air between the sealed space and the first mold base and the second mold base; Providing a first injection device having a first injection hole, the first injection device is extending through the sealing device such that the central axis of the first injection hole is at the same level as the first parting line to The first molten material is injected between the first mold base and the middle mold; a second injection device having a second injection hole, the second injection device penetrating the sealing device such that the central axis of the second injection hole is at the same level as the second parting line, a second molten material is injected between the second mold base and the middle mold; the mold shifting step is to open the second mold base and move away from the middle mold, and then re-join the second mold base and the first mold base; a vacuuming step of the second mold, after the mold shifting step, extracting air in the sealed space and between the first molten material and the second molten material; and heating and ripening step, heating and heating the first mold base and the second mold base And continuing to make the first molten material and the second molten material foam to form a molding material; and the removing step, opening the second mold base to take out the molding material.

For the convenience of the description, the central idea expressed by the present invention in the column of the above summary of the invention is expressed by the specific embodiments. The various items in the embodiments are set forth in proportion to the description and not in the

2 to FIG. 8 , FIG. 2 is a flow chart of the EVA external vacuum injection molding method of the present invention, and FIGS. 3 to 8 are the devices used in the present invention. The present invention is mainly used for making a sole, and the molding thereof is formed. Proceed as follows:

The mold clamping step 100 is to provide a first mold base 10 and a second mold base 20 joined to the first mold base 10, and the second mold base 20 is operated by hydraulic driving to make the second mold base 20 Engagement is performed toward the first die holder 10 such that there is a parting line 30 between the second die holder 20 and the first die holder 10, as shown in FIG. The first mold base 10 has a first mold 11 , and the second mold base 20 has a second mold 21 opposite to the first mold 11 , and a cavity 31 is formed between the first mold 11 and the second mold 21 . And the parting line 30 passes through the cavity 31, and one end of the cavity 31 has a filling port 32. Further, the peripheral end of the second die holder 20 has a pushing portion 22, and the pushing portion 22 is a guiding angle. shape. In the present invention, the first mold base 10 can be a lower mold, and the second mold base 20 can be an upper mold.

The sealing step 101 provides a sealing device 40 disposed on the periphery of the first mold base 10. The sealing device 40 includes a vacuum cover 41 and a sealing member 42. The vacuum cover 41 is disposed on the periphery of the first die holder 10. The vacuum cover 41 is a rectangular shape, and the sealing member 42 is made of rubber. It is disposed at the edge of the vacuum cover 41 and is slightly inclined toward the first die holder 10. When the second die holder 20 is to be engaged with respect to the first die holder 10, the pusher portion 22 of the second die holder 20 can be opened and sealed. The member 42 biases the sealing member 42 away from the vacuum cover 41 to facilitate the closing of the second die holder 20 and the first die holder 10, and after the air pushing portion 22 passes the sealing member 42, the sealing member 42 can abut the first The outer periphery of the die holder 20 is such that a sealed space 43 is formed between the second die holder 20 and the first die holder 10.

Wherein, when the second die holder 20 is joined to the first die holder 10, the pusher portion 22 can gradually push a portion of the air in the vacuum cover 41 from between the second die holder 20 and the sealing member 42 during movement to The vacuum cover 41 is provided with a feed hole 44. The periphery of the feed hole 44 is provided with a valve 45. The valve 45 is driven by a pressure cylinder 46 to selectively shield the feed hole 44. A gasket 47 is provided at the inner edge of the inlet hole 44.

The vacuum pumping step 102 is performed by a vacuum pumping device 60 disposed on the outer side of the vacuum cover 41, and one end of the vacuum pumping device 60 communicates with the sealed space 43 to extract the air in the sealed space 43. In other words, when the vacuum extracting device 60 is actuated, the air in the cavity 31 can be extracted from between the second die holder 20 and the first die holder 10.

The projecting step 103 is to provide an injection device 50 having an injection hole 51. The central axis of the injection hole 51 is at the same level as the parting line 30 for injecting a molten material into the second mold base 20 and In the cavity 31 between the mold bases 10, wherein the molten material is EVA, and the injection device 50 can be inserted into the sealed space 43 when the valve 45 is opened relative to the inlet hole 44, so that the injection hole 51 is butted to The injection port 32 performs the shot operation. Through the arrangement of the gasket 47, a better sealing effect can be achieved when the injection device 50 is extended into the hole 44 to avoid air communication. Thereby, the injection device 50 of the present invention firstly projects into the sealed space 43, and then vacuums the outside of the mold to obtain a better shot effect.

In the heating and aging step 104, the second mold base 20 and the first mold base 10 are heated and heated, and after a aging time, the molten material is foamed to form a molding material. The heating and aging step 104 is performed by the two heating members 23 and 13 disposed on the second mold base 20 and the first mold base 10, and the heating members 23 and 13 are passed through to heat the second mold 21 and the first mold 11. Heating to form the molten material into a molded material. Among them, the heating members 23 and 13 can also be heated during the manufacturing process to facilitate the ripening operation.

In step 105, the second mold base 20 is opened to take out the molded material.

Therefore, the present invention performs EVA molding by means of injection, and vacuums the outside with the cavity 31, so that the invention has the dual advantages of injection molding and vacuum evacuation, and is quite convenient in manufacturing, and does not There is a problem that a vacuum in the mold of the conventional skill produces a large number of defective products, effectively avoiding cost waste.

Furthermore, since the central axis of the injection hole 51 of the injection device 50 is at the same level as the parting line 30, the soles of different patterns are to be made, even if different second molds 21 are replaced (sole of different patterns) The required second mold 21 has a difference in thickness, and does not affect the alignment of the injection hole 51 of the injection device 50 with the injection port 32 to maintain a normal shot program.

9 to FIG. 11 are another embodiment of the present invention, FIG. 9 is a flowchart of the embodiment, and FIG. 10 and FIG. 11 are structures used in the embodiment, and the molding steps of the embodiment as follows:

The mold clamping step 300 is to provide a first mold base 10 and a second mold base 20 joined to the first mold base 10. The second mold base 20 and the first mold base 10 have a middle mold 70, and a second The die holder 20 and the middle die 70 are respectively driven by the hydraulic driving method to engage the second die holder 20 with the first die holder 10 such that the first die holder 10 and the middle die 70 have a first A mold line 80 is divided, and a second parting line 90 is disposed between the second mold base 20 and the middle mold 70, as shown in FIG. The first mold base 10 has a first mold 11 , a first mold cavity 81 between the first mold 11 and the middle mold 70 , and the second mold base 20 has a second mold 21 , and the second mold 21 and the middle mold 21 . There is a second cavity 91 between the die 70. The first cavity 81 has a first injection port 82 at one end and a second injection port 92 at one end of the second cavity 91. The peripheral end of the second die holder 20 also has a pusher portion 22 having a conductive angle.

The sealing step 301 provides a sealing device 40 disposed between the circumferences of the first mold base 10. The sealing device 40 includes a vacuum cover 41 and a sealing member 42. The vacuum cover 41 is disposed on the periphery of the first die holder 10. The vacuum cover 41 is a rectangular shape, and the sealing member 42 is made of rubber. It is disposed at the edge of the vacuum cover 41 and is slightly inclined toward the first die holder 10. When the second die holder 20 is to be engaged with respect to the first die holder 10, the pusher portion 22 of the second die holder 20 can be opened and sealed. The member 42 is adapted to facilitate closing of the second die holder 20 and the first die holder 10, and after the pusher portion 22 passes over the sealing member 42, the sealing member 42 can abut against the outer periphery of the second die holder 20, so as to make A sealed space 43 is formed between the die holder 20 and the first die holder 10.

The vacuum cover 41 is provided with a first inlet hole 44a and a second inlet hole 44b. The first inlet hole 44a and the second inlet hole 44b can be selectively subjected to at least one or two valves 45 selectively. Shaded. Each of the first inlet hole 44a and the second inlet hole 44b has a gasket 47.

The first vacuum pumping step 302 is performed by a vacuum pumping device 60. The vacuum pumping device 60 is disposed on the outer side of the vacuum chamber 41, and the vacuum pumping device 60 communicates with the airtight space 43 to open the air in the airtight space 43. The air is taken out to form a vacuum state, and even the air of the first cavity 81 and the second cavity 91 is extracted.

The first projecting step 303 is to provide a first injection device 50a having a first injection hole 51a. The first injection device 50a extends into the sealed space 43 via the first inlet hole 44a to make the first injection hole. The central axis of the 51a is at the same level as the first parting line 80, so that the first injection hole 51a is butted against the first injection port 82 for injecting a first molten material into the first cavity 81.

The second shot step 304 is provided with a second ejection device 50b having a second ejection hole 51b, and the second ejection device 50b extends into the sealed space 43 via the second inlet hole 44b to enable the second ejection. The central axis of the hole 51b is at the same level as the second parting line 90, so that the second injection hole 51b is butted against the second injection port 92 for injecting a second molten material into the second cavity 91. And the selection of the materials of the first molten material and the second molten material varies with demand. Thereby, the first injection device 50a and the second injection device 50b of the present embodiment first extend into the sealed space 43, and then vacuum the outside of the mold to obtain a better shot effect.

The mold shifting step 305 opens the second mold base 20 and moves away from the middle mold 70, and then re-engages the second mold base 20 with the first mold base 10.

The second external vacuuming step 306 is performed after the mold shifting step 305, and the air in the sealed space 43 is extracted by the vacuum extracting device 60, so that the sealed space 43 is in a vacuum state, even if the first cavity 81 and the second die are formed. The air of the cavity 91 is extracted while also allowing the air between the first molten material and the second molten material to be extracted.

In the heating and aging step 307, the second mold base 20 and the first mold base 10 are heated and heated for a aging time to foam the first molten material and the second molten material to form a shaped material. The heating and ripening step 305 is performed by the two heating members 23 and 13 disposed on the second mold base 20 and the first mold base 10. Among them, the heating members 23 and 13 can also be heated during the manufacturing process to facilitate the ripening operation.

In step 308, the second mold base 20 is opened to take out the molded material.

Therefore, in addition to the advantages of the foregoing embodiments, the present embodiment has the advantages of two-shot injection molding by arranging a middle mold 70 between the second mold base 20 and the first mold base 10. Double sole.

While the invention has been described in terms of a preferred embodiment, the various embodiments may The above embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention. All modifications or changes made without departing from the spirit of the invention are within the scope of the invention.

Conventional part
1‧‧‧上模
3‧‧‧ cavity
5‧‧‧ extraction device part of the invention
10‧‧‧ first mold base
13‧‧‧heating parts
21‧‧‧Second mold
23‧‧‧heating parts
31‧‧‧ cavity
40‧‧‧ Sealing device
42‧‧‧Seal
44‧‧‧Inlet hole
44b‧‧‧Second feed hole
46‧‧‧pressure cylinder
50‧‧‧Injection device
50b‧‧‧second injection device
51a‧‧‧First shot hole
60‧‧‧Vacuum extraction device
80‧‧‧First parting line
82‧‧‧First injection port
91‧‧‧Second cavity
100, 300‧‧ ‧ moulding steps
102‧‧‧External vacuuming step
306‧‧•External vacuuming step
303‧‧‧First shot step
305‧‧‧Molding step
105, 308‧‧‧ removal steps
2‧‧‧Down
4‧‧‧Injector
6‧‧‧ airway
11‧‧‧First mould
20‧‧‧Second mold base
22‧‧‧Pushing Department
30‧‧ ‧ parting line
32‧‧‧ injection port
41‧‧‧vacuum cover
43‧‧‧Confined space
44a‧‧‧First feed hole
45‧‧‧ valve
47‧‧‧Washers
50a‧‧‧first injection device
51‧‧‧ shot hole
51b‧‧‧second shot hole
70‧‧‧中模
81‧‧‧ first cavity
90‧‧‧Second parting line
92‧‧‧second injection port
101, 301‧‧‧ Sealing steps
302‧‧‧First external vacuum step
103‧‧‧Shipping steps
304‧‧‧second shot step
104, 307‧‧‧ Heating ripening steps

[Fig. 1] is a schematic diagram of a conventional in-mold evacuation. [Fig. 2] A flow chart of the molding method of the present invention. Fig. 3 is a schematic view showing the appearance of the apparatus used in the present invention. [Fig. 4] is a schematic view showing the unsealed state of the device used in the present invention. [Fig. 5] is a schematic view showing a sealed state of the device used in the present invention. Fig. 6 is a schematic view showing another appearance of the apparatus used in the present invention. Fig. 7 is a schematic view showing the state of the shot of the present invention. Fig. 8 is an enlarged schematic view showing the state of the shot of the present invention. FIG. 9 is a flow chart of another embodiment of the present invention. Fig. 10 is a schematic view showing an unsealed state of another embodiment of the present invention. Fig. 11 is a schematic view showing the state of a shot of another embodiment of the present invention.

100‧‧‧Molding steps

101‧‧‧ Sealing step

102‧‧‧External vacuuming step

103‧‧‧Shipping steps

104‧‧‧heating and ripening steps

105‧‧‧ removal steps

Claims (8)

An EVA external vacuum injection molding method, comprising the following steps: a molding step, providing a first mold base and a second mold base, and engaging the second mold base with respect to the first mold base, so that the a first mold base and the second mold base have a parting line; a sealing step is provided with a sealing device disposed between the circumferences of the first mold base for making the first mold base and the first mold base After the two mold bases are joined, a sealed space is formed between the two mold bases, wherein the sealing device comprises a vacuum cover disposed on the periphery of the first mold base, the vacuum cover is provided with a feed hole, and a selective shielding a valve for the inlet hole; an external vacuuming step of extracting the air between the sealed space and the first mold base and the second mold base; and the projecting step is to provide an injection device having an injection hole. The injection device penetrates the sealed space through the inlet hole such that the central axis of the injection hole is at the same level as the parting line to inject a molten material into the first mold base and the second mold. Between the seats; the heating and ripening step is performed on the first mold base Up heating for the second block, and a post-ripening duration, so that the molten material is molded to a foamed into profiles; and removing step, turning on the second block line, to take out the shaped profile. The EVA external vacuum injection molding method of claim 1, wherein the sealing device comprises a sealing member disposed at an edge of the vacuum cover, when the second die holder is coupled to the first die holder, The seal abuts the outer periphery of the second mold base. The EVA extra-mold vacuum injection molding method according to claim 2, wherein the sealing member is made of a rubber material. The EVA extra-mold vacuum injection molding method according to claim 1, wherein the vacuum evacuation step is performed by a vacuum extraction device. The EVA external vacuum injection molding method according to claim 1, wherein the heating and aging step is performed by two heating members disposed on the first mold base and the second mold base. The EVA external vacuum injection molding method of claim 1, wherein a cavity is formed between the first die holder and the second die holder, and a cavity is provided at one end of the cavity to engage the injection hole. . An EVA external vacuum injection molding method includes the following steps: a mold clamping step of providing a first mold base and a second mold base joined to the first mold base, the first mold base and the second mold Between the seats, there is a middle mold, the second mold base is engaged with the first mold base, so that the first mold base and the middle mold have a first parting line, and the second mold base is a second parting line is disposed between the middle molds; and a sealing step is provided between the periphery of the first mold base for engaging the first mold base and the second mold base Forming a closed space between the two, wherein the sealing device comprises a vacuum cover disposed on a periphery of the second mold base, the vacuum cover being provided with a first feed hole and a second feed hole, and a valve for selectively shielding the first inlet hole and the second inlet hole; the first external vacuuming step is to evacuate the sealed space and the air between the first mold base and the second mold base; The first projecting step is to provide a first injection device having a first injection hole, and the first injection device extends the sealing space through the first inlet hole to make the central axis of the first injection hole Is at the same level as the first parting line to inject a first molten material between the first mold base and the middle mold; and the second shot step provides a second injection device having a a second injection hole, the second injection device extends the sealing space through the second inlet hole, so that the central axis of the second injection hole is at the same level as the second parting line, so as to be a second molten material is injected between the second mold base and the middle mold; a mold shifting step is to open the second mold base and move away from the middle mold, and then the second mold base and the first mold base are again a second vacuum pumping step, after the mold shifting step, extracting air between the first molten material and the second molten material in the sealed space; and heating the ripening step to the first mold base Warming and heating with the second mold base, and continuing for a time between maturing, so that the first Into molten material and the second material is molded to a foamed into profiles; and removing step, turning on the second block line, to take out the shaped profile. The EVA external vacuum injection molding method of claim 7, wherein the sealing device comprises a sealing member disposed at an edge of the vacuum cover, when the second die holder is coupled to the first die holder, The seal abuts the outer periphery of the second mold base.