JP2005144794A - Molding machine of thermoplastic resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding machine of a thermoplastic resin constituted so as to mold a molded product uniform in resin density from the thermoplastic resin by a simple constitution without requiring high pressure. <P>SOLUTION: In the molding machine 10 of the thermoplastic resin for holding the molten thermoplastic A to the space between an upper mold 40 and a lower mold 60, the upper mold 40 has an upper core 45 comprising heat-resistant glass and is held to an upper base 20 equipped with a heat source 30 for emitting radiant heat through the upper core 45 while the lower mold 60 has a cavity 65 for receiving the radiant heat from the heat source 30 through the upper core 45 of the upper mold 40 and is held to a lower base 50. The powdery or pellet-like thermoplastic resin A is charged in the cavity 65 of the lower mold 60 to be melted by the radiant heat from the heat source part 30 of the upper mold 40 and the molten thermoplastic resin A is held between the upper and lower molds 40 and 60 to be compression-molded. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a thermoplastic resin molding apparatus that molds by sandwiching a molten thermoplastic resin between an upper mold and a lower mold.

As a technique for molding a conventional thermoplastic resin, for example, there is an injection molding apparatus.
That is, as is well known, the injection molding apparatus melts a thermoplastic resin in advance and stores it in a heating cylinder, and the molten resin introduced from the heating cylinder is inserted into a gap in the form of a molded product formed between molds. It is filled with high pressure and cooled and solidified.

  However, in such a conventional technique, the thermoplastic resin must be melted and stored in advance, and it must be led to the mold while being melted. Also, since high pressure is required, high power is required, and the equipment is There was a problem of becoming a big deal. Also, since a high melting temperature is set to ensure fluidity when filling, the resin is likely to deteriorate, and as the distance from the filling gate increases, the resin becomes less dense, and the uneven density tends to deform the product. In order to prevent this, it is necessary to manage the temperature of the mold in a complicated manner, and it is necessary to provide a large number of filling gates. There was a problem that it took.

  The present invention has been made by paying attention to such problems of the conventional technology, and can be molded with a simple structure from a thermoplastic resin that does not require high pressure and has a uniform resin density. An object of the present invention is to provide a thermoplastic resin molding apparatus.

The gist of the present invention for achieving the object lies in the inventions of the following items.
[1] A thermoplastic resin molding apparatus (10) for sandwiching and molding a molten thermoplastic resin (A) between an upper mold (40) and a lower mold (60),
The upper mold (40) has an upper core (45) made of heat-resistant glass, and is held by an upper base (20) including a heat source (30) that radiates radiation heat through the upper core (45).
The lower mold (60) has a cavity (65) that receives radiation heat from the heat source section (30) through the upper core (45) of the upper mold (40) and is held by the lower base (50). And
Powder or pellet-shaped thermoplastic resin (A) is put into the cavity (65) of the lower mold (60), and the thermoplastic resin (A) is radiated from the heat source (30) of the upper base (20). A thermoplastic resin molding apparatus (10), wherein the molten thermoplastic resin (A) is sandwiched between the upper mold (40) and the lower mold (60) and compression molded.

[2] A thermoplastic resin molding apparatus (10) for sandwiching and molding a molten thermoplastic resin (A) between an upper mold (40) and a lower mold (60),
The upper mold (40) has an upper core (45) made of heat-resistant glass, and is held by an upper base (20) including a heat source (30) that radiates radiation heat through the upper core (45).
The lower mold (60) has a cavity (65) that receives radiation heat from the heat source section (30) through the upper core (45) of the upper mold (40) and is held by the lower base (50). And a resin leakage gate (70) for releasing excess resin during molding,
Powder or pellet-shaped thermoplastic resin (A) is put into the cavity (65) of the lower mold (60), and the thermoplastic resin (A) is radiated from the heat source (30) of the upper base (20). The molten thermoplastic resin (A) is sandwiched between the upper mold (40) and the lower mold (60) and compression-molded, and excess resin is released from the resin leakage gate (70). A thermoplastic resin molding device (10) characterized in that:

  [3] The heat according to item 1 or 2, wherein the heat source section (30) has a variable wavelength and amplitude of radiation corresponding to the physical properties of the thermoplastic resin (A) to be molded. Plastic resin molding device (10).

  [4] The thermoplastic resin according to item 2, wherein the resin leakage gate (70) maintains a temperature equal to or higher than a temperature at which the thermoplastic resin (A) is melted, and an in-mold pressure can be adjusted. Resin molding device (10).

  [5] The resin leakage gate (70) maintains a temperature equal to or higher than the temperature at which the thermoplastic resin (A) is melted, and the degree of opening of the excess resin discharge gate (71) is adjusted so that the pressure inside the mold can be adjusted. Item 5. The thermoplastic resin molding device (10) according to Item 2 or 4, further comprising a valve member (73) for adjustment and a cylinder (75) for driving the valve member (73).

The present invention operates as follows.
The thermoplastic resin molding apparatus (10) molds by sandwiching the molten thermoplastic resin (A) between the upper mold (40) and the lower mold (60). The upper mold (40) radiates radiant heat from the heat source part (30) toward the lower mold (60) through the upper core (45) made of heat-resistant glass. The heat source part (30) adjusts the wavelength and amplitude of the radiation corresponding to the physical properties of the thermoplastic resin (A) to be molded.

  In the lower mold (60), the thermoplastic resin (A) in the form of powder or pellets is put into the cavity (65), and the thermoplastic resin (A) is melted by the radiation heat from the heat source part (30) of the upper base (20). Is done. Therefore, when the molten thermoplastic resin (A) is sandwiched between the upper mold (40) and the lower mold (60) and compression molded, the molded product becomes a predetermined shape.

  The input amount of the thermoplastic resin (A) is set to be larger than the necessary amount, and the excess resin is allowed to escape from the resin leakage gate (70). The resin leakage gate (70) is closed when the predetermined mold closing amount and in-mold pressure (pressure of the molten resin in the cavity (65)) are reached, the heat source part (30) is stopped, and the thermoplastic resin (A) is When the temperature is lowered to a temperature at which the product can be taken out, the upper die (40) and the lower die (60) are separated from each other, and the molded product is taken out. Molding is performed by repeating these steps.

  The resin leakage gate (70) is maintained at a temperature equal to or higher than the temperature at which the thermoplastic resin (A) is melted. The valve member (73) corresponds to the specifications of the molded product and the physical properties of the thermoplastic resin (A) to be molded. And the cylinder (75) to be driven adjust the opening of the surplus resin discharge gate (71), thereby adjusting the pressure in the mold (pressure of the molten resin in the cavity (65)).

  That is, since the thermoplastic resin (A) is melted by radiation such as infrared rays or laser beams, the equipment is simple and the operation is easy. The melting temperature may be the minimum necessary heating so that the thermoplastic resin (A) can melt and flow in the cavity (65). The thermoplastic resin (A) in the cavity (65) does not decrease in temperature as long as there is radiant heat from the heat source section (30), and there is no need to worry about the decrease in temperature as in normal injection molding. Moreover, since the molten thermoplastic resin (A) in the cavity (65) is compressed as a whole, the resin density becomes uniform. For this reason, problems such as warping and twisting hardly occur.

  Even if it is cooled, it can be subtly cooled while applying radiant heat, so uniform and subtle molding is possible. The position and number of the resin leakage gate (70) are also flexible and do not hinder the molded product. In the first place, no means for transferring the molten resin is required, and no high pressure is required, so that the apparatus is simple and inexpensive.

  According to the thermoplastic resin molding apparatus of the present invention, since the thermoplastic resin put into the lower mold cavity is melted by radiant heat and then compression molded, no high pressure is required and the resin density is uniform. In addition, an apparatus having a simple configuration can be provided at low cost.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.
1 to 3 show an embodiment of the present invention.
The thermoplastic resin molding apparatus 10 is configured to sandwich a molten thermoplastic resin A between an upper mold 40 and a lower mold 60 for molding.

  The upper mold 40 has an upper core 45 made of heat-resistant glass such as quartz glass and is held by an upper base 20 having a heat source section 30 that radiates radiation heat through the upper core 45. The upper mold 40 is provided with a mold temperature control water channel 41 and a proximity sensor 42 that detects the approach to the lower mold 60. The upper base 20 is configured by supporting an upper base plate 25 on support rods 21, 21, a through hole 26 is formed in the upper base plate 25, and a heat source unit 30 is installed on the upper base 20.

  As shown in FIG. 3, the heat source unit 30 includes an infrared lamp 31 and a guide rod 35 on a light collecting member 33 installed on the upper base plate 25. The condensing member 33 has a reflecting surface 34 on the inner surface, and guides the infrared rays from the infrared lamp 31 to the guide rod 35. The infrared lamp 31 is supported by an adjustment screw 32 so that the position of the infrared lamp 31 relative to the light collecting member 33 can be adjusted. The infrared lamp 31 can change the wavelength and amplitude of radiation corresponding to the physical properties of the thermoplastic resin A to be molded.

  The lower mold 60 has a cavity 65 that receives radiation heat from the heat source section 30 through the upper core 45 of the upper mold 40 and a mold temperature adjustment water channel 61 and is held by the lower base 50, and excess resin is removed during molding. A resin leakage gate 70 for escaping is provided.

  The lower base 50 is configured by supporting an upper base plate 55 on an elevating cylinder 51, and a lower mold 60 is installed on the upper base plate 55. The upper base plate 55 is fitted to the support rod 21 via a guide member 56.

  As shown in FIG. 2, the resin leakage gate 70 is a valve that maintains the temperature above the temperature at which the thermoplastic resin A is melted, and adjusts the opening of the excess resin discharge gate 71 so that the pressure inside the mold can be adjusted. A member 73 and a cylinder 75 for driving the valve member 73 are provided.

  The valve member 73 is supported by the outer cylinder 72 so as to be able to advance and retreat, and a cylinder 75 is connected to the rear end of the valve member 73. The outer cylinder 72 is provided with a band heater 74 so as to keep the resin leakage gate 70 at or above the resin melting temperature. The surplus resin discharge gate 71 communicates with a surplus resin discharge port 76 that discharges surplus resin to the outside, and a temperature sensor 77 that detects the temperature of the resin leakage gate 70 is provided.

  With the above configuration, at the time of molding, the powder or pellet-shaped thermoplastic resin A is put into the cavity 65 of the lower mold 60, and the thermoplastic resin A is melted by the radiant heat from the heat source section 30 of the upper base 20. The molten thermoplastic resin A is sandwiched between the lower mold 60 and the lower mold 60, and compression molding is performed. The excess resin is molded by letting it escape from the resin leakage gate 70.

Next, the operation will be described.
The thermoplastic resin molding apparatus 10 performs molding by sandwiching the molten thermoplastic resin A between the upper mold 40 and the lower mold 60. The upper mold 40 radiates radiant heat from the heat source unit 30 toward the lower mold 60 through the upper core 45 made of heat-resistant glass. The heat source unit 30 adjusts the wavelength and amplitude of the radiation corresponding to the physical properties of the thermoplastic resin A to be molded.

  In the lower mold 60, powder or pellet-shaped thermoplastic resin A is put into the cavity 65, and the thermoplastic resin A is melted by radiation heat from the heat source section 30 of the upper base 20. Therefore, when the molten thermoplastic resin A is sandwiched between the upper mold 40 and the lower mold 60 and compression molding is performed, the molded product has a predetermined shape.

  The input amount of the thermoplastic resin A is set to be larger than the required amount, and the surplus resin is allowed to escape from the resin leakage gate 70. When the predetermined mold closing amount and the internal pressure of the mold (pressure of the molten resin in the cavity 65) are reached, the resin leakage gate 70 is closed, the heat source section 30 is stopped, and the thermoplastic resin A is cooled to a temperature at which it can be taken out. Then, the upper mold 40 and the lower mold 60 are separated and the molded product is taken out. Molding is performed by repeating these steps.

  The resin leakage gate 70 is maintained at a temperature equal to or higher than the temperature at which the thermoplastic resin A is melted, and is surplus by the valve member 73 and the driven cylinder 75 corresponding to the specifications of the molded product and the physical properties of the thermoplastic resin A to be molded. The in-mold pressure is adjusted by adjusting the opening degree of the resin discharge gate 71.

  The operation will be described in more detail with reference to FIGS. FIG. 5 is an explanatory view sequentially showing the progress of molding from (a) to (d). FIG. 6 is a process description block diagram. FIG. 7 is a process flowchart. FIG. 8 is a process timing chart. The step numbers in FIG. 7 correspond to the numbers in the lower part of FIG. Further, in FIG. 8, (a) shows the mold opening / closing stroke, (b) shows an enlarged stroke near the mold opening / closing zero, (c) shows the mold clamping force by the upper and lower molds, (D) shows the internal pressure of the resin in the mold, (e) shows the opening of the resin leakage gate 70, and (f) shows the temperature change of the resin during molding.

  FIG. 5A shows a state of preparation for molding. The lower mold 60 is lowered by the elevating cylinder 51 and the upper mold 40 and the lower mold 60 are separated from each other. In the resin leakage gate 70, the surplus resin discharge gate 71 is closed, and the powder / grain / bulk thermoplastic resin A is put into the cavity 65 of the lower mold 60. The feeding is performed by a well-known conveying means. FIG. 7 shows the steps from the start to the resin charging.

  Next, when the upper base plate 55 of the lower base 50 and the lower mold 60 installed on the lower base 50 are raised by the elevating cylinder 51, the state shown in FIG. The mold is closed in step 1 in FIG. 7, and the lower mold 60 is raised to the predetermined mold clamping force in step 2. Therefore, infrared radiation is emitted in step 3 and the temperature is raised to a set value in step 4. In FIG. 6, in “resin temperature setting”, the wavelength and amplitude of radiation such as infrared rays and laser beams from the heat source unit 30 are set in accordance with the properties of the thermoplastic resin A, and the cavity 65 of the lower mold 60 from the upper core 45 is set. The thermoplastic resin A is irradiated.

  The resin temperature is compared with the set temperature, and when the temperature is equal to or higher than the set temperature, the process proceeds from step 4 to step 5 and step 6 in FIG. In FIG. 6, the hydraulic pressure is applied to the elevating cylinder 51 in “mold pressure setting”, and the timing for opening the resin leakage gate 70 is also determined by comparison with a predetermined value. Then, in step 7 of FIG. 7, the end of molding is reached, and in step 8, the valve member 73 of the resin leakage gate 70 is retracted, and the surplus resin discharge gate 71 is opened. In FIG. 6, the process proceeds while watching a delicate stroke by the proximity sensor 42 in the “mold closing amount setting”.

  When the completion of molding is confirmed in step 7 of FIG. 7, the surplus resin discharge gate 71 of the resin leakage gate 70 is closed in step 9, and radiation of radiation from the heat source unit 30 is also stopped in step 10. Next, when the effect of the resin temperature is confirmed in step 11, the lower base 50 and the lower mold 60 are lowered, the mold clamping force is lowered in step 12, and the upper mold 40 and the lower mold 60 are opened in step 13. 5 (d) is reached, and the molded product P is taken out. And if it returns to the state of Fig.5 (a) and the said process is repeated, the molded article P will be produced one after another.

FIG. 4 shows another embodiment of the present invention.
In the present embodiment, the heat source unit 30a is configured to emit radiation in parallel. In addition, the same code | symbol is attached | subjected to the site | part of the same kind as the said embodiment, and the overlapping description is abbreviate | omitted.

  The reflecting surface 34a of the light collecting member 33 is configured to send out radiation rays in parallel. The heat source unit 30 of the previous embodiment is suitable for a case where the heating target is small and a relatively high temperature is required, and this embodiment is suitable for a case where the heating cross section is large and a high temperature is not required. .

It is front explanatory drawing which shows the molding apparatus of the thermoplastic resin which concerns on one embodiment of this invention. It is a section explanatory view showing the important section of the molding device of the thermoplastic resin concerning one embodiment of the present invention. It is a section explanatory view showing the heat source part of the molding device of the thermoplastic resin concerning one embodiment of the present invention. It is sectional explanatory drawing which shows the heat-source part of the shaping | molding apparatus of the thermoplastic resin which concerns on other embodiment of this invention. It is explanatory drawing which shows the shaping | molding process by the shaping | molding apparatus of the thermoplastic resin which concerns on one embodiment of this invention. It is process description block diagram which shows the shaping | molding process by the shaping | molding apparatus of the thermoplastic resin concerning one embodiment of this invention. It is a process flowchart which shows the shaping | molding process by the shaping | molding apparatus of the thermoplastic resin which concerns on one embodiment of this invention. It is a process timing diagram of the molding process by the thermoplastic resin molding apparatus according to an embodiment of the present invention.

Explanation of symbols

A ... thermoplastic resin P ... molded product 10 ... molding device 20 ... upper base 21 ... support rod 25 ... upper base plate 26 ... through hole 30 ... heat source 31 ... infrared lamp 32 ... adjusting screw 33 ... condensing member 34 ... reflecting surface 35 ... induction rod 40 ... upper mold 41 ... mold temperature control channel 42 ... proximity sensor 45 ... upper core 50 ... lower base 51 ... lifting cylinder 55 ... upper base plate 56 ... guide member 60 ... lower mold 61 ... mold temperature control channel 65 ... Cavity 70 ... Resin leakage gate 71 ... Excess resin discharge gate 72 ... Outer cylinder 73 ... Valve member 74 ... Band heater 75 ... Cylinder 76 ... Excess resin discharge port 77 ... Temperature sensor

Claims (5)

A thermoplastic resin molding apparatus for sandwiching and molding a molten thermoplastic resin between an upper mold and a lower mold,
The upper mold has an upper core made of heat-resistant glass, and is held by an upper base having a heat source that radiates radiation heat through the upper core.
The lower mold has a cavity that receives radiation heat from the heat source section through the upper core of the upper mold and is held by the lower base,
The powder or pellet-shaped thermoplastic resin is put into the lower mold cavity, and the thermoplastic resin is melted by the radiant heat from the heat source part of the upper base, and then the heat melted between the upper mold and the lower mold. A thermoplastic resin molding apparatus, wherein a thermoplastic resin is sandwiched and compression molded. A thermoplastic resin molding apparatus for sandwiching and molding a molten thermoplastic resin between an upper mold and a lower mold,
The upper mold has an upper core made of heat-resistant glass, and is held by an upper base having a heat source that radiates radiation heat through the upper core.
The lower mold has a cavity that receives radiation heat from the heat source section through the upper core of the upper mold and is held by the lower base, and includes a resin leakage gate that allows excess resin to escape during molding,
The powder or pellet-shaped thermoplastic resin is put into the lower mold cavity, and the thermoplastic resin is melted by the radiant heat from the heat source part of the upper base, and then the heat melted between the upper mold and the lower mold. A thermoplastic resin molding apparatus, wherein a plastic resin is sandwiched between the resin leakage gates and compression molding is performed by sandwiching the plastic resin.   3. The thermoplastic resin molding apparatus according to claim 1, wherein the heat source unit has a variable wavelength and amplitude of radiation corresponding to physical properties of a thermoplastic resin to be molded. 4.   The apparatus for molding a thermoplastic resin according to claim 2, wherein the resin leakage gate holds a temperature equal to or higher than a temperature at which the thermoplastic resin is melted, and an in-mold pressure can be adjusted. The resin leakage gate holds a temperature higher than the temperature at which the thermoplastic resin is melted, and a valve member that adjusts the opening degree of the excess resin discharge gate so that the pressure inside the mold can be adjusted, and a cylinder that drives the valve member The thermoplastic resin molding apparatus according to claim 2, wherein the thermoplastic resin molding apparatus comprises:

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