JP2007069355A - Mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep the degassing capacity of a mold preventing from a low melting point component from being solidified and accumulated in a degassing route to be deposited by regulating the temperature of the degassing route to the melting point of a volatile component or above. <P>SOLUTION: In the mold equipped with the degassing passage 12 for discharging the gas, which is produced from the molten resin being the member to be molded charged in a cavity 7 at the time of molding, to the outside, a heater 31 for regulating the temperature of the degassing core 11 is provided to the degassing core 11 provided to the degassing passage 12 and a heater 31 is provided so as to regulate the temperature of the degassing core 11 to a temperature higher than the melting point of the gas or above. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a configuration of a molding die having a deaeration path for discharging a volatile component generated from a molding member filled in a cavity to the outside during molding.

In general, in injection molding, a molten resin raw material heated and compressed is filled into a cavity 107 formed between an upper mold 102 and a lower mold 103 of a molding die 101 as shown in FIG. This is carried out through a process of taking out after holding pressure and cooling in the molding die 101.
In this case, the molten resin filled in the cavity 107 contains a low molecular weight component having a low melting point, and when the molten resin is filled in the cavity 107, the low molecular weight component volatilizes and the cavity 107 Gas is generated in 107.
The molten resin is filled into the cavity 107 from the runner 105 of the molding die 101 through the gate 106, and the gas originally generated in the cavity 107 and the gas generated from the molten resin flows into the cavity 107. Of the molding die 101 from the mating surface of the upper mold 102 and the lower mold 103 forming the parting line PL and the gap between the push pin 108 and the hole 108a into which the pin 108 is inserted. It is discharged to the outside.

However, when the gas is discharged from the mating surface of the upper mold 102 and the lower mold 103 or the gap between the pin 108 and the hole 108a, the gas component is solidified during the discharge because the temperature of the molding die 101 is low. Then, it accumulates on the mating surfaces and gaps.
As described above, when deposits accumulate in the mating surface of the upper mold 102 and the lower mold 103 or in the gap between the pin 108 and the hole 108a, the deposits are formed during the opening / closing operation of the molding die 101, etc. This causes a drop in the surface of the cavity 107 for molding and causes appearance defects such as leaving traces of the deposited deposit on the design surface of the molded product after the next shot.

For this reason, there is an example in which a deaeration path that connects the inside of the cavity of the molding die and the outside is formed, and the gas in the cavity is discharged to the outside through the deaeration path.
For example, Patent Document 1 discloses a technique for discharging a gas generated by vaporizing a low molecular weight component such as a release agent, an antioxidant, or an unreacted monomer to the outside through a gas vent formed in a molding die. .
JP 2004-209814 A

In the injection molding apparatus and the like described in Patent Document 1 described above, the gas in the cavity can be discharged to the outside through the deaeration path. However, since the discharged gas is a low melting point component, the gas is removed. Some are cooled and solidified while passing through the air passage.
And the gas solidified in the deaeration channel will accumulate over time, and will block this deaeration channel, and deaeration performance will fall.

A molding die for solving the above problems has the following characteristics.
That is, as described in claim 1, a molding die having a degassing path for discharging volatile components generated from a member to be molded filled in a cavity to the outside during molding, The passage is provided with temperature adjusting means for adjusting the temperature of the degassing path, and the temperature adjusting means adjusts the temperature of the degassing path to a temperature equal to or higher than the melting point of the volatile component.
Thereby, the low melting point component does not solidify and accumulate in the deaeration path, and the deaeration performance of the molding die does not deteriorate.
In other words, since the low melting point volatile component that is kept in the gas state without being solidified in the deaeration channel is pushed out to the outside with the filling of the molten resin at the time of molding, the low melting point component is deposited in the deaeration channel. There is no, and can maintain a beautiful state.
In addition, there is no need to perform complicated maintenance such as disassembling the molding die and cleaning the deaeration path, as in the case where low melting point components are accumulated in the deaeration path, and the molding becomes maintenance-free. Die maintenance man-hours can be greatly reduced.

According to a second aspect of the present invention, the deaeration path is further provided with temperature detection means for detecting the temperature of the deaeration path.
As a result, only when the temperature of the deaeration channel becomes low, the temperature of the deaeration channel can be automatically raised, and low-melting-point components are prevented from accumulating in the deaeration channel with certainty and energy saving. it can.

The molding die according to claim 3, further comprising a degassing path for discharging a volatile component generated from a molding member filled in the cavity to the outside during molding. A deaeration core configured by laminating a plurality of flat members at predetermined intervals is installed in the opening to the cavity of the passage, and a temperature for adjusting the temperature of the deaeration core is set in the deaeration core. Adjusting means is provided, and the temperature adjusting means adjusts the temperature of the degassing core to a temperature equal to or higher than the melting point of the volatile component.
Thereby, a low melting-point component does not solidify and accumulate on a deaeration core, and the deaeration performance of a deaeration core does not fall.
In other words, the low melting point component that is kept in a gas state without being solidified in the degassing core is pushed out to the degassing hole side with the filling of the molten resin at the time of molding, so that the low melting point component is deposited in the degassing core. There is no, and can maintain a beautiful state.
Therefore, there is no need to perform complicated maintenance such as disassembling the molding die and removing the degassing core from the molding die for cleaning, as in the case where a low melting point component is accumulated in the degassing core. It becomes maintenance-free, and the maintenance man-hours for the mold can be greatly reduced.

According to a fourth aspect of the present invention, the degassing core is further provided with temperature detecting means for detecting the temperature of the degassing core.
As a result, the temperature of the degassing core can be automatically raised only when the temperature of the degassing core is lowered, and the low melting point component is prevented from being deposited in the degassing core with certainty and energy saving. it can.

According to the present invention, the low melting point component does not solidify and accumulate in the degassing path, and the degassing performance of the molding die does not deteriorate.
Therefore, it is not necessary to perform complicated maintenance such as disassembling the molding die and cleaning the deaeration path, and maintenance is free, so that the number of maintenance steps for the molding die can be greatly reduced.

  A mode for carrying out the present invention will be described with reference to the accompanying drawings.

First, the schematic structure of the molding die concerning this invention is demonstrated.
As shown in FIG. 1, a molding die 1 is a die used for injection molding of a polymer resin, and includes an upper die 2 and a lower die 3.
A cavity 7 is formed between the upper mold 2 and the lower mold 3, and a mating surface between the upper mold 2 and the lower mold 3 is a parting line PL.

The cavity 7 is filled with heated and compressed molten resin material from the runner 5 of the molding die 1 through the gate 6. The filled molten resin is held and cooled in the cavity 7, cooled and solidified to be a molded product and taken out from the molding die 1.
Further, the molding die 1 is provided with an extrusion pin 8 for facilitating the release of the molded product when the molded product is taken out. The extrusion pin 8 is formed on the molding die 1. The pin hole 8a is slidably inserted.

The cavity 7 of the upper mold 2 is formed with a deaeration hole 12 that is a deaeration path that communicates the inside of the cavity 7 with the outside of the molding die 1. A deaeration core 11 constituting a part of the deaeration path is provided.
The degassing core 11 is disposed at the downstream end of the cavity 7 in the molten resin flow direction, that is, at the end of the cavity 7, and further forms a non-design surface of a molded product molded by the molding die 1. It is arranged on the side cavity surface 7a.

  As shown in FIGS. 2 and 3, the deaeration core 11 includes a slit portion 11a in which a plurality of opening slits 11d, 11d,... Are formed, and fixed portions 11b, which are disposed on both sides of the slit portion 11a. 11b, and is attached to the upper mold 2 so that the surface F side is flush with the cavity surface 7a. Further, the back surface B side of the deaeration core 11 is connected to the deaeration hole 12.

Further, heaters 31 and 31 are provided inside the deaeration core 11, and the temperature of the deaeration core 11 (particularly, the slit portion 11a) is adjusted by the heaters 31 and 31.
The lead wires 31a for supplying power to the heaters 31 are guided to the back surface B side of the deaeration core 11 through the wiring holes 11f formed in the fixing portion 11b, and are then removed from the back surface B side of the deaeration core 11 to the deaeration holes 12. It is led to the outside of the molding die 1 through.

  In this example, since the cavity surface 7a of the lower mold 3 is configured to form the design surface of the molded product, the deaeration core 11 is installed on the cavity surface 7a of the upper mold 2. When the cavity surface 7a that forms the design surface of the molded product is in the upper mold 2, the deaeration core 11 can be installed on the lower mold 3 side.

As shown in FIGS. 4 to 6, the slit portion 11 a is configured by laminating a plurality of plates 21.
The plate 21 is a flat member, and includes a slit forming portion 21a on the front surface F side of the degassing core 11, a degassing passage portion 21b positioned on the back surface B side from the slit forming portion 21a, and a back surface of the degassing core 11. And a connecting portion 21c located on the B side. A connecting hole 21 d is formed in the connecting portion 21 c of the plate 21.
The deaeration passage portion 21b is formed with a heater hole 21e through which the heater 31 passes.

In the plate 21, the plate thickness of the slit forming portion 21a is formed thicker than the plate thickness of the deaeration passage portion 21b, and the plate thickness of the connecting portion 21c is formed thicker than the plate thickness of the slit forming portion 21a. ing.
Therefore, when a plurality of plates 21 are stacked, the connecting portions 21c of the plates 21 come into contact with each other, and a predetermined gap is formed between the slit forming portions 21a and the deaeration passage portions 21b of the plates 21.

Thus, the slit forming portion 21a and the deaeration passage portion 21b of the plate 21 are stacked with a predetermined gap therebetween, and the gap formed between the slit forming portions 21a is the surface F of the deaeration core 11. It becomes the said opening slit 11d located in.
And the slit formation part 21a which forms the opening slit 11d is a gas intake part of the deaeration core 11. FIG.
Further, as shown in FIG. 7, since the thickness of the slit forming portion 21a is thicker than the thickness of the deaeration passage portion 21b, the gap dimension tb formed between the deaeration passage portions 21b is The gap dimension ta formed between the slit forming portions 21a is larger.

The fixing portion 11b is formed of, for example, a block-like member, and a connecting hole 11e penetrating in the stacking direction of the plates 21 is formed in the fixing portion 11b.
Then, by inserting and fastening a fastening member such as a bolt into the connecting hole 11e of the fixing portion 11b and the connecting portion 21c of each plate 21, a plurality of the stacked plates 21, 21. The deaeration core 11 is configured by connecting the fixing portions 11b arranged on both sides of 21.

In the degassing core 11 configured as described above, the gap formed between the degassing passage portions 21 b is continuously formed to the back surface B side of the degassing core 11. The A side and the back surface B side communicate with each other through a slit forming portion 21a and a deaeration passage portion 21b.
Therefore, by installing the degassing core 11 in the upper mold 2 so that the surface F thereof is flush with the cavity surface 7a, the slit forming portion 21a becomes a gas intake portion in the cavity 7, and the slit formation is performed. The gas in the cavity 7 taken from the opening slit 11d of the part 21a can be discharged to the deaeration hole 12 through the deaeration passage part 21b located on the downstream side in the gas flow direction of the slit forming part 21a.

Here, since the surface F of the degassing core 11 where the opening slit 11d is formed between the slit forming portions 21a is in contact with the molten resin filled in the cavity 7, the gap dimension ta of the opening slit 11d is The dimensions are set so as to prevent the molten resin from entering the opening slit 11d. For example, in the present example, the gap dimension ta is set to about 0.03 mm.
On the other hand, the gap dimension tb between the deaeration passage parts 21b arranged adjacent to the slit forming part 21a is set to be larger than the gap dimension ta of the opening slit 11d. It is set to be about 2 mm or more.
Further, the smaller the dimension tc (shown in FIG. 7) from the front surface F side to the rear surface B side of the slit forming portion 21a, the smaller the deaeration resistance can be made. However, the workability on the design surface side and the degree of freedom of design change are considered. The minimum dimension is set (in this example, it is set to about 2.0 mm or less).

Thus, the slit width (gap between the slit forming portions 21a) dimension ta of the opening slit 11d is set to a small dimension such that the molten resin does not enter, thereby preventing the molten resin from leaking from the cavity 7. .
Further, since the deaeration core 11 is formed by laminating a plurality of plates 21 while being separated by the slit width dimension ta, it is possible to form the opening slits 11d by the number of the laminated plates 21.

Therefore, in the degassing core 11, the area of the opening opening on the surface F is (slit width dimension ta) × (length dimension La of the opening slit 11d (shown in FIG. 2)) × (number of opening slits 11d). Thus, a large opening area can be secured by stacking a large number of plates 21.
Thus, even when the slit width dimension ta of the opening slit 11d is set small to prevent leakage of the molten resin from the cavity 7, it is possible to secure a sufficient opening area for discharging the gas in the cavity 7. It becomes possible.
Then, the amount of gas discharged from the cavity 7 from the parting line PL part of the molding die 1 and the gap part between the extrusion pin 8 and the pin hole 8a is reduced, and solidified gas components are deposited in these parts. During the opening / closing operation of the molding die 1, the deposit falls on the cavity surface 7 a for molding the design surface of the molded product, and falls on the design surface of the molded product after the next shot. It is possible to prevent appearance defects such as deposit marks remaining.

  Further, by forming the plate 21 in a thin plate shape and setting its thickness dimension td (shown in FIG. 7) to be small, even when a large number of plates 21 are stacked, the area occupied by the surface F of the deaeration core 11 is reduced. Therefore, it is possible to obtain a large opening area with the compact degassing core 11. For example, the thickness dimension td is set to about 1.0 mm in this example.

The gas in the cavity 7 enters the deaeration core 11 through the opening slit 11d and passes through the slit formation part 21a → the deaeration passage part 21b → the deaeration hole 12 of the deaeration core 11 in this order. Since the gap dimension tb of the deaeration passage part 21b located on the downstream side in the gas flow direction of the formation part 21a is formed larger than the gap dimension ta of the slit formation part 21a, the gas flowing in the deaeration core 11 The resistance received by can be reduced.
As a result, the gas that has entered the degassing core 11 from the opening slit 11d easily passes through the degassing passage portion 21b, and the degassing flow rate of the degassing core 11 can be increased. An efficient gas discharge device can be configured, and most of the gas in the cavity 7 can be discharged from the degassing core 11 while the degassing core 11 is compactly configured.

Here, as described above, the gas in the cavity 7 discharged from the degassing core 11 to the outside is a volatile component in which the low-melting-point component contained in the molten resin that is a member to be molded filled in the cavity 7 is volatilized. is there.
The melting point of the low melting point component is, for example, about 70 ° C., and is mainly composed of an antistatic agent, a talc dispersant, a light stabilizer and the like.
Further, when the molding die 1 is cooled by filling the cavity 7 with molten resin during molding, the molding die 1 is lowered to a temperature lower than the melting point of the low melting point component (for example, about 40 ° C.). The deaeration core 11 attached to the mold 1 also has a temperature lower than the melting point of the low melting point component.

Thus, as it is, the gas passing through the degassing core 11 is cooled and solidified by the degassing core 11 and is deposited in the slit portion 11 a of the degassing core 11.
Therefore, in the present molding die 1, the temperature of the degassing core 11 is adjusted to a temperature at which the gas is not solidified by the heaters 31 and 31 provided in the degassing core 11, and the gas passing through the degassing core 11 is cooled. To avoid solidification.
That is, the temperature is adjusted by the heaters 31 and 31 so that the temperature of the degassing core 11 is equal to or higher than the melting point of the low melting point component constituting the gas that is a volatile component, and the temperature is maintained. The temperature of the deaeration core 11 maintained by the heaters 31 and 31 is set such that, for example, the temperature of the opening slit 11d is in the temperature range of about 70 ° C. to 100 ° C., and further about 80 ° C. .

Thus, by adjusting the temperature of the deaeration core 11 with the heaters 31 and 31 so as to be equal to or higher than the melting point of the low melting point component constituting the gas, the slits of the plate 21 constituting the deaeration core 11 are adjusted. The low melting point component does not solidify and accumulate in the formation portion 21a and the degassing passage portion 21b, and the degassing performance of the degassing core 11 does not deteriorate.
That is, the low melting point component that has been kept in a gas state without solidifying in the degassing core 11 is pushed out to the degassing hole 12 side with the filling of the molten resin at the time of molding. It does not accumulate and can maintain a beautiful state.

  Therefore, complicated maintenance such as disassembling the molding die 1 and removing the deaeration core 11 from the molding die 1 and cleaning it as in the case where a low melting point component is accumulated in the deaeration core 11. There is no need to carry out the operation, and maintenance-free operation can be achieved, and the maintenance man-hours of the molding die 1 can be greatly reduced.

The degassing core 11 is provided with a temperature sensor 32 that detects the temperature of the degassing core 11. In the case of this example, the temperature sensor 32 is provided integrally with the heater 31.
As shown in FIG. 8, the temperature sensor 32 and the heater 31 are connected to a temperature control device 35, and the temperature of the degassing core 11 detected by the temperature sensor 32 is lower than a preset temperature. In this case, the heater 31 is operated so that the deaeration core 11 is raised to a predetermined temperature.
For example, when the temperature of the deaeration core 11 detected by the temperature sensor 32 falls below 70 ° C., the heater 31 can be operated.

  Thereby, only when the temperature of the degassing core 11 becomes low, the temperature of the degassing core 11 can be automatically raised, and the low melting point component is deposited in the degassing core 11 reliably and with energy saving. Can be prevented.

Further, when the temperature adjustment of the deaeration core 11 to the melting point of the low melting point component or more at the time of molding affects the quality of the molded product, the heater 31 is turned off at the time of molding, After the heater 31 is turned on to melt the low melting point component, the low melting point component can be scattered and removed by air blow or the like.
Also in this case, since it is not necessary to disassemble the molding die 1 and remove the deaeration core 11, the maintenance man-hour of the molding die 1 can be greatly reduced.

  In addition, although the example which provided the heater 31 in the deaeration core 11 was demonstrated in this example, this heater 31 can also be provided in the part of the deaeration hole 12. FIG. Furthermore, it is possible to provide both the deaeration hole 12 and the deaeration core 11.

It is side surface sectional drawing which shows the shaping | molding die concerning this invention. It is a front view which shows the deaeration core with which a shaping die is equipped. It is a side view which shows a deaeration core. It is a bottom view which shows the plate which comprises the slit part of a deaeration core. It is a side view which shows the plate which comprises the slit part of a deaeration core. It is a side view which shows the clearance gap formed between the laminated | stacked plates. It is an enlarged side view which shows the part of the opening slit in a slit part. It is the schematic which shows the heater and temperature sensor which are provided in a deaeration core. It is side surface sectional drawing which shows the conventional shaping die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molding die 2 Upper mold 3 Lower mold 7 Cavity 7a Cavity surface 11 Deaeration core 11a Slit part 12 Deaeration hole 31 Heater 32 Temperature sensor

Claims (4)

A molding die having a deaeration path for discharging volatile components generated from a member to be molded filled in a cavity to the outside during molding,
The deaeration path is provided with temperature adjusting means for adjusting the temperature of the deaeration path,
The temperature adjusting means adjusts the temperature of the deaeration path to a temperature equal to or higher than the melting point of the volatile component.
A molding die characterized by that.   The molding die according to claim 1, wherein the deaeration path is further provided with temperature detection means for detecting the temperature of the deaeration path. A molding die having a deaeration path for discharging volatile components generated from a member to be molded filled in a cavity to the outside during molding,
In the opening to the cavity of the deaeration path, a deaeration core configured by laminating a plurality of flat plate members at a predetermined interval is installed,
The degassing core includes temperature adjusting means for adjusting the temperature of the degassing core,
The temperature adjusting means adjusts the temperature of the degassing core to a temperature equal to or higher than the melting point of the volatile component.
A molding die characterized by that. The molding die according to claim 3, wherein the degassing core is further provided with temperature detecting means for detecting the temperature of the degassing core.

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