KR20110131828A - Injection Molding Device - Google Patents

Abstract

The injection mold apparatus of the present invention has a hollow part, and a shutter is installed at the outlet, the main body, a screw rotatably installed at the main body, a heater installed at the outer circumferential surface of the main body, and gas supply means for supplying gas into the outlet side of the main body. An injection machine provided;
Molding the product by using the resin supplied from the injection machine, having a lower mold supported on the lower fixing plate, and an upper mold to form a cavity for injection molded with the lower mold, the lower mold and the upper mold Cooling means for supplying cooling water to at least one cooling passage formed on one side to cool the injection mold before taking out the molded product from the injection mold, and installed on at least one side of the upper and lower molds to separate, remove and mold the upper and lower molds. And a mold unit provided with heating means for heating the upper and lower molds and maintaining the temperature during injection.

Description

 Injection mold apparatus

The present invention relates to an injection mold apparatus, and more particularly, an injection mold capable of cooling and heating an injection mold during injection using the injection mold, and preventing weld lines from being generated when molding using a resin containing pearl. Relates to a device.

In general, molding of a polymer resin has a problem in that the appearance is not beautiful due to a weld line generated when the molten resin meets inside the injection mold, and the glossiness of the surface is also not excellent. In order to improve this point, a heating molding method that sets the injection mold temperature higher than the melting temperature of the polymer resin to be molded is widely used. Examples thereof include Japanese Patent Application Laid-Open No. 45-22020 (heating method by hot air), and special places. 51-22759 (heating method and electric cooling method by electric heater), Japanese Patent Application Laid-Open No. 55-109639 (high frequency induction heating method), Japanese Patent Application Laid-Open No. 57-165229 (heating by blowing steam into the cavity), Japanese Patent Application Laid-Open No. 61- 79614 (method of inserting a hot plate between the cavity and the core) and Japanese Patent Laid-Open No. Hei 4-265720 (method of heating the surface of a mold by an electrically conductive layer).

However, when molding the polymer resin by setting the mold higher than the melting temperature of the polymer resin in this way, no weld line is formed and the appearance quality is improved in terms of glossiness, but the cooling time is long due to the high mold temperature and the overall molding cycle. This increases the production efficiency is lowered, there is a problem that the deformation caused by shrinkage is larger than the general injection because the polymer resin is not cooled to below the melting temperature and separated from the mold.

As described above, the mold heating methods used in the early days take a long time to heat the mold due to a low heating rate for heating the surface of the mold, thereby increasing the overall product cycle time and improving productivity. There is a problem that the cooling time is long when falling and the temperature of the mold is set to a very high temperature.

The automatic temperature control system of the injection mold in consideration of this point is disclosed in Korea Patent Registration No. 00811909, the automatic injection mold temperature control system, Patent No. 0167711 discloses a mold cooling system, Patent No. 0470835 A mold temperature control system is disclosed. In addition, Patent No. 0701229 has a structure in which rapid heating and cooling of a mold is performed within a range of 100 to 200 degrees / minute.

However, such a structure does not fundamentally solve the above-mentioned problems because cooling and heating of the injection mold are not made in a short time, and in particular, such an injection structure has many cooling lines and hot water supply lines for cooling and heating. There is a problem in that the mold is deformed during repeated molding operation because the structure of the mold is relatively weak.

However, in the injection mold as described above, there is a problem that the weld line is generated by the non-uniform distribution of the pearl during injection molding using the pearl.

The present invention is to solve the problems as described above, it is an object of the present invention to provide an injection mold apparatus that can improve the efficiency of cooling and heating by reducing the heat capacity of the injection mold.

Another object of the present invention is to provide an injection mold apparatus capable of fundamentally preventing the generation of a weld line caused by the appearance of pearls or a difference in density of pearls during injection molding of a resin containing pearls.

Injection mold apparatus of the present invention for achieving the above object

An injector having a hollow portion, a shutter having a main body at the outlet, a screw rotatably installed at the main body, a heater provided at an outer circumferential surface of the main body, and gas supply means for supplying gas into the outlet side of the main body;

Molding the product by using the resin supplied from the injection machine, having a lower mold supported on the lower fixing plate, and an upper mold to form a cavity for injection molded with the lower mold, the lower mold and the upper mold Cooling means for supplying cooling water to at least one cooling passage formed on one side to cool the injection mold before taking out the molded product from the injection mold, and installed on at least one side of the upper and lower molds to separate, remove and mold the upper and lower molds. And a mold unit provided with heating means for heating the upper and lower molds and maintaining the temperature during injection.

In the present invention, the upper mold or the lower mold has a plurality of support holes are formed on the lower surface corresponding to the cavity, is provided with a reinforcing rod that is supported on the fixed plate and inserted into the support hole, and supported at the ends of the reinforcing rods And a first insulation means for blocking heat transfer of the reinforcing rod from the inner surface side of the upper surface of the support hole, and a second insulation means installed between the upper or lower die and the fixing plate to block heat transfer.

In the present invention, it is provided at the inlet side of the heat exchange medium passage formed on one side of the upper and lower molds, and includes a turbulence generating unit for turbulizing the heat exchange medium.

As described above, the injection mold apparatus according to the present invention is a high quality molded article because the polymer resin to be molded has improved fluidity within the injection mold, so that a weld line does not occur, and the surface gloss of the molded product is very excellent. There is an advantage that can be obtained. In addition, it is possible not to cool the molded product outside the mold after molding, but to allow the molded product to be cooled inside the mold, thereby improving post-deformation generated after molding. In particular, it is possible to prevent the generation of the weld line due to the pulverized to one side or the difference in density when molding the resin containing the pearl.

1 is a view schematically showing an injection mold apparatus according to the present invention,
Figure 2 is an exploded perspective view of the upper mold according to the present invention,
3 is a perspective view of an upper mold according to the present invention,
4 is a perspective view of a lower mold according to the present invention,
5 is a cross-sectional view showing an extraction of the cooling passage in which the electric heater is installed;
Figure 6 is a perspective view showing an extract of the turbulence generating portion formed in the inlet of the cooling passage of the injection mold according to the present invention.

One embodiment of the injection mold apparatus according to the present invention is shown in Figs.

Referring to the drawings, the injection mold apparatus 10 includes an injection unit for injecting a resin through a mold unit and a sprue bush of the mold unit.

The mold unit includes a lower mold 20 supported by the lower fixing plate 11 and an upper mold 30 which is combined with the lower mold 20 to form a cavity 12 for injection and is installed on the upper fixing plate 12. ). The first heat exchange medium 42, which is a coolant, is supplied to the cooling passage 41 formed on at least one side of the lower mold 20 and the upper mold 30 to cool the injection mold before taking out the molded product. Cooling means 40 and at least one side of the upper and lower molds 30 and 20 are installed to heat the upper and lower molds during mold separation, product extraction and molding of the upper and lower molds, and to maintain temperature during injection. Means 50 are provided.

The injection molding machine 200 has a hollow portion 201 and a shutter 202 (valve) is installed at the outlet of the main body 203, a screw 204 rotatably installed at the main body 203, and the main body 203. A heater 205 provided on an outer circumferential surface thereof and a gas supply means 300 for supplying gas into the outlet side of the main body 205. The gas may be nitrogen gas or carbon dioxide gas, but is not limited thereto. The gas supply means 300 includes a gas tank 301, a connecting pipe 302 connecting the tank and the hollow portion 201 of the main body 203, and a control valve installed at the connecting pipe 302 ( 303), the connection pipe may be further provided with a pressure pump 305.

The injection mold apparatus 10 according to the present invention configured as described above will be described in detail for each component as follows.

In the mold unit, a plurality of support holes 31 are formed on the side corresponding to the forming portion of the cavity 12 of the upper mold 30 supported by the upper fixing plate 13, and the upper fixing plate 13 is formed. Is inserted into the support hole 31 is provided with reinforcing rods 32 for improving the structural strength during molding. And a first heat insulating means supported at the ends of the reinforcing rods 32 to prevent heat transfer of the reinforcing rods from the inner surface side of the support hole 31 and heat transfer from the upper mold 30 to the upper fixing plate 13. 61 is provided. The first insulation means 61 of the first insulation material 62 is installed between the end of the reinforcing rod 32 and the inner surface of the support hole 31, the upper mold 30 and the upper fixing plate 13 The plate-shaped 2nd heat insulating material 63 provided in between is provided. Insulation of the upper mold 30 and the upper fixing plate 13 may be made by forming a plurality of protrusions on the upper mold or the lower mold to reduce the contact area thereof.

The lower mold 20 of the mold unit has a mold mounting portion 11a formed on the lower fixing plate 11 and is inserted into the mold mounting portion 11a. The mold mounting portion 11a and the lower portion of the lower fixing plate 11 are installed. Second insulation means 63 is provided between the outer circumferential surface of the mold 20. The heat insulating means is preferably formed on the outer surface of the mold mounting portion (11a) or the lower mold 20 to reduce the contact area between them, it is preferable to be insulated between them or to be insulated by air.

The cooling means 40 cools the upper mold 30 and the lower mold 20 at the time when injection is completed by injecting resin into the cavity 12 in which the upper mold 30 and the lower mold 20 are combined. The cooling tank 43 in which the first heat exchange medium 42 made of cooling water or cooling oil is stored, and the cooling line 41 formed on at least one side of the cooling tank 43 and the upper and lower molds 30 and 20. ) And a first connecting pipe (45) provided with a first pump (44). The cooling tank 43 is connected to the first heat exchange medium refill tank 46 for replenishing the lost first heat exchange medium 42. The first heat pipe 45 is connected to the pneumatic supply means 47 for discharging the first heat exchange medium 42 in the cooling line 41 by the first three-way valve 48. In addition, a drain line is installed at the outlet side of the cooling line 41 or a drain line connected to the cooling tank 43 or the supplemental tank 46 is installed. The pneumatic supply means 47 may be composed of a compressor and a surge tank.

The cooling means 40 is not limited to the above-described embodiment and can be any structure as long as it can cool the mold in a short time. For example, by supplying nitrogen to the cooling line 41 can be cooled, for this purpose it may be provided with a nitrogen tank, valve means for intermittent nitrogen.

The heating means 50 is installed on at least one side of the upper and lower molds to heat the upper and lower molds during mold separation, product extraction, and molding of the upper and lower molds, and to maintain the temperature during the injection. The same second heat exchange medium 51 can be used.

5 may be installed in the cooling passage 41 using the heat transfer heater 70, in which case the cooling line 41 and the heat transfer heater 70 installation line may be connected in the longitudinal direction. It is preferable to install side by side so that the heat transfer heater 70 can be cooled by the first heat exchange medium 42 during cooling.

On the other hand, the heating means 50 using the second heat exchange medium 51 is formed on at least one side of the upper and lower molds 30 and 20 and includes a heating passage 52 through which the second heat exchange medium 51 flows. The heating passage 52 has a second heat exchange medium 51 is provided with a warm oil tank 53, the warm oil tank 53 is the heating passage by the second connecting pipe 54 is provided with a second pump (59). Connected with 52. The outlet of the heating passage 52 is connected to the oil tank 53 in the third connecting pipe 56, and the return tank 57 is installed in the third connecting pipe 56. The warm oil tank 53 is provided with a first heater 53a for heating warm oil, and the return tank 57 is provided with a second heater 57a for heating the returned second heat exchange medium 51. do.

Turbulence generating portions 41a and 52a in the upper or lower molds of one side of the cooling passage 41 and the heating passage 52 for turbulent heat exchange medium flowing into the cooling passage 41 and the heating passage 52, respectively. ) Is formed. As shown in FIG. 6, the turbulence generating unit 52a may be formed by forming a helical groove or forming a helical protrusion on the inner peripheral surface of the inlet side. The weldless injection mold apparatus includes control means 80 for controlling the temperature of each of the pumps, the valves, and the first and second heat exchange media.

Referring to the operation of the injection mold apparatus according to the present invention configured as described above are as follows.

First, in order to increase the temperature of the upper and lower molds 30 and 20, the valves of the first heater 53a and the second pump 59 of the oil tank 53 are controlled to heat the second heat exchange medium 51. 52). In this process, since the turbulence generating unit 52a is formed at the inlet side of the heating passage 52, the second heat exchange medium is turbulent while passing through the heating passage, thereby improving heat exchange efficiency.

In this state, the upper and lower molds 30 and 20 are molded, and resin is injected into the cavity to mold the product. The injection of the resin is made by the injection machine 300, the injection machine 200 has a hollow portion 201, the shutter 202 (valve) at the outlet is rotated in the main body 203, the main body 203 And a gas supply means 300 for supplying gas into the outlet side of the main body 205 and the heater 205 provided on the outer circumferential surface of the main body 203. Nitrogen or carbon dioxide gas is injected into the resin so that the resin is entrapped.

When the molding is completed as described above, the supply of the second heat exchange medium to the heating passage 52 is cut off, and the remaining second heat exchange medium is recovered by pneumatic pressure. That is, by supplying air to the heating passage 52 by the pneumatic means, the second heat exchange medium 51 is recovered.

Then, before the mold separation of the upper and lower molds 30 and 20 is performed, the first heat exchange medium 42 is supplied to the cooling line by the cooling means to rapidly cool the mold. When the cooling is completed, the upper and lower molds are separated from each other, and the second heat exchange medium 51 is supplied by the heating means 50 as described above, and the product is taken out and heated during the molding and injection. At this time, the returned second heat exchange medium is heated by a second heater installed in the return tank and then flows into the warm oil tank.

Since the reinforcing rod 32 is installed at one side of the upper mold 30 or the lower mold in a process corresponding to the cavity 12, the cooling passage or the heating passage is relatively weakened. Deformation of the upper mold 30 or the lower mold 20 can be prevented. In particular, when molding as described above using a resin containing a pearl can improve the fluidity of the resin it is possible to fundamentally prevent the generation of the weld line caused by the pearl is pushed to one side. In addition, it may be foamed by including the injected foam material of the gas.

The injection mold apparatus configured as described above can increase the heating and cooling efficiency of the polymer resin mold, thereby shortening the overall product production cycle.

According to the above, the method of manufacturing the polymer resin by the rapid heat treatment according to the present invention and the polymer resin mold temperature control device are limited to the molding. However, the rapid heat treatment method and the mold temperature control device according to the present invention include a transfer molding method, It can also be used for compression molding, reactive molding, blow molding, thermoforming and the like. As the molding method, in addition to the usual molding method, injection molding method, localized heat-pressing method, gas press method, gas assist method, blow molding method, sandwich molding method, two-color molding method, in-mold molding method, push-pull molding method It is applicable to high speed molding method.

Claims (2)

An injector having a hollow portion, a shutter having a main body at the outlet, a screw rotatably installed at the main body, a heater provided at an outer circumferential surface of the main body, and gas supply means for supplying gas into the outlet side of the main body;
Molding the product by using the resin supplied from the injection machine, having a lower mold supported on the lower fixing plate, and an upper mold to form a cavity for injection molded with the lower mold, the lower mold and the upper mold Cooling means for supplying cooling water to at least one cooling passage formed on one side to cool the injection mold before taking out the molded product from the injection mold, and installed on at least one side of the upper and lower molds to separate, remove and mold the upper and lower molds. An injection mold apparatus, comprising: a mold unit provided with heating means for heating the upper and lower molds and maintaining a temperature during injection. The method of claim 1,
The gas supply means is an injection mold apparatus, characterized in that provided with a gas tank, a connecting pipe connecting the hollow portion of the tank and the main body and a control valve installed in the connecting pipe.

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