KR910005198B1 - Method and device for heating and cooling in slash molding - Google Patents

Abstract

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Description

Method of heating and cooling a mold in slush molding and apparatus therefor

1 is a view showing a portion of a part of a mold box equipped with a slush molding die.

2 is an overall perspective view of a frame in which a mold box and a receiver tank are installed.

3 is an enlarged cross-sectional view of the III-III line of FIG.

4 is a cross-sectional view of the center when the mold box and the receiver tank are combined.

5 is a cross-sectional view corresponding to when the material is supplied to the mold.

6 is a cross-sectional view corresponding to FIG. 4 at the time of forming the next semi-melt thin film by using preheating on the mold surface.

7 is a cross-sectional view of the center of the mold box during heat curing of the epidermis.

8 is a cross-sectional view of the center of the mold box during the cooling process.

9 is a heating medium supply piping diagram (only the movable circuit is indicated by a thick line).

10 is a cooling medium supply piping diagram (only the processing circuit is shown in bold lines).

11 is a graph showing the temperature change of the mold during the molding operation.

The present invention relates to a method for heating and cooling a mold in slush molding and an apparatus thereof.

In the slush molding method, powder or liquid resin material is put into a preheated mold, and a part of the input material is melt-bonded to the cavity surface of the mold as the mold is heated. Then, the material remaining in the non-melt state is discharged from the mold and is still It becomes a process of demolding the molded article by cooling a metal mold | die by cooling the metal mold | die again by increasing the viscosity in the form of a thin film on the surface, and heat-hardening it again. A more specific embodiment of the slush molding method is to form a synthetic resin skin material having a thickness of about 0.4-2.0 mm that covers the inner surface of a semi-rigid or soft urethane foam with an interior of an automobile interior or furniture.

To provide a medium for heating and cooling to the back side of the mold, as disclosed in Japanese Laid-Open Patent Publication No. 54-10581, for example, in order to quickly change the heating and cooling operations in accordance with the time zone of the mold. Weld pipes are formed to roughly cover the mold back surface, and heating and cooling of the mold have been performed by alternately supplying the heat medium in the pipe.

However, the heating or cooling medium is alternately supplied to each other in the heat medium supply pipe welded to the back of the mold, and the heat exchange of the thermal energy held by the heat medium is via the supply pipe. In other words, since the heating and cooling of the mold are indirectly performed through the supply pipe, the efficiency cannot be sufficiently satisfied. Also, the heating medium and the heating medium of the heating system and the cooling system are mixed in the same supply pipe during the conversion of the heating and cooling operations. When the medium temperature of the heat medium is generated, and the heat exchange is changed to this heat medium, energy is lost, and the cooling operation requires cooling by the fruit, and thus requires an electric resistance or the like, thus expanding the cooling energy.

In addition, the welding pipe work of the mold and the supply pipe on the surface of the device requires a lot of skill and manual work. Also, the supply pipe of heterogeneous copper, iron, etc. is placed on the back side of the nickel casting agent with a thickness of 2-5 mm. Due to the difference in the coefficient of linear expansion for welding, cracks are generated in the mold due to thermal stress during heating and cooling, electroplating of nickel casting molds, or residual stress such as pipe spooling. Occasionally, there was a situation such as cracking in the pipe part.

Therefore, first, the heating and cooling method of the mold according to the present invention alternately sprays a plurality of independent jet stream-forming heating media and cooling media alternately at predetermined time points toward the approximately front side of the mold back side, and at the same time, the jet-flow cooling media. It is characterized in that a cooling medium composed of sprayed cooling water is mixed in some of them, and by heating and cooling the heating medium independently and directly to the mold, the efficiency of heat treatment for the mold and the energy loss due to the mixing of the heating medium The purpose of the present invention is to significantly improve the method of heating and cooling the mold through the pipes welded and disposed on the mold back surface.

In the mold box equipped with the mold of the invention, a storage tank is disposed in a box in which the mold back side is inserted, and the storage tank has a plurality of nozzles protruding from the mold tank to cover the entire mold surface. The main pipe part which has a separate independent nozzle group over the entire length of the heating medium generator and the cooling medium generator in contact with each other and has a separate supply circuit. The cooling water and the feeder are connected to each other, and the heating and cooling of the mold is performed by directly injecting the jetted heat medium onto the mold back side, and the welding pipe to the mold back side of the pipe group that supplies the heat medium as in the conventional apparatus. This eliminates the need for cracks caused by pipe welding etc. It is possible to extend the life of the mold and to simplify the device itself. Next, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

EXAMPLE

1 is a perspective view of a portion of a mold box equipped with a slush molding die, wherein the slush molding die 1 is inserted into the mold box 2 from the mold rear portion and the opening 3 of the mold is opened. 2) A relatively large chamber 4 is formed between the rear surface of the mold and the inner wall of the box, and the bottom 9 of the chamber 4 is a storage for firstly retaining the medium for heating and cooling. A tank 5 is formed, and a plurality of nozzles 6 protrude from the storage tank 5 so as to cover the entire surface of the mold back portion toward the mold back surface.

In addition, the chamber 4 part of the mold box 2 includes a plurality of main pipes 7 which branch into two or more chambers, for example, from both sides of the mold box 2, from the main pipe 7 toward the back of the mold. The nozzle 8 which covers the front surface protrudes. In addition, the support shafts 11 and 11 are fixed to the lower portion of the left and right end walls of the mold box 2, and one end is connected to the storage tank 5 in the mold box at the shaft center of one support shaft 11. The relay pipe 12 is fitted. The mold box 2 equipped with the above-described mold 1 has a pair of support shafts 11 and 11 above the support 14 of the frame 15 having a pair of left and right supports 14 and 14. In the lower frame of the mold box 2, a receiver tank 18, which is lifted and lifted by a heavy lifter 16, is installed in the lower frame of the mold box 2, and at the opening side of the receiver tank 18. The air supply pipe 20 of several compressed air which protrudes the group of nozzles 19 at predetermined intervals is arrange | positioned in the longitudinal direction of the receiver rubber tank 18, and the tank inside the receiver tank rather than the air supply pipe 20 A louver 21 for controlling the input or discharge of the powder material 22 accommodated in the 18 is provided (see FIGS. 3 to 6).

9 and 10 are piping circuit diagrams for supplying a medium for heating and cooling to the mold box 2. First, as shown in FIG. 9, a case in which the mold 1 is heated is an air blower. (25) forcibly introduces high-pressure air into the air circulation mounting furnace 26, and the heating medium in which the high pressure air is converted into heated high pressure air by the gas 27 supplied into the mounting furnace 26 is opened. It is supplied into the storage tank 5 in the mold box 2 via the control valve 28 and the relay pipe 12, and the heating medium is pressurized in the storage tank 5 to interpose the nozzle group 6. The mold 1 is heated and is added to the circulation blower 30 via the control valve 29 opened from the chamber 4 of the mold box 1. Once used, the heating medium with sufficient thermal energy is brought back into the mounting 26 above. By flow it used again. In this heating circuit, the control valve 29 which extends from the mounting path 26 and extends from the mold box 2 through the control valve 31 being closed and the circuit extending from the mounting valve 26 to the control valve 28 is closed. The bypass pipe 32 is provided in the form of connecting the circuit between the mounting paths 26. The operation centering on the bypass pipe 32 will be described in detail in the cooling circuit described below.

Next, in the case of cooling the mold, as shown in FIG. 10, the control valves 28 and 29 operated in the heating circuit are closed at this time, and the outside air introduced after the air blower 34 is opened. It is supplied via the side pipe 35 to the storage tank 5 in the mold box 2 through the relay pipe 12, and the cooling medium pressurized in the tank 5 is removed from the nozzle 6 group. (1) It is ejected toward the back. The cooling medium once used in the chamber 4 of the mold box 2 is discharged through the open control valve 36.

In addition to the cooling operation of the mold by the injection of the cooling medium from the storage tank 5, the control valves 38 and 39 are respectively provided in the main pipe 7 portion piped in the chamber 4 of the mold box 2. The cooling medium in which the cooling water and the compressed air are mixed with the cooling water and the compressed air through the control valves 38 and 39 opened by the water cooling pipe 40 and the compressed air pipe 41 in the communication through It is injected from the nozzle 8 group of the main pipe 7 toward the front surface part of the metal mold 1, and the rapid cooling operation of the metal mold is added.

In addition, during the mold cooling, the control valves 38 and 39 operated at the time of heating are closed, but only the control valves 31 installed at the bypass pipe 32 during the cooling are opened and added to the circulation blower 30. The heating medium generated in the mounting passage 26 is circulated by using the bypass pipe 32 to prepare for the next heating operation.

A process for producing a thin film epidermis using the apparatus of the present invention will be described.

① The mold box 2 equipped with the mold 1 is rotated 180 degrees about the support shafts 11 and 11 to stop the opening 3 of the mold from below.

② Raise the receiver tank 18 by lifting the lifter 16 to the mold box 2 position, and the receiver tank 18 and the opening 3 of the mold 1 are in close contact with each other. 2) and the receiver tank 18 are fixed by using fixtures (not shown) or the like.

③ At this time, the heating circuit described above in Fig. 9 is operated to spray a heating medium of about 400 ° C. onto the mold back surface to preheat the mold 1 to 110 ° to 150 ° C. In the case of dry sol powder in which the input powder material 22 is vinyl chloride resin and the surface of the powder material is impregnated with a plasticizer, a stabilizer, a lubricant, the gelling of the material starts, and the powder surface gradually becomes visible and adheres to the mold cavity surface. Becomes more remarkable. Therefore, the preliminary heating of the mold for each input material is followed by the rising temperature appropriately (this process corresponds to the area A of FIG. 4 and FIG. 11).

④ The combined mold box 2 and receiver tank 18 are rotated 180 degrees about the support shafts 11 and 11 of the mold box 2 and the louver of the receiver tank 18 located above. 21 is opened and the powder material 22 in the receiver tank 18 is introduced into the mold 1 by its own weight, and a part of the input material in contact with the mold cavity surface is 150 ° -190 ° C by continuing heating. The molten metal is partially melted in a mold heated to a low temperature, adhered in a thin film, and the material is retained in the mold 1 for several seconds (this process corresponds to the region B of FIGS. 5 and 11).

⑤ The mold box 2 and the receiver tank 18, which are in the coalescing state after completion of the above-mentioned thickness attaching work, are rotated 180 degrees to return to their original positions, and the ungelled material 22 remaining in the unmelted melt is returned to the receiver. It collect | recovers in the tank 18. At this time, if necessary, compressed air is injected into the mold 1 from the compressed air supply pipe 20 provided in the receiver tank 18 to remove the non-gelling material from the mold surface. In this step, the semi-melt thin film 43 is formed and adhered to the mold cavity surface (this step corresponds to the region B in Figs. 6 and 11).

⑥ Unfasten the fixture and lower the receiver tank 18 under the frame and operate the heating circuit to adjust the circulating blower 30 so that the heating medium at about 400 ℃ is about 10m / sec at the wind speed. The jets are sprayed to heat the mold 1 to 210 ° C., and the semi-melt thin film 43 is completely cured (this process corresponds to the region C of FIGS. 7 and 11).

(7) In the next finishing process, the cooling circuit described above in Fig. 10 is operated to inject the cooling medium (outside air) from the nozzle 6 of the storage tank 5 to the back of the mold 1 and at the same time the water cooling pipe 4 And sprayed cooling medium of 2 ° -35 ° C., which is mixed with cooling water and compressed air into the compressed air pipe 41, from the nozzle 8 group of the main pipe 7 to the entire surface of the mold 1 By spraying, the mold 1 is cooled to 70 ° -100 ° C. At this time, the mold box 2 is intended to simplify the demolding operation of the finished skin 44, and the adjustment position is maintained at the center of the support shafts 11 and 11 at an angle that is easy to demold (this step is the ninth step). And area D in FIG. 11). After cooling, the cooling circuit is completely stopped, but at this time, only the control valve 31 is opened so that the circulation flow of the heating medium via the bypass pipe 32 is prepared for the start of the next heating process.

⑧ After completion of the molding, cool the mold 44 to be adjusted to 0.4-2.0mm thickness attached to the mold cavity surface by cooling (applied to area E in Fig. 11).

In the present invention, by directly ejecting the heating and cooling medium to the mold back to directly control the temperature of the mold itself, the energy of the heat medium can be used directly, and the work efficiency can be improved, and the heating medium and When converting the cooling medium, there is little chance of mixing both heat mediums and the loss of thermal energy can be reduced to a minimum, and the cooling water is sprayed onto the mold surface by spraying the cooling water into the mold surface. The cooling promoting effect becomes more remarkable, and in comparison with the heat control of the mold using the circulating pipe of the fruit disposed on the conventional mold back surface, it is possible to reduce the thermal energy of 10000-6000 kcal in the molding of one object. The overall temperature of the mold is controlled by the direct action on the mold back of this heating medium. It was possible to make it possible to reliably prevent the occurrence of defective products with uneven thickness depending on the place of the molded product. Specifically, the locational temperature difference inside the mold was about 30 ° C in the conventional apparatus by pipe piping, but when the present method was implemented, the temperature difference was reduced to about 5 ° C. 1.0 ± 0.4mm was present, but when the present method was implemented, a significant improvement of 1.0 ± 0.2mm was observed.

)를 전면적으로 배제할 수 있으며 장치전체의 수명연장을 실현하였다. 또 본 장치에 있어서는 열매체로서 대기, 물등 비교적 염가인 열매체를 전면적으로 사용할 수 있으므로 장치자체의 원가절감은 제품의 저염으로 연결시키는 큰 장점으로 구형하게 된다.In addition, in the apparatus surface of the present invention, the heating and cooling medium is sprayed by using a plurality of nozzles directly laid toward the mold rear surface, which is simplified mechanically, and the front surface of the conventional mold is approximately the front surface. Compared to the mechanism that welded the pipe in the form of cover, the device is simplified and the coefficient of linear expansion between the mold and the pipe is made by welding the pipe of heterogeneous pipe with a large area on the relatively thin mold surface of 2.0-5.0mm. It is also possible to reduce the life of expensive molds due to the occurrence of cracks in both parts due to the stress during repeated heating and cooling or the difference in residual stress and pipe stress during pipe welding. In regard to these things,

) Can be completely eliminated and the life of the whole device is realized. In addition, in this device, since a relatively inexpensive heat medium such as air and water can be used as the heat medium, the cost reduction of the device itself is spherical as a great advantage of connecting the product with low salt.

In addition, the heat medium sprayed from the mold box to the back of the mold does not scatter largely out of the box part, and the heat energy of each heat medium can be effectively used, and the heating medium in the mold box has a circulation circuit. The remaining thermal energy can be reused, contributing to saving of thermal energy, and by adding a bypass circuit in the heating circuit, cultivation of the heating medium can be performed in parallel during the cooling of the mold. Can be reduced significantly and contribute to the improvement of work efficiency.

Claims (3)

A plurality of independent jetted heating media and cooling media are alternately sprayed with each other at a predetermined time toward the front side of the back side of the slush molding die, and at the same time, a part of the jetted cooling media has sprayed coolant. A method of heating and cooling a die in slush molding, wherein a mixture of cooling media is mixed. The heating medium is a heating pressurized atmosphere and the cooling medium is pressurized atmosphere and cooling pressurized water. The method of heating and cooling a die in slush molding according to claim 1. The storage tank is placed in the box where the mold back side is inserted among the mold boxes equipped with the mold. In this storage tank, several nozzles protrude toward the mold back to cover the front of the mold, and the storage tank is heated. Spraying coolant is provided in the main pipe part which has a separate supply circuit connected to the medium generating furnace and the cooling medium generator, respectively, and is formed to cover the entire surface toward the mold back side over the entire length. Heating and cooling device of a mold in slush molding to which a feeder is connected.

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