JPH0760767A - Powder slush molding device - Google Patents

Abstract

PURPOSE:To unify coverage of resin powder adhering to an electroformed mold and reduce a material loss of the resin powder. CONSTITUTION:A temperature of resin powder P within a powder box 30 is controlled evenly and precisely by installing a temperature control devices 50, 60 respectively to a powder box 30 and powder reservoir tank 41 and agitating devices 33, 44 agitating the resin powder within the powder box 30 and a powder reservoir tank 41, through which coverage to an electroformed mold 20 is fixed, moldability is improved and a material loss is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder slush molding apparatus suitable for molding a skin material or the like in automobile interior parts, and in particular, by precisely controlling the temperature of a resin powder, The present invention relates to a powder slush molding device capable of precisely controlling the amount of resin powder attached.

[0002]

2. Description of the Related Art Conventionally, powder slush molding has been widely used as a molding method for interior parts such as automobile door trims, instrument pads, etc., which require relatively good surface appearance and feel. Has been done.

This powder slush molding is one of the methods for molding a skin material, and a resin powder such as a vinyl chloride resin is attached and gelled on the inner surface of an electroforming mold heated to a predetermined temperature to form a soft skin material. The skin material obtained by this powder slush molding has a good surface feel, and the powder slush molding method is extremely excellent in moldability as compared with vacuum molding, cold press molding and the like. No wrinkles, no wrinkles, etc., a good surface appearance can be obtained, and since excess material can be recovered, there is almost no material loss and it is economically efficient.

FIG. 3 shows the entire structure of a conventional powder slush molding apparatus. The conventional powder slush molding apparatus is a powder box 2 filled with a resin powder 1 and is joined to the powder box 2 to form a resin powder. 1 is attached to the inner surface of the electroforming mold 3 heated to a predetermined temperature, and a powder supplying device 4 for supplying the resin powder 1 into the powder box 2 after a predetermined shot. , A powder reservoir tank 4a, a powder supply pipe 4b for supplying the resin powder P from the powder reservoir tank 4a into the powder box 2, and a screw mechanism 4c inserted in the powder supply pipe 4b for automatically supplying the resin powder P. It consists of

Then, the skin material 5 obtained by powder slush molding by joining and fixing the opening of the powder box 2 and the electroforming mold 3 and performing a rotating operation, as shown in FIG. Of the core material 7 formed in a step (not shown) is temporarily fixed to the upper crimping die 6b, and the upper and lower crimping dies 6a and 6b are crimped to form a skin material on the surface of the core material 7. 5 is integrated to complete the production of interior parts with good surface appearance and surface feel.

[0006]

However, in the conventional powder slush molding apparatus, the used resin powder 1 is automatically supplied from the powder feeder 4 side every predetermined molding cycle. Although the supply amount into the powder box 2 is controlled, the temperature control of the resin powder 1 in the powder box 2 is not actually performed.

As shown in the graph of FIG. 5, the relationship between the temperature of the resin powder 1 and the amount adhered to the electroforming mold 3 is about 6.5 g each time the temperature of the resin powder 1 rises by 1 ° C.
There is a tendency to increase each time.

Therefore, due to the temperature variation of the resin powder 1, the thickness of the skin material 5 due to the powder slush molding is likely to vary, the molding failure of the product is likely to occur, and the material loss is often pointed out. ing.

Normally, 30 shots are required until the temperature of the resin powder 1 in the powder box 2 stabilizes, as shown in the graph of FIG.

Therefore, in the initial stage of operation, the amount of adhesion to the electroforming mold 3 is small, so that the wall thickness tends to be thin.
It has been pointed out that it is difficult to maintain good molding accuracy.

The present invention has been made in view of the above circumstances, and in a powder slush molding apparatus, by precisely controlling the temperature of the resin powder in the powder box, defective molding (variation in wall thickness) is possible. It is an object of the present invention to provide a powder slush molding apparatus which can be prevented as much as possible and has less material loss.

[0012]

In order to achieve the above object, the present invention provides a powder box filled with a resin powder and a powder box fixedly joined to the powder box, and by rotating both the powder box and the resin powder, In a powder slush molding machine consisting of an electric mold to be attached to the inner surface and a powder feeder that supplies resin powder to the powder box after a predetermined shot, resin powder is stored in the powder box and the reservoir tank of the powder feeder. It is characterized in that a temperature control device for maintaining the reference temperature and a stirring device for stirring the resin powder are installed.

Further, the temperature control device used in the present invention comprises a heating pipe and a cooling pipe arranged on the outer surfaces of the powder box and the reservoir tank, and a heating medium for the heating pipe and the cooling pipe, respectively. It is composed of a medium supply unit that circulates and supplies a cooling medium, and a control device that controls the start and stop of supply of the medium from the medium supply unit by a temperature sensor installed in the powder box and the reservoir tank. It is characterized by

[0014]

[Function] As is apparent from the above configuration, since the temperature control device and the stirring device for stirring the internal resin powder are set in the powder tank and the reservoir tank of the powder feeder, the resin powder and the powder in the powder box are The temperature of the resin powder in the reservoir tank supplied in the box can be controlled precisely.

That is, when the resin powder in the powder box and the reservoir tank has not reached the reference temperature, the heating medium is supplied from the medium supply unit through the heating pipe and is agitated by the agitator to obtain the powder box and the reservoir. The resin powder in the tank is heated to a uniform temperature.

When the temperature sensor reaches the reference temperature or higher, the supply of the heating medium from the medium supply unit is stopped by the signal from the control device, and the cooling medium is supplied from the medium supply unit to the cooling pipe. By the stirring by the stirring device, the resin powder in the powder box and the reservoir tank is uniformly cooled, and the resin powder in the powder box and the reservoir tank is constantly maintained at a predetermined temperature.

[0017]

Embodiments of the powder slush molding apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing the overall structure of the powder slush molding apparatus according to the present invention, and FIG. 2 is a graph showing the temperature of resin powder by the molding apparatus according to the present invention.

In FIG. 1, a powder slush molding apparatus 10 according to the present invention has an electric mold 20 having a desired mold surface and heated to a predetermined temperature, and a powder box 30 having a resin powder P filled therein. And resin powder P
Use the resin powder P as needed for powder box 30
A powder feeder 40 for supplying the powder is generally provided.

More specifically, the powder box 30
Has a reservoir portion 31 formed on an upper portion of the powder box 30 and a seal member 32 provided at a tip thereof.
0 and the powder box 30 through the seal member 32
Is fixed and bonded, and by performing a rotation operation, the resin powder P is adhered to the inner surface of the electroforming mold 20 and gelated to obtain a desired molded body.

Then, the resin powder P in the powder box 30 is used by a predetermined number of rotation operations. In order to keep the amount of the resin powder P in the powder box 30 constant, the powder feeder 40 is used. The resin powder P is automatically supplied into the powder box 30.

The powder feeder 40 includes a powder reservoir tank 41 and a powder reservoir tank 4
1, a powder supply pipe 42 that supplies the resin powder P into the powder box 30 and a supply screw 43 that is inserted into the powder supply pipe 42 and automatically supplies the resin powder P.

By the way, a feature of the present invention is that the resin powder P in the powder box 30 is constantly controlled at a predetermined temperature during powder slush molding, so that the resin powder P attached to the electroforming mold 20 during powder slush molding is supplied. The feature is that the amount is always kept constant to prevent molding defects as much as possible and material loss is reduced.

That is, both the powder box 30 and the powder reservoir tank 41 have temperature controllers 50 and 60.
And stirring devices 33 and 44 are installed.

More specifically, the temperature control device 50 installed in the powder box 30 and the stirring device 33 will be described. The temperature control device 50 has a heating pipe 51 and a cooling pipe 52 on the outer surface of the powder box 30. Are connected to the heating medium supply unit 53 and the cooling medium supply unit 54 that circulate and supply the heating medium and the cooling medium, respectively, and the temperature set in the powder box 30. Information from the sensor 55
It is input to the control device 56, and by the command of the control device 56, operation stop and operation start of the heating medium supply unit 53 and the cooling medium supply unit 54 are switched and controlled.

That is, when the resin powder P in the powder box 30 has not reached the predetermined temperature, the controller 56 issues a command to drive the heating medium supply unit 53.

When a heating medium such as hot oil or hot water is circulated through the heating pipe 51 through the heating medium supply unit 53, the resin powder P in the powder box 30 is heated and the agitator 33, In the embodiment, the stirring screw 33b which is rotationally driven by the screw rotation motor 33a is used.
As a result, the resin powder P in the powder box 30 is uniformly heated without unevenness.

Then, when the heating of the resin powder P is continued and reaches a predetermined temperature, the operation of the heating medium supply unit 53 is stopped in response to a command from the control device 56 in response to the information from the temperature sensor 55. The operation of the cooling medium supply unit 54 is started. Therefore, the temperature of the resin powder P in the powder box 30 is cooled uniformly.

In practice, the lower limit temperature is set to 31 ° C. and the upper limit temperature is set to 35 ° C., the lower limit temperature is set to the operating temperature start temperature of the heating medium supply unit 53, and the upper limit temperature is set to the operation start of the cooling medium supply unit 54. It may be set as the temperature.

Similarly, also in the powder feeder 40 for supplying the resin powder P into the powder box 30, the temperature controller 60 installed in the powder reservoir tank 41.
The configurations of the stirring device 44 are the same as those of the heating pipe 61, the cooling pipe 62, and the heating medium supply unit 6.
3. The cooling medium supply unit 64, the temperature sensor 65, and the control device 66 are provided. Since the operation of the temperature control device 60 is the same as that of the temperature control device 50 on the powder box 30 side,
It is omitted here.

The stirring device 44 installed in the powder reservoir tank 41 is composed of a motor 44a and a stirring blade 44b attached to the rotating shaft of the motor 44a. It has the function of stirring powder P uniformly.

Since the powder slush molding machine according to the present invention is constructed as described above, the temperature controller 50,
By the function of 60, the temperature of the resin powder P in the powder box 30 and the powder reservoir tank 41 is always kept constant, and the stirring action of the stirring devices 33 and 44 enables uniform and precise temperature control. Therefore, as shown in the graph of FIG. 2, an ideal temperature of the resin powder P is obtained from the initial stage of operation, molding defects due to variations in wall thickness in powder slush molding are almost eliminated, and material loss is significantly reduced.

[0033]

As described above, the powder slush molding apparatus according to the present invention has the following special operational effects.

(1) In the powder slush molding apparatus according to the present invention, the temperature control device is installed in the powder box and the powder reservoir tank, and the stirring device is provided, so that the temperature of the resin powder in the powder box is controlled. Since uniform and accurate control can be performed without unevenness, there is an effect that molding defects such as the variation in the wall thickness of the molded body that has conventionally occurred are remarkably reduced and the moldability is greatly improved.

(2) According to the present invention, the temperature of the resin powder in the powder box can be precisely controlled by installing the temperature control device and the stirring device in the powder box and the powder reservoir tank. It has an effect that it is economically advantageous because it does not become thicker than the above thickness, the material loss is reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the overall configuration of a powder slush molding apparatus according to the present invention.

FIG. 2 is a graph showing the correlation between the number of shots and the powder temperature in the powder slush molding apparatus according to the present invention.

FIG. 3 is a sectional view showing the overall configuration of a conventional powder slush molding apparatus.

FIG. 4 is a cross-sectional view showing a pressure bonding step of a skin material and a core material by a conventional powder slush molding apparatus.

FIG. 5 is a graph showing the correlation between powder temperature and the amount of resin powder attached.

FIG. 6 is a graph showing the correlation between the number of shots and the powder temperature in a conventional powder slush molding apparatus.

[Explanation of symbols]

 10 Powder Slush Molding Device 20 Electroforming Mold 30 Powder Box 33 Stirrer 40 Powder Feeder 41 Powder Reservoir Tank 44 Stirrer 50,60 Temperature Controller 51,61 Heating Pipe 52,62 Cooling Pipe 53,63 Heating Medium Supply Unit 54,64 Cooling medium supply unit 55,65 Temperature sensor 56,66 Control device

Claims (2)

[Claims] 1. A powder box (30) filled with a resin powder (P) and a powder box (30) which is joined and fixed to the powder box (30), and by rotating both of them, the resin powder (P) is attached to the inner surface thereof. Electroforming mold (20)
And a powder feeder (40) for supplying the resin powder (P) to the powder box (30) after a predetermined shot, the powder box (30) and the powder feeder (40) In the reservoir tank (41), a temperature controller (50, 6) for maintaining the resin powder (P) at a reference temperature.
0) and a stirring device (3) for stirring the resin powder (P)
3, 44) is installed, powder slush molding equipment. 2. The temperature control device (50, 60) comprises heating pipes (51, 61) and cooling pipes (52, 62) arranged on the outer surfaces of the powder box (30) and the reservoir tank (41). ) And the heating pipes (51, 6)
1), heating medium in the cooling pipes (52, 62),
A medium supply unit (53, 5 for circulating and supplying a cooling medium)
4, 63, 64) and the temperature sensors (55, 65) installed in the powder box (30) and the reservoir tank (41), the medium supply unit (53, 5).
4. The powder slush molding apparatus according to claim 1, further comprising: a control device (56, 66) for switching control of starting and stopping the supply of the medium from (4, 63, 64).