JP3209401B2 - Powder slush molding method and molding apparatus - Google Patents

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 method and a molding apparatus capable of simultaneously forming two or more powder slush molded products from a thermoplastic resin powder.

[0002]

2. Description of the Related Art In recent years, instrument panel pads,
Demand is increasing for powder slush-molded skin materials, mainly for console boxes and other automobile interior parts.

[0003] As a method for efficiently mass-producing this kind of skin material, a molding die in which two or more mold parts of the same shape and the same size are connected is used, and a large number of skin materials are simultaneously produced. A molding method is employed. In this case, in the preheating step or the like, as shown in FIG. 4, the shape of the molding die is two so that the molding die is uniformly preheated from the outside in the heating furnace. It has mold parts 51a and 51b, and has a shape in which these are joined symmetrically.

In the case of molding using a molding die 51 of this shape, a powder box 52 containing a powder material 53 is fixed below a preheated molding die 51 by an appropriate fixing means, and these are appropriately attached. Is rotated in the direction of the arrow 54 by the rotating means, and the powder material is adhered to the inside of the molding die 51 to be brought into a semi-molten state.
The powder box 52 is removed from the mold, and the mold 51 is heated and then cooled, so that the semi-molten molded article is solidified and is taken out of the mold 51 after the temperature reaches room temperature.

[0005]

However, as shown in FIG. 5, in the step of rotating the molding die 51 in the direction of the arrow 54 to adhere the resin of the powder material, the molding die 51 is locally When viewed from the right, the right half mold part 51a
, The powder material enters from the direction of the arrow 55, and the left half mold portion 51b enters the powder material from the direction of the arrow 56. That is, the directions in which the powder material enters the right half mold portion 51a and the left half mold portion 51b of the same shape and size are relatively reversed.

Therefore, as shown by a broken line, for example, during one rotation, a longer and larger amount of powder material stays in the portion A than in the portion C to form a thick layer. Further, in the portion C, the underfill and pinhole failure due to insufficient material filling that can be avoided in the portion A occur frequently in the portion C. The same occurs in the B and D sections. Therefore, the shape of the molded product adhered to the molding die 51 is not symmetrical, and a product formed from the right half mold portion 51a and a left half mold portion 51a are formed.
b, the thickness distribution, the occurrence rate of pinhole defects, the weight, and the like differed from the product made from b, resulting in a remarkable difference in quality.

The present invention has been made in view of the above problems, and an object thereof is to use a molding die in which a first mold portion and a second mold portion of the same shape are joined symmetrically. An object of the present invention is to provide a powder slush molding method and a molding apparatus which do not cause a difference in finish between a first molded product and a second molded product molded by a first mold part and a second mold part.

[0008]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, the first mold part and the second mold part face each other so as to be symmetrical. A powder slush molding method for simultaneously molding two or more slush molded products using a molding die having one or more of the front and back ones joined together, wherein the powder slush molding method can be opened toward the first mold part. A pre-heated molding die is placed and fixed on the powder box by using a powder box comprising a first storage part and a second storage part capable of opening toward the second mold part; With the storage portion closed and the first storage portion opened, the molding die to which the powder box is fixed is rotated to charge the powder material into the first mold portion and discharge excess powder material. Of the first mold part A first molding step of forming a semi-molten first molded article on a surface, and in a state in which the first storage section is closed and the second storage section is opened, the molding die is rotated in a direction opposite to the first step. And forming a semi-molten second molded product on the inner surface of the second mold part by discharging powder material into the second mold part and discharging surplus powder material. A powder slush molding method characterized by comprising: Here, the powder material is a thermoplastic elastomer used as a skin material, such as PVC, styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer (TPO), urethane-based thermoplastic elastomer (TPU), and polyester-based thermoplastic. Plastic elastomer (T
PAE) is used. As described above, when the first molding step and the second molding step are divided, the powder material is injected into the first mold part and the second mold part having the same shape and the same size from the directions which are relatively in the same direction when viewed from the shape. In addition, excess powder material can be eliminated. Therefore, the difference in thickness between the semi-molten resin layers formed inside the first mold portion and the second mold portion is reduced.

According to a second aspect of the present invention, the first mold portion and the second mold portion are arranged in a substantially arc shape such that the respective convex portions protrude outward. This is a powder slush molding method. This arrangement allows the width of the device to be kept to a minimum. Further, in the preheating step, it is easy to quickly raise the entire molding die to a uniform temperature. Therefore, the powder material adheres and melts evenly.

According to a third aspect of the present invention, the preheating of the molding die is performed so that the mold temperature of the second mold part is equal to the first temperature so as to compensate for the temperature decrease of the second mold part in the first molding step. The powder slush molding method according to claim 1 or 2, wherein the method is performed so that the temperature is higher than a mold temperature of the mold portion. This allows
The difference between the mold temperature of the first mold part in the first molding step and the second mold temperature in the second molding step is eliminated.

According to a fourth aspect of the present invention, there is provided a molding die having at least one of a first die portion and a second die portion joined to face each other so as to be symmetrical, and A powder box having a first storage portion and a second storage portion separated by a partition plate provided on a line of symmetry of the mold, and a preheated molding die placed on and fixed to the powder box. A rotation mechanism that can rotate the molding die to which the powder box is fixed in one direction and the opposite direction, a first opening and closing mechanism provided between the first mold part and the first storage part, A second opening / closing mechanism provided between the second mold portion and the second storage portion, and closing the second opening / closing mechanism and opening the first opening / closing mechanism when the molding die is rotated in one direction. , When rotating in the opposite direction The closing said first opening and closing mechanism the second
A control mechanism for opening and closing the opening / closing mechanism and controlling the rotation mechanism so that the direction in which the powder material enters the first mold part and the direction in which the powder material enters the second mold part are relatively the same. It is a powder slush molding apparatus characterized by the following.
This allows the powder material to enter and be removed from the first mold portion and the second mold portion having the same shape and the same size in directions that are relatively the same as viewed from the shape. The first storage part and the second storage part of the powder box can be formed only by providing the partition plate on the line of symmetry.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to illustrated examples. FIG. 1 is a schematic view of a powder slush molding apparatus of the present invention. FIG. 2 is a schematic diagram of a powder slush molding method using the molding apparatus of FIG. FIG. 3 is a schematic explanatory diagram of the preheating step.

The powder slush molding method of the present invention comprises:
Using a molding die shown in FIG. 1, two molded products of the same shape and the same size are simultaneously formed. First, the molding apparatus will be described with reference to FIG.

In FIG. 1, a powder slush molding apparatus includes a molding die 3 having a first mold portion 1 and a second mold portion 2.
And a powder box 4 connected below the molding die 3.

The powder box 4 is divided into a first storage section 6 and a second storage section 7 by a partition plate 5, and a first opening / closing mechanism 8 and a second opening / closing mechanism 9 are provided in the opening. . Mold 3 and powder box 4
Is fixed by appropriate fixing means 10 such as a clamp,
An appropriate rotating mechanism 3 such as connecting the fixing means 10 to a rotating shaft.
By means of 1, it is possible to rotate in the direction of arrow 11 or 12 in the reverse direction to reverse the top and bottom according to a command from the control mechanism 32. The control mechanism 32 includes a first opening / closing mechanism control device 33 that controls opening and closing of the first opening / closing mechanism 8 and a second opening / closing mechanism control device 34 that controls opening and closing of the second opening / closing mechanism 9.
And a rotation mechanism control device 35 for controlling the rotation of the rotation mechanism 31, a timing for opening and closing the first opening and closing mechanism 8, a timing for opening and closing the second opening and closing mechanism 9, and a direction and timing for the rotation of the rotation mechanism 31. And a control device 36 for controlling the

In FIG. 1, a molding die 3 is for forming two convex molded products by adhering a powder material on the inner side, and has a first mold portion 1 and a second mold portion having the same shape and size. 2 are arranged in a substantially arc shape such that the respective convex portions project outward, and have a bilaterally symmetric mountain shape as a whole. FIG.
As shown in (2), since the symmetrical mold 3 is preheated in the heating furnace 30 so that the temperature distribution is also symmetrical, the powder material can be attached symmetrically. Further, since the convex portions of the mold portions 1 and 2 are formed in a mountain shape projecting outward, the hot air indicated by the arrow 30a hits from the outside almost uniformly, so that the preheating is performed so that the temperature of each portion becomes equal. can do. Also, let hot air flow in from the inside,
Also in the method of raising the temperature, if the shape is substantially circular, there is no obstacle, the flow of hot air is performed smoothly, and the temperature can be raised quickly and uniformly. When the mold 3 is fixed to the powder box 4, the central portion 13 has both ends 14,
It is fixed so as to be located above 15, that is, convex upward. With this arrangement, the width of the powder box 4 can be kept to a minimum.

Incidentally, as the left-right symmetrical mold, it is also possible to abut each mold part 1 and 2 with a valley shape in which each convex part faces inward. However, in such a valley mold, the first mold portion and the second mold portion are spaced apart from each other at a certain distance so that the opposed convex portions do not overlap or hot air easily hits the deep portion of the valley. Must be provided, and the lateral width of the mold may be increased. Therefore, in order to reduce the size of the mold, the powder box, and the entire apparatus, it is necessary to use a chevron shape in which the convex portion faces outward (in the case of FIG. Is preferable).

Returning to FIG. 1, the partition plate 5 provided inside the powder box 4 is on the symmetrical line of the molding die 3,
A packing 16 is attached to the upper end of the packing so that no gap is formed when the molding die 3 is fixed on the powder box 4. Packings 17 and 18 are provided at the upper ends of the left and right walls of the powder box 4 so that no gap is formed. The first storage unit 6 and the second storage unit 7 store the same type and the same amount of powder material. In addition, a first opening / closing mechanism 8 and a second opening / closing mechanism 9 communicating with the first mold part 1 and the second mold part 2 are provided inside each.

The first opening / closing mechanism 8 is located between the first storage section 6 and the first mold section 1, and controls the charging and discharging of the powder material.
The same applies to the second opening / closing mechanism 9, and the first opening / closing mechanism 8 and the second opening / closing mechanism 9 are preferably configured to be symmetrical. For example, the opening and closing mechanisms 8 and 9 in FIG.
Is a louver type that rotates the doors all at once, and it is preferable because the doors are easy to fully open, and when the doors are opened, each door 19 does not hinder the charging and discharging of the powder material. It is also preferable in that the powder material is uniformly introduced into each part of the mold. In addition, the first storage unit 6 and the second storage unit 7
If it is possible to adopt a structure in which the flow of charging and discharging of the powder material does not differ between the two, a conventionally known opening mechanism such as a double door, an accordion curtain system, or a sliding system can be appropriately used.

The control mechanism 32 includes, for example, the first opening / closing mechanism 8.
Is closed, the second opening / closing mechanism 9 is opened, and the powder box 4 is opened.
The molding die 3 to which is fixed is controlled to make one rotation in the direction of arrow 11. At this time, the arrow 2
The powder material enters in the 0 direction, and the adhesion proceeds from the portion D to the portion C. Next, the second opening / closing mechanism 9 is closed, the first opening / closing mechanism 8 is opened, and the molding die 3 to which the powder box 4 is fixed is attached.
Is rotated once in the direction of arrow 12. At this time, the powder material enters the first mold part 1 in the direction of the arrow 21 and the adhesion proceeds from the part B to the part A. Therefore, the portion A and the portion C and the portion B and the portion D are formed under the same conditions, and the thickness and the like can be made equal.

Next, the powder slush molding method of the present invention will be described with reference to FIG. As shown in FIG. 2, all steps of the powder slush molding method of the present invention include a preheating step (9) for increasing the temperature of a molding die, first molding steps (1) to (3), and a second molding step (4). ) To (6), a heating step and a cooling step (7) for the slush molded product, and a demolding step (8).

The preheating step (9) for increasing the temperature of the mold is a step of warming the molding die 3 from which the slush molded product has been removed. The powder material is adhered to the inside of the molding die 3 to be in a semi-molten state. The temperature of the molding die 3 is increased to such an extent that it can be performed. In the present invention, as shown in FIG. 3, since a mold having a mountain shape in which the convex portions of the mold portions 1 and 2 are projected outward is used, in this preheating step, Hot air easily hits the entire outer surface, and the temperature of the entire mold can be quickly and uniformly increased. In the case of a valley-shaped mold in which the convex portions of the mold portions 1 and 2 are opposed to face inward, there is a case where the temperature of the deep part of the valley is difficult to rise only by hot air from the outside. It should just be applied.
As for the shape of the mold that is easily preheated, it is important that both mold parts are arranged and joined in a semicircular shape as much as possible in an axially symmetric manner.

In FIG. 2, a first molding step (1)-
(3) is a step of welding a semi-molten resin to the second mold part 2. As shown in the first molding step (1), first, the preheated molding die 3 is placed on the powder box 4, and both are fixed by the fixing means 10 and connected to the rotating means 31.
As shown in the first molding step (2), the first opening / closing mechanism 8
Is closed, and the second opening / closing mechanism 9 is opened. As shown in the first molding step (3), the molding die 3 to which the powder box 4 is fixed is rotated once counterclockwise. Then, the powder resin flows in and out of the first mold part 2 as indicated by an arrow from the symmetry line toward the end, and a semi-molten powder material layer having a predetermined thickness is formed on the inner surface of the second mold part 2. .

The second molding steps (4) to (6) are steps of welding a semi-molten resin to the first mold part 1. As shown in the first molding step (4), the second opening / closing mechanism 9 is closed and the first opening / closing mechanism 8 is opened. As shown in the second molding step (5), the molding die 3 fixed to the powder box 4 is rotated one turn clockwise. Then, powder resin flows in and out of the first mold part 1 as shown by an arrow from the symmetry line toward the end, and a semi-molten powder material layer having a predetermined thickness is formed on the inner surface of the first mold part 1. .

After that, the molding die 3 in which the semi-molten resin is welded to both the mold parts 1 and 2 is removed from the powder box 4, and the heating and cooling step (7) and the demolding step (8) are performed. The two finished slash products are removed from the mold 3. The molding die 3 is returned to the preheating step (9) for preheating.

After the semi-solid resin layer is formed on the second mold part 2 in the first molding steps (1) to (3), the first mold part 1 is formed in the second molding steps (4) to (6). In order to form the semi-molten resin layer, the second molding steps (4) to (6) are performed after the first molding steps (1) to (3). Therefore, while the first molding steps (1) to (3) are being performed on the second mold part 2, the temperature of the first mold part 1 is slightly lowered. Due to the mold temperature difference between the first mold part 1 and the second mold part 2, the thickness of the slush molded product may be different.
In such a case, in FIG.
One that can be divided into a first heating zone 38 in the left half and a second heating zone 39 in the right half is used. Then, the temperature of the hot air blown out of the first heating zone 38 is changed to the second heating zone 39.
Preheating so that the mold temperature of the first mold part 1 is higher than the mold temperature of the second mold part 2. The difference between the mold temperature of the first mold part 1 and the mold temperature of the second mold part 2 is such that the temperature drop of the first mold part 1 after one rotation of the second mold part 2 is compensated. Then, the mold temperatures during molding of the first mold part 1 and the second mold part 2 become substantially the same.

There is also a method of performing preheating by applying hot air while rotating a mold. In this case, the stop position and the stop time are appropriately set during the rotation, taking into account the level of the temperature in the heating furnace. In this way, each mold part 1, 2
In order to give a temperature difference to the stop position, the setting of the stop time may be changed at the corresponding stop position.

Further, when hot air is blown as shown by an arrow 40 in FIG. 3, the mold 1 on the side where the hot air enters becomes slightly higher than the mold 2 on the exit side. By appropriately adjusting the blowing direction, speed and the like of the hot air, a proper temperature difference can be given to each of the mold parts 1 and 2.

In the above description of the embodiment, the case where two slush molded products are obtained at one time has been described. However, the first mold portion and the second mold portion are joined to face each other so as to be symmetrical. If two or more of these are connected in the front-rear direction and used, it is possible to obtain a large number of 4, 6, 8,...

Next, an apparatus for molding two concave molded articles will be described with reference to FIG. The mold 3 shown in FIGS. 1 to 3 is, as shown in the demolding step (8) of FIG.
This is to form two convex molded products having a convex surface. As shown in FIG. 4 (b), the mold 43 shown in FIG. 4 forms two concave molded products having a concave surface 23 side. This mold 43 also has a first mold portion 41 and a second mold portion 42 arranged in a substantially circular arc shape such that the respective convex portions protrude outward. Is disposed so as to be convex downward. When the mold 43 is turned upside down, it has substantially the same shape as the mold 3 described above. In the preheating step, the mold 3 shown in FIG.
It can be preheated in the same manner as described above. Further, in order to attach the powder material to the outside of the chevron, the chevron is fixed to the powder box 44 with the chevron facing down. In this case, however, the size of the mold is the minimum necessary. Can be reduced in size.

[0031]

As described above, according to the first aspect of the present invention, a molding die in which a first mold portion and a second mold portion are joined to face each other so as to be symmetrical. Since the molding is divided into the first molding step and the second molding step by the reverse rotation, the first and second mold parts having the same shape and the same size are placed in the powder material from the direction which is relatively the same direction when viewed from the shape. And eliminating excess powder material to eliminate unevenness in product thickness due to the shapes of the first and second mold portions, and to make the finish of the first and second molded products uniform. It has the effect of being able to do so.

According to a second aspect of the present invention, in addition to the effect of the first aspect, the first mold portion and the second mold portion are arranged in a substantially arc shape such that each convex portion protrudes outward. Therefore, the size of the apparatus can be reduced.

According to a third aspect of the present invention, in addition to the effects of the first or second aspect, by preheating the mold temperature of the second mold portion to be higher than the mold temperature of the first mold portion, Since the difference between the mold temperature of the first mold part at the time of the first molding step and the second mold temperature at the time of the second molding step is eliminated, the powder material adheres and melts evenly, and the first molded product This has the effect of making the finish of the second molded product more uniform.

According to a fourth aspect of the present invention, the molding of the first mold part and the second mold part which are joined to face each other so as to be symmetrical with each other are performed by reverse rotation to form the first mold part and the second mold part. Since the apparatus is configured such that the molding of the two mold parts can be separated, the first mold part and the second mold part having the same shape and the same size are formed in the same direction as viewed from the shape. A powder material is charged from a certain direction to eliminate unevenness in product thickness due to the shapes of the first mold part and the second mold part, and to eliminate excess powder material, to thereby obtain a first molded article and a second molded article. There is an effect that the finish can be made uniform.

[Brief description of the drawings]

FIG. 1 is a schematic view of one embodiment of a powder slush molding apparatus of the present invention.

FIG. 2 is a schematic view of a powder slush molding method using the apparatus of FIG.

FIG. 3 is a schematic explanatory view of a preheating step.

FIG. 4 is a schematic view of another embodiment of the powder slush molding apparatus of the present invention.

FIG. 5 is an explanatory view of a conventional powder slush molding apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first mold portion 2 second mold portion 3 molding die 4 powder box 6 first storage portion 7 second storage portion 8 first opening / closing mechanism 9 second opening / closing mechanism 10 fixing means 31 rotating means 32 control mechanism

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 41/18 B29C 41/22 B29C 41/52

Claims (4)

(57) [Claims] A first mold part and a second mold part are symmetrical.
A powder slush molding method for simultaneously molding two or more slash molded products using a molding die having at least one of the front and rear mold parts joined face to face, wherein an opening toward the first mold part is provided. A first storage part that can be opened and a second storage part that can be opened toward the second mold part.
Using a powder box consisting of a storage part, the preheated molding die is placed and fixed on the powder box, and with the second storage part closed and the first storage part opened, the powder box is By rotating the fixed molding die, and charging the powder material into the first mold portion,
A first molding step of discharging a surplus powder material to form a semi-molten first molded product on an inner surface of the first mold part;
With the storage part closed and the second storage part opened, the molding die is rotated in a direction opposite to that of the first step, and the powder material is charged into the second mold part and excess powder material is added. And forming a semi-molten second molded product on the inner surface of the second mold portion by discharging the powder. 2. The powder slush molding method according to claim 1, wherein the first mold portion and the second mold portion are arranged in a substantially arc shape such that respective convex portions protrude outward. 3. The preheating of the molding die is performed so that the mold temperature of the second mold portion is lower than the mold temperature of the first mold portion so as to compensate for the temperature decrease of the second mold portion in the first molding step. The powder slush molding method according to claim 1, wherein the method is performed so as to increase the height. 4. The first mold part and the second mold part are symmetrical.
A molding die having at least one of the front and rear mold parts joined face to face, and a first storage part and a second storage part separated by a partition plate provided on a line of symmetry of the molding die. A powder box, and a rotating mechanism capable of mounting and fixing the preheated molding die on the powder box, and rotating the molding die to which the powder box is fixed in one direction and the opposite direction. A first opening / closing mechanism provided between the first mold part and the first storage part; a second opening / closing mechanism provided between the second die part and the second storage part; When rotating in one direction, the second
When the first opening / closing mechanism is opened by closing the opening / closing mechanism, and when rotating in the opposite direction, the first opening / closing mechanism is closed and the second opening / closing mechanism is opened, and the powder material enters the first mold part. And a control mechanism for controlling the rotation mechanism so that the direction and the direction of entering the second mold part are relatively the same direction.