JP2008238435A - Press die and press molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press die in which burr removing operation is unnecessary. <P>SOLUTION: The press die 10 is equipped with a male die 20 and a female die 30 for forming a molding space 14 in which a stampable sheet 12 is pinched and molded so as to form a product with a specified shape. In the male die 20, a rectangular parallelepiped placing stand 22 on which the stampable sheet 12 is placed before press processing, a lower stand 24 continuously positioned below this placing stand 22, and a base stand 26 for supporting these placing stand 22 and lower stand 24. In the female die 30, a molding face 32 formed so as to surround the upper face of a rectangular parallelepiped-shaped space (a part of this space constitutes the molding space 14) and the outer wall face, and a partitioning face 34 being at a position corresponding to the peripheral edge part of the bottom face of this space and spreading orthogonally to the lower end of the molding face 32. A step difference 36 is formed by the lower end part of the molding face 32 and the partitioning face 34. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a press mold having a male mold and a female mold that form a molding space in which a fluid raw material is sandwiched and molded so as to form a product having a predetermined shape, and a press molding method using the press mold About.

  2. Description of the Related Art A press working method is widely employed in which a raw material having fluidity is sandwiched and press-molded so as to become a product having a predetermined shape. In this press working method, a press die having a male die and a female die forming a molding space in which a fluid raw material is sandwiched and molded into a predetermined shape is used. A stampable sheet is known as one of the fluid raw materials.

  A stampable sheet is a composite material sheet obtained by mixing glass fibers and the like with a thermoplastic resin, and is a semi-finished product before molding. When the stampable sheet is pressed, the stampable sheet is heated and softened by a heater or the like, and then the male mold and the female mold are brought close to each other while being sandwiched between the male mold and the female mold. The stampable sheet flows to every corner in a space (molding space) sandwiched between a male mold and a female mold, and is molded into a product that follows the shape of this space.

  Since the above-mentioned stampable sheet is mixed with glass fiber, when the stampable sheet is heated and softened, its thickness expands to about three times, and air enters the stampable sheet being heated. . Therefore, compared with the case of pressing a semi-molten resin, when the stampable sheet is pressed, the amount of air and gas discharged during molding is large. For this reason, discharging these air and gas smoothly is an important point when forming a stampable sheet.

  The stampable sheet has a variation of about 5% in the weight of the raw material itself and presses the raw material (stampable sheet) to flow when the press molds (male and female) are closed (closed). Due to the nature of molding, it is also an important point to put a large amount of raw material in the mold so that excess raw material is squeezed out (leaked out) during molding. This devoured (leaky) ingredient becomes a “burr”. This “burr” needs to be removed in a later process. The man-hour for this “burr” removal is enormous.

In order to eliminate (or facilitate) this “burr” removal work, the raw material was leaked to the outside only from a predetermined location (overflow gate), and this leaked portion was cut with a shear edge. A technique using a press die has been proposed (see, for example, Patent Document 1).
JP 09-267344 A

  However, in the above-described technology, the raw material has fluidity even when the mold is completely closed, and even if the raw material leaked from the overflow gate is cut with a shear edge, the raw material is not discharged from the overflow gate. There is a risk of leaking and becoming a “burr”.

  In view of the above circumstances, an object of the present invention is to provide a press die and a press molding method that eliminate the need for a “burr” removing operation.

In order to achieve the above object, a press die according to the present invention comprises a male die and a female die that form a molding space in which a fluid raw material is sandwiched and molded so as to become a product having a predetermined shape. In the mold,
(1) The raw material leaked to the outside from the molding space when the raw material is sandwiched in the molding space is separated by separating the male mold and the female mold in order to take out the product after molding. It is characterized by being separated from the product.

In order to achieve the above object, another press mold of the present invention comprises a male mold and a female mold that form a molding space in which a fluid raw material is sandwiched and molded so as to become a product having a predetermined shape. In the press mold provided,
(2) The space area of the external space at the boundary surface between the external space adjacent to the molding space and the molding space is narrower than the space area of the portion following the boundary surface of the external space, and the boundary It is characterized by being narrower than the space area of the molding space on the surface.

here,
(3) A portion of the male mold that forms the external space and a portion of the female mold that forms the external space may approach each other to form the boundary surface.

further,
(4) The female mold may be formed with a step that protrudes toward the male mold and forms the boundary surface.

Still another press mold of the present invention for achieving the above object is a male mold and a female mold that form a molding space in which a fluid raw material is sandwiched and molded so as to become a product of a predetermined shape. In press dies with
(5) The female mold is characterized in that a step is formed to narrow the opening at the boundary between the external space adjacent to the molding space and the molding space.

here,
(6) The step may be in a range of (the plate thickness of the product at the boundary × the molding shrinkage rate of the raw material) or more and (the outer dimension of the product × the molding shrinkage rate of the raw material ÷ 2) or less. .

Further, the press molding method of the present invention for achieving the above object includes a male mold and a female mold that form a molding space in which a fluid raw material is sandwiched and molded so as to become a product having a predetermined shape. In a press molding method using a press mold, the raw material is sandwiched in the molding space and molded into the product.
(7) When the raw material is sandwiched and molded in the molding space, a part of the raw material leaks out of the molding space,
(8) solidify the raw material, then
(9) The leaked part of the raw material is separated from the product by separating the male mold and the female mold.

  According to the present invention, when the male mold and the female mold are separated in order to take out the product after press molding, the raw material leaked outside from the molding space is separated from the product. Since the raw material leaked to the outside from the molding space becomes a “burr”, the “burr” removing operation becomes unnecessary.

  The present invention has been realized in a press die used when pressing a stampable sheet.

  An example of the press die of the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1A is a perspective view showing a female mold, and FIG. 1B is a perspective view showing a male mold. FIG. 2 is an enlarged side view showing characteristic portions of the male and female dies. In FIG. 1, the unevenness | corrugation currently formed in the female type | mold and the male type | mold is exaggerated and shown.

  The press mold 10 includes a male mold 20 and a female mold that form a molding space 14 in which a raw material having fluidity (for example, a stampable sheet 12 (see FIG. 3)) is sandwiched and molded so as to become a product having a predetermined shape. 30. The molding space 14 here is a space formed by the press die 10 in the state shown in FIG. 3C and has a shape substantially the same as the shape of the product. The male mold 20 includes a rectangular parallelepiped mounting table 22 on which the stampable sheet 12 is mounted prior to press working, a lower table 24 continuously located below the mounting table 22, and the mounting table 22 and the lower table. A base 26 for supporting 24 is formed. The mounting table 22, the lower table 24, and the base 26 are manufactured as a single unit, but may be manufactured separately.

  The top surface (mounting surface) 22a of the mounting table 22 has a rectangular shape, and a rectangular parallelepiped stampable sheet 12 having a bottom surface slightly narrower than the mounting surface 22a is placed on the mounting surface 22a (see FIG. 3 (a)). The peripheral surface of the mounting table 22 is a side wall surface 22 b, and the side wall surface 22 b and the mounting surface 22 a form a molding space 14 together with a molding surface (inner wall surface) 32 of the female mold 30. That is, the space surrounded by the side wall surface 22b, the mounting surface 22a, and the molding surface 32 becomes the molding space. Although the side wall surface 22b is made into a suitable shape according to the shape of the target product, here, the flat side wall surface 22b without unevenness is shown.

  The lower base 24 has a top surface 24a that is slightly wider than the bottom surface of the mounting table 22, and a side wall 24b connected to the top surface 24a. A step 23 according to the present invention is formed by the side wall surface 22 b of the mounting table 22 and the top surface 24 a of the lower table 24. The step 23 narrows the opening 15 at the boundary between the outer space 16 adjacent to the molding space 14 and the molding space 14. The opening 15 is also narrowed by a partition surface 34 of the female mold 30 as will be described later.

  As shown in FIG. 1B and FIG. 2, the unevenness of the side wall 24b is connected to a curved surface 24c that extends downward from the periphery of the top surface 24a and curves inward, and a lower end of the curved surface 24c. It is composed of a smooth surface 24d extending downward. The smooth surface 24 d is parallel to the side wall surface 22 b of the mounting table 22. The lower end of the smooth surface 24 d is connected to the top surface 26 a of the base 26.

  As shown in FIGS. 1A and 2, the female mold 30 is formed so as to surround the upper surface and outer wall surface of a rectangular parallelepiped space (a part of this space constitutes the molding space 14). A surface 32 and a partition surface 34 extending at a right angle to the lower end of the molding surface 32 at a position corresponding to the peripheral edge of the bottom surface of the space are formed. A step 36 is formed by the lower end portion of the molding surface 32 and the partition surface 34. Further, the female die 30 is formed with an outer peripheral surface 38 that is bent at a right angle from the periphery of the partition surface 34 and extends downward. When the male mold 20 and the female mold 30 are located at the positions shown in FIGS. 2 and 3C, the curved surface 24 c and the smooth surface 24 d of the male mold 20 are opposed to the outer peripheral surface 38 of the female mold 30. The space surrounded by the curved surface 24c, the smooth surface 24d, and the outer peripheral surface 38 is the external space 16. The female mold 30 is also formed with a bottom surface 39 that faces the top surface 26 a of the base 26.

  Here, the width W (amount of protrusion from the lower end portion of the molding surface 32) of the partition surface 34 constituting the step 36 will be described.

  The width W (also referred to as a step) of the partition surface 34 is equal to or greater than (the product thickness t × the molding shrinkage ratio of the stampable sheet 12), and (the outer dimension L of the product × the molding shrinkage ratio of the stampable sheet 12 ÷ 2). It is preferable that Here, the plate thickness t of the product refers to the thickness of the product at the boundary between the molding space 14 and the external space, and is t shown in FIG. 3 (e), from T (width of the molding space 14) in FIG. Is also slightly smaller. For example, when the molding shrinkage ratio is 5/1000, the plate thickness t, and the outer dimension L is 3 mm and 300 mm, respectively, the step may be in the range of 0.015 mm or more and 0.75 mm or less. In consideration of wear and the like, it is preferable to be within a range of 0.2 mm to 0.5 mm.

  With reference to FIG. 3 and FIG. 4, the press work method by the press die 10 is demonstrated.

  FIG. 3A is a side view showing a state where the raw material is placed on the male mold, and FIG. 3B is a side view showing a state where the female mold approaches the raw material placed on the male mold and is slightly crushed. And (c) is a side view showing a state in which the raw material is sandwiched between the male mold and the female mold and finished being molded, and (d) is a state where the raw mold is finished into the product and the female mold is slightly removed from the male mold. It is a side view which shows the state which released | separated, (e) is a side view which shows the state which separated the female type | mold from the male type | mold after shaping | molding. FIGS. 4A to 4E are cross-sectional views showing the boundary between the molding space and the external space and the vicinity thereof in correspondence with FIGS. 3A to 3E. In these drawings, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

  When the stampable sheet 12 is pressed into a product having a predetermined shape (in this case, a rectangular parallelepiped box shape), first, the stampable sheet 12 is preheated to a predetermined temperature and softened, and then the stampable sheet 12 shown in FIGS. As shown to (a), this softened thing is mounted on the mounting surface 22a of the male type | mold 20. As shown in FIG. The amount of the stampable sheet 12 placed is slightly larger than the amount of the product 12 '. Subsequently, the female die 30 is brought close to the male die 20 with a press machine (not shown), and the stampable sheet 12 is compressed and molded as shown in FIGS. 3 and 4B. Thereby, the stampable sheet 12 is formed to flow and follow the forming space 14. Gas and air generated due to this compression are discharged from the opening 15 to the external space 16.

  The molding space 14 is formed by further bringing the female mold 30 closer to the male mold 20, whereby the stampable sheet 12 flows to the end of the molding space 14 as shown in FIG. 3 and FIG. The excess portion 13 leaks from the opening 15 to the external space 16. In this state, the product 12 ′ is completed, but an extra portion 13 (portion that becomes a “flash”) remains connected to the end of the product 12 ′. After the product 12 ′ is sufficiently solidified, the female mold 30 is raised and moved away from the male mold 20 without moving the male mold 20. When the female mold 30 is separated from the male mold 20 as described above, the edge of the lower end surface of the product 12 ′ is caught on the partition surface 34 of the female mold 30 as shown in FIG. 3 and FIG. The product 12 ′ rises with the mold 30. Here, at the boundary surface between the molding space 14 and the external space 16, as clearly shown in FIG. 2, the space area of the external space 16 is narrower than the space area of the molding space 14. 16 is connected (connected) by a narrow opening 15. In other words, the male mold 30 and the female mold 20 are formed with steps 23 and 36 that narrow the opening 15 at the boundary between the external space 16 adjacent to the molding space 14 and the molding space 14. That is, the female mold 30 has a step 36 that protrudes toward the male mold 20 to form a boundary surface, and the male mold 20 has a step 23 that protrudes toward the female mold 30 to form a boundary surface. Is formed. Therefore, as shown in FIG. 3 and FIG. 4D, when the female mold 30 is pulled away from the male mold 20, the excess portion 13 cannot pass through the narrow opening 15 and the side wall 24b of the male mold 20 is removed. It is captured by the curved surface 24c, pulled and separated from the product 12 '.

  As shown in FIGS. 3 and 4 (e), the product 12 'from which the excess portion 13 has been separated as described above is subjected to the restraining force of the male mold 20 by further lifting the female mold 30. As a result, the product 12 ′ is slightly contracted, the lower end surface of the product 12 ′ is detached from the partition surface 34, and the product 12 ′ is dropped. As a result, only the product 12 'can be taken out. When the width of the partition surface 34 is too narrow (the step 36 is too small), the female mold 30 contracts to the step 36 or more when the female mold 30 is lifted, and the product 12 ′ is not pulled up together with the female mold 30 and the male mold is used. 20, the excess portion 13 (“burr”) is not cut from the product 12 ′. On the contrary, when the width of the partition surface 34 is too wide (the step 36 is too many), the product 12 ′ is pulled up together with the female mold 30, and the excess portion 13 (“burr”) is cut from the product 12 ′. However, the lower end surface of the product 12 ′ does not come off the partition surface 34 and the product 12 ′ does not fall, and the product 12 ′ cannot be removed from the female mold 30.

  Another example of the press die will be described with reference to FIG.

  FIG. 5 is a cross-sectional view showing another example of a press die.

  In the press die 60 of another example, the male mold 20 has the same shape as the male mold 20 shown in FIG. 1 and the like, but the female mold 40 has a different shape from the female mold 30 shown in FIG. The feature of the female mold 40 is that a portion 42 of the female mold 40 that becomes the opening 15 is cut away in order to form the opening 15. A step 44 corresponding to the step 36 shown in FIG. In this way, by cutting off a part of the female die 40, the outer peripheral end of the product 61 'spreads outward, but the female die can be easily remodeled, and the costs associated with the remodeling can be minimized. .

  With reference to FIG. 6, still another example of the press die will be described.

  FIG. 6 is a cross-sectional view showing still another example of the press mold.

  Still another example of the press die 70 is characterized by an external space 71 in which the external space 16 shown in FIG. In order to form such an external space 71, a male mold 50 having a concave shape toward the inside thereof was produced. Since the external space 71 is wider as it goes downward, the cut excess portion 13 does not stay at the same place in the external space 16 and the removal of the “burr” is facilitated. An extra portion 13 indicated by a two-dot chain line indicates a state in which the extra portion 13 indicated by a solid line is falling.

  In each of the above-described examples, the boundary surface between the molding space formed by the male mold and the female mold and the outer space and the entire periphery in the vicinity (over the entire circumference) formed the irregularities of the partition surface 34 and the side wall 24b. These may be partially formed, and in the remaining portion, the opening 15 may be narrowed. In this case, it is possible to prevent the “burr” from continuing around the entire circumference of the product. "Falls very easily.

(A) is a perspective view which shows a female type | mold, (b) is a perspective view which shows a male type | mold. It is a side view which expands and shows the characteristic part of a male type | mold and a female type | mold. (A) is a side view showing a state where the raw material is placed on the male mold, (b) is a side view showing a state where the female mold approaches the raw material placed on the male mold and is slightly crushed, (C) is a side view showing a state in which the raw material has been sandwiched between the male mold and the female mold and has been molded, and (d) is a part of the female mold slightly separated from the male mold after the raw material has been molded into the product. It is a side view which shows a state, (e) is a side view which shows the state which separated the female type | mold from the male type | mold after shaping | molding. (A)-(e) is sectional drawing which expands and shows the boundary of shaping | molding space and external space, and its vicinity corresponding to (a)-(e) of FIG. It is sectional drawing which shows the other example of a press metal mold | die. It is sectional drawing which shows the further another example of a press die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Press die 12 Stampable sheet 14 Forming space 16 External space 20 Male mold 23, 36 Level difference 30 Female mold

Claims (7)

In a press mold having a male mold and a female mold that form a molding space that is sandwiched and molded so that a raw material having fluidity becomes a product of a predetermined shape,
The raw material leaked outside from the molding space when the raw material is sandwiched in the molding space is separated from the product by separating the male mold and the female mold in order to take out the product after molding. A press die characterized by In a press mold having a male mold and a female mold that form a molding space that is sandwiched and molded so that a raw material having fluidity becomes a product of a predetermined shape,
The space area of the external space at the boundary surface between the external space adjacent to the molding space and the molding space is:
A press die characterized by being narrower than a space area of a portion of the external space following the boundary surface and smaller than a space area of the molding space at the boundary surface. The portion of the male mold that forms the external space and the portion of the female mold that forms the external space approach each other to form the boundary surface. The described press die. The press die according to claim 2 or 3, wherein the female die is formed with a step projecting toward the male die to form the boundary surface. In a press mold having a male mold and a female mold that form a molding space that is sandwiched and molded so that a raw material having fluidity becomes a product of a predetermined shape,
The female mold is
A press die characterized in that a step for narrowing an opening at a boundary between an external space adjacent to the molding space and the molding space is formed. The step is in a range of (plate thickness of the product at the boundary × molding shrinkage rate of the raw material) or more and (external dimension of the product × molding shrinkage rate of the raw material ÷ 2) or less. Item 6. A press die according to Item 4 or 5. Using a press mold having a male mold and a female mold forming a molding space in which a raw material having fluidity is sandwiched and molded so as to become a product of a predetermined shape, the raw material is sandwiched in the molding space and In the press molding method for molding into products,
When the raw material is sandwiched in the molding space and molded, a part of the raw material leaks out of the molding space,
Solidify the raw material, then
A press molding method, wherein the leaked part of the raw material is separated from the product by separating the male mold and the female mold.

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