JP2001205679A - Simple mold for molding and method for molding it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple mold for molding suitable for a short developing period, a low development cost and a multi-kind small quantity production in association with a loose core 4 and a slide core 7 in the mold having undercuts 5a, 5b at an inside and an outside of a molding. SOLUTION: The simple mold for molding comprises a loose core 4 having a shape obtained by inverting the inside undercut 5a of the molding 5 and inserted into or removed from a hole perforated at a movable side mold 3, a slide core 7 having a shape obtained by inverting the outside undercut 5b of the molding and slidably fixed in a direction perpendicular to an inserting and removing direction of the core 4 in a mold releasing direction of the outside undercut 5b in the mold 3. Thus, when the core 7 is advanced to the undercut 5b an L-shaped part 4b of the core 4 is superposed with an inverted L-shape part 7c of the core 7, thereby positioning the core 4 at the mold 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple mold using a placing core when molding a molded product having an undercut on the inner and outer surfaces of a plate-like portion. More specifically, the present invention relates to a simple molding die in which an inner undercut is formed by using a core and an outer undercut is formed by a slide core.

2. Description of the Related Art In general, when molding an undercut in an injection mold, a slide core is often used.
CAD / CAM / CAE (computer aid)
d design / computer aided m
anfactoring / computer aid
GWS (gra) such as ed engineering
Due to the development design using the phys work station, the product development cycle has become extremely short. Therefore, in the case of recent new products, every time a design change is made, it is necessary to use a resin model molded with a newly designed mold and develop the product and the mold in parallel while confirming the design and functions. However, with the progress of development, molds for different lots, such as those for trial operation, evaluation, and production, have been required. For this reason, it is difficult for the conventional mold to satisfy the conditions of a small lot, a short delivery time, and a low cost, and the development period is short in accordance with the product development cycle, the number of shots is small (for example, 100
A mold that satisfies the inexpensive condition, but has the same performance as the conventional mold is required. For that purpose, it is necessary to develop a simple mold corresponding to a small number of shots, not to mention cost reduction such as reduction of material and parts of the mold and common use. From such a background, it is wasteful to make a mold having a complicated structure such as a slide core at a high cost, for example, in order to form an undercut. A simple mold using a child is sufficient to respond. However, in the case of using the placing core, as shown in FIG.
Although it is possible to form the undercut 105 inside of the molded product 5, as shown in FIG. 1, in the case where the molded product 5 has undercuts 5a and 5b on both the inside and the outside, Cannot deal with it. In such a case, by using both the placing core and the slide core together, a reliable, highly accurate, and inexpensive simple mold can be realized.

DISCLOSURE OF THE INVENTION The present invention has been invented in the background as described above, and when a molded article has undercuts on both inner and outer sides, the placing core and the undercut can be efficiently removed. It is another object of the present invention to provide a simple molding die which has a short mold development period, has a low development cost, and is not inferior in performance to the conventional one and is suitable for high-mix low-volume production.

The simple molding die of the present invention has a first undercut portion on a core side and a second undercut portion on a cavity side opposite to the first undercut portion. A molding die having a shape obtained by inverting the first undercut, and a placing core inserted into and removed from a hole formed in a mold plate;
A slide core having an inverted shape of an undercut, and being fixed to the template in a mold release direction of the second undercut, and slidably fixed in a direction orthogonal to a direction in which the placing core is inserted and removed. When the slide core advances to the second undercut, a part of the slide core engages with a part of the placing core, so that the slide core fixes the placing core to the template. It is characterized by doing. Further, in the molding method using a simple molding die of the present invention, the first undercut on the core side is formed by a placing core, and the second undercut on the cavity side is formed by a slide core. When advancing to the second undercut,
It is characterized by engaging with the placing core and fixing the placing core to the template. In addition, the placing core or
An inclined surface is provided at the tip of the engaging portion of the slide core. Further, the placing core has a plurality of placing cores arranged in parallel with the slide core.

DETAILED DESCRIPTION OF THE INVENTION In general,
For injection molding a molded article having an undercut,
A simple injection molding die using a placing core will be described with reference to FIG. As shown in FIG. 5, the simple injection mold 100 is
Fixed mold 102, movable mold 103 and placing core 10
4 and the fixed mold 102 and the movable mold 1
A molded product 105 is formed by filling a molten resin into a closed mold space formed by the core 03 and the placing core 104, and cooling and solidifying the resin. The placing core 104 constitutes a part of the core of the movable mold 3 and forms an undercut 105 a provided inside the molded product 105 (on the core side). The placing core 104 is sandwiched between the fixed mold 102 and the movable mold 103 when the movable mold 103 is in close contact with (closed to) the fixed mold 102, and the movable mold 103 is fixed to the fixed mold 102. When the mold 102 is in close contact with the mold 102, the divided surface (part) 106 of the fixed mold 102 and the movable mold 103
It is positioned with. Also, when molding is completed and the movable mold 3 is separated (opened) from the fixed mold 2, the placing core 104 is taken out of the movable mold 103 while being attached to the molded article 105, and It is removed from the molded article 105 outside, and only the placing core 104 is fitted back into the movable mold 103 again. 107, the upper part is inserted into the bottom of the placing core 104 in the figure, the lower part penetrates the movable mold 3 and is connected to an ejector plate (not shown), and slides up and down in conjunction with the ejector plate. Ejector pin, and ejector plate, set core 1
04 is projected from the movable mold 103 together with the molded article 105. However, in the conventional simple injection mold described above, the undercut 105a that can be formed by the placing core 104 is limited only to the inside of the molded product 105, and is not limited to the inside of the molded product 5 as shown in FIG. If the outer side has undercuts on both sides, it cannot be formed by the placing core 104. Next, an embodiment of an injection molding die using the simple molding die of the present invention will be described with reference to FIGS. In FIG. 1, a simple injection mold 1 is composed of a fixed mold 2, a movable mold 3, a placing core 4, a slide core 7, an angular pin 8, an ejector pin 9, and an ejector plate (not shown). ing.
The movable-side mold 3 can be separated (opened) downward from the fixed-side mold 2 in the drawing at the divided part (part) 6. A mold space 5 surrounded by the fixed mold 2, the movable mold 3 and the placing core 4 is filled with a molten resin, cooled and solidified to form a molded product 5. The placing core 4 constitutes a part of the core of the movable mold 3, and has a reverse shape 4 a of an undercut 5 a formed on the inner side (core side) of the molded product 5 on the right side in the figure. In addition, placing core 4
A step L-shaped portion 4b is provided below the inverted shape 4a.
Reference numeral 7 denotes a slide core slidably fitted in a groove 3a formed in the movable mold 3, and an upper end surface of the slide core 7 forms a division surface 6, and the movable mold 3 is fixed to the fixed mold. When it comes into close contact with the mold 2 (closes), it is positioned by the fixed mold 3. The slide core 7 is located on the right side in the drawing,
It has an inverted shape 7b of the outer shape of the undercut 5b formed outside the molded product 5, and an inverted L-shaped portion 7 is provided below the inverted shape.
and polymerizes on the L-shaped portion 4b of the placing core 4. The slide core 7 positions the placing core 4 on the movable mold 3 by overlapping the inverted L-shaped portion 7c with the L-shaped portion 4b. Also, by forming a gradient 4c or 7d at the tip of the L-shaped portion 4b of the placing core 4 or the tip of the inverted L-shaped portion 7c of the slide core 7, the placing core 4 is formed.
And the slide core 7 can smoothly slide and polymerize without collision. 8 is the fixed mold 2
An angular pin fixed at a predetermined inclination angle.
Reference numeral 9 denotes an inclined hole 7d formed in the slide core 7 at the same inclination angle as the angular pin 8. The inclined hole 7d slides along the angular pin 8 as the movable mold 3 opens and closes. As the inclined hole 7d slides along the angular pin 8, the slide core 7 slides in the groove 3a left and right in the figure. That is, in a state where the movable mold 3 is in close contact with the fixed mold 2 (closed state), the slide core 7 moves to the left end in the figure, and the inverted shape 7b of the undercut 5b The undercut 5b is opposed to a predetermined forming position of the undercut 5b, and the undercut 5b can be formed. At the same time, the L-shaped portion 4b and the inverted L-shaped portion 7b overlap, and the placing core 4 is positioned by the slide core 7, and The undercut 5a can be formed by the child. Also,
As shown in FIG. 4, a plurality of placing cores 4 for forming a plurality of undercuts 5a can be arranged in parallel and positioned by one slide core 7. Needless to say, a plurality of undercuts 5b can be formed on the front surface of the slide core 7. Reference numeral 9 denotes an ejector pin which is inserted into the ejector hole 4d formed in the bottom of the placing core 4 through the movable mold 3 from below in the figure. When the movable mold 3 is released from the fixed mold, the ejector pin 9 releases the ejector pin 9 by ejector play (not shown) at the same time as the stacking of the placing core 4 and the slide core 7 is released. It is driven upward, and the placing core 4 is protruded from the core surface of the movable mold 3. Next, the operation of the simple injection molding die of this embodiment having the above-described configuration will be described with reference to FIGS. (1) As shown in FIG. 1, the movable mold 3 is fixed
Meanwhile, when the divided core 6 is in close contact with (closed to) the slide core 7, the core 4 is moved by the movable mold 3.
At a predetermined position. A molten resin is injected from a gate (not shown) into a molding space 5 formed by the cavity surface of the fixed mold 2, the core surface of the movable mold 3, and the placing core 4. 5 is filled with a molten resin, cooled and solidified. (2) As shown in FIG. 2, when the molten resin is solidified, the movable mold 3 opens downward from the fixed mold 2 in the figure,
The movable mold 3 separates from the fixed mold 2. Movable mold 3
Moves downward from the fixed mold 2,
When the inclined hole 7d formed in the slide core 7 slides along the angular pin 8, the slide core 7 slides right along the groove 3a, and the inverted shape 7b of the slide core 7 The mold is released from the undercut 5b of the molded product 5. When the movable mold 3 is separated from the fixed mold 2 by a predetermined distance, the slide core 7 moves to the right end of the groove 3a, and the L-shaped part 4b of the placing core 4 and the inverted L-shaped part of the slide core 7 are moved. The polymerization of 7b is released, and the positioning of the placing core 4 is released. (3) As shown in FIG. 3, the ejector pins 9 project the placing core 4 from the core surface of the movable mold 3 and eject the molded product 5 from the movable mold 3 by an ejector plate (not shown). Project from the core surface. (4) The molded product 5 is taken out of the mold with the placing core 4 attached to the molded product 5. Then, the placing core 4 is taken out of the molded product 5 (by pulling out the placing core 4 from the undercut 5a). (5) The core placed out of the molded product 4 is fitted back into the movable mold 3, and the injection molding is started again from (1). As described above, the present invention relates to a conventional molded product 5 having an undercut on both the inner and outer sides of the plate-shaped portion.
Can not be formed using a placing core, but is made possible by efficiently using a placing core and a slide core together. In general, in a resin molded part constituting a product, the cavity often constitutes the appearance of the product, and the core often constitutes the inside of the product. A mold that can mold products with excellent aesthetics is used.The mold is simplified by using a core placed on the core side that is not so aesthetically pleasing. In this way, it is possible to efficiently develop dies, reduce the development time and processing time of dies, reduce the development cost of dies, and realize simple molding dies suitable for high-mix low-volume production. be able to.

According to the present invention, in the case where the molded article has undercuts on both the inside and outside sides, the inside undercut is placed and the core is used by efficiently using the placing core and the slide core together. Simplifies the molding die,
Inexpensive development dies, suitable for high-mix low-volume production, using a slide core for the outer undercut, and using the same mold structure as before, providing a versatile and precise appearance. And a highly accurate molding die can be realized. In other words, by using the placing core and the slide core efficiently in place, it is possible to efficiently develop the mold, reduce the development period and development costs, and provide a simple molding mold suitable for high-mix low-volume production. it can. Also, a plurality of placing cores can be positioned by one slide core.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an essential part showing an embodiment of an injection molding die using a simple molding die of the present invention, in which a movable mold 3 is in close contact with a fixed mold 2 (closed). Show.

FIG. 2 is a cross-sectional view of a main part showing a state where the movable mold 3 is separated (opened) from the fixed mold 2 in the same manner.

FIG. 3 is a cross-sectional view of a main part showing a state where the placing core 4 is projected by the ejector pin 9 in the same manner.

FIG. 4 is a perspective view of an essential part showing one embodiment of an injection molding die using the simple molding die of the present invention, and shows how a plurality of placing cores 4 are positioned by one slide core.

FIG. 5 is a sectional view of a main part showing a configuration of a conventional simple molding die.

[Explanation of symbols]

 5a Inner undercut 5b Outer undercut 5 Molded product 1 Injection mold (simple mold) 2 Fixed mold 3 Movable mold (mold plate) 4 Placement core 7 Slide core 4c, 7d Inclined surface

Claims (4)

[Claims] 1. A molding die for molding a molded product having a first undercut portion on a core side and having a second undercut portion on a cavity side opposite to the first undercut portion, 1 has a shape in which the undercut is inverted, has a core inserted into and removed from a hole formed in the template, and has a shape in which the second undercut is inverted. In the release direction of the undercut, and having a slide core slidably fixed in a direction perpendicular to the insertion and removal direction of the placing core, when the slide core advances to the second undercut, A simple molding die, wherein a part of a slide core is engaged with a part of the placing core so that the slide core fixes the placing core to the template. 2. A method according to claim 1, wherein the first undercut on the core side is formed by a placing core, and the second undercut on the cavity side is formed by a slide core, and when the slide core advances to the second undercut. And a step of engaging with the placing core and fixing the placing core to the template. 3. The simple molding die according to claim 1, wherein an inclined surface is provided at a tip of the engaging part of the placing core or the slide core. 4. The simple molding die according to claim 1, wherein the placing core has a plurality of placing cores arranged in parallel with the slide core.