JPH03180312A - Cassette mold for injection molding - Google Patents

Abstract

PURPOSE:To facilitate mold changing work and make it possible to obtain product excellent in quality having no flash or the like by a constitution wherein sections, by which a cavity is formed, consists of a movable cassette part and a fixed cassette part, both of which are circular in plan view, and the mating surface of either one of the cassette parts is formed to be recessed, while the other mating surface is formed to be projected. CONSTITUTION:Cassette mold 1 consists of a fixed cassette part 2 and a movable cassette part 3, both of which are circular in plan view. A cavity C is formed at the mating surfaces of both the cassette parts 2 and 3. In the cassette mold 1, the mating surface of the fixed cassette part 2 is formed to be recessed, while that of the movable cassette part 3 is formed to be projected so as to be fitted to the recessed mating surface of the fixed cassette part. Accordingly, without removing all the matrices, only by removing the cassette mold 1 and setting cassette mold, which has another predetermined cavity shape, mold change can be performed. Further, since the mating surfaces of the cassette mold come into accurate contact with each other at mold closing, high quality molded it or item without flash due to poor contact of the mating surfaces and non-conforming portion can be obtained.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a cassette mold used in plastic injection molding, that is, a mold that is removably attached to a plastic injection molding machine via a matrix to form a cavity for molding a product.

[Conventional technology]

Injection molding is a method of manufacturing molded products by injecting thermoplasticized plastic into a mold cavity under high pressure and solidifying it, but the mold used in this injection molding method is generally Its main components include a spool bush that forms the spool, a runner plate that forms the runner, and mold plates on the fixed side (nozzle side) and movable side (anti-nozzle side) that form the product molding cavity. The structure includes an ejector bin that ejects the product from the mold. Then, the molten resin injected from the nozzle of the injection molding machine is transferred to the spool,
After it is injected into the cavity through the runner and solidified in the cavity to form a molded product, the two mold plates are separated, that is, the mold is opened, and in this state, the ejector bin protrudes to release the product into the mold. It is designed to be released from the mold. As described above, conventional injection molds have various component parts such as a template plate and an ejector mechanism, and have a fairly complex structure because they need to be able to perform a predetermined mold opening operation. . Therefore, in the past, it took a considerable number of days to manufacture molds, and it was necessary to prepare different mold sets for different products, and managing and replacing these mold sets was troublesome. A problem had arisen. Therefore, in order to deal with such problems, in recent years, a cassette type injection mold as described in, for example, Japanese Utility Model Application Publication No. 61-272120 has been proposed. This consists of a die set that is directly attached to an injection molding machine, a cassette unit that is removable from the die set, and an insert that is removable from the cassette unit and forms a cavity that has a shape that corresponds to the molded product. It consists of a cassette unit (hereinafter referred to as an in-cassette). According to this, when replacing the mold, it is only necessary to remove the cassette unit from the die set and replace only the in-cassette, making the mold replacement work faster and easier than with conventional integrated molds. can be done,
Furthermore, even when molds are manufactured for each product with a different shape, only the incaset with the cavity shape corresponding to the product needs to be manufactured instead of the entire mold, which simplifies and lowers the cost of mold manufacturing. can be achieved.

[Problem to be solved by the invention]

However, even in the cassette type mold as shown in the above publication, when replacing the in-cassette for cavity formation, the cassette unit in which the in-cassette is installed must first be removed from the die set. Moreover, in this case, it is necessary to perform troublesome work such as removing and reattaching bolts and the like one by one for various templates and attachments. Also, when installing the incaset inside the die set as described above, it is necessary to provide an appropriate gap between the two, but if there is such a gap, generally
When the mold is closed, the pair of mating surfaces for forming the cavity do not necessarily come into close contact with each other in a predetermined state, so the molding accuracy decreases or worsens, resulting in so-called cracks and defective products. Problems such as smearing are likely to occur. This invention was created in view of the above-mentioned actual situation regarding injection molding molds, and aims to reduce the overall mold production cost and facilitate management and transportation of the product. This cassette is a mold that unitizes only the mold parts necessary for the process, making it easier to replace than conventional cassettes and producing high-quality products with no cracks. The purpose is to provide molds.

[Means to solve the problem]

To achieve the above object, the present invention provides a cassette mold for injection molding that is detachably attached to an injection molding machine via a matrix, and is characterized by having the following configuration. That is, the cassette mold is composed of a fixed side cassette part and a movable side cassette part, which are circular in plan view and are movable toward and away from each other to form a product molding cavity on the mating surfaces. so that the mating surfaces of the fixed side cassette part and the movable side cassette part are in close contact with each other in a predetermined state,
One of the mating surfaces is formed into a concave shape, and the other mating surface is formed into a convex shape that can fit into the concave shape.

[For production]

According to the above configuration, the part forming the product molding cavity is constituted by a cassette mold consisting of a movable side cassette part and a fixed side cassette part, which are circular in plan view. Because it is removably attached, when replacing the mold, you only need to remove the relevant cassette mold from the mother mold and attach the other required cassette mold. There is no need to perform labor-intensive work such as installing and removing the entire mold including the mold. Moreover, since the mating surface of either the movable cassette part or the fixed cassette part is formed in a concave shape, and the other mating surface is formed in a convex shape that can fit into the concave shape,
When the mold is closed, the mating surfaces come into close contact with high precision, and as a result, a high-quality molded product can be obtained without any cracks or defective parts due to poor contact between the mating surfaces. In addition, by adopting a circular shape in plan view as the shape of the double-force setting part constituting the cassette mold, it can be manufactured or processed more easily than a mold having a rectangular outer shape. Therefore, in combination with converting the product molding section into a cassette using the cassette mold itself of the present invention, the overall mold cost and mold manufacturing time can be reduced.

【Example】

The present invention will be explained in detail below. As shown in FIGS. 1 and 2, the cassette mold 1 for injection molding according to this embodiment is composed of a fixed cassette part 2 and a movable cassette part 3, which are circular in plan view. , a cavity C is formed in the mating surfaces of the two-sided force setting portion 2.3. The fixed side cassette part 2 has a structure in which a cavity upper half forming member 5 forming the cavity upper half C1 is fitted into a sleeve-shaped cavity plate 4, and a cavity back plate 6 is coupled to the upper surface side of the cavity upper half forming member 5. be. The cavity upper half forming member 5 and the cavity back plate 6 have a cavity upper half C1 as shown in an enlarged view in FIG.
A runner 7 and a hot water pool 8 are formed, leading to
Molten resin, which is a molding material, is supplied to the cavity C via the pool 8 and the runner 7. On the other hand, the movable cassette part 3 sequentially connects a circular first plate 9, a second plate 10 having a smaller diameter than the first plate 9, and a sleeve 11 having a smaller diameter than the second plate IO. The cavity lower half forming member 12 forming the cavity lower half C2 is attached to the upper surface side of the first plate 9, and the sleeve back plate 13 is fixed to the lower surface of the sleeve 11 to form an assembly. , this assembly is equipped with an ejector mechanism 14. This ejector mechanism 14 includes an ejector back plate [5] slidably fitted into the sleeve 11, and an ejector plate 1 coupled to the upper surface side of the plate 15.
6, an ejector pin 17 for mold release whose lower end is in contact with the ejector back plate 15 through the ejector plate 16, and the ejector back plate 15.
An ejector lock plate 18 is connected to the lower surface of the sleeve, and is interposed between the bottom 18a of the plate 18 and the sleeve back plate 13, so that the plate 13 is constantly moved in the backward direction (downward in FIG. 3). It is composed of a biasing spring 19. And the ejector lock plate 18
When the ejector bin I7 is pushed toward the assembly against the spring 19, the tip of the ejector bin I7 protrudes from the lower half C2 of the cavity to release the molded product. In addition, the sleeve 11 and the ejector lock plate 18
The portion between the bottom portion 18a and the bottom portion 18a is an engaging small diameter portion 18b, and a locking means in a mother die, which will be described later, can be engaged with this small diameter portion 18b. Furthermore, in this cassette mold l, as a feature of the present invention, the mating surface of the stationary cassette part 2 (the lower surface of the cassette part 2 in FIG. 2.3) is concave, and the mating surface of the movable cassette part 3 is concave. (The upper surface of the cassette portion 3) is formed into a convex shape that can fit into the concave shape. That is, in the state shown in FIG. 3, for the fixed cassette part 2, the lower end position of the cavity upper half forming member 5 is displaced upward by a predetermined amount with respect to the lower end position of the cavity plate 4, and the other movable Regarding the side cassette portion 3, the upper end position of the cavity lower half forming member 12 is displaced upward by a predetermined amount with respect to the upper end position of the first plate 9. Moreover, in this case, the cavity lower half forming member 12 protrudes upward from the upper end position of the first plate 9.
The convex portion 12a has a tapered portion 12b whose upper portion is tapered by a slight height of 1 minute (for example, 1 mm) from the upper end position of the first plate. When the mold is closed, the convex portion 12a of the cavity lower half forming member 12 relatively protrudes into the concave portion 4a of the cavity plate 4. In this case, the lower edge portion of the circumferential surface of the concave portion 4a is
By receiving and guiding the two force setting parts 2.3, even if the positional relationship of the two force setting parts 2.3 is slightly out of order, the mating surfaces thereof can be reliably brought into close contact with each other. According to the above configuration, the fixed side and movable side force setting portions 2.3 forming the cassette mold l have a circular shape in plan view, that is, a round shape, so that they have a square outer shape. It can be manufactured and processed more easily than conventional injection molds. Therefore, in addition to making the product molding section into a cassette, it is possible to reduce the mold cost and the mold manufacturing time as a whole. Further, the mating surface of the fixed side cassette part 2 is formed in a concave shape having a concave part 4a, and the mating surface of the movable side cassette part 3 is formed in a convex shape having a convex part 12a that can fit into the concave part 4a. The upper part of the convex part 12a is made into a tapered part 12b, and the lower edge part of the circumferential surface of the recessed part 4a in the stationary side cassette part 2 is received and guided by the tapered part 12b, so that the mold can be closed. Sometimes both power set part 2
．． Even if the positional relationship between the parts 3 and 3 is slightly out of order, their mating surfaces will surely come into close contact with each other with high precision. Therefore, it is possible to obtain a high-quality molded product without any cracks or defective parts due to poor contact between the mating surfaces. Next, in order to explain the replacement work of the cassette mold 1, a mother mold used when the mold 1 is attached to an injection molding machine will be described. The cassette mold 1 is attached to an injection molding machine (not shown) while being set in a mother mold 50, as shown in FIG. As shown in FIG. 5, this mother mold 50 has a fixed side unit 23, which is mainly made up of a plate 20, a runner plate 21, and a cavity plate 22 stacked on top of each other, which are mounted on the fixed side in order from the top. Overlap the core plate 24, core back plate 25, block 26, and plate 27 for movable side mounting, and then tighten the bolts 28...
- It is composed of a movable side unit 29 which is connected by 28. The mating surface between the cavity plate 22 and the core plate 24 is a PL surface (part surface), and by using this PL surface as a boundary surface, both units 23 and 29 are separated from each other or brought into close contact with each other to form a mold. Opening and closing operations are performed. As shown in FIG. 5.6, the fixed side unit 23 includes a fixed side mounting part 30 into which the fixed side cassette part 2 of the cassette mold l is mounted, and four parts each having a tapered surface 32a on the lower side. Taper guide insertion holes 32 . . . 32 are arranged at predetermined positions. Among these, the fixed side mounting part 30 is formed in a shape corresponding to the fixed side cassette part 2 of the cassette mold l in a predetermined state so that the fixed side cassette part 2 of the cassette mold l can be stored therein in a predetermined state. An insertion opening 30a is provided with a pair of presser plates 33.33 that can be opened and closed at the edge of the insertion opening 30a.
It has a configuration in which the two are arranged facing each other. As shown in FIG. 6.7, these presser plates 33, 33 are each formed with an operation recess 33a so as to be easily operated by hooking a finger therein, and also have an operation recess 33a formed on both sides 33b, 3.
3b is engaged with the guide plate 34.34 and the mounting part 30
It is possible to slide in the radial direction. When the fixed side cassette part 2 of the cassette mold l is inserted through the insertion opening 30a and set in the mounting part 30 in a predetermined state, the fixed side cassette part 2 of the cassette mold l is initially mounted on the holding plate 33 as shown by the chain line in FIG. The end of the holding plate 30 is located on the outside of the insertion port 30a, but after the fixed cassette portion 2 is set, the end of the presser plate is located on the inside of the insertion port 30a, as shown by the solid line in the figure. The cassette part 2 is slid to a position where it protrudes by a predetermined amount, and the lower surface of the fixed side cassette part 2 is stopped at that protruding position, thereby preventing the cassette part 2 from coming off from the fixed side mounting part 30. There is. On the other hand, as shown in FIG. 5.8, the movable unit 29 includes a movable mounting part 35 to which the movable force setting part 3 of the cassette mold l is mounted, and each support pin of the fixed unit 29. A plurality of guide holes 36...3 for guiding the respective guide holes 31
6, and four taper guides 37 that respectively enter the respective taper guide insertion holes 32 when the mold is closed and position both the fixed side and movable side units 23.29 and the cassette part 2.3 in a predetermined close state.・37 are arranged respectively. Among these, the movable side mounting part 35 is formed in a shape corresponding to the movable side cassette part 3 so that the movable side cassette part 3 can be stored in a predetermined state therein, and its upper end is formed as a cassette part insertion opening 35a. The opening edge of the insertion opening 35a is provided with a pair of presser plates 33, 33 facing each other, which can be opened and closed in the same way as the fixed side attachment part 30. Each of the tapered guides 37 includes a guide shaft portion 37a that enters into the tapered guide insertion hole 32 in the stationary unit 23 when the mold is closed, and a tapered portion 37b that comes into close contact with the tapered surface 32a of the insertion hole 32 when the guide shaft portion 37a enters into the fixed side unit 23. It consists of a support shaft 37c slidably inserted into a holding bush 38 provided on the core plate 24, and the support shaft 37c side is coupled to a bolt 39 inserted from the lower side of the holding bush 38. be. And when the mold is open,
The head of the bolt 39 comes into contact with the lower surface of the retaining bush 38 by a plurality of Belleville springs 40 interposed between the lower surface of the support shaft 37c and the bottom surface of the retaining bush 38, and at that position the tapered portion 37b becomes larger. A predetermined gap is formed between the lower surface of the diameter end and the upper surface of the holding bush (the upper surface of the core plate, that is, the PL surface). Further, in the movable unit 29 of the mother mold 50, a predetermined space a is formed in the block 26, and a locking means 41 for the movable cassette portion 3 is provided within the space a. As shown in FIG. 5.8.9, this locking means 41 includes a plate member 42 having a bifurcated portion 42a and a protrusion portion 42b extending to one side from the proximal end thereof, and a protrusion portion 42 of the plate member 42.
b and an operating handle 44 connected to the tip via a connecting member 43. Of these, the bifurcated portion 42a of the plate material 42 has a U-shaped notch in its approximate center when viewed from above, and the notched portion forms the engagement small diameter portion 18b (the first.
(see Figure 2), and each of the branch parts constituting the bifurcated part 42a is provided with elongated holes 42d, 42d. 42d and 142d, a rod 46 having a flanged bushing 45 fitted therethrough is passed through. As shown in FIG. 1O, these rods 46 have one end supported by the core plate 24 and the other end supported by the plate 27 on the fixed side. In addition, the flange 45 of the bushing 45
a is located on the upper surface side of the plate material 41, and the flange 4
A compression spring 47 is interposed between 5a and the core plate 24, and the spring force acting through the flange 45a causes the plate 41 to be in close contact with the upper surface of the plate 27 when attached to the movable side. It is constantly pressed. Then, with the plate 42 located at the solid line position in FIG.
When the entire cassette is moved back to the chain line position in the figure, the retaining part 42c is disengaged from the engagement small diameter part 18b of the movable cassette part 5, and the locking is released, and conversely, the operation from the chain line position in the figure Push the handle 44 and move the locking means 4 to the solid line position in the figure.
1, the retaining portion 42c engages with the engagement small diameter portion 18b of the movable cassette portion 3, thereby fixing the cassette portion 3 at a predetermined storage position. In this case, an elongated guide hole 42e is formed in the protrusion 42b of the locking means 41 in its longitudinal direction (that is, in the sliding direction of the locking means 41). A pin 48 is provided so as to pass through this guide hole 42e, and both ends of the pin 48 are attached to the core pack plate 25.
and the fixed side mounting are supported by the plate 27, so that the locking means 41 moves in the above-mentioned predetermined engagement or disengagement direction (ninth direction) when the operating handle 29 is operated.
It is designed to be guided in the direction opposite to A or in the direction A in the figure. The replacement work of the cassette mold 1 for such a mother mold 50 is performed as follows. That is, with the fixed side unit 23 and the movable side unit 29 constituting the mother mold 50 being separated from each other on the PL plane, each of the fixed side units 23 at the edge of the cassette part mounting opening 30a is Place the presser plate 33.33 on the 6th
When sliding from the closed position shown by the solid line in the figure to the open position shown by the chain line, the fixed side attachment part 30 of each presser plate 33.
Since the side end portion is located outward from the edge of the cassette portion mounting port 30a, the fixed side cassette portion 2 can be easily taken out from the fixed side mounting portion 30 in this state. Next, when installing the fixed side cassette part of another new cassette mold into the fixed side mounting part 30 after removing the fixed side cassette part 2 in this way, reverse the above case. The fixed side cassette part is inserted into the fixed side mounting part 30 to a predetermined position through the cassette mounting opening 30a, and each of the pressing plates 33, 33 is slid to the closed position shown by the solid line in the figure. As a result, a part of the cassette part mounting opening 30a is closed by both pressing plates 33 and 33 with the lower surface of the new fixed side cassette part stored in a predetermined position within the fixed side mounting part 30, so that The cassette part is securely mounted and held at a predetermined position within the fixed side mounting part 30. On the other hand, in the movable unit 29, its mounting portion 35
Since the movable cassette part 3 housed therein is locked by the locking means 41, in order to release the lock, first pull the operating handle 44 of the locking means 41 in the direction of arrow A in FIG. 9 to release the lock. The means 41 is moved from the locked position shown by the solid line in the figure to the unlocked position shown by the chain line. In this way, the engaging portion 42 of the locking means 41
c is disengaged from the engagement small diameter portion 18b of the movable side cassette portion 3 and the engagement between the two is released. 3 can be easily removed. Next, when installing a new movable side cassette part, set the new movable side cassette part in the movable side mounting part 35, and move it to the unlocked position indicated by the chain line in Fig. 9, contrary to the above case. Push the operating handle 44 located on the locking means 4.
1 in the opposite direction of A. In this way, since the engaging portion 42c engages with the small diameter engaging portion 18b of the movable cassette portion 3, the movable cassette portion 3 is reliably fixed at a predetermined position within the mounting portion 35. Become. Therefore, according to the above configuration, an injection molding machine (not shown)
With the mother mold 50 attached to the molding machine, the cassette mold l can be removed from the mother mold 50 and a cassette mold having another predetermined cavity shape can be set without removing the mother mold 50 from the molding machine. The mold can be replaced simply by Moreover, when attaching or removing the cassette mold l from the mother mold 50 in this way, there is no need to perform troublesome work such as loosening or tightening bolts for the attachment, which can be done using conventional methods. Mold replacement work can be performed much more easily and quickly than with conventional cassette-type molds as well as with integrated molds.

【Effect of the invention】

As described above, according to the cassette mold of the present invention, it can be extremely easily attached to and removed from the mother mold attached to the injection molding machine, so that the entire mold including the mother mold can be removed unlike the conventional method. There is no need to perform labor-intensive work such as attaching and removing the product to the injection molding machine, which makes it easier to replace molds in injection molding and shortens mold replacement time. can. In addition, according to the cassette mold of the present invention, only the product molding part, which is the most important part of an injection mold, can be made into a cassette, making it easy to handle and store the molding part. Since the shapes of the fixed side cassette part and the movable side cassette part that make up the cassette mold are circular in plan view, they can be easily molded compared to conventional square molds. It can be manufactured or processed. Therefore, together with the cassette formation of the product molding section, the overall mold cost and mold manufacturing time can be reduced. Furthermore, in the cassette mold of the present invention, the mating surface of either the movable side cassette part or the fixed side cassette part is formed in a concave shape, and the other mating surface is formed in a convex shape that can fit into the concave shape. When the mold is closed, the mating surfaces come into close contact with each other with high accuracy, so it is possible to obtain a high-quality molded product without any cracks or defective parts due to poor contact between the mating surfaces.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show an embodiment of the present invention, and FIGS. 1 and 2 are an exploded perspective view and a vertical cross-sectional view showing a cassette mold according to the embodiment, and FIG. 4 is a perspective view showing the cassette mold set in the mother mold, FIG. 5 is a longitudinal sectional view of the mother mold, and FIG. Fig. 6 is a bottom view of the stationary side unit in the mother mold, Fig. 7 is a partial sectional view taken along the line ■-■ in Fig. 6, Fig. 8 is a plan view of the movable side unit in the mother mold, and Fig. 9 5 is a cross-sectional view taken along the line IX--IX in FIG. 5, and FIG. 1O is a central longitudinal sectional view of the matrix. ■...Cassette mold, 2...Fixed side cassette part, 3
...Movable side cassette part, 50...Mother die C...Cavity.

Claims (1)

[Claims] (1) A cassette mold for injection molding that is removably attached to an injection molding machine via a matrix, and is circular in plan view and can be moved toward and away from each other to form a product molding cavity on the mating surfaces. It is composed of a pair of fixed side cassette parts and a movable side cassette part, and the mating surfaces of the fixed side cassette parts and the movable side cassette parts are in close contact with each other in a predetermined state when the mold is closed. A cassette mold for injection molding, characterized in that one mating surface is formed in a concave shape, and the other mating surface is formed in a convex shape that can fit into the concave shape.