JPH01123714A - Automatically gate cutting mold - Google Patents

Abstract

PURPOSE:To make it possible to automatically release a gate from a mold by a structure wherein the gate is provided along the parting line of other mold member in the sliding direction of a slide core and a recessed part producing a projecting portion, which makes an undercut in the sliding direction of the slide core, is provided in the interior of the slide core. CONSTITUTION:A fitting part 14 is formed in a movable retainer plate 11 so as to face to a molded item cavity 12 and a dented part 13. To the fitting part 14, a slide core 16, which forms the molded item cavity 12 together with both retainer plates 11, is fitted slidably in the direction normal to the mutual moving direction of both the retainer plates 11. A gate 21 formed on the side surface deep in the sliding direction and along the parting line P.L 3, which comes into contact with and parts from the movable retainer plate 11 by being dented only in the slide core 16. Further, a recessed part 22 having a projecting portion 32, which faces to the side part of the gate 21 and is made by engraving in the slide core 16, slants to the sliding direction, resulting in forming an undercut. When a molded item is released from a mold, the projecting portion 32 makes resistance, resulting in disconnecting the gate 21 together with the slide core 16 from a molded item 31.

Description

Detailed description of the invention (Purpose of development) (Industrial application field) The present invention relates to an automatic gate cutting tool in which a gate is automatically cut from a molded product during mold release in a mold. Regarding types.

(Prior Art) As a conventional gate automatic cutting mold used for injection molding, there is, for example, a mold having a submarine gate as shown in FIG. In FIG. 4, 1 is a stationary mold plate, 2 is a movable mold plate, and these mold plates 1.2 have a molded product cavity 3 and a runner 4 facing the parting lines P and L, that is, the dividing surface. is formed. These runners 4 and the cavity 3 are communicated with each other by a gate 5 formed in the movable mold plate 2, and this gate 5 faces the runner 4 at an angle α with respect to the mold release direction of the molded product 6. a tapered primary gate 5a inclined at
A short and thin 2 facing the cavity 3 and perpendicular to the mold release direction
It consists of a next gate 5b. In addition, runner 4 is
A sprue 7 formed on the stationary template 1 communicates with a nozzle of an injection molding machine. Further, 8 is an ejector pin for ejecting the molded product 6 during mold fitting, and 9 is an ejector pin for ejecting the runner 4 and gate 5 when the mold is opened.

For the sake of explanation, the runner 4, gate 5, and sprue 6
The hollow part in the mold and the 1111 ferns there
The name and code are not distinguished from the f part.

After the mold plates 1.2 are separated at P and L, the molded product 6, runner 4 and gate 5 are removed by the ejector pin 8.9.
Both start from template 2, but at this time gate 5
is an undercut, and since the primary gate 5a is inclined in the direction away from the molded product 6 in the ejection direction, the gate 5 receives a force in the direction away from the molded product 6. Therefore, the secondary gate 5b is automatically cut from the molded product 6.

By the way, if the gate angle α is less than 35'', the primary gate 5a will become too long, resulting in a large pressure loss of the molten resin and causing insufficient filling.On the other hand, if the gate angle α is more than 60°, the gate 5 will not automatically close. In addition, if the distance between the cavity 3 and the gate 5 at P and L, that is, the gate land distance, is less than 7 am, the template 1 is Causing the collapse and occurrence of Paris.

Due to such dimensional limitations of the gate 5, depending on the shape of the molded product, it may not be possible to use a submarine gate mold as shown in FIG. 4.

In that case, a side gate mold as shown in Figure 5 will be used, but with a side gate mold it is not possible to automatically cut the gate 5 within the mold when the mold is released. After molding, the operator must cut the gate 5 from the molded product 6 with a tool, which increases the number of man-hours.

By the way, in the molded product 6 shown in FIGS. 4 and 5, the upper surface side of the flange portion 6a becomes the front surface side during use. In the submarine gate mold shown in Figure 4, the gate 5 is placed at a lower position out of the visual range during use.
However, in the side gate mold shown in FIG. 5, since the gate 5 is communicated with the cavity 3 at a position corresponding to the side surface of the flange portion 6a, cutting of the gate 5 is necessary. The marks will remain within the visible range of the molded product 6 during use, resulting in poor appearance quality. Therefore, the cut fI mark of the gate 5 must be finished, which significantly increases the number of man-hours.

Further, as a conventional gate automatic cutting mold, there is one described in Japanese Utility Model Publication No. 57-55066. In this mold, a gate is provided on the dividing surface between the slide core and the fixed side mold plate, located inside the dividing surface between the slide cores, that is, the dividing surface in the sliding direction of these slide cores, and the gate and the cavity A protrusion is provided opposite to the connection portion with the gate, and the protrusion allows the gate to be cut off from the molded product by itself during mold release.

However, even the mold described in the above publication has a problem with the strength of the protrusion. In addition, when molding a molded product with the shape shown in Figures 4 and 5, a gate is communicated with the cavity at a position corresponding to the side surface of the flange part, and the cut marks of the gate are left behind during use. It occurs within the visual range.

(Problems to be Solved by the Invention) As mentioned above, the submarine gate mold, which is a conventional gate automatic cutting mold, has the problem that it cannot be used depending on the shape of the molded product due to the dimensional limitations of the gate. Ta. In addition, the mold described in Japanese Utility Model Publication No. 57-55066 had a problem with the strength of the protrusion for cutting the gate, and also had the problem that cut marks on the gate were likely to appear within the visual range when the molded product was in use. . Furthermore, with side gate molds used when submarine gate molds cannot be used, not only can the gates not be cut automatically, but the cut marks on the gates can also be used when the molded product is in use. There was a problem that was likely to occur in the 1st range.

The present invention aims to solve the above-mentioned problems, and even if it is a molded product whose shape does not allow the use of a submarine gate mold, 1! An object of the present invention is to provide an automatic gate cutting mold that can automatically cut a gate from a molded product during molding and also easily set the cut mark of the gate to 9 haze so that it is not noticeable when the molded product is used. That is.

(Structure of the Invention) (Means for Solving the Problems) The gate automatic cut mold of the present invention has a molded product cavity 1.
At least a part of the slide core 16 is formed of the slide core 1G, and the gate 21 leading to the cavity 12 along the dividing plane P of the other mold member 11 in the sliding direction of the slide core 16 is Further, the slide core 16 is provided facing the side of the gate 21.
A recess 22 is provided inside the slide core 16 in which a protruding portion 32 that is an undercut with respect to the sliding direction of the slide core 16 is formed.

(Function) In the gate automatic cut mold of the present invention, when the molded product 31 is released after molding, when the slide core 16 slides and separates from the other mold members 11 and the molded product 31, the slide core A protruding portion 32 formed in the slide core 16 facing the side of the gate 21 along the dividing plane P, [3] of the other mold member 11 in the sliding direction of the slide core 1
6, the gate 21 remains on the slide core 16 side and detaches from the molded product 31 together with the slide core 16, so that the gate 21 is removed from the molded product 31. automatically disconnected.

(Example) Hereinafter, an example of the gate self-help cut mold of the present invention will be described as a first example.
This will be explained based on FIGS. 3 to 3.

This mold includes a fixed side mold plate (not shown) and a movable side mold plate 11 as another mold member that approaches and separates from the fixed side mold plate. The dividing plane P, [1
A molded product cavity 12 is formed along. It should be noted that only the main parts of the movable template 11 are shown in the drawings. A recess 13 is formed on the movable mold plate 11 on the side of the cavity 12, and a protrusion that fits into the recess 13 is formed on the fixed mold plate. has been done. Furthermore, a fitting portion 14 is formed in the movable template 11 so as to face the molded product cavity 12 and the recess 13 .

A slide core 16 is fitted into this fitting portion 14 so as to be slidable in a direction perpendicular to the direction in which both templates 11 move relative to each other. This slide core 16 is connected to both templates 11
Together with this, a molded product cavity 12 is formed.
The upper surface forms a dividing surface P, [2 that approaches and separates from the fixed side mold plate, and the rear side surface in the sliding direction forms the movable side mold plate 1.
The dividing plane P, which approaches and separates from 1, forms the [3.

The slide core 16 also has a through hole 17 that is inclined downwardly away from the dividing planes P and L3.
is formed, and an angular bottle 18 fixed to the stationary side mold plate is slidably passed through this through hole 17.

A gate 21 is formed along the dividing plane P, [3 between the movable template 11 and the slide core 16 and recessed only within the slide core 16. This gate 21 connects the molded product cavity 1 from the step surface 13a of the recess 13.
It extends horizontally to the side surface of 2 and tapers toward the molded product cavity 12. In addition, an elongated recess 22 is formed on the side of the gate 21 by being carved into the slide core 16 at the same angle. This recess 2
2 is inclined with respect to the sliding direction of the slide core 16, and has an undercut shape.

Furthermore, both the mold plates 11 formed by the bottom surfaces of the recessed portions 13
A runner 23 communicating with the gate 5 is formed along the dividing planes P and L4. Further, a sprue 24 communicating with the runner 23 is formed on the stationary template. Note that the depressions 13 are formed in the movable template 11 on the dividing planes P, L1. This is because the runners 23 are arranged horizontally with respect to the gate 21 located below P and L2.

Next, the operation of the above configuration will be explained.

When releasing the molded product 31, the fixed side mold plate and the movable side mold plate 11
As the molded product 31 and the runner 23 are separated, the molded product 31 and the runner 23 are each pushed upward by an ejection pin (not shown). At the same time, the slide core 16 slides laterally with respect to the movable template 11 by the angular bin 18, and the slide core 16 and the movable template 11 are 7+
'J side P, L3 is shortened. At this time, slide core 1
The protruding portion 3 formed in the recess 22 facing the gate 21 of No. 6
2 is an undercut with respect to the sliding direction of the slide core 16, the protruding portion 32 acts as a resistance, and the gate 21 remains on the slide core 16 side and comes off from the molded product 31 together with the slide core 1G. Let go. therefore,
Goos 1 to 21 are automatically cut from the molded product 31.

Note that the gate 21 is forcibly released from the slide core 16 together with the runner 23 by an ejector.

According to the above configuration, since the length of the gate 21 can be freely set, there is no possibility that the pressure loss of the molten resin becomes large and insufficient filling occurs. Further, since the angle and length of the recess 22 for automatically cutting the gate 21 can be set relatively freely, the gate 21 will not become unable to be automatically removed from the slide core 16. Furthermore, concave 12
2 can be provided at a certain distance from the molded product cavity 12, so that the molded product cavity 12 will not be deformed. In addition, since a certain distance can be secured between the end position of the runner 23 and the cavity 12, mold deformation and occurrence of cracks in this section can be prevented.

By the way, the molded product 31 consists of a cylindrical main body part 31a and a flange part 31b located at the upper end of this main body part 31a. flange part 3
The main body portion 31a located below 1b is out of the visual range. However, according to the above configuration, during molding, the dividing planes P and L1 between the movable side template 11 and the slide core 16 and the fixed side template
．． The flange portion 31b is located at P and L2, whereas the gate 21 is located at the dividing plane P and [3 between the movable side template 11 and the slide core 16, and the appearance of the molded product 31 is not important. 31a, there is no problem even if the cut marks of the gate 21 remain, and finishing of this cut mark (9) is not necessary.

(Effects of the Invention) According to the present invention, a gate is provided along the separation from other mold members in the sliding direction of the slide core, and the slide core is placed inside the slide core facing the gate. Since a recess is provided in which a protruding part that is undercut in the direction of movement is formed, the length of the gate can be set freely, eliminating pressure loss of the molten resin, and also adjusting the inclination angle of the recess. Since the length and length can be set relatively freely, automatic mold release of the gate is not impossible, and furthermore, a certain distance can be secured between the runner end position and the molded product cavity. , it is possible to prevent mold deformation and occurrence of cracks in this section, and even when molding a molded product with dimensions that make it impossible to use a submarine gate mold, the gate can be automatically cut without causing the above-mentioned inconveniences. In addition, since the position of the gate facing the molded product cavity can be set relatively freely, it is also possible to easily create gate cut marks at positions that do not affect the appearance of the molded product. , it is possible to eliminate the need for finishing processing of this cutting trace.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view of the main parts showing one embodiment of the automatic gate cutting mold of the present invention, Fig. 2 is a schematic side view of the same, Fig. 3 is a schematic plan view of the same, and Fig. 4 is a conventional submarine. FIG. 5 is a schematic cross-sectional view of the main parts of a conventional side gate mold. 11...Movable side template as a mold member, 12...Molded product cavity, 1G...Slide core, 21...Gate, 22...Concave portion, 31...Molded product, 32...Protruding portion , P, L3... Division plane. November 9, 1986

Claims (1)

[Claims] (1) At least a part of the molded product cavity is formed by a slide core, and a gate communicating with the cavity is provided along a dividing plane from other mold members in the sliding direction of the slide core, Gate automatic cutting metal, characterized in that a concave portion is provided inside the slide core facing the side of the gate, in which a protruding portion that is an undercut with respect to the sliding direction of the slide core is formed. Type.