JPH0777743B2 - Mold device for molding disk case - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a molding die for molding a disk case for accommodating a disk-shaped storage disk body such as a magnetic disk, an optical disk, or an optical-magnetic disk. Regarding the device.

[Conventional technology]

Conventionally, when molding this kind of disc case, gates (injection ports) are provided at positions corresponding to the four corners of the surface of the disc case, and molten resin is supplied from the four-point gate into the cavity to form the disc case. Since the case is molded, the molten resin injected from the four gates flows toward the central portion of the disk case.

[Problems to be Solved by the Invention]

By the way, in the case of molding by the four-point gate as described above, especially in the upper case where there is no through hole in the central portion,
There is a problem that the degassing in the central portion is likely to be insufficient, a wet surface is formed on the surface of the molded product, or the molded product is warped because pressure is not uniformly applied to the molded product.

Therefore, as a solution to the above problem, two points of molten resin injection holes arranged on the engraved surface of the die are to be covered by a normal shutter of the disk case to be molded and on the outside of the storage section of the storage disk body. The applicant has proposed a molding die device provided at a corresponding position (Japanese Patent Application No. 62-325).
See No. 950).

However, when molding is performed using the molding die device, there is a problem that the final weld line is displaced from the center. As a result of the inventors studying the cause of this, as the thickness of the recess for storing the spring for urging the shutter to one side is thinner than the thickness of the other part, this part is It was found that the resistance became a factor and the balance of the amount of resin filled from the pair of left and right inlets (gates) was lost. For this reason, conventionally, the diameters of the left and right injection ports are changed to change the injection amount of the resin so that the final weld line is located at the center, but in this case, the diameter is large. There was a problem that the resin was poorly broken at the injection port on one side, a problem such as string pulling occurred on the product, and the same torpedo (heating body) could not be used on the left and right gates.

The present invention has been made in view of the above circumstances, and its object is to position the final weld line at the center even if the resin flows smoothly in the cavity and the diameters of the pair of inlets are the same. It is an object of the present invention to provide a mold device for molding a disk case, which is capable of smoothly performing degassing, and can prevent defects such as a wetting surface and warpage in a molded product.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a molding die apparatus for forming a disk case for storing a disk-shaped storage disk body by supplying the molten resin to a cavity in the mold, The injection ports into the cavity of the cavity are arranged at two points on the engraved surface of the mold which is a portion which is normally covered by the shutter and which corresponds to the outside of the storage portion of the storage disk body, and the side of the cavity far from the injection port. A gas vent is formed at the center of the cavity, and the resin flow is balanced with respect to the spring accommodating portion side across the center line of the cavity at the position corresponding to the spring accommodating portion, and the final weld line is formed. A resistance portion is provided so as to resist the flow of the resin, which is located at the center between the one injection port side and the other injection port side.

[Action]

In the mold device for molding the disc case of the present invention,
The molten resin supplied into the cavity from two inlets (gates), which are normally hidden by the shutter and located on the engraving surface of the mold corresponding to the outside of the storage portion of the storage disk body, is stored in the spring. Part and the resistance part receive the same resistance of the resin flow to balance the resin flow, and the resin flow from one injection port side and the resin flow from the other injection port side are well balanced. The resin reaches the gas vent formed in the central portion of the cavity that is far from the inlet and completes the filling of the resin into the entire space inside the cavity.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a sectional view showing a part of a mold device for molding an upper case 1 for a floppy disk as shown in FIGS. 2 and 3. The upper case 1 is formed in a substantially square thin-walled surface, and a surface 1a has a shutter area 1b for mounting the shutter 6 and a label area 1c for sticking a label. Each is formed to be slightly depressed from the other portions. Further, the upper case 1 is formed with a window portion 1d for introducing a magnetic head and a hole portion 1e for a light protector, respectively. further,
On the inner surface 1f side of the upper case 1, an outer frame portion 1g is formed over substantially the entire outer edge portion thereof, and an arc-shaped rib portion 1h is formed so as to be continuous with the outer frame portion 1g. The inner side of the rib portion 1h serves as a disc body storage portion 1i for storing a disc-shaped storage disc body, and the outer side of the rib portion 1h is the upper right portion of FIG. A spring storage portion 1i for storing a spring for urging the shutter 6 to the right. Furthermore, the resin flow is balanced with respect to the spring accommodating portion 1j side at a position facing the spring accommodating portion 1j across the center line 1 of the upper case 1 and the final weld line is set to one side. A resistance portion 1m, which is a resistance against the flow of resin, is provided so as to be positioned at the center between the injection port 5 side and the other injection port 5 side. As the resistance portion 1m, a thin portion having substantially the same area and the same thickness as the spring storage portion 1j is provided, or the rib 1h near the position facing the spring storage portion 1j is intermittently divided, Alternatively, it is appropriately selected to reduce the thickness of the outer frame portion 1g near the position facing the spring storage portion 1j.

It should be noted that the disc body storage portion 1i is more than the disc body storage portion 1i.
The outer face plate portion is formed thicker. In particular, the face plate portions at the lower left corner and the lower right corner in FIG. 3 are set to be thicker than the thickness of the disc body storage portion 1i.

The mold for molding the upper case 1 configured as described above is
As shown in FIG. 1, a fixed template 2 having an engraved surface for forming the surface 1a of the upper case 1, and an inner surface 1f of the upper case 1.
And a movable mold plate 3 having an engraved surface for forming a mold, and an injection port (gate) 5 for injecting a molten resin into a cavity 4 formed between these mold plates 2 and 3 is shown in FIG. As shown in FIG. 3, the shutter area 1b of the upper case 1 is covered with the shutter 6 urged by the spring (shown as a gate mark 1k in FIG. 2) and shown in FIG. As shown in FIG. 3, outside of the disk housing 1i of the upper case 1, as close as possible to the center 7 of the upper case 1 and at a position symmetrical with respect to the center line 1 (in FIG. 3, it faces the gate line 1k). Is formed on the engraved surface of the corresponding fixed mold plate 2 (represented as a convex portion 1). Further, a plurality of gas venting inserts 8 are attached to the movable mold plate 3, and the gas venting inserts 8 sandwich a center 7 and are opposite to the window 1d as shown in FIG. It is located at the position corresponding to the side. In addition, in FIG.
The upper case 1 in the cavity 4 is shown by I-I in FIG.
A cross section along the line is shown, and in FIG. 3, a cross section along the line I'-I 'is shown.

When the upper case 1 for a floppy disk is formed by using the mold apparatus configured as described above, the space between the fixed mold plate 2 and the movable mold plate 3 is closed and both mold plates are closed as in the conventional case. 2,
Molten resin is supplied from a pair of injection ports 5 into the cavity 4 formed by 3. At this time, two injection ports 5 are arranged at positions symmetrical with respect to the center line l, and the upper case 1
It is formed at a position covered by the shutter 6 in the shutter area portion 1b outside the disc body storage portion 1i at a position corresponding to the center 7 of the case 1 as much as possible, and
The thickness of the portion corresponding to the outer face plate portion of the disc body storage portion 1i is set larger than the thickness of the portion of the cavity 4 corresponding to the disc body storage portion 1i, and the thickness of the central portion on the side far from the inlet 5 is set. Since the gas venting insert 8 is mounted on the movable template 3, the resin injected from the inlet 5 into the cavity 4 flows from one end side to the other end side (gas venting insert 8 side) and is thick. The thin portion (disc body storing portion 1i) is filled from the meat portion (outer side of the disc body storing portion 1i) and finally reaches the degassing insert 8. As a result, the molten resin is sufficiently supplied to the thin portion, the flow of the molten resin is smoothly adjusted, and the resin is surely spread to each portion, and degassing is easily performed. Therefore, a product of good quality can be obtained without causing defects such as a wetting surface and warpage in the molded product. Also, in this case, across the center line l,
In order to balance the resin flow with respect to the spring housing 1j side at a position facing the spring housing 1j, and to position the final weld line at the center between one injection port 5 side and the other injection port 5 side. Since there is a resistance part 1m that is a resistance against the flow of resin,
And since the resistance portion 1m has the same resistance, the flow of the resin supplied from the left and right injection ports 5 is balanced, so that the resin amount can be made uniform, and therefore the injection ports 5 having the same diameter are used. However, the resin can be filled in a good balance, and the final weld line can be aligned with the center line l.

Although the molding of the upper case 1 has been described in the above embodiment, as shown in FIGS.
The same can be applied to the molding of.

〔The invention's effect〕

As described above, the present invention relates to a molding die device for forming a disk case for storing a disk-shaped storage disk body by supplying the molten resin to the cavity in the mold, wherein the cavity of the molten resin is Two inlets are provided on the engraved surface of the mold corresponding to the outside of the storage portion of the storage disk body, which is usually covered by the shutter, and the central portion of the cavity on the side far from the inlet. In addition to forming a degassing part in the cavity, balance the resin flow with respect to the spring accommodating part side across the center line of the cavity at a position corresponding to the spring accommodating part, and connect the final weld line to one side. Since a resistance portion for resisting the flow of the resin is provided at the center between the inlet side and the other inlet side, two inlets (gates are arranged on the engraved surface of the mold. The molten resin supplied from the g) to the inside of the cavity receives equal resistance by the spring housing part and the resistance part, flows in the cavity in a well-balanced manner, and is formed in the central part on the side far from the injection port of the cavity. It is possible to reliably fill each part of the cavity with resin by reaching the degassed part and filling the entire space of the cavity with resin, and the diameters of the pair of inlets are the same. Even in this case, the final weld line can be positioned at the center, and degassing can be performed smoothly, so that it is possible to prevent defects such as a wetting surface and warpage in the molded product.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 and FIG.
The figure shows an example of an upper case molded by using the mold device of the present invention. Fig. 2 is a plan view seen from the surface side of the upper case, Fig. 3 is a bottom view seen from the inner surface side of the upper case, 4 and 5 show an example of a lower case molded by using the mold apparatus of the present invention. FIG. 4 is a plan view of the lower case seen from the front side, and FIG. 5 is an inner surface of the lower case. It is a bottom view seen from the side. 1 ... Upper case for floppy disk, 2 ... Fixed mold plate, 3 ... Movable mold plate, 4 ... Cavity, 5 ... Filling port (gate), 8 ... Gas venting inlet (gas venting part), 9 ...
… Lower case, 1j …… Spring storage part, 1m… Resistor part,
l …… Center line.

Claims (1)

[Claims] 1. A molding die apparatus for forming a disk case for accommodating a disk-shaped storage disk body by supplying molten resin to a cavity in the mold, wherein the molten resin is injected into the cavity. Are arranged at two points on the engraving surface of the mold that is normally covered by the shutter and outside the storage part of the storage disk body, and the degassing part is provided in the central part of the cavity far from the injection port. In addition, the resin flow is balanced with respect to the spring accommodating portion side across the center line of the cavity at a position corresponding to the spring accommodating portion, and the final weld line is connected to one inlet side and the other. A mold device for molding a disk case, which is provided with a resistance portion for resistance to the flow of resin for being positioned at the center of the injection port side.