JPH0617041B2 - Mold device of disk injection molding machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a mold device of an injection molding machine used for molding disks such as record disks, magnetic disks, and optical disks.

(Prior Art) At the time of injection, since the mold cavity is filled with gas and air, it is necessary to remove the gas and air from the mold cavity. For this reason, various measures have been taken.

However, in all of these known techniques, the molds are brought into contact with each other to support the mold clamping force, so that the structure is complicated.

Therefore, the mold clamping force is supported by the locate ring by abutting the locate rings attached to the mold without supporting the mold clamping force by the mold, and the fixed side mold and the movable side mold are vented. The vent structure is simplified by forming the gap.

FIGS. 3 and 4 show a conventional mold device of this type, in which 1 is a fixed side mold, 2 is a movable side mold, and a fixed side locate is provided on the outer periphery of each of the molds 1 and 2. The ring 3 and the movable side locate ring 4 are attached, and the end faces of the locate rings 3 and 4 facing each other are formed with inclined surfaces 5 and 6 having the same inclination direction.

The bottoms of the fixed-side mold 1 and the movable-side mold 2 that face each other are composed of a fixed-side mirror surface plate 1a and a movable-side mirror surface plate 1b, and the central portion of the fixed-side mirror surface plate 1a has a truncated cone shape. An annular recess 7 is formed on the outer circumference of the movable side mirror surface plate 1b.

An annular stamper outer peripheral pressing ring 8 is disposed in the annular recess 7. This stamper outer peripheral pressing ring 8 is for fixing the outer peripheral portion of a stamper 9 attached to the movable side mirror surface plate 1b to the mirror surface plate 1b, and the inner peripheral surface thereof is the side mirror surface plate 1b.
It is formed to have an inclination almost equal to the inclination of the generatrix of the truncated cone portion 10a of a, and the inner peripheral surface and the peripheral surface of the truncated cone portion 10 have a space for pent for venting gas in the mold cavity 11. 12 are formed.

Numeral 13 is a bolt for fixing the stamper outer peripheral pressing ring 8 to the movable side mirror surface plate 1b, the shaft portion of which penetrates the pressing ring 8 and reaches the movable side mirror surface plate 1b.

Next, the operation of the conventional mold device will be described. When the movable-side mold 2 is brought close to the fixed-side mold 1, the movable-side locate link 4 comes into contact with the fixed-side locate ring 3, but at this time, the inclined surface 6 of the movable-side locate ring 4 moves to the fixed-side locate ring 3. Since the slidable surface 5 is slidably contacted, the fixed-side mold 1 and the movable-side mold 1 and 2 approach each other so that their axes coincide with each other. The mold clamping is completed when the fixed and movable locate rings 3, 4 come into contact with each other and their opposing end surfaces come into close contact with each other. This figure shows this state. In this state, a vent gap 12 is formed between the stamper outer peripheral pressing ring 8 and the truncated cone portion 10.

(Problems to be Solved by the Invention) In the conventional example as described above, if the stamper outer peripheral presser ring 8 is improperly attached, as shown by A in FIG. 5, the presser ring 8 and the frustoconical portion. 10 biting occurs.

Even if the stamper outer peripheral presser ring 8 has no mounting defect, if the base of the injection molding machine is tilted, or if the mold is not mounted properly and the machine is continuously operated, B is shown in the same figure.
As shown by, fixed side and movable side locate rings 3,
When galling occurs on the inclined surfaces 5 and 6 of No. 4 and the length of galling becomes 5 μm or more, galling also occurs at the part A.

Thus, the above-mentioned part A, that is, the stamper outer peripheral pressing ring 8
When galling occurs on the truncated cone portion 10 and the frustoconical portion 10, burrs 13a are generated on the outer edge of the disk molded product 13, as shown in FIG.
It cannot be used as a product.

In order to avoid this, when scuffing occurs, the frusto-conical portion 10 is also processed, but in such a case, the outer diameter of the molded product becomes small, so it is necessary to replace it with a new mirror surface plate. In this case, it is necessary to replace the stamper outer peripheral pressing ring 8 accordingly, and the cost required for this is enormous.

The present invention has been made to solve the above problems,
An object of the present invention is to obtain a mold device for a disk injection molding machine in which galling does not occur between the stamper outer peripheral pressing ring and the mold.

(Means for Solving the Problems) A disk mold of the present invention is a ring member for attaching a stamper to the surface of one of a fixed-side mold and a movable-side mold and holding the outer periphery of the stamper. Is arranged so that the ring member can be slightly displaced in the radial direction with respect to the fastening member fixed by being attached to the one mold via a spring member fitted into the fastening member. An annular flank is formed at the tip peripheral edge of the tip peripheral surface of the projecting outer peripheral surface of the die that is face-to-face fitted with the inner peripheral surface, and a vent path communicating with the annular flank is formed on the inclined surface. It is characterized by being installed in.

(Operation) With this configuration, the stamper outer peripheral pressing ring member can be displaced in a direction that alleviates the surface pressure, and by providing the annular flank at the tip peripheral edge of the protruding outer peripheral surface of the mold, At the time of mold clamping, the protruding outer peripheral surface of the mold can be fitted face-to-face with the stamper outer peripheral pressing ring member and can be slidably contacted thereto without damaging the mirror surface and the protruding outer peripheral surface of the mold.

Therefore, no galling phenomenon occurs between the inner peripheral surface of the ring member and the protruding outer peripheral surface of the mold, and the inner peripheral surface of the ring member is not centered with respect to the protruding outer peripheral surface of the mold. Even in this case, the displacement of the ring member that holds the outer periphery of the stamper can be automatically adjusted.

Further, even when the inner peripheral surface of the ring member and the projecting outer peripheral surface of the die are face-to-face fitted with each other at the inclined surface when the mold clamping is completed, the annular flank formed on the tip peripheral edge of the projecting outer peripheral surface of the die. A passage for degassing can be formed by communicating with the vent passage of the inclined surface.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In FIG. 1, the same symbols as in FIG. 3 indicate the same or corresponding portions.

As shown in FIGS. 1 and 2, a plurality of bolt holes 13 are formed in the stamper outer peripheral pressing ring 8 in the circumferential direction at substantially equal intervals, and through holes 14 are formed at the bottoms of the bolt holes 13.
Are formed.

A bolt 15 is inserted into the bolt hole 13, and the tip of the shaft portion thereof penetrates through the through hole 14 and the movable side mirror surface plate 1
It is screwed to b.

A cylindrical set piece 16 is slidably inserted into the shaft of the bolt 15. A gap is provided between one end of the set piece 16 and the through hole 14 and between the other end of the set piece 16 and the bolt hole 13 that forms the flange portion 16a. The set piece 16 fixed by the bolt 15 can be slightly displaced in the radial direction.

A coil spring 17 is disposed on the outer periphery of the set piece 16, one end of which is in contact with the bottom of the bolt hole 13 and the other end is in contact with the flange 16, so that the flange portion is elastically urged. 16 is brought into contact with the head portion 15a of the bolt 15.

The inner surface of the stamper outer peripheral pressing ring 8 is formed as an inclined surface having substantially the same inclination as the inclination of the generatrix of the truncated cone portion 10 of the fixed-side mirror surface plate 1a as described above. Ring 8
Frusto-conical portion 10 forming a protruding outer peripheral surface facing the inclined surface of
An annular flank is provided on the peripheral edge of the tip of the. For this reason, a plurality of vent grooves 19 that open to the inner surface of the pressing ring 8 are formed between the inner peripheral surface of the ring and the vent grooves 19 communicate with the vent gaps 18 during mold clamping and are connected to the mold cavity. The gas inside 11 is discharged to the outside of the mold cavity 11 through the gap between the stamper outer peripheral pressing ring 8 and the fixed side mirror surface plate 1a.

A part of the stamper outer peripheral pressing ring 8 is a movable side mirror surface plate 1b.
Of the stamper outer peripheral pressing ring 8 and the movable side locate ring 4 in the annular recess 7, and a gap 20 is formed between the outer peripheral surface of the stamper outer peripheral pressing ring 8 and the movable side locate ring 4. A gap 21 is formed on the inner surface of the recess 7, and the presence of these gaps 21 and 21 allows the stamper outer peripheral pressing ring 8 to be displaced slightly in the radial direction.

The gap 18 for venting is usually 5 to 20 μm.

Next, the operation of the mold device having the above configuration will be described.
When the movable-side mold 2 is brought close to the fixed-side mold 1 to perform mold clamping, the shaft side of the movable-side mold 2 is fixed to the fixed-side mold due to mutual contact between the fixed-side and the movable-side locate rings 3, 4. As described above, the movable-side mold 2 approaches the fixed-side mold 1 so as to coincide with the axis of 1.

On the other hand, at the time of this mold clamping, the outer side portion 8a on the inner surface of the stamper outer peripheral pressing ring 8 makes sliding contact with the peripheral surface of the truncated cone portion 10.
This sliding contact corrects the position of the stamper outer peripheral presser ring 8 when the stamper outer peripheral presser ring 8 is not properly attached. That is, when the stamper outer peripheral pressing ring 8 is improperly mounted, the surface pressure on the truncated cone portion 10 becomes high, and the stamper outer peripheral pressing ring 8 is pressed by the spring member including the coil spring 17 as described above. As described above, the stamper outer peripheral pressing ring 8 is displaceable in the direction in which the surface pressure is alleviated,
The position is corrected.

Then, when the opposing end surfaces of the fixed side and movable side locate rings 3, 4 come into close contact with each other, the approach of the movable side mold 2 is stopped, and a gap g is formed between the stamper outer peripheral pressing ring 8 and the fixed mirror surface plate 1a. .

Next, injection is performed, but at this time, the mold cavity 11
The gas inside is discharged to the outside of the mold cavity 11 through the vent gap 18, the vent groove 19 and the gap g.

(Effect of the Invention) As described above, according to the present invention, the stamper outer peripheral pressing ring member can be displaced minutely in the radial direction, so that the inner peripheral surface of the ring member is the protruding outer peripheral surface of the mold. Even if it is not centered, the protruding outer peripheral surface of the mold fits face-to-face with the slanted inner peripheral surface of the ring member and slides into contact with it, so that the ring member that presses the outer periphery of the stamper is automatically displaced. Can be aligned with.

In addition to the fact that the stamper outer peripheral pressing ring member is displaceable in the direction that alleviates the surface pressure of the stamper, by forming an annular flank at the tip peripheral edge of the protruding outer peripheral surface, a mirror surface of the mold is obtained. Also, the galling phenomenon due to the collision of the outer peripheral surface with the ring member does not occur.

Therefore, since the mirror surface of the mold is not damaged, the appearance of the disk as a product and the formation of burrs on the peripheral edge do not occur, so that the workability in the product selection process can be improved.

In addition, since the burrs do not remain on the mold, no trouble occurs during recycling of molding work.

Further, when the mold clamping is completed, even when the inner peripheral surface of the ring member and the projecting outer periphery of the mold are face-to-face fitted to each other with inclined surfaces,
An annular flank formed on the peripheral edge of the tip of the protruding outer peripheral surface of the mold communicates with the inclined vent passage to form a gas vent passage.

[Brief description of drawings]

FIG. 1 is a view corresponding to FIG. 4 showing a main part of a mold device of a disk injection molding machine according to the present invention, FIG. 2 is a front view of a stamper outer peripheral pressing ring, and FIG. 3 is a cross section of a conventional mold device. FIG. 4, FIG. 4 are enlarged views showing a part of FIG. 3, FIG. 5 is an explanatory view showing galling, and FIG. 6 is a schematic view showing defective molded products. 1 …… Fixed side mold 2 …… Movable side mold 3 …… Fixed side locate ring 4 …… Movable side locate ring 8 …… Stamper outer peripheral presser ring 15 …… Bolt (fastening member) 15a …… Head 18… … Vent gap} (vent path) 19 …… Vent groove} (vent path)

Claims (1)

[Claims] 1. A mold in which a fixed-side locate ring and a movable-side locate ring are attached to a fixed-side mold and a movable-side mold, respectively, and a mold clamping force is supported by mutual contact between the fixed-side and movable-side locate rings. In the apparatus, a stamper is attached to the surface of one of the fixed-side mold and the movable-side mold, and a ring member that holds the outer periphery of the stamper is inserted into a fastening member through a spring member to insert the one mold. A die that is arranged such that the ring member can be slightly displaced in the radial direction with respect to a fastening member that is fixed by being attached to a mold, and that is fitted in a face-to-face manner with the inner peripheral surface of the ring member at inclined surfaces. A mold device for a disk injection molding machine, characterized in that an annular flank is formed at a tip peripheral edge portion of the projecting outer peripheral surface, and a vent path communicating with the annular flank is provided on the inclined surface.