JP3162884B2 - Die equipment for disk molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk molding die apparatus, and more particularly to a so-called sprueless die apparatus for forming a disk without a sprue.

[0002]

2. Description of the Related Art In a so-called sprueless molding in which a sprue is not formed together with a molded product, a sprue solidified at the time of molding is not formed in a mold. Disappears. Therefore, smooth continuous molding becomes possible, and it is not necessary to take out the sprue, so that the molded product can be taken out by opening and closing the mold according to the width of the molded product,
The molding cycle can also be shortened. Further, since there is no need to discard the sprue, not only the material can be saved, but also there are many advantages such as the problem of disposal treatment being eliminated. The mold for this kind of sprueless molding is
A portion corresponding to the conventional sprue is formed as a resin reservoir of a molten resin material, and the molten resin material in the resin reservoir is sequentially injected into a molded product cavity to perform molding. Had a problem.

First, as a major problem, a gate opening / closing mechanism for injecting or stopping a molten resin material from a resin reservoir into a molded product cavity becomes complicated, and it is particularly difficult to adjust the alignment between the movable member and the gate. Was. Also, it cannot be said that there is a portion such as a support portion in the resin reservoir that divides the flow, or that the volume of the resin reservoir is taken into consideration. For this reason, at the time of injection, a weld line appears in the molded product as if the divided portion was projected, or a uniform molded product could not be obtained due to a difference in the thermal history of the molten resin in one shot.

[0004]

SUMMARY OF THE INVENTION The present invention has been developed mainly to solve the above-mentioned problems, and has a gate for injecting or stopping a molten resin material into a molded article cavity. To provide a mold apparatus for a new disk molded product that can easily open and close the mechanism and reliably align the movable member, and does not create weld lines or uneven parts in the molded product. It is assumed that.

[0005]

That is, the present invention provides:
A mold apparatus in which one or more shots of a molten resin material for a disk molded product is held in a resin reservoir in a fixed mold and the molten resin material is sequentially injected from a gate portion into a molded product cavity and molded. An outer peripheral recess connected to a communicating portion communicating with the sprue bush, the center opening of the disk molded product, and a central opening of the disc molded product. A movable central member including a distal end protruding toward the opposing movable mold side, a step formed at a boundary between the outer peripheral concave portion and the distal end, and a movable central member disposed outside the movable central member, An inner cylindrical portion that slidably holds and forms an annular resin reservoir between the outer peripheral concave portion of the movable center member and
A fixed mold-side sleeve member having a tip portion which faces the molded product cavity and has an end portion which opens and closes a gate portion to the molded product cavity when an inner edge portion thereof comes into contact with or separates from a step portion of the movable central member; A movable mold side sleeve member having an inner cylindrical portion disposed on a side facing the fixed mold side sleeve member and slidably holding a distal end portion of the movable center member. The present invention relates to a mold apparatus.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view of a main part showing an embodiment of a disk molding die apparatus according to the present invention, and FIG. 2 is an enlarged sectional view partially showing a movable center member in a different position from above and below.

[0007] The disk molding die apparatus 10 shown in FIG.
One in which one or more shots of a molten resin material for a disk molded product is held in the resin reservoir 25 in the fixed mold 11 and the molten resin material is sequentially injected into the molded product cavity C from the gate portion G and molded. It is.

In FIG. 1, reference numeral 11 denotes the whole fixed type, 12 denotes a fixed block, 13 denotes a fixed fitting member, 1
4 is a fixed side mirror plate. On the other hand, reference numeral 15 denotes the entire movable mold, 16 denotes a movable block, 17 denotes a movable fitting member, 18 denotes a movable mirror plate, and C denotes a molded product cavity. Reference numerals 14a and 18a denote cooling grooves provided on the fixed mirror plate 14 and the movable mirror plate 18, respectively. In this embodiment, a stamper 23 is provided on the surface of the movable mirror plate 18 by a stamper inner holder 21 and a stamper outer holder 22.

A sprue bush 26 for introducing a molten resin material into the mold from a nozzle N of an injection device (not shown) is fixed to the fixed mold 11. Reference numeral 26a is a cylindrical portion of the sprue bush, 26b is an injection hole, and 26R is a locate ring. A movable center member 30 is arranged in connection with the sprue bush 26.

The movable center member 30 stores the molten resin material injected into the mold from the sprue bush 26 into the resin reservoir 2.
5 is provided in connection with the sprue bush 26 so as to be able to open and close the gate that flows into or stops from the molded product cavity C while holding the sprue bush 26. It is provided to be able to move forward and backward. This movable center member 30
Are connected base 31, outer peripheral recess 32, tip 33 and step 3
4 is included.

The connecting base 31 is connected to the sprue bush 26.
The base 31 has an outer peripheral surface 31b that is slidably held by a fixed-type sleeve member 40 described later.

As shown in the figure, the outer peripheral concave portion 32 forms a circular concave portion formed on the outer periphery of the movable center member 30 to form the inner side surface of the resin reservoir 25, and the hole 31 of the connecting base 31 is formed.
The plurality of communicating portions 28 formed from the portion a are connected to and connected to the sprue bush 26.

The distal end portion 33 of the movable center member 30 is formed to have a larger diameter than the outer peripheral concave portion 32, and penetrates the cavity C and protrudes toward the opposing movable mold 15 to define the center opening of the molded product. The distal end portion 33 is slidably held by a movable type sleeve member 50 described later.

A step 34 is formed at the boundary between the outer peripheral recess 32 and the tip 33. As is well understood from FIG. 2, the stepped portion 34 is separated from the distal end portion 42 of the fixed-type sleeve member 40 to open the gate portion G (upper portion in the drawing) by moving the movable center member 30 forward and backward, or The gate portion G is brought into contact and closed (lower portion in the drawing).

The movable center member 30 shown in FIG.
5 are furnished. This heat storage member 35 is
In this embodiment, a known heat pipe is used to keep the molten resin material held at a predetermined resin temperature. Before the start of molding, the heat storage member 35 is heated to a predetermined temperature by contacting the heating member 55 of the movable mold side sleeve member 50, and thereafter, the heat of the molten resin material introduced into the resin reservoir 25. Accumulates and generates heat. Reference numerals 36 and 37 are heaters, 38 is a bush,
The bush 38 includes a heat pipe and a heating member 5 described later.
The heat transfer contact area may be provided when the heat transfer contact area is insufficient, and is not always necessary.

A fixed type side sleeve member 40 is fixed outside the movable center member 30. The fixed type sleeve member 40 is formed of a tubular member having an inner tubular portion 41 and a distal end portion 42.

The inner cylindrical portion 41 has a rear portion 41a which slidably holds the connecting base portion 31 of the movable central member 30 and a ring-shaped resin reservoir 25 between the outer cylindrical concave portion 32 of the movable central member 30.
To form The resin reservoir 25 has an annular capacity having a capacity capable of holding one or more shots of the molten resin material in the cavity C by the outer peripheral concave portion 32 of the movable center member 30 and the inner cylindrical portion 41 of the fixed mold side sleeve member 40. Formed. By forming the resin reservoir 25 in an annular shape, that is, in an annular shape in cross section, the connecting base 31 of the movable center member 30 is formed.
The molten resin material that has flowed through the plurality of communicating portions 28 formed in the nozzle is once mixed, and there is no member for dividing the flow in the annular resin reservoir 25. It can be formed continuously without producing.

The distal end portion 42 of the fixed side sleeve member 40
Constitutes a gate portion G facing the molded product cavity C. That is, as can be clearly understood from the enlarged view of FIG. 2, the inner diameter of the inner edge 43 of the distal end portion 42 is formed to be substantially the same as the outer diameter of the step portion 33 of the movable center member 30. When the movable center member 30 moves forward and backward, the inner edge 43 of the distal end portion 42 is moved to the movable center member 30.
The gate portion G is opened and closed by joining or separating from the step portion 33 of FIG.

On the other hand, on the movable mold 15 side, a movable mold side sleeve member 50 is provided. The movable-side sleeve member 50 has an inner cylindrical portion 51 that is disposed to face the fixed-side sleeve member 40 and that slidably holds the distal end portion 33 of the movable central member 30. Since the movable center member 30 has the distal end portion 33 held by the inner cylindrical portion 51 of the movable-side sleeve member 50, the center alignment in the gate portion G can be performed reliably. In this embodiment, the movable mold-side sleeve member 50 is configured as an ejector sleeve which can be moved forward and backward for projecting the molded product as shown in FIG. 1, but is not limited to this example.

A heating member 55 is provided in the movable-side sleeve member 50. This heating member 55
Is for heating the heat storage member 35 housed in the movable central member 30 before the start of molding.
6 and is disposed in the inner cylindrical portion 51 so as to be movable back and forth.
The heating member 55 is urged toward the fixed mold side by a spring 57. Heat storage member 3 in the movable center member 30
5 contacts the heating member 55 and accumulates its heat.

According to this structure, first, in the mold clamped state,
The movable central member 30 is retracted by the cylinder device 27, and the step portion 34 and the inner edge 43 of the fixed-type sleeve member 40 are joined to close the gate portion G (the cylinder device in the lower portion of FIG. 2). 27B and movable center member 30
B). Then, the heating member 55 is advanced and brought into contact with the tip of the heat storage member 35 for several minutes. The heat of the heating member 55 is accumulated in the heat storage member 35 via the contact surface at the tip. At this time, since the gate portion G is closed, the molten resin does not flow into the cavity C from the resin reservoir 25.

After the heating of the heat storage member 35, the heating member 55 is retracted if necessary, and a molten resin material is injected into the resin reservoir 25 from the sprue bush 26. Thereafter, the movable center member 30 is moved forward by the cylinder device 27 to separate the joint portion, and the gate portion G
, The molten resin material is injected from the nozzle of the injection device, and the molten resin material held in the resin reservoir 25 is injected into the molded product cavity C from the gate G (the cylinder device 27A in the upper part of FIG. 2). And movable center member 30A
reference).

After the injection of a predetermined amount of the molten resin material, the movable center member 30 is retracted again, the gate portion G is closed, and molding is performed. At this time, the molten resin material in the resin reservoir 25 is used as a heat storage member 35 for storing heat of the molten resin material.
Is maintained in an appropriate molten state. After opening the mold and removing the molded product, the molded product cavity C
A molten resin material is injected into the inside, and molding can be performed sequentially.

[0024]

As shown and described above, according to the disk molding die apparatus of the present invention, the gate opening / closing mechanism for injecting or stopping the molten resin material into the molded product cavity is a very simple mechanism. In particular, since the distal end of the movable center member is slidably held in the inner cylindrical portion of the movable sleeve member, the movable member that opens and closes the gate can be reliably centered. became.

Moreover, since the resin reservoir is formed in an annular shape and there is no portion that divides the flow, the molten resin material is injected into the cavity in the form of a plane without forming a weld line in the molded product. Since the volume of the reservoir is formed to be larger than one shot, it is possible to mold a high-quality disc molded product.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a disk molding die apparatus of the present invention.

FIG. 2 is an enlarged cross-sectional view showing upper and lower different positions of a movable center member, partially omitted.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 Mold for disk forming 11 Fixed mold 15 Movable mold 25 Resin reservoir 26 Sprue bush 30 Movable center member 32 Outer peripheral recess 33 Tip section 34 Step section 40 Fixed mold side sleeve member 41 Inner cylinder section 42 Tip section 50 Movable mold side sleeve Member 51 Inner cylinder part G Gate part C Molded product cavity

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI // B29L 17:00

Claims (3)

(57) [Claims] 1. A molten resin material for one or more shots for a disk molded product is held in a resin reservoir in a fixed mold, and the molten resin material is sequentially injected from a gate portion into a molded product cavity to be molded. An outer peripheral recess connected to a fixed type sprue bush, provided so as to be able to advance and retreat with respect to the sprue bush, and connected to a communication portion communicating with the sprue bush;
A movable center member that defines a center opening of the disk molded product and protrudes toward the opposing movable mold, a stepped portion formed at the boundary between the outer peripheral concave portion and the end portion, and a movable center member outside the movable center member. An inner cylindrical portion disposed to slidably hold the movable central member and forming an annular resin reservoir between the movable central member and an outer peripheral concave portion; and an inner edge facing the molded product cavity. A fixed-side sleeve member having a tip portion for opening and closing a gate portion to a molded product cavity by joining or separating a step with the step portion of the movable central member; and a movable-side opposed to the fixed-side sleeve member. And a movable-side sleeve member having an inner cylinder portion slidably holding a distal end portion of the movable center member. 2. The disk molding die device according to claim 1, wherein a heat storage member is provided inside the movable center member. 3. The disk forming die apparatus according to claim 2, wherein a heating member for heating the heat storage member of the movable center member is provided in the movable mold side sleeve member.