JPS604731Y2 - Plastic processing equipment - Google Patents

Description

[Detailed Description of the Invention] This invention relates to improvement of plastic processing equipment such as resin molding equipment.

FIG. 1 is a front view of a conventional resin molding apparatus, and FIG. 2 is a perspective view of a heat insulating plate used in the conventional resin molding apparatus.

In the figure, 1a is an upper mold holding plate fixed to a support 3 with a nut 2, and 1b is a lower mold holding plate that slides with a cylinder 4 and a piston 5 using the support 3 as a guide.

The support column 3 is fixed to a frame 7 with a nut 6.

The cylinder 4 is fixed to the frame 7 with bolts 8, and the piston 5
is fixed to the lower mold holding plate 1b with bolts 9.

The upper mold 10b has an upper heat insulating plate 11 between it and the upper mold holding plate 1a.
It is fixed to the upper mold holding plate 1a with bolts 12 so as to sandwich the part a.

The lower mold 10b has a lower heat insulating plate 11 between it and the lower mold holding plate 1b.
It is fixed to the mold holding plate 1b with bolts 13 across b.

Resin molding using such a resin molding device is performed using the upper mold 10a.
This is done by pressing the and lower mold 10b into close contact with each other, forming a cavity by the recess 10a1 of the upper mold 10a and the recess 10b of the lower mold 10b, and injecting molten resin into this cavity. .

Note that the thread path through which the molten resin is injected is not shown in FIG.

During resin molding, it is necessary to heat the mold 10 and the resin, and the mold 10 is heated to a predetermined temperature by a heater (not shown).

In order to always maintain the heating temperature of the mold 10 with high accuracy, heat is applied to the mold 10 by a heater (not shown), and conversely, in order to prevent the heat applied to the mold 10 from escaping as much as possible, the contact surface of the mold 10 is A heat insulating plate 11 is placed between the and mold holding plate 1.
The mold 10 is fixed to the mold holding plate 1 by sandwiching the two.

Heat loss in the mold 10 is due to natural heat radiation caused by the mold 10 being in contact with the atmosphere and heat conduction from the contact surface between the mold 10 and the heat insulating plate 11.

In order to minimize heat loss due to such heat conduction, the heat insulating plate 11 is made of a material with low thermal conductivity.

Conventionally, as the heat insulating board 11, one made of asbestos and having the shape shown in FIG. 2 has been used.

Length L1 Width W1 Thickness T1 of this heat insulating board 11 Mounting hole 11c
The position of the mounting hole 11c and the diameter of the mounting hole 11c are determined by the shape of the mold 10 and the pressing force applied to the mold 10.

In the selection of the heat insulating board 11 in conventional resin molding equipment, asbestos is used primarily because of its low thermal conductivity, as described above.

However, asbestos is susceptible to deformation and distortion when subjected to large amounts of force or compressed at high temperatures for long periods of time, and is also brittle and easily damaged.

When the heat insulating plate 11 is deformed or distorted during resin molding, even if the upper mold 10a and the lower mold 10b are pressurized so that they come into surface contact with each other, the upper mold 10a and the lower mold 10 1
The contact surface with the upper mold 10b does not adhere uniformly over the entire surface, and a gap is created in the contact surface between the upper mold lea and the lower mold 10b, causing the resin to protrude from the cavity.

This idea was made in order to eliminate the drawbacks of the conventional ones as described above, and it requires an interposition between a pair of molds that mold the workpiece by injecting it and a support that supports this mold. and a metal heat insulating body having a contact portion in contact with the surface of the mold or the support and a non-contact portion opposed to the surface so as not to contact the surface, and to prevent leakage of the workpiece from the mold. The object of the present invention is to provide a plastic working device that does not cause the occurrence of.

FIG. 3 is a plan view of an embodiment of this invention, and FIG. 4 is a sectional view of an embodiment of this invention.

An embodiment of this invention will be described in detail below with reference to FIGS. 3 and 4.

In the figure, 14 is a cast iron insulating body, and 14a is a hole provided in the insulating body 14 for inserting bolts 12 and 13 for attaching the mold 10 and the insulating body 14 to the mold holding plate 1. be.

Reference numeral 15 denotes a cast iron protrusion formed integrally with the heat insulator body 14, and a plurality of these protrusions 15 are provided so as to protrude from both mold surfaces 14b and 14C of the heat insulator body 14 in mutually opposite directions. .

In addition, this protruding portion 15 is formed on both mold surfaces 14b of the heat insulator main body 14.
, 14c are provided at positions facing each other.

Reference numeral 16 denotes a heat insulating body according to an embodiment of this invention, which is composed of a heat insulating body 14 and a protrusion 15.

Note that the top portions 15a and 15b of the protrusion portion 15 that protrude in opposite directions are formed to have the same area and to be parallel to each other.

The top portion 15a or the top portion 15b is pressed onto the mold holding plate 1 or the mold 10.

Further, the total area of the top portion 15a or the top portion 15b is determined by the material of the heat insulator 16 and the pressing force applied to the mold 10.

The top portion 15a in this embodiment is formed so that its total area is 1770 times the contact area of the conventional asbestos heat insulating plate 11 with the mold holding plate 1 or the mold 10.

FIG. 5 is a partial cross-sectional view of the resin molding apparatus, showing a state in which the heat insulator according to one embodiment of the invention is attached to the resin molding apparatus.

As shown in this figure, the heat insulator 16 is attached so that the tops 15a and 15b of the projections 15' projecting in opposite directions are in close contact with the mold holding plate 1 and the mold 10, respectively.

Needless to say, cast iron is used instead of asbestos for such a heat insulating body 16 in order to increase its mechanical strength. A structure is adopted in which a plurality of protrusions 15 having a total cross-sectional area that is small enough not to bend are provided on both mold surfaces 14b and 14c of the heat insulator main body 14.

According to the heat insulator 16 of the above-described embodiment, distortion due to aging does not occur unlike the conventional heat insulator 11 made of asbestos, and therefore the upper mold 10a and the lower mold 10b are molded with resin. Since no gaps are created during processing, no cracks will occur in the molded product.

In addition, in the above embodiment, cast iron was used as the material for the heat insulating plate 16, and the heat insulating body 14 and the protrusion 15 were integrally formed, but this invention is not limited to the above embodiment. For example, as shown in FIG. 6, it may be composed of a plurality of spacers 17 made of metal columns and a holder 18 made of a metal plate that holds the spacers 17.

Furthermore, similar effects can be expected even if a large number of through holes are provided in the metal plate.

Note that this invention can be applied not only to the resin molding apparatus described above but also to plastic processing apparatuses in general.

As explained above, according to this invention, metal is used for the heat insulator of the plastic processing equipment, so there is no gap between the joint surfaces of a pair of molds during plastic processing, and therefore the gap between the molds is This has the excellent effect of completely eliminating the occurrence of cracks caused by the protrusion of the workpiece.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a conventional resin molding device, and FIG. 2 is a perspective view showing a heat insulating plate used in the conventional resin molding device.
Fig. 3 is a plan view showing a heat insulating body according to an embodiment of this invention, Fig. 4 is a sectional view of the heat insulating body according to the above embodiment, and Fig. 5 is a resin molding apparatus for molding a heat insulating body according to an embodiment of this invention. FIG. FIG. 6 is a sectional view showing another embodiment of this invention. The same reference numerals in the drawings indicate corresponding parts. 1 is a mold holding plate, 10
is a mold, and 16 is a heat insulator.

Claims (1)

[Scope of utility model registration request] a pair of molds that form a cavity by facing each other at a predetermined distance and in close contact with each other, and molding the workpiece by injecting the workpiece into the cavity;
A support body that supports the mold, and a heat insulator that is interposed between the mold and the support and prevents heat from the mold from escaping to the support. A plastic working device, wherein the heat insulator is made of metal and has a contact portion that contacts the surface of the mold or the support and a non-contact portion that faces so as not to contact the surface.