JPH0722951B2 - Injection compression molding machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an injection compression molding machine used for ultra-precision molding.

(Prior art and its problems) Conventionally, after filling the cavity with resin, in order to compress the molded body during the process in which this resin changes from the molten state to the solidified state, a part of the mold (compression The child) is provided on the movable side mold, and the hydraulic cylinder for moving the nest is provided on the movable platen. When the compression mechanism is provided on the movable side as described above, it is necessary to design the mold in consideration of the engagement with the protrusion mechanism for releasing the molded product. Therefore, for the lens and the disc, the mold structure is relatively simple and the mold design is easy, so it is convenient to install it on the movable side, but for the ultra-precision mechanical parts, An extremely complicated mold structure was required, and it was difficult to manufacture the mold.

(Object of the Invention) The present invention has been made to solve the above-described conventional problems, and easily accommodates various mold structures by incorporating one compression cylinder for moving the compression insert on the fixed platen side. The purpose is to be able to.

(Means for Solving the Problems) In the injection compression molding machine of the present invention, the fixed platen or the sub platen mounted on the fixed platen is formed with an annular groove having a center substantially at the center of the platen. A ring-shaped piston is fitted into the mold, and a mold inserted into the fixed platen or the sub-platen via a fixed side mounting plate is fitted with a compression insert forming a cavity so as to be able to move forward and backward in the anti-clamping direction. It is characterized in that the anti-cavity side of the compression insert penetrates the fixed side mounting plate and extends to the fixed platen side so as to face the piston.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In the figure, 1 is an annular groove centered on the center of the platen.
It is formed on the fixed platen 2 as shown in the drawing, or on the sub platen 3 mounted on the fixed platen 2 as shown in FIG. An annular piston 4 is fitted in the annular groove 1, and the piston 4 is fixed by a bolt 5 to a fixed platen 2
Alternatively, the holding plate 6 for holding the piston 4 mounted on the sub platen 3 prevents the piston 4 from being pulled out to define oil chambers 7a, 7b. The piston 4 can be moved back and forth in the anti-clamping direction by the pressure oil supplied to the oil chamber 7a or 7b, and the pressure oil supply to the oil chamber 7a on the side for moving the piston 4 forward is controlled in multiple stages. Is configured to be possible. Also, the piston 4 is at the most retracted position from the platen surface.
It is retracted by about 20 mm, and a large number of bolt hole screws 8 are provided at equal intervals so as to be symmetrical with respect to the center of the piston 4.

Reference numeral 9 denotes a fixed-side template, which is attached to the fixed platen 2 or the sub-platen 3 via a fixed-side mounting plate 10. A plurality of compression inserts 12 (four in the embodiment) forming a cavity 11 are fitted into the fixed-side mold plate 9 and are equally arranged on the same circumference centered on the mold plate center. On the side opposite to the cavity 11 of the compression insert 12, there is provided a protrusion 14 penetrating through the hole 13 formed in the fixed side mounting plate 10 and extended to the fixed platen 1 side. A ring-shaped height adjusting tool 15 is attached to the
A height adjuster 15 is brought into contact with the compression insert 12 to be advanced by the piston 4. In addition, the compression nest 12
A flange piece 17 is provided on the side opposite to the cavity, and is inserted between the fixed-side mold plate 9 and the fixed-side mounting plate 10, and the flange piece 17 is provided.
A rubber ring 18 fitted to the compression insert 12 is attached to the cavity 11 side of 17, or a spring (not shown) is interposed between the fixed side mold plate 9 and the collar piece 17. The spring or rubber ring 18 is configured to be compressed by the forward movement of the compression insert 12.

Reference numeral 19 denotes a movable side mold plate, which is mounted on the movable platen 22 via a mold member 20 and a movable mold mounting plate 21. A molding insert 23 that faces the compression insert 12 and forms the cavity 11 is attached to the movable mold plate 19.

24 and 25 are ejector pins, which are respectively inserted into the mold member 20, the molding insert 23, the mold member 20 and the movable side mold plate 19 so as to face the cavity 11 and the lantern 26, and are connected to each other by the ejector plate 27, The ejector cylinder 28 is configured to advance and project in the mold clamping direction via the ejector plate 27.

29 is a plasticizer, 30 is a sprue bush, 31 is a sprue, and 32 is a gate.

Although the present embodiment has been described with reference to the example of taking four pieces, as long as the cavity arrangement with respect to the center of the template is balanced so that the thrust received by the compression inserts 12 from the pistons 4 does not vary, the molded articles are taken in a well-balanced manner. The number is not limited at all (for example, one disk-shaped molded product having a central hole is taken, and plural lenses, ultra-precision mechanical parts, etc. are taken). Piston 4
Since a large number of bolt holes 8 are provided in the cylinder so as to be symmetrical with respect to the center of the piston, the cavity arrangement,
Therefore, it is possible to easily change the number and position of the height adjusters 15 according to the arrangement of the compression inserts 12.

(Operation) In the mold clamping state shown in FIG. 1, when the molten resin is injected and filled from the plasticizing device 29 into the cavity 11 through the sprue 31, the runner 26 and the gate 32, the resin begins to be cooled after completion of the filling, and the gate portion is first Is solidified, and the pressure on the plasticizing device 29 side is not transmitted to the cavity 11. The resin in the cavity 11 contracts in volume upon cooling.

After the injection is started, the compression delay timer (which can be set arbitrarily) works, and after the time is up, the piston 4 moves the compression insert 12 with the compression force obtained by multiplying the oil pressure on the oil chamber 7a side pressure receiving area according to the compression force program. Push forward to move forward.

The program of compressive force is actually a program of hydraulic pressure applied to the oil chamber 7a, and is set in consideration of the resin temperature in the cavity 11, and the high compression occurs when the resin in the cavity begins to solidify and approaches the heat deformation temperature. It is better to apply force and then gradually reduce the compression force.

Even after the program is completed, a hydraulic pressure of 1 kg / cm ² or less is applied to the piston 4 to create a condition in which the compression insert 12 is in light contact with the molded body in the cavity 11 (decompression), and this decompression increases the time of the cooling timer. Continue until time.

When the mold is opened after the cooling timer has timed out, and hydraulic pressure is simultaneously applied to the oil chamber 7b to retract the piston 4, the compression insert 12 returns to the original retracted position by the spring and the rubber ring 18.

After opening the mold, ejector pin 28
4,25 is projected to separate the molded product from the molded sprue / runner, and it is taken down by gravity or by a unloader.

(Effects of the Invention) As described above, in the present invention, the projecting mechanism is set to the movable side and the compression mechanism is set to the fixed side.
In addition, an annular piston centered on the center of the platen is moved by one compression cylinder that can move back and forth in the anti-clamping direction.
Since one or more compression inserts are moved forward, the degree of freedom in arranging the compression inserts is considerably high. Therefore, even if an extremely complicated mold structure is required for ultra-precision mechanical parts, it can be easily and surely dealt with.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing a partially modified example, and FIGS. 3 and 4 are III-III of FIG.
FIG. 4 is a sectional view taken along line IV-line. 1 ... Annular groove, 2 ... Fixed platen, 3 ... Sub platen, 4 ... Annular piston, 5 ... Bolt, 6 ... Holding plate, 7a, 7b ... Oil chamber, 8 ... Screw, 9 ... … Fixed side template, 1
0 …… Fixed side mounting plate, 11 …… Cavity, 12 …… Compression insert, 13 …… Hole, 14 …… Protrusion, 15 …… Height adjustment tool, 16 ……
bolt.

Claims (1)

[Claims] 1. A fixed platen or a sub-platen mounted on the fixed platen is formed with an annular groove having a center substantially at the center of the platen, and an annular piston is fitted in the annular groove, and the fixed platen or A compression insert forming a cavity is fitted in a mold attached to the sub platen via a fixed side mounting plate so as to be able to advance and retreat in the anti-clamping direction, and the non-cavity side of the compression insert is attached to the fixed side mounting plate. An injection compression molding machine, characterized in that it penetrates and extends to the fixed platen side and faces the piston.