JPH0443016A - Injection molding die and its temperature control method - Google Patents

Abstract

PURPOSE:To make warpage of a molded product small by forming a channel for passing through a temperature control medium on one of mating surfaces of a fixed side mold and a movable side mold and extremely minimizing the temperature difference between the fixed side mold and the movable side mold. CONSTITUTION:A channel 4 is formed around a spool 3 formed at the center of a parting surface 2 of a fixed side mold 1, while a channel 9 is formed in the position corresponding to the channel 4 of a cavity surface 2 of the fixed side mold 1 around a cavity section 8 of a movable side mold 5. Both ends 9a and 9b of the channel 9 are connected with holes 11a and 11b bored from a side face section 10 of a movable template 6 through a parting surface 7, and holes 12a and 12b connected with the side holes of the side face sections 10 of the holes 11a and 11b are connected with a temperature controller 13. The temperature difference can be extremely minimized by passing a temperature control medium through parting surfaces 2 and 7 and temperature controlling simultaneously the fixed side mold 1 and the movable side mold 5 by means of the temperature medium used in common, and molten resin is cured uniformly in the state of minimized warpage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an injection mold for maintaining an injection mold at a constant temperature and a method for controlling the temperature thereof.

[Conventional technology]

Conventionally, temperature control of injection molding molds has been carried out by forming temperature control holes in each of a stationary mold and a movable mold, and supplying a temperature control medium to the temperature adjustment holes.

For example, in the invention described in JP-A-1-278322, a fixed mold and a movable mold have a plurality of temperature control holes as a mold for molding a disk substrate that requires highly accurate flatness. An invention has been proposed to form a.

[Intelligence B that the invention attempts to solve] However, the prior art has the following serious drawbacks.

In other words, temperature control is performed by supplying temperature control medium to the temperature control holes of the stationary mold and the movable mold through separate routes, respectively.
A temperature difference occurs between the stationary mold and the movable mold, which causes warpage in the molded product.

40wX33s+aX1.5m shown in Figure 15 a and b
FIG. 16 shows the experimental results of the temperature difference (°C) between the stationary mold and the movable mold and the amount of warpage Δ (μ) in the longitudinal direction using the molded product No. s.

Further, it is difficult to form the temperature control hole so that the shape of the temperature control hole matches the outer peripheral shape of the molded product.

Furthermore, in order to improve heat exchange between the mold and the temperature regulating medium, it is necessary to form a number of temperature regulating holes.

The present invention was developed in view of the above-mentioned shortcomings in the conventional technology, and is an injection molding method that can reduce warpage of molded products by extremely reducing the temperature difference between the fixed side mold and the movable side mold. The purpose of the present invention is to provide a mold for use and a method for controlling its temperature.

[Means to solve the problem]

The present invention is an injection mold having a fixed side mold and a movable side mold, in which a groove for passing a temperature regulating medium is formed in at least one of the mating surfaces of each mold. Moreover, this is a temperature control method in which this injection mold is used, and after mold clamping, a temperature control medium is supplied to the grooves to perform molding, and then gas is supplied to the wire grooves to remove the temperature control medium.

[Effect]

The present invention enables heat to be transferred from the stationary mold and the movable mold under the same conditions by controlling the temperature of the fixed mold and the movable mold at the same time using a common temperature control medium. ,
The temperature difference between the stationary mold and the movable mold can be made extremely small.

(Example) Hereinafter, an example of an injection molding die and a temperature control method thereof according to the present invention will be described with reference to the drawings.

(First Embodiment) FIGS. 1 to 3 show an injection mold used in the temperature control method of the first embodiment of the present invention, FIG. 1 is a perspective view showing a schematic configuration, and FIG. 2 is a partially enlarged cross-sectional view, FIG. 3 is a longitudinal cross-sectional view of the temperature controller, and FIGS. 4 to 10 show modifications of this embodiment.
Figure 4a is a longitudinal sectional view, Figures 4 and C are partially enlarged sectional views, Figure 5a is a plan view, Figure 5 is a front view, Figure 6 is a longitudinal sectional view, and Figure 7 is a plan view. 8 is a partially enlarged sectional view, FIG. 9 is a longitudinal sectional view, and FIG. 10 is a plan view.

Reference numeral 1 denotes a fixed mold, and a spool 3 is formed in the center of a mating surface (hereinafter referred to as parting surface) 2 of the fixed mold 1. A semicircular groove 4 is formed around the spool 3.

A cavity portion 8 is formed in the center of the parting surface 7 of the movable mold plate 6 of the movable mold 5.

A semicircular groove 9 is formed around the cavity portion 8 at a position corresponding to the groove 4 of the cavity surface 2 of the stationary mold 1. Both ends 9a, 9b of the groove 9 are holes 11a, 1 bored from the side surface 10 of the movable template 6 to the parting surface 7.
It is connected to lb.

A hose 12a is provided at the end of the side surface 10 of the holes 11a and 11b.
, 12b are connected, and the hoses 12a and 12b are connected to a warm UAl 113 provided near the movable mold 5. The temperature controller 13 is connected to the injection molding machine 14 by a wire 15.
It is configured to be able to receive a mold clamping signal from the injection molding machine 14 (see FIGS. 1 and 2).

A storage tank 17 for the temperature control medium 16 is installed inside the temperature controller 113, and a heater 18 is installed inside the storage tank 17.

The ends of the hoses 12a, 12b are provided so as to be located within the temperature regulating medium 16 of the storage 1a17. warm v4111
A switching valve 19 is attached to the upper part of the hose 12a in the hose 12a, and a pump 20 is attached to the vicinity of the end. (See Figure 3).

The temperature control method using the injection mold having the above configuration is as follows: First, the parting surfaces 2 and 7 of the stationary side mold 1 and the movable side mold F1.6 are joined, and then the fixed side mold 1 and the movable mold 5 are clamped together. The temperature controller 13 operates the pump 20 in response to a mold clamping signal from the injection molding machine 14 .

The operation of the pump 2o causes the temperature regulating medium 16 to be sucked into the molds 1 and 5 through the hose 12b. The temperature regulating medium 16 passes through the hole 11b, passes through the tubular space formed by the grooves 4 and 9 formed on the parting surface 2.7,
The temperature is controlled again via the hole 11a and the hose 12a [113
Return to At this time, the temperatures of the stationary mold 1 and the movable mold 5 are uniformly controlled by the temperature control medium 16. After temperature control, resin is injected and molded. After the molding is completed, operate the magnetic valve 22 to send air by suction instead of the temperature control medium 16 (the temperature of the air should be about the same temperature as the temperature control medium 16), and inside the molds 1 and 5. The temperature control medium 16 is removed. Thereafter, the air supply is stopped, the mold 1°5 is opened, and the molded product is taken out.

According to this embodiment, the temperature control medium 1 is placed on the parting surface 2.7.
6, it is possible to simultaneously control the temperature of the fixed mold 1 and the movable mold 5 using a common temperature medium 16, and to reduce the temperature difference between the fixed mold 1 and the movable mold 5. It can be made extremely small. As a result, the molten resin in the cavity is cooled uniformly from the fixed mold 1 and the movable mold 5, and is cooled with very little warpage.

In addition, since the suction type temperature controller 13 is used in this embodiment, the temperature regulating medium 16 is always operated under negative pressure, and the temperature regulating medium 16 oozes out from within the tubular space formed by the groove 4.9. When using a positive pressure temperature controller, groove 4.
A storage groove 23 is provided around the housing groove 9, and an elastic member 24 (such as an O-ring) is stored in the storage groove 23 for sealing (FIGS. 4a and 4b).

(see C).

Furthermore, in this example, a rectangular flat plate is molded, but the same effect can be obtained by molding a circular flat disc (No. 5
(See figures a and b).

Furthermore, in the case of molding a concave lens where the cavity shape is thick at the periphery, the temperature control medium 16 can be passed near the thick part, making uniform cooling possible and making it possible to mold a plastic lens with high surface accuracy. (See Figure 6).

In addition, even in the case of multiple cavities, complex grooves 4.9 can be easily formed, the cavity 8 can be uniformly cooled, and the grooves 4, 9 can be brought close to the runner part 25. It becomes possible to stop cooling the runner part 25, which shortens the cycle time (7th
(see figure).

Furthermore, the grooves 4 and 9 are not limited to a semicircular shape, but may be square shaped (see FIG. 8).

Further, in this embodiment, the grooves 4 and 9 were formed in both the fixed mold 1 and the movable mold 5, but the grooves may be formed in either one of the molds. It is more effective to form grooves in a mold that has been molded (see Figure 9).

Furthermore, the temperature of the mold can be stabilized in a shorter time by forming a wide groove 4.9 on the parting surface 2.7 (see FIG. 10).

(Second Embodiment) FIGS. 11 to 13 are partially enlarged cross-sectional views showing grooves formed in an injection mold used in a temperature control method according to a second embodiment of the present invention.

The present embodiment has the advantage that the grooves 26, 27, and 28 of the first embodiment have an under-shaped cross-sectional shape (the opening thereof is narrow with respect to the parting surface). However, the other configurations are the same, and a description of the same components will be omitted.

In the first embodiment, air is sent to the temperature regulating medium 16.
At this time, if the temperature regulating medium 16 is not completely removed, the temperature regulating medium 16 may flow out onto the parting surface 2.7 and stain the molded product when the mold is opened. There is.

According to the present embodiment, by making the cross sections of the grooves 26, 27, and 28 under-shaped, it is possible to prevent the temperature regulating medium 16 from flowing out.

(Third Embodiment) Figures 14a and 14b show grooves formed in an injection mold used in the temperature control method of the third embodiment of the present invention.
4a is a partially enlarged sectional view, and FIG. 14 is a partially enlarged perspective view.

This embodiment differs from the first embodiment in that the bottoms of the grooves 4 and 9 are constructed with a groove 29 formed into an uneven shape, and the other configurations are the same, and the explanation of the same components will be given below. Omitted.

In this embodiment, the bottom of the groove 29 is formed in an uneven shape. Therefore, the flow of the temperature regulating medium is always in a turbulent state, and heat exchange between the temperature regulating medium and the mold can be enhanced.

[Effect of the invention] A groove for temperature control common to the stationary side mold and the movable side mold is formed on at least one mating surface (parting surface) of the stationary side mold and the movable side mold, and the fixed side mold and the movable side mold are fixed. By controlling the temperature of the side mold and the movable mold at the same time, it is possible to minimize the temperature difference between the fixed mold and the movable mold, thereby reducing warpage of the molded product. .

[Brief explanation of the drawing]

1 to 3 show an injection mold used in a temperature control method according to a first embodiment of the injection mold and its temperature control method according to the present invention, and FIG. 1 is a perspective view showing a schematic configuration. Figure 2 is a partially enlarged cross-sectional view, Figure 3 is a longitudinal cross-sectional view of the temperature controller, Figures 4-
10 shows a modification of the first embodiment, FIG. 4a is a longitudinal sectional view, FIGS. 4A and 4C are partially enlarged sectional views, and FIG.
Figure 5 is a plan view, Figure 5 is a front view, Figure 6 is a vertical sectional view, Figure 7 is a longitudinal sectional view, and Figure 7 is a front view.
The figure is a plan view, FIG. 8 is a partially enlarged sectional view, FIG. 9 is a longitudinal sectional view, FIG. 10 is a plan view, and FIGS. 11 to 13 are injection molding used in the temperature control method of the second embodiment. FIGS. 14a and 14b are partially enlarged cross-sectional views showing grooves formed in a mold for injection molding, and FIGS. 14 is a partially enlarged sectional view, FIG. 14 is a partially sectional perspective view, FIGS. 15 to 16 show a conventional example, FIG. 15a is a plan view during molding, and FIG. 15 is a sectional view of the molded product. , Figure 16 shows the temperature difference ('C) between the fixed mold and the movable mold.
) and the warpage amount Δ(μ■) of the molded product in the longitudinal direction. l...Fixed side mold 2.7...Parting surface 3...Spool 4.9.26.27.28゜5...Movable side mold 6...Movable side mold plate 8. ... Cavity part 10 ... Side part 11 ... Hole 12 ... Hose 13 ... Temperature controller 14 ... Injection molding machine 15 ... Wire 16 ... Temperature control medium 17 ... Storage tank 18... Heater 19... Switching valve 20... Pump 29... Groove 21... Pipe 22... Solenoid valve 23... Storage groove 24... Elastic member 25... Runner part 2

Claims (2)

[Claims] (1) An injection mold having a fixed side mold and a movable side mold, characterized in that a groove for passing through a temperature regulating medium is formed in at least one of the mating surfaces of each mold. Mold for injection molding. (2) Using the injection mold according to claim 1, after mold clamping, supplying a temperature regulating medium to the groove to perform molding, and then supplying gas to the groove to remove the temperature regulating medium. A method for controlling the temperature of an injection mold, characterized by: