JPS5812714A - Controller for temperature of mold - Google Patents

Abstract

PURPOSE:To prevent the interruption of heating caused by, for example, the disconnection of a resistance wire heater and to facilitate a temperature fall, by a method wherein a part of a circulating system of fluid for heating a mold is formed with a magnetic metal pipe, and an electromagnetic induction heating coil is wound around the pipe to control electric current flowing in the coil. CONSTITUTION:A heating fluid circulating system, which heats molds 1 and 2, and consists of hoses 3-9, and a pump 13, is formed at the outside of the molds 1 and 2 for plastic molding. A pipe 10, made of a magnetic metal, is installed to a part of the circulating system to form an electromagnetic induction heating part 12 in which an electromagnetic induction heating coil 11 is wound around the pipe 10. A current to the coil 11 is controlled by a drive circuit of a control panel 16.

Description

Detailed Description of the Invention: This relates to a device for keeping a mold for plastic molding at a predetermined temperature, particularly a type of mold that adjusts the temperature of the mold by circulating water or oil fluid inside the mold. This invention relates to a temperature control device.

In plastic molding machines, it is necessary to adjust the temperature of the mold to a predetermined temperature according to the unique temperature characteristics of the plastic being molded, and especially in molding processes that require precise dimensions and shapes, delicate temperature control is necessary. required.

Conventionally, methods for keeping the mold temperature at a high temperature include a heating method using a heater that heats the mold by inserting a rod-shaped heater (sheathed heater) using a -10mm wire as a heating element into the mold, and a heating method that heats the mold. Two oil heating methods are mainly known and used, in which heated oil is circulated within the mold to heat the mold, but these methods have the following problems.

That is, heating θ by a heater is likely to cause the nichrome wire to break, making it difficult to lower the temperature. In addition, since the mold is locally heated by the heater, distortion occurs in the mold, making it unsuitable for precision molds.

In the heating method using oil, there is no problem that it is difficult to lower the temperature because the oil can be used as a medium to remove heat, and it has the advantage that it is suitable for uniformly heating the entire mold. Since oil is stored in an oil tank and a sheathed heater is installed in this oil tank, the problem of the nichrome wire breaking is unavoidable. Also, there is a large amount of oil in the oil tank (approximately 2
Since it is necessary to store (I l), the device is thick (
Therefore, it must be floor-standing, so consider the floor space1.
(・Above, there is also the disadvantage that the hose that connects the mold and the equipment is long and thick, leading to loss of heat radiation.

Furthermore, because the oil capacity is large, the heat pressure is also large, and delicate temperature control is not possible. F. Oil remains in the oil tank and burns (sludge).
1. You can safely clean the hoses and pumps. However, there are many points that need to be improved in practical terms.

In view of these problems, it is an object of the present invention to provide a mold temperature regulating device that takes advantage of the N=lJ point of the oil heating method and eliminates its drawbacks. It is.

In other words, the present invention enables precision molding by uniformly heating the entire mold.There is no risk of wire breakage, there is little heat loss in a small space, and the temperature can be adjusted with a small amount of oil. The object of the present invention is to provide a mold temperature control device that makes it possible to perform delicate temperature control.

The mold temperature control device of the present invention circulates a small amount of fluid such as oil (for example, about 051) into the mold without using an oil tank, and replaces a part of this circulation system with a magnetic metal pipe.

The feature is that an electromagnetic induction heating coil is wound around each pipe to heat the fluid by electromagnetic induction.

According to the present invention, instead of using a sheathed heater to heat the fluid (thermal medium) such as oil, an electromagnetic induction coil that does not generate heat is used, so only the pipe generates heat, and there is no risk of wire breakage. do not have.

Also, since oil 1/river is not used, oil or Wtk %i□1
Since no sludge is generated, and the entire device can be made compact, it can be attached directly to the molding machine, which is advantageous when floor space is limited. Furthermore, since there is no need to use a long hose, there is no problem of heat radiation loss, and since the oil capacity is small, the responsiveness of the temperature WAI node is improved, making delicate temperature control possible. Also,
Circulating the oil The pipe itself becomes a heating element, which improves thermal efficiency and saves power consumption. Furthermore, the metal pipe that becomes the heating element is heated to
The temperature of both molds can be controlled independently by setting the temperature of both molds separately.
I can also do things like roto.

In addition to solving all the problems of the conventional oil heating method, it also achieves even better effects and provides an extremely excellent mold temperature control device for practical use.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

The drawing shows an embodiment of the present invention, in which a movable mold l,
Short hoses 3, 4, 5, 6, 7.8 through which oil is passed to heat each mold of the molding machine that controls the stationary mold 2, and a pump and motor unit 9 connected to these hoses. An electromagnetic induction heating system consisting of an oil circulation system consisting of an oil circulation system, a pipe 10 made of magnetic metal installed in a part of this circulation system (see Figure 2), and an electromagnetic induction heating coil 11 wound around this pipe. A section 12 is provided. '1- That is, valves 3a and 4a are connected between the oil passages (not shown) passing inside the molds 1 and 2 and the magnetic metal pipe IO, respectively.
The two outbound hoses 3 and 4 having a
The other end of 0 is connected to a pump 13 and a motor 14 via a hose 9.
A unit 15 consisting of is connected, and the bomb 13 and the oil passage of the stationary mold 2 are connected by two return hoses 6°7 having valves 6a and 7a, respectively, which merge with the hose 8. At the other ends of the molds 1 and 2, the outward and return paths of oil within the molds are connected by two hoses (not shown). An electromagnetic induction heating coil 11 is wound around the magnetic metal pipe 10, and a current is passed through the coil 11 by a control panel 16 that controls the drive circuit, and the magnetic metal pipe 10 is heated by electromagnetic induction. It is heated, generates heat, and heats the oil passing through it to a predetermined temperature.

By controlling the current flowing through this coil 11, the temperature of the pipe 10 is controlled by L, thereby controlling the temperature of the oil and controlling the temperature of the mold.

This heating circuit can maintain the temperature of the mold at a predetermined temperature by a signal from a temperature sensor provided in the mold.

The electromagnetic induction heating section 12 consisting of the pipe 10 and the coil 11 can be connected to a part of the hoses 5 and 9, and the unit 1 has a pump 13 and a motor 4 in diameter.
Since it is not large compared to 5, there is no need to take special consideration of floor space (it is easy to install).

It is also possible to use a metal pipe as a part of the hose and wrap a nichrome wire around it to heat it as a compact temperature control device, but this may cause a fire or burns due to the heating of the nichrome wire. In the past, there was a risk that the nichrome wire would break due to overheating, which is undesirable for use. In addition, there is a problem that the response of r/W degree control and heat conduction efficiency are poor, making delicate temperature control impossible.

In this regard, according to the electromagnetic induction heating method of the present invention, the responsiveness of temperature control is good, delicate temperature control is possible, and there is no risk of fire or burns.

According to the temperature control device of the present invention, in addition to eliminating all the drawbacks of conventional heating methods using heaters and heating methods using oil, the temperature control device eliminates all the disadvantages of conventional heating methods using heaters and heating methods using oil.
Since heating can be carried out at 0cc), the responsiveness of the temperature opening side j is good and the power consumption is low, making it economical. Furthermore, since the pipe through which the oil passes serves as a heating element itself, the heating efficiency is good, which is advantageous.

In addition, in the illustrated example, the movable mold 1 and the fixed mold 2 are
Although heating is performed using two heating parts 12, the valves 3a and 4a
, 6a and 7a, it is also possible to separately heat and control the temperature of both molds.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the whole mold temperature regulating device of the present invention, and FIG. 2 is a sectional view of the heating section thereof.

Claims (1)

[Claims] A heating fluid passage is formed in the mold of a plastic molding machine, a circulation system with a pump is connected to this passage to circulate the fluid, and the temperature of the fluid is adjusted to adjust the temperature of the mold. In the mold temperature control device as described in 1"4), a part of the circulation system is formed of a magnetic metal pipe, an electromagnetic induction heating coil is wound around this pipe, and the pipe generates heat by electromagnetic induction heating. The temperature of the fluid is increased by controlling the current flowing through the coil.
A temperature control device for a mold, characterized in that it controls the temperature of a mold.