JPH0788611A - Mold temperature control - Google Patents

Abstract

PURPOSE:To execute precise temp. control of a mold by allowing a medium passing a bypass passage to induce deformation to a thermally deformable material, thereby making control action. CONSTITUTION:A spot temp. control instrument 4 is mounted at the stationary mold 2. The refrigerant flowing-in from a refrigerant inlet 11 passes a pipe 12 and arrives at the rear surface of the cavity of the stationary mold 2. The refrigerant is heated up by depriving the mold 2 of its heat quantity and is flowed out of a refrigerant outlet 5 after passing the bypass passage 7. The refrigerant gradually heats the thermally deformable material 9 until the driving power of the thermally deformable material 9 overcomes the force of a spring 10. A valve plug 8 is opened by this force to allow a large amt. of the refrigerant to flow-in so that the temp. of the refrigerant in contact with the thermally deformable material 9 falls. The force of the spring 10 overcomes the force of the thermally deformable material 9 and the valve plug 8 is closed to the state that only the bypass passage 7 is opened. The mold 2 is controlled to a specific temp. by repeating this operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control method in the field of injection molding, casting, and other fields in which a molten material is solidified by a mold.

[0002]

2. Description of the Related Art Generally, in the molding of a mold, a cavity is formed in the mold as an outer shape of the product, and a molten material is put into the mold to solidify and mold the product. At that time, when the product shape forms a concave portion, the mold forms a convex portion and is likely to be locally overheated. Further, a mold having a plurality of convex portions having a large amount of heat per unit area of such a cavity is generally used. Solidification is delayed around the overheated convex portion, and if that happens, defects such as residual stress and segregation occur in that portion, which does not have a good effect on the product.

As a countermeasure against this, as shown in FIGS. 5 and 6, a refrigerant passage 32 is formed near the cavity 31 of the fixed mold 2 to allow the refrigerant to pass therethrough, but to control the temperature to a uniform or predetermined temperature. Too simple. Further, it is said that it is possible to produce a good product by providing a temperature gradient such as directional solidification as a whole, and the published utility model publications Nos. 2-123352 and 2-123353.
In some cases, spot cooling equipment such as No. 2-123354 was used. In that case, as shown in FIG. 7, spot cooling devices 33, 33, 3 are provided on the back surface of the fixed mold 2.
3, the inlet hose 34, 34 of the refrigerant and the outlet hose of the refrigerant.
, 35, 35 are connected to each other, and the valves 37 are controlled downstream of the manifold 36 that groups the inlet hoses 34, so that the difference in heat quantity between the mold parts can be accurately identified. I couldn't do it, and couldn't control it to a proper temperature.
Therefore, the amount of refrigerant flowing through each cooling device is rough, and it is difficult to realize precise temperature control.

[0004]

The intent of the present invention is to improve the spot control device so that the temperature can be controlled to an appropriate temperature corresponding to each main part, and to optimize the optimum temperature control including a predetermined temperature gradient. It is to realize temperature control over the mold cavity in general.

[0005]

Therefore, the improvement of the spot control device is to provide a temperature-changing material capable of responding to each control temperature in the vicinity of the bypass passage of the control device, and to change the temperature-changing material by the temperature change of the medium. It is to be able to control the flow rate within a single unit by deforming. In this way, a control device with a selected temperature-changing material is assigned to a part of the cavity from behind the cavity so that an optimum temperature gradient is defined over the entire cavity.

[0006]

By doing so, in the case of cooling control, the refrigerant flowing from the inlet of a certain control device takes away more heat than near the cavity, and the temperature rises to that extent, and the flow path with a valve element that moves by the power of the shape-changing material is used to control the valve. When the body is open, some media pass through the bypass passages and out to the control device outlet. Then, when the amount of heat near the cavity is small and the temperature of the cavity corresponding to this control device is low and is significantly lower than the deformation temperature of the shape-changing material, the shape-changing material is gradually cooled when the medium passes through the flow path where the valve body is located. The valve body closes. Alternatively, depending on the temperature, it may be opened and closed in the middle. In this way, when the temperature of the refrigerant is low, it is restricted to flow in the bypass passage, so the temperature of the refrigerant gradually rises as the temperature of the mold rises, and the shape deforming material provided near the bypass passage deforms and operates. , Open the valve body. After that, the flow rate of the refrigerant is increased to rob the heat of the cavity and the temperature of the refrigerant gradually decreases.

In any case, since the refrigerant always flows in the bypass passage, the temperature can be controlled by repeating this, and the cavity is almost stabilized at the temperature corresponding to the selected shape-changing material. As a result, appropriate products can be obtained by arranging selected spot control devices from the back of the cavities at the required points aiming for a predetermined temperature gradient. Further, in the case of heating control, if the operation of the shape-changing material due to the heat medium is reversed, it is possible to similarly control over a predetermined temperature gradient over the entire mold.

[0008]

Embodiments will be described with reference to the drawings. FIG. 1 is an elevation view in which a pair of molds is attached to a die casting machine 1, 2 is a fixed mold, and 3 is a movable mold. Figure 2
Shows that the spot control device 4 of the present invention is attached to the fixed mold 2. And refrigerant outlet screw 5
The valve body 8 having the bypass passage 7, the shape memory alloy 9 and the spring 10 are incorporated in the main body 6 in which the refrigerant is present, and penetrates the refrigerant inlet screw 11, the valve body 8, the shape memory alloy 9 and the spring 10. The sub body 13 including the pipe 12 is inserted and assembled into the main body 6 through the O ring 14, and the main body 6 and the sub body 13 are paired and fixed to the fixed mold 2 through the O ring 15 by the presser foot 16. Has been done.

FIG. 3 shows that the fixed mold 2 is fitted with different types of spot control devices 17 of the present invention. A coolant inlet screw 19 and a coolant outlet screw 20 are formed on the main body 18, and the pipe 21 is connected to the outlet passage hole 22.
In addition, a bimetal 24 having a valve element 23 at its tip is assembled near the bypass passage 26 of the oblong hole 25. A lid 27 is provided to prevent the refrigerant from leaking, and the holding die 28 holds the stationary die 2 through an O-ring 29. FIG. 4 is a diagram showing the relationship between the opening / closing operation of the valve body 8 and the flow rate flowing to the spot control device 4 in FIG. 2, where T0 is the proper refrigerant passage temperature of each device and A1 is the valve body opening. The moment, A2 is the moment when the valve is fully opened, B1 is the moment when the valve body is closed, and B2 is the moment when it is fully closed.

Next, how the individual spot control devices operate independently will be described. As shown in FIG. 2, when a shape memory alloy is used, the refrigerant inlet screw 1 is usually used.
The refrigerant of 15 ° C to 25 ° C that has flowed in from 1 passes through the pipe 12 and reaches the rear surface of the cavity (not shown) of 50 ° C to 100 ° C of the fixed mold 2 to remove the heat of the mold 2 to increase the temperature. The temperature rises, passes through the valve body 8 at 40 ° C. to 80 ° C., partially passes through the bypass passage 7, and flows out from the refrigerant outlet 5. Initially, since the refrigerant whose flow rate at point Cl in FIG. 4 was flowing only in the bypass passage 7 touches the mold 2 at 50 ° C. to 100 ° C., the temperature is raised and the shape memory alloy 9 is gradually heated.
Since the transformation temperature (Ts) is set to any of 50 ° C. to 80 ° C., the power of the shape memory alloy 9 overcomes the force of the spring 10. Then, the valve body 8 that allows a large amount of refrigerant to pass therethrough
The shape memory alloy 9 is operated and opened. As a result, O in FIG.
A large amount of refrigerant at point p is allowed to pass, the mold 2 is cooled, and the temperature of the refrigerant gradually increases from 30 ° C along with the temperature of the mold 2.
It goes down to 50 ° C. Then, when the temperature of the refrigerant drops to the temperature (Tb), the force of the spring 10 overcomes the cooled shape memory alloy 9 to operate, the valve body is closed, and the Cl amount of the refrigerant flows only in the bypass passage 7. Then, after a lapse of time, the temperature of the refrigerant rises with the temperature of the mold again, an amount of Op of the refrigerant flows, and these operations are repeated many times.

Therefore, if the transformation temperature of the shape memory alloy is selected and set in the part of the mold, each spot control device operates with a small fluctuation range according to the temperature of the part of the mold, Properly control the whole. When the shape memory alloy is used, the digital operation is performed, and when the bimetal is used, the analog operation is performed to control the temperature. Since the proper temperature is different in the part of the mold, if the spot control device of the present invention is used to control the temperature of the point point, the proper temperature is maintained in each part of the cavity, so that directional solidification, etc. The intended temperature gradient can be realized and high quality products can be produced. Moreover, although the mold for heating is explained, it goes without saying that a heat medium can also be applied to a mold for cooling. Further, the temperature deformable material may be a polymer resin. Further, if a medium is selected, it can be applied to a mold having a wider temperature range than the above.

[0012]

As described above, since a plurality of spot control devices that operate at different temperatures are attached to the respective main parts of the mold to automatically enable the intended temperature control such as directional solidification, Good products are produced, and once the proper operating temperature of the temperature-deformable material is set, there is no need to make further adjustments, so work such as setup change can be shortened.

[Brief description of drawings]

FIG. 1 is an elevation view of a die-casting machine attached to a die.

FIG. 2 is an elevational view of a spot control device of the present invention placed on a fixed mold.

FIG. 3 is an elevational view of different types of spot control devices of the present invention placed in a fixed mold.

FIG. 4 is a diagram of a refrigerant temperature of an arbitrary portion and an opening / closing operation diagram of a valve body when the spot control device of the present invention is used.

FIG. 5 is an elevational view of a fixed mold that has been subjected to conventional line cooling.

6 is a sectional view taken along line XX of FIG.

FIG. 7 is an elevational view of the rear surface of a fixed mold on which a conventional spot cooling device is arranged.

[Explanation of symbols]

 1 Die casting machine 2 Fixed mold 3 Movable mold 4 Spot control device 5 Refrigerant outlet screw 6 Main body 7 Bypass passage 8 Valve body 9 Shape memory alloy 10 Spring 11 Refrigerant inlet screw 12 Pipe 13 By-product 14 O-ring 15 O-ring 16 Presser Plate 17 Spot control device 18 Main body 19 Refrigerant inlet screw 20 Refrigerant outlet screw 21 Pipe 22 Refrigerant passage hole 23 Valve body 24 Bimetal 25 Oval hole 26 Bypass passage 27 Lid 28 Holding plate 29 O-ring 31 Cavity 32 Refrigerant passage 33 Spot cooler 34 Cooling water inlet hose 35 Cooling water outlet hose 36 Manifold 37 Valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29C 33/04 8823-4F 45/73 7639-4F

Claims (2)

[Claims] 1. An apparatus for controlling temperature by bringing a medium into contact with the vicinity of a main part of the die from behind a cavity of the die, wherein the medium passes through at least a bypass passage, and is controlled by activating the deformation of the temperature deformable material. A control device which performs an operation and optimally selects and controls a deformation temperature of the temperature-deformable material to the main part. 2. A temperature control method for controlling each main part of a mold to a predetermined temperature, by removing or heating the amount of heat of each overheated or cooled main part, and controlling each to an appropriate temperature. A method for controlling the temperature of a mold, wherein the temperature is controlled by a plurality of tools according to claim 1.