JP2024057212A - Mold temperature control method - Google Patents

Abstract

A mold temperature control method is provided that can keep the temperature of the entire mold uniform even if the cycle time is variable.
[Solution] The fixed mold 200 and the movable mold 300 each have a cavity side heating mechanism 20, 60 that heats the vicinity of the cavity 100a, a cavity side temperature sensor 30, 70 that measures the temperature near the cavity 100a, an outer periphery side heating mechanism 40, 80 that heats the vicinity of the outer periphery of the mold 100, and an outer periphery side temperature sensor 50, 90 that measures the temperature near the outer periphery, and a mold temperature control method in which, when the casting cycle time is fast, the cavity side heating mechanism 20, 60 is stopped and the outer periphery side heating mechanism 40, 80 is operated, and when the temperature near the cavity 100a falls below a predetermined value, the cavity side heating mechanism 20, 60 is operated, and when the casting cycle time is slow, both the cavity side heating mechanism 20, 60 and the outer periphery side heating mechanism 40, 80 are operated.
[Selected Figure] Figure 1

Description

This disclosure relates to a method for controlling the temperature of a mold.

If temperature distribution occurs in the mold when preheating and maintaining the casting mold, the mold may deform, causing deformation and burrs in the finished product. Patent Document 1 discloses a technique for suppressing temperature distribution in the mold by installing a heater or the like on the outer periphery of the mold and casting in a state where the temperature of the outer periphery is higher than that of the center of the mold.

JP 2004-090064 A

The inventors have found the following problems regarding the mold temperature control method.
When manufacturing a small number of products, the cycle time may be variable depending on the number of products. When casting with a slow cycle time, the mold cools more quickly than when casting with a fast cycle time, and the temperature in the vicinity of the mold cavity is particularly likely to drop.

In the technology disclosed in Patent Document 1, heaters are installed only on the outer periphery of the mold, so it is not possible to heat the vicinity of the mold cavity and maintain the temperature. Therefore, if the technology disclosed in Patent Document 1 is applied to a case where the cycle time is variable, it is difficult to maintain the temperature near the cavity when casting with a slow cycle time is performed.

This disclosure has been made in consideration of these problems, and aims to provide a mold temperature control method that can keep the temperature of the entire mold uniform even when the cycle time is variable.

One aspect of the present invention to achieve the above object is to
A fixed mold and a movable mold that is combined with the fixed mold to form a cavity,
A mold temperature control method comprising: injecting and filling the cavity with molten metal; and opening the mold after the molten metal has solidified, to remove a molded product,
The fixed die and the movable die are
a cavity side heating mechanism for heating the vicinity of the cavity;
a cavity-side temperature sensor for measuring a temperature in the vicinity of the cavity;
an outer periphery side heating mechanism for heating the vicinity of the outer periphery of the mold;
and an outer periphery side temperature sensor for measuring a temperature in the vicinity of the outer periphery,
When the cycle time of casting is fast, the cavity side heating mechanism is stopped and the outer periphery side heating mechanism is operated, and when the temperature in the vicinity of the cavity becomes lower than a predetermined value, the cavity side heating mechanism is operated;
When the casting cycle time is slow, both the cavity side heating mechanism and the outer periphery side heating mechanism are operated.

This disclosure provides a mold temperature control method that can keep the temperature of the entire mold uniform even if the cycle time is variable.

FIG. 2 is a schematic cross-sectional view of a mold according to an embodiment. 4 is a flowchart showing the flow of a mold temperature control method according to the embodiment.

Below, the embodiments of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are given the same reference numerals, and duplicate explanations will be omitted as necessary for clarity of explanation.

<Embodiment>
First, the configuration of a mold for carrying out a mold temperature control method according to an embodiment (mold according to an embodiment) will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view of the mold according to the embodiment. As shown in Fig. 1, the mold 100 includes a fixed mold 200 and a movable mold 300. The fixed mold 200 includes a cavity side heating mechanism 20, a cavity side temperature sensor 30, an outer periphery side heating mechanism 40, and an outer periphery side temperature sensor 50. The movable mold 300 includes a cavity side heating mechanism 60, a cavity side temperature sensor 70, an outer periphery side heating mechanism 80, and an outer periphery side temperature sensor 90.

The movable die 300 is movable relative to the fixed die 200 and is combined with the fixed die 200 to form the cavity 100a. In a manufacturing method of a molded product using the metal mold 100, the movable die 300 is combined with the fixed die 200, i.e., the die is clamped, and molten metal is injected to fill the cavity 100a. After the molten metal has solidified, the movable die 300 is separated from the fixed die 200, i.e., the die is opened, and the molded product is removed. The molten metal is, for example, molten aluminum.

The cavity-side heating mechanism 20 heats the vicinity of the cavity 100a of the fixed mold 200. In the example shown in FIG. 1, the cavity-side heating mechanism 20 includes heaters 20a to 20e. The fixed mold 200 also includes a control system I (not shown). The heaters 20a to 20e are arranged near the cavity 100a of the fixed mold 200 and can heat the fixed mold 200. The heaters 20a to 20e are electric heaters that are turned on and off by a single control system I. When the heaters 20a to 20e are arranged to achieve a predetermined density near the cavity 100a of the fixed mold 200, the temperature near the cavity 100a of the fixed mold 200 can be kept more uniform, which is preferable.

The cavity-side temperature sensor 30 measures the temperature near the cavity 100a of the fixed mold 200. The cavity-side temperature sensor 30 is, for example, a thermocouple. The control system I that controls the heaters 20a to 20e controls the power on/off of the heaters 20a to 20e based on the temperature measured by the cavity-side temperature sensor 30.

The outer peripheral heating mechanism 40 heats the vicinity of the outer peripheral portion of the fixed mold 200. In the example shown in FIG. 1, the outer peripheral heating mechanism 40 includes heaters 40a to 40f. The fixed mold 200 also includes a control system II (not shown). The heaters 40a to 40f are arranged on the outer peripheral side of the fixed mold 200 and can heat the fixed mold 200. The heaters 40a to 40f are electric heaters whose power is turned on and off by a single control system II. It is preferable that the heaters 40a to 40f are arranged at a predetermined density on the outer peripheral side of the fixed mold 200, since this allows the temperature on the outer peripheral side of the fixed mold 200 to be kept more uniform.

The outer peripheral side temperature sensor 50 measures the temperature on the outer peripheral side of the fixed mold 200. The outer peripheral side temperature sensor 50 is, for example, a thermocouple. The control system II that controls the heaters 40a to 40f controls the power on/off of the heaters 40a to 40f based on the temperature measured by the outer peripheral side temperature sensor 50.

The cavity-side heating mechanism 60 heats the vicinity of the cavity 100a of the movable mold 300. In the example shown in FIG. 1, the cavity-side heating mechanism 60 includes heaters 60a to 60f. The movable mold 300 also includes a control system I (not shown). The heaters 60a to 60f are arranged near the cavity 100a of the movable mold 300 and can heat the movable mold 300. The heaters 60a to 60f are electric heaters that are turned on and off by a single control system I. When the heaters 60a to 60f are arranged to have a predetermined density near the cavity 100a of the movable mold 300, the temperature near the cavity 100a of the movable mold 300 can be kept more uniform, which is preferable.

The cavity-side temperature sensor 70 measures the temperature near the cavity 100a of the movable mold 300. The cavity-side temperature sensor 70 is, for example, a thermocouple. The control system I that controls the heaters 60a to 60f controls the power on/off of the heaters 60a to 60f based on the temperature measured by the cavity-side temperature sensor 70.

The outer peripheral heating mechanism 80 heats the vicinity of the outer peripheral portion of the movable mold 300. In the example shown in FIG. 1, the outer peripheral heating mechanism 80 includes heaters 80a to 80f. The movable mold 300 also includes a control system II (not shown). The heaters 80a to 80f are arranged on the outer peripheral side of the movable mold 300 and can heat the movable mold 300. The heaters 80a to 80f are electric heaters whose power is turned on and off by a single control system II. When the heaters 80a to 80f are arranged at a predetermined density on the outer peripheral side of the movable mold 300, the temperature on the outer peripheral side of the movable mold 300 can be kept more uniform, which is preferable.

The outer peripheral side temperature sensor 90 measures the temperature on the outer peripheral side of the movable mold 300. The outer peripheral side temperature sensor 90 is, for example, a thermocouple. The control system II that controls the heaters 80a to 80f controls the power on/off of the heaters 80a to 80f based on the temperature measured by the outer peripheral side temperature sensor 90.

Next, a mold temperature control method according to an embodiment will be described with reference to FIG. 2. FIG. 2 is a flow chart showing the flow of the mold temperature control method according to an embodiment. The mold temperature control method according to an embodiment is a temperature control method performed when casting is performed in the mold 100.

As shown in FIG. 2, when casting is performed in the mold 100, preheating is started first (step S1). At this time, the power supplies of the control system I and control system II equipped in the fixed mold 200 and the movable mold 300, respectively, are all turned on, i.e., ON (step S2). When preheating is completed (step S3), the molten metal is injected and filled into the cavity 100a in the mold closed state, i.e., casting is started (step S4). If the casting cycle time is fast (step S5 Yes), the power supplies of the control system I equipped in the fixed mold 200 and the movable mold 300, respectively, are turned off, i.e., OFF, and the control system II equipped in the fixed mold 200 and the movable mold 300, respectively, are turned ON (step S6).

When the cycle time is fast, the temperature near the cavity 100a of the mold 100 is kept high by the heat of the molten metal. Therefore, the control system II provided on each of the fixed mold 200 and the movable mold 300 heats the outer periphery of the mold 100 so that the temperature on the outer periphery side of the mold 100 becomes the same as the temperature near the cavity 100a of the mold 100. Specifically, the control system II operates the heaters 40a-40f, 80a-80f to heat the outer periphery of the mold 100 so that the temperature measured by the outer periphery side temperature sensors 50, 90 approaches the temperature measured by the cavity side temperature sensors 30, 70.

If, during casting with a fast cycle time, the temperature near the cavity 100a of the mold 100 falls below a predetermined value (step S7 No), the control system I equipped in each of the fixed mold 200 and the movable mold 300 is turned on (step S8), and the cavity side heating mechanisms 20, 60 are operated to heat the vicinity of the cavity 100a of the mold 100. In this way, when the cycle time is fast, the occurrence of temperature distribution in the mold 100 can be suppressed, i.e., the temperature of the entire mold 100 can be kept uniform, by operating or stopping the cavity side heating mechanisms 20, 60 depending on the temperature near the cavity 100a of the mold 100.

If the casting cycle time is slow (step S5 No), the control system I and control system II provided in the fixed mold 200 and the movable mold 300, respectively, are all turned ON (step S9). If the cycle time is slow, the mold 100 is likely to cool during the process of solidifying the molten metal, and the temperature near the cavity 100a of the mold 100 is likely to drop. Therefore, the control system I and control system II provided in the fixed mold 200 and the movable mold 300, respectively, heat the vicinity of the cavity 100a and the outer periphery of the mold 100 so that the temperature near the cavity 100a of the mold 100 and the temperature near the outer periphery of the mold 100 are the same.

In this way, in the mold temperature control method according to the embodiment, the temperature near the cavity 100a of the mold 100 and the outer periphery of the mold 100 are controlled by separate control systems, so that temperature control can be switched appropriately according to the cycle time. Therefore, even if the cycle time is variable, the occurrence of temperature distribution throughout the mold 100 can be suppressed, that is, the temperature of the entire mold 100 can be kept uniform.

<Other embodiments>
In the above-described embodiment, the cavity side heating mechanisms 20, 60 and the outer periphery side heating mechanisms 40, 80 are heaters that heat the fixed mold 200 and the movable mold 300. However, the cavity side heating mechanisms 20, 60 and the outer periphery side heating mechanisms 40, 80 may have any configuration as long as they are capable of heating the mold 100. The cavity side heating mechanisms 20, 60 and the outer periphery side heating mechanisms 40, 80 may be configured to heat the mold 100 by providing a heating path in the fixed mold 200 and the movable mold 300 and conducting a heating medium through the heating path, for example.

In the above-described embodiment, the cavity side heating mechanisms 20, 60 and the outer periphery side heating mechanisms 40, 80 are each controlled by a single control system. However, the cavity side heating mechanisms 20, 60 and the outer periphery side heating mechanisms 40, 80 may each be controlled by two or more control systems. When the cavity side heating mechanisms 20, 60 and the outer periphery side heating mechanisms 40, 80 are each controlled by two or more control systems, the mold temperature can be kept more uniform than when they are controlled by a single control system.

In the above-described embodiment, a case has been described in which one temperature sensor is provided for each control system. However, two or more temperature sensors may be provided for each control system. Providing two or more temperature sensors for each control system makes it possible to measure the mold temperature more accurately and maintain a uniform mold temperature compared to a case in which one temperature sensor is provided for each control system.

Note that this disclosure is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present disclosure.

100 Mold 100a Cavity 200 Fixed mold 300 Movable mold 20, 60 Cavity side heating mechanism 30 Cavity side temperature sensor 40 Outer periphery side heating mechanism 50 Outer periphery side temperature sensor 20a to 20e, 40a to 40f, 60a to 60f, 80a to 80f Heater

Claims (1)

A fixed mold and a movable mold that is combined with the fixed mold to form a cavity,
A mold temperature control method comprising: injecting and filling the cavity with molten metal; and opening the mold after the molten metal has solidified, to remove a molded product,
The fixed die and the movable die are
a cavity side heating mechanism for heating the vicinity of the cavity;
a cavity-side temperature sensor for measuring a temperature in the vicinity of the cavity;
an outer periphery side heating mechanism for heating the vicinity of the outer periphery of the mold;
and an outer periphery side temperature sensor for measuring a temperature in the vicinity of the outer periphery,
When the cycle time of casting is fast, the cavity side heating mechanism is stopped and the outer periphery side heating mechanism is operated, and when the temperature in the vicinity of the cavity becomes lower than a predetermined value, the cavity side heating mechanism is operated;
When the casting cycle time is slow, both the cavity side heating mechanism and the outer periphery side heating mechanism are operated.
Mold temperature control method.

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