KR101066845B1 - Method for controlling temperature in manufacturing mold and dies with thermal spraying - Google Patents

Abstract

The present invention provides a method of manufacturing a thermal spray mold by forming a metal thermal spray layer on a thermal spray pattern having a shape opposite to a desired shape, the process of preheating the thermal spray pattern to a desired temperature and forming a metal thermal spray layer. In maintaining the surface temperature of the metal sprayed layer at a desired temperature, the heating element is accommodated therein so as to be preheated to a desired temperature by placing a spray pattern on a holder configured to be adjustable to a desired temperature, thereby forming a metal sprayed layer. In the process, together with the arc sprayer provides a spray mold manufacturing method characterized in that used as a heat source that can be maintained at a constant temperature to the target surface of the metal spray layer. As described above, the surface temperature distribution of the metal spray layer formed on the thermal spray pattern may be maintained in a constant state, and a larger thermal spray mold may be embodied using the same number of arc thermal sprayers.

Thermal spray mold, holder, heating element, arc sprayer

Description

Temperature control method in the process of manufacturing sprayed molds {METHOD FOR CONTROLLING TEMPERATURE IN MANUFACTURING MOLD AND DIES WITH THERMAL SPRAYING}

The present invention relates to a method for manufacturing a mold using a thermal spray, and more particularly, to a method of preheating a thermal spray pattern and adjusting a surface temperature of a metallic thermal spray layer in a process of forming a metallic thermal spray layer using thermal spraying.

Generally, molds such as plastic injection molding molds, press molds, and die casting molds are manufactured by machining metal materials. As the competition intensifies in recent years, mold users are demanding the rapid supply of molds as much as possible in consideration of early product launch. For this reason, various kinds of high speed mold manufacturing methods have been developed.

One such high speed mold manufacturing method is a metal thermal spraying device. The metal spray device forms a metal spray layer on a material having a shape opposite to a mold to be manufactured (hereinafter, referred to as a “spray pattern”). The metal spray layer is separated from the thermal spray pattern, and the back surface is filled with a material such as epoxy to be used as a mold.

Conventionally, materials such as wood, plastic, synthetic silicon, and the like are used as a thermal spray pattern, and a metal having a low melting point such as zinc or aluminum is used as the metal thermal spray layer. On the other hand, when the metal sprayed layer is made of a material such as steel, the temperature of the metal sprayed layer should be maintained at a high temperature so that the metal sprayed layer hardly deforms during the formation of the metal sprayed layer. However, wood, plastic, and synthetic silicon, which are conventionally used as a thermal spray pattern, cannot withstand the temperature for forming a metal thermal spray layer with little deformation. Thus, a thermal spraying pattern using a ceramic may be manufactured, and a metal spray layer may be formed on the ceramic thermal spraying pattern to produce a metal mold. However, the ceramic thermal spray pattern requires a lot of manufacturing time, and not only defects such as cracks occur, but also dimensional deformation due to shrinkage that occurs during drying or sintering. In molds where dimensional precision is important, dimension deformation in particular degrades the final mold's precision. Because of this, the thermal spraying pattern is made of graphite in place of the ceramic can reduce the manufacturing step of the mold.

On the other hand, the thermal spray pattern should be preheated to an appropriate temperature before the metal thermal spray layer is formed, and should be maintained at a constant temperature during formation of the metal thermal spray layer so that the metal thermal spray layer is not deformed.

First, preheating of the thermal spray pattern is performed by a heating furnace or a heat generating device. In general, the thermal spray pattern is heated to a temperature higher than a preset preheating temperature by using a separate heating furnace, and the thermal spray pattern is placed on the thermal spray pattern holder in a state of being heated to a higher temperature. When the preheat temperature set at this time is reached, a metal spray layer starts to form in a thermal spray pattern. Meanwhile, instead of using the heating furnace as described above, a separate heating device may be used. In the state where the thermal spray pattern is located in the thermal spray pattern holder, the heat generating device heats the upper portion of the thermal spray pattern to reach the predetermined temperature, and then moves to the outside. At this time, the metal spray layer starts to be formed on the thermal spray pattern having a predetermined temperature. However, in the case of using a heating furnace, the thermal spray pattern is difficult to move in a heated state, and there is a risk that damage may occur even if it is moved. In addition, in the case of using the heat generating device, the thermal spraying pattern is troublesome to move the heat generating device after heating.

Next, the method of adjusting the surface temperature of a metal sprayed layer is as follows. An arc sprayer is generally used to form the metal spray layer. When a metal spray layer is formed using an arc sprayer, the metal spray layer requires a heat source to maintain a constant surface temperature. In general, the heat source is a molten metal that reaches the thermal spray pattern from the thermal sprayer. Therefore, the surface temperature of the metal thermal spraying layer is adjusted in accordance with the output of the thermal spraying machine. Specifically, when the surface temperature of the metal sprayed layer is lower than the set temperature, the output of the thermal sprayer is increased to increase the injection amount of the molten metal to increase the surface temperature of the metal sprayed layer. However, the thermal spraying machine does not spray molten metal evenly over the entire surface of the thermal spray pattern, so that the surface temperature difference of the metal thermal spraying layer occurs. If the surface temperature difference of the metal sprayed layer is 50-100 degreeC or more, a metal sprayed layer will bend by heat deformation. In addition, the output of the thermal sprayer is limited, there is a disadvantage that the size of the metal mold using the metal spray layer is also limited.

The present invention is to provide a method for easily maintaining a constant surface temperature distribution of the metal spray layer in the process of forming a metal spray layer on the thermal spray pattern.

In addition, the present invention is to provide a thermal spraying system that can increase the size of the thermal spraying mold can be manufactured using the same number of arc thermal spraying machine.

The present invention is a method for maintaining a constant surface temperature of the metal spray layer of the thermal spraying in order to produce a thermal spraying mold, the preheating is performed by placing a thermal spray pattern on the cradle which can be controlled temperature to start the thermal spraying It provides a temperature control method characterized in that by controlling the output of the thermal sprayer and the temperature of the cradle so that the surface temperature of the metal spray layer can be constantly maintained at the target temperature during the spraying process.

In addition, the present invention comprises the steps of preparing a thermal spray pattern capable of forming a metal thermal spray layer by processing to the opposite shape of the thermal spray mold to be manufactured; Preheating the thermal spray pattern and maintaining a constant temperature of the thermal spray pattern to finally spray the metal to be used as the thermal spray mold on the thermal spray pattern to form the metal thermal spray layer having a predetermined thickness; And separating the metal thermal spraying layer from the thermal spray pattern and using the same or backfilling to form the thermal spray mold, and installing a heating element in the holder on which the thermal spraying pattern is placed, from the heating element. The thermal spray pattern is preheated using the generated heat, and the thermal spraying is performed by adjusting the temperature of the cradle and the output of the arc thermal sprayer, and maintaining the surface temperature of the metal thermal spray layer as set. Disclosed is a temperature control method in a mold manufacturing process.

In addition, the cradle includes a plate on which the thermal spray pattern is supported while closing the heating element, wherein heat generated from the heating element is transferred to the thermal spray pattern through the plate. A temperature control method is disclosed.

In addition, the cradle, the thermocouple for measuring the temperature of the thermal spray pattern between the heating element and the plate; And a temperature controller controlling the heat generated from the heating element in accordance with the temperature measured by the thermocouple, thereby maintaining a constant temperature of the thermal spray pattern. do.

In addition, the temperature control method in the thermal spraying mold manufacturing process, the thermal imaging camera unit measuring the surface temperature of the metal spray layer to measure; Analyzing a surface temperature of the metal thermal sprayed layer measured by the temperature analyzer by the thermal imaging camera; Generating, by the arc sprayer output controller, a signal for controlling the output of the arc sprayer by the surface temperature of the analyzed metal spray layer; And controlling, by the arc sprayer controller, the arc sprayer by a signal output from the arc sprayer output controller to maintain a constant surface temperature of the metal spray layer. Disclosed is a temperature control method in.

In addition, the temperature control method in the thermal spray mold manufacturing process, the temperature control method in the thermal spray mold manufacturing process characterized in that using the thermal spraying pattern made of ceramic or graphite.

According to the temperature control method in the process of manufacturing a thermal spray mold of the present invention, the thermal spray pattern is placed on a holder that can be temperature-controlled to facilitate heating and maintain a constant temperature distribution of the thermal spray pattern and the metal spray layer formed on the thermal spray pattern. In addition, the heating element inside the cradle acts as a heat source of the metal spray layer together with the arc sprayer, thereby forming a larger metal spray layer than the arc sprayer only as a heat source, thereby manufacturing a larger spray mold.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a view showing the spray system 100 used in the temperature control method in the process of manufacturing a spray mold according to a preferred embodiment of the present invention, Figure 2 is a cradle 102 of the thermal spray system 100 shown in FIG. ) Is a cross-sectional view. As shown in FIGS. 1 and 2, the thermal spray system 100 includes a thermal spray pattern 101, a cradle 102, and an arc thermal sprayer 103.

The thermal spray pattern 101 has a shape opposite to that of the final thermal spray mold, and a metal thermal spray layer 111 (shown in FIG. 3) is formed according to the shape. In addition, the thermal spray pattern 101 is made of ceramic or graphite.

The cradle 102 arranges the thermal spray patterns 101 and provides heat to the thermal spray patterns 101 to maintain a constant temperature distribution of the thermal spray patterns 101. In addition, the cradle 102 includes a heating element 121, a plate 123, a thermocouple 125 and a temperature controller (not shown).

The heating element 121 is in a state accommodated in the holder 102, and heat generated therefrom is transferred to the thermal spray pattern 101 to heat the thermal spray pattern 101. Thus, the heating element 121 also heats the metal spray layer 111 formed on the thermal spray pattern 101.

The plate 123 closes the heating element 121 and supports the thermal spray pattern 101 so that the thermal spray pattern 101 is disposed on the holder 102. Meanwhile, heat generated from the heating element 121 is transferred to the thermal spray pattern 101 through the plate 123. Therefore, the metal spray layer 111 may be maintained in a constant temperature distribution state by the heating element 121.

The thermocouple 125 is positioned between the heating element 121 and the plate 123 to measure the temperature of the thermal spray pattern 101.

The temperature control unit maintains a constant temperature distribution of the thermal spray pattern 101 by controlling the heat generated from the heating element 121 according to the temperature measured by the thermocouple 125.

The arc sprayer 103 sprays the metal with the spray pattern 101 disposed on the holder 102 to form the metal spray layer 111 having a predetermined thickness. At this time, the sprayed metal is in a molten state. In addition, the arc sprayer 103 may also be used to maintain a constant temperature distribution of the metal spray layer 111. Specifically, the arc sprayer 103 sprays the metal uniformly melted on the spray pattern 101 or adjusts the output of the arc sprayer 103 to maintain the temperature distribution of the metal spray layer 111 in a constant state. Can be controlled. Meanwhile, the thermal spraying system 100 includes a thermal imaging camera unit 104, a temperature analyzing unit 105, an arc sprayer output control unit 106, and an arc sprayer control unit 107, and includes the arc sprayer 103. The surface temperature of the used metal spray layer 111 can be controlled.

The thermal imaging camera unit 104 detects and measures the surface temperature of the metal thermal spraying layer 111. The temperature analyzer 105 analyzes the surface temperature of the metal spray layer 111 sensed and measured by the thermal imaging camera unit 104. Specifically, the temperature analysis unit 105 analyzes the temperature distribution of the metal sprayed layer 111 and calculates an average temperature.

The arc sprayer output controller 106 generates a signal for controlling the output of the arc sprayer 103 by the surface temperature of the analyzed metal spray layer 111. The arc sprayer controller 107 controls the arc sprayer 103 by a signal output from the arc sprayer output controller 106 to maintain a constant surface temperature distribution of the metal spray layer 111. Therefore, the arc sprayer 103 increases its output when the measured surface temperature of the metal spray layer 111 is lower than the reference value, so that the thermal spraying amount of the molten metal is increased so that the surface temperature of the metal spray layer 111 is increased. Increases. On the other hand, the arc sprayer 103 decreases the output when the measured surface temperature of the metal spray layer 111 is higher than the reference value, thereby increasing the thermal spraying amount of the molten metal to increase the surface temperature of the metal spray layer 111. Decreases. In addition, the arc sprayer 103 is connected to the robot 108, it is possible to spray the molten metal in the sprayed pattern 101 at various locations by the operation of the robot 108.

Meanwhile, in the present invention, using the heating element 121 and the arc sprayer 103 of the cradle 102, the metal spray layer 111 is maintained at a constant temperature distribution to minimize the deformation to form the spray mold 112 Used for Conventionally, the temperature distribution of the metal spray layer 111 was kept constant using only the arc sprayer 103, but in the present invention, the heating element 121 of the holder 102 is also used together with the arc sprayer 103. A wider metal spray layer 111 can be formed. In order to confirm this, the following experiment was conducted.

It is an experiment which forms the 10-mm-thick metal thermal spraying layer 111 which used the graphite flat plate of 300 mm x 300 mm x 30 mm, and the graphite flat plate of 500 mm x 500 mm x 40 mm as the thermal spray pattern 101. FIG. At this time, when forming the metal spray layer 111 in the thermal spray pattern 101 of the same size to check the effect of the heating element 121 of the cradle 102, the output of the arc thermal sprayer 103 was measured, In order to compare the temperature difference of the surface of 111), the temperature was measured using the thermocouple at the point 20 mm from the center and the edge of the thermal spraying pattern 101. In addition, the molten metal used for the thermal spraying was 0.8% carbon steel, four arc thermal sprayers 103 were used, and nitrogen gas was used to spray the molten metal.

Table 1 below shows the temperature difference between the center and the edge of the thermal spray pattern 101 according to the operation of the heating element 121 of the cradle 102 and the output of the arc thermal sprayer 103 according to the present invention. Comparative Examples 1 to 3 used a separate heating device without operating the heating element 121 of the cradle 102, and moved the separate heating device to the outside when the molten metal was sprayed by the thermal spray pattern 101. . On the other hand, Inventive Example 1 and Inventive Example 2 were operated even when spraying the molten metal in the thermal spray pattern (101) of the holder (102). Here, the temperature between the heating element 121 and the plate 123 was maintained at 500 ℃, the maximum output of the arc sprayer 103 is 400 amps.

Whether the heating element of the holder works Size of thermal spray pattern (mm) Temperature difference between the center and the edge of the thermal spray pattern (℃) Average output of arc sprayers (amps) Pressure of gas used to spray (psi) Comparative Example 1 radish 300 × 300 25 210 45 Comparative Example 2 radish 500 × 500 50 340 45 Comparative Example 3 radish 500 × 500 50 320 15 Inventory 1 U 300 × 300 15 160 45 Inventory 2 U 500 × 500 25 230 45

First, when comparing Comparative Example 1 and Inventive Example 1 using a graphite spray pattern of 300 mm × 300 mm, the heating element 121 is used, so that the temperature difference between the center and the edge of the spray pattern 101 is 25 ° C. to 15 ° C. And the average power of the arc sprayer 103 is reduced from 210 amps to 160 amps.

Next, when comparing Comparative Example 2 and Inventive Example 2 using a graphite spray pattern of 500 mm × 500 mm, the heating element 121 is used, whereby the temperature difference between the center and the edge of the spray pattern 101 is 50 ° C. to 25 ° C. And the average power of the arc sprayer 103 is reduced from 340 amps to 230 amps. On the other hand, the maximum output of the arc sprayer 103 used in the experiment is 400 amps. The arc sprayer 103 used in Comparative Example 2 had an output of 340 amps, and approached 400 amperes, which is the maximum output of the arc sprayer 103, the arc sprayer 103 alone had a spray of 500 mm × 500 mm. It can be predicted that the metal spray layer 111 can be formed using the pattern 101. Meanwhile, the sprayed gas injected from the arc sprayer 103 acts as a cooling medium. In Comparative Example 3, the pressure of the sprayed gas was minimized, but the output of the arc sprayer 103 was reduced by only about 20 amps. The effect is minor.

Looking at the comparison as described above, the heating element 121 of the cradle 102 can maintain the surface temperature distribution of the metal spray layer 111 in a constant state by reducing the temperature difference between the center and the edge of the spray pattern 101 have. In addition, when the thermal spray metal layer 111 is formed using the thermal spray pattern 101 having the same size, the output of the low arc thermal sprayer 103 is used. In particular, although the size of the thermal spray pattern 101 used in this experiment is limited to 500 mm x 500 mm, invention example 2 has a margin of about 170 amps to the maximum output of the arc thermal sprayer 103 used for the experiment. In addition, when comparing the comparative example 1 and the invention example 2, although the magnitude | size of the thermal spray pattern 101 of the invention example 2 is larger than the comparative example 1, the temperature difference of the center part and the edge of the thermal spray pattern 101 is the same, and it is for arc The output of fraud 103 is almost similar. Therefore, since the surface temperature of the thermal spraying pattern 101 can be kept constant by the heating element 121 of the holder 102 of the invention example 2, and the output of the arc thermal sprayer 103 can afford, the invention example 2 It is applicable to the thermal spray pattern 101 at least 500 mm x 500 mm or more. That is, the heating element 121 may maintain the surface temperature distribution of the thermal spray pattern 101 in a constant state to maintain a constant temperature distribution of the metal thermal spray layer 111 formed on the thermal spray pattern 101, thereby spraying a mold 112. ) Can be extended or can be manufactured without restrictions.

3 is a view showing a process of manufacturing a thermal spraying mold 112 including a temperature control method according to a preferred embodiment of the present invention. As shown in Figure 3, the process of manufacturing the thermal spraying mold 112 according to a preferred embodiment of the present invention is as follows.

A step (S1) of manufacturing a thermal spray pattern 101 having a shape opposite to that of the thermal spray mold 112 to be formed and on which a metal thermal spray layer 111 is formed is performed. At this time, the thermal spray pattern 101 is made of ceramic or graphite.

While the spray pattern 101 is heated and maintains a constant temperature distribution, a step (S2) is performed in which a metal spray layer 111 is formed by spraying a metal to be used as the spray mold 112. At this time, the thermal spraying system 100 shown in Figs. 1 and 2 is used. As the metal sprayed layer 111 is used for the thermal spraying die 112, the size of the thermal spraying die 112 is determined according to the size of the metal thermal spraying layer 111, and the heating element of the thermal spraying system 100 of the present invention ( 121) and the arc thermal sprayer 103 determines the size of the metal thermal spraying layer 111 and has a constant temperature distribution as set by the metal thermal spraying layer 111.

A step S3 of separating the metal spray layer 111 formed on the thermal spray pattern 101 from the thermal spray pattern 101 is performed.

Step S4 is performed in which the thermal spraying mold 112 is formed by using the metal thermal spraying layer 111 separated from the thermal spraying pattern 101 or performing back peeling. For this reason, the thermal spraying die 112 generally uses the shape according to the surface of the metal thermal spraying layer 111 which contacted the thermal spraying pattern 101.

While the present invention has been described in connection with certain exemplary embodiments, it will be understood by those skilled in the art that various changes may be made without departing from the scope of the present invention.

1 is a view showing a spray system used in the temperature control method in the process of manufacturing a spray mold according to a preferred embodiment of the present invention.

2 is a cross-sectional view showing a cradle of the thermal spray system shown in FIG.

3 is a view showing a process of manufacturing a thermal spraying mold including a temperature control method according to a preferred embodiment of the present invention.

Claims (5)

Manufacturing a thermal spray pattern capable of forming a metal thermal spray layer by processing the opposite shape of the thermal spray mold to be manufactured; Positioning the thermal spray pattern on a holder (a heating element is installed inside the holder); Preheating the thermal spray pattern with heat generated from the heating element; By spraying the metal to be used as the thermal spraying die with the arc spraying pattern to form the metal spraying layer having a predetermined thickness, while forming the metal spraying layer, the heat generated from the heating element and the output of the arc spraying machine are controlled. To maintain a constant surface temperature of the metal spray layer; And And separating the metal thermal spray layer from the thermal spray pattern. The method of claim 1, wherein the cradle, While closing the heating element, including a plate on which the thermal spray pattern is supported, Heat generated from the heating element is a temperature control method in the thermal spraying mold manufacturing process, characterized in that transferred to the thermal spray pattern through the plate. The method of claim 2, wherein the cradle, A thermocouple measuring a temperature of the thermal spray pattern between the heating element and the plate; And And a temperature control unit for controlling the heat generated from the heating element according to the temperature measured by the thermocouple to maintain a constant temperature of the thermal spray pattern. The method of claim 1, wherein the temperature control method in the thermal spray mold manufacturing process, A thermal imaging camera unit detecting and measuring a surface temperature of the metal spray layer; Analyzing a surface temperature of the metal thermal sprayed layer measured by the temperature analyzer by the thermal imaging camera; Generating, by the arc sprayer output controller, a signal for controlling the output of the arc sprayer by the surface temperature of the analyzed metal spray layer; And And controlling the arc sprayer by a signal output from the arc sprayer output control unit to maintain a constant surface temperature of the metal spray layer. Temperature control method. The method of claim 1, wherein the temperature control method in the thermal spray mold manufacturing process, Method of controlling the temperature in the thermal spray mold manufacturing process, characterized in that using the thermal spraying pattern made of ceramic or graphite.

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