JP7575259B2 - Apparatus and method for evaluating die-casting release agents or lubricants - Google Patents

Description

The present invention relates to an evaluation device and evaluation method for die casting release agents or lubricants.

One example of such an evaluation device for die-casting release agents or lubricants is disclosed in Patent Document 1. The evaluation device for die-casting release agents or lubricants disclosed in Patent Document 1 applies a release agent or lubricant to the flat surface of a heated metal block, and places the metal block on the cylindrical metal block so as to close the bottom end of the metal block. Molten aluminum is poured into the metal block, and the molten aluminum is actually solidified to form an aluminum casting. After the molten aluminum has solidified, the metal block is pulled, and the tensile force is measured when the metal block and the aluminum casting inside it begin to move on the flat surface of the metal block. The releasability of the release agent or lubricant is evaluated based on the measured tensile force.

JP 2005-009971 A

The present inventors have discovered the following problems.
In addition to the mold releasability, the release agent or lubricant has, for example, a heat transfer property from the release agent or lubricant to the die. With such an evaluation device for die casting release agents or lubricants, it was not possible to evaluate the heat transfer property from the release agent or lubricant to the die.

In view of the above-mentioned problems, the present invention aims to provide an evaluation device and evaluation method for die-casting release agents or lubricants that can evaluate the releasability and heat transferability to a die.

The evaluation device for a die casting release agent or lubricant according to the present invention is
A metal block;
A cylindrical portion;
A force measuring unit;
A die casting release agent or lubricant evaluation device comprising:
The metal block has a release surface to which a release agent or lubricant is applied,
the cylindrical portion is placed on the release surface of the metal block so as to close a lower end of the cylindrical portion,
The force measuring unit measures a pushing force or a pulling force when the tubular portion is pushed out or pulled after pouring molten metal into the inside of the tubular portion and solidifying the molten metal to form a solidified piece,
The temperature measuring unit measures the temperature of the lower part of the metal block at one point in time from when the solidified piece is formed to when the cylindrical portion is pushed out or pulled.

With this configuration, the heat transferability to the die can be evaluated based on the temperature of the lower part of the metal block. Also, the releasability of the die-casting release agent or lubricant can be evaluated based on the pushing force or pulling force. Therefore, the releasability and the heat transferability to the die can be evaluated.

The temperature measuring unit may also be characterized by having a thermoelectric element in contact with the lower part of the metal block and a cooling block in contact with the thermoelectric element.

This configuration allows the temperature of a specific area at the bottom of the metal block to be measured. This makes it possible to evaluate the heat transfer to the mold with high accuracy.

The cooling block may also be cooled so that the temperature difference between the metal block and the cooling block is 50°C or more.

With this configuration, the temperature difference between the metal block and the cooling block is sufficient, increasing the power generated by the thermoelectric element. This allows the temperature of the lower part of the metal block to be measured stably.

The method for evaluating a die casting release agent or lubricant according to the present invention includes the steps of:
a step of applying a release agent or a lubricant to a release surface of a metal block, placing a cylindrical portion on the release surface of the metal block so as to close a lower end of the cylindrical portion, pouring molten metal into the inside of the cylindrical portion and solidifying it to form a solidified piece, and then measuring a pushing force or a pulling force when the cylindrical portion is pushed out or pulled;
and measuring the temperature of the lower part of the metal block at a point in time between when the solidified piece is formed and when the tubular portion is pushed out or pulled.

With this configuration, the heat transferability to the die can be evaluated based on the temperature of the lower part of the metal block. Also, the releasability of the die-casting release agent or lubricant can be evaluated based on the pushing force or pulling force. Therefore, the releasability and the heat transferability to the die can be evaluated.

Further, in the step of measuring the temperature of the lower part of the metal block at one time point from the time point when the solidified piece is formed to the time point when the cylindrical part is pushed out or pulled,
The thermoelectric element may be in contact with a lower portion of the metal block, and the cooling block may be cooled while the cooling block is in contact with the thermoelectric element so that the temperature difference between the lower portion of the metal block and the cooling block is 50° C. or more.

With this configuration, the temperature difference between the metal block and the cooling block is sufficient, increasing the power generated by the thermoelectric element. This allows the temperature of the lower part of the metal block to be measured stably.

The present invention provides an evaluation device and evaluation method for die-casting release agents or lubricants that can evaluate their releasability and heat transfer to a die.

FIG. 1 is a schematic diagram showing an evaluation device according to a first embodiment. 4 is a flowchart showing a method for evaluating a release agent using the evaluation device according to the first embodiment. 1 is a schematic diagram showing a main part of a specific example of an evaluation device according to a first embodiment; 1 is a partially cutaway cross-sectional view showing a main part of a specific example of an evaluation device according to a first embodiment. 11 is a partially cutaway cross-sectional view showing a main part of another specific example of the evaluation device according to the first embodiment. FIG. 11 is a partially cutaway cross-sectional view showing a main part of another specific example of the evaluation device according to the first embodiment. FIG. 1 is a graph showing tensile force versus generated voltage. 1 is a photograph showing the bottom surface of an example of a solidified piece.

Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments. In addition, the following descriptions and drawings have been simplified as appropriate for clarity of explanation.

(Embodiment 1)
A first embodiment will be described with reference to Fig. 1. It should be noted that the right-handed XYZ coordinate system shown in Fig. 1 and other drawings is, of course, for the sake of convenience in explaining the positional relationship of components. Normally, the positive direction of the Z axis is vertically upward, and the XY plane is a horizontal plane, which is common among the drawings.

As shown in FIG. 1, the evaluation device 10 includes a metal block 1, a cylindrical portion 2, a hot water supply guide 3, a tensile force measuring device 4, and a temperature measuring unit 5.

The metal block 1 is a block made of a metal material. For example, a die-casting mold material for which a release agent is expected to be used can be used as such a metal material. The metal block 1 has main surfaces 1a and 1b. The main surface 1a is preferably a flat surface facing upward (here, the positive side of the Z axis). The main surface 1a may also be referred to as a release surface. The main surface 1b is preferably a flat surface facing downward (here, the negative side of the Z axis).

The cylindrical portion 2 is, for example, a cylinder. An eyebolt 4a is fastened to the outer circumferential surface of the cylindrical portion 2. The cylindrical portion 2 is mechanically connected to the tensile force measuring device 4 via the eyebolt 4a.

The hot water supply guide 3 is a cylindrical body having an inlet 3a and an outlet 3b. The outlet 3b has a smaller diameter than the inlet 3a. The hot water supply guide 3 is arranged so as to be positionable above the cylindrical portion 2.

The tensile force measuring device 4 includes, for example, a drive source and a force sensor (not shown). The force sensor is, for example, a load cell. The drive source pulls the cylindrical portion 2 via the force sensor and the eye bolt 4a. The force sensor receives pressure and generates a signal indicating the tensile force.

The temperature measuring unit 5 is provided below the metal block 1. Furthermore, when the temperature measuring unit 5 is positioned below the cylindrical portion 2, it may be able to measure the temperature of a portion of the metal block 1 at a position close to the solidified piece SL1. The temperature measuring unit 5 may be any device that measures a signal indicating temperature or a temperature difference, such as a thermocouple or a thermoelectric element. The temperature measuring unit 5 may be equipped with a processing device that performs an amplification process on the signal indicating the temperature or the temperature difference, as appropriate.

(Evaluation Method)
Next, a method for evaluating a release agent will be described with reference to Fig. 2. Fig. 2 is a flow chart showing a method for evaluating a release agent using the evaluation device 10 shown in Fig. 1.

The release agent is applied to the main surface 1a of the metal block 1 (release agent application step ST1). A film of the release agent is formed on the main surface 1a of the metal block 1. The application conditions, such as the application method and the temperature of the metal block 1, may be set to the same conditions as those of the release agent and the mold used in die casting. For example, the release agent may be applied to the main surface 1a using a spray, or the temperature of the metal block 1 may be adjusted to be the same as that of the mold. Furthermore, measurement of the temperature of the lower part of the metal block 1 may be started before the start of this step. The lower part of the metal block 1 may be any part of the metal block 1 that is located below the main surface 1a.

Next, the cylindrical portion 2 is placed on the main surface 1a of the metal block 1 (cylindrical portion placing step ST2). The space between the lower end of the cylindrical portion 2 and the main surface 1a of the metal block 1 is blocked.

Then, the molten metal is passed through the molten metal guide 3 and poured into the inside of the cylindrical portion 2 (molten metal supply step ST3). The molten metal is preferably a molten alloy used in die casting. The die casting alloy is, for example, an aluminum alloy or a magnesium alloy. Since the gap between the lower end of the cylindrical portion 2 and the main surface 1a of the metal block 1 is blocked, the molten metal remains inside the cylindrical portion 2 and hardly flows outside the cylindrical portion 2.

The molten metal is then solidified to form solidified piece SL1 (solidified piece formation step ST4). The metal block 1 and the cylindrical portion 2 cool the molten metal, and the shapes of the metal block 1 and the cylindrical portion 2 are transferred to the solidified piece SL1. The metal block 1 and the cylindrical portion 2 correspond to the die-casting mold, and the solidified piece SL1 corresponds to the die-casting casting.

Finally, the temperature measuring unit 5 measures the temperature of the lower part of the metal block 1 while the tensile force measuring device 4 measures the tensile force (temperature and tensile force measuring step ST5). Specifically, the tensile force measuring device 4 may pull the solidified piece SL1 until it separates from the main surface 1a and measure the tensile force. The tensile force measuring device 4 may measure the tensile force while a predetermined load is applied to the solidified piece SL1 by placing a weight on the solidified piece SL1, for example. The load on the solidified piece SL1 may be set in consideration of the molten metal pressure in die casting. In addition, the temperature of the lower part of the metal block 1 may be measured at least at one time point from the time when the solidified piece SL1 is formed to the time when the cylindrical part 2 is pulled. The heat transferability from the mold release agent to the mold is evaluated based on the measured value of the temperature of the lower part of the metal block 1. The measured value of the temperature of the lower part of the metal block 1 at one time point from the time when the solidified piece SL1 is formed to the time when the cylindrical part 2 is pulled may be used as the measured value of the temperature of the lower part of the metal block 1.

From the above, it is possible to evaluate the heat transferability to the die based on the temperature of the lower part of the metal block 1 measured by the temperature measuring unit 5. In addition, it is possible to evaluate the releasability of the die-casting release agent or lubricant based on the tensile force measured by the tensile force measuring device 4. Therefore, it is possible to evaluate the releasability and the heat transferability to the die.

(Specific examples)
Next, specific examples of the evaluation device 10 will be described with reference to Figures 3 to 6. Each of the specific examples of the evaluation device 10 shown in Figures 3 to 6 has the same configuration as the specific example shown in Figure 1, except for the temperature measurement unit 5.

(First Specific Example)
3 and 4 includes one thermocouple 5a, which is one specific example of the temperature measurement unit 5. The one thermocouple 5a is inserted into one hole 1c provided in the main surface 1b of the metal block 1. With this configuration, the one specific example of the temperature measurement unit 5 shown in Fig. 3 and 4 can measure the temperature of one portion located in the lower part of the metal block 1 and below the solidified piece SL1, thereby measuring the temperature of the lower part of the metal block 1.

(Second Specific Example)
5 includes a plurality of thermocouples 5b, which are a specific example of the temperature measuring unit 5. The plurality of thermocouples 5b are inserted into a plurality of holes 1d provided in the main surface 1b of the metal block 1. With this configuration, the specific example of the evaluation device 10 shown in FIG. 5 can measure the temperature of the lower part of the metal block 1 by measuring the temperatures of a plurality of locations located in the lower part of the metal block 1 and below the solidified piece SL1.

As shown in FIG. 8, there is solidified piece SL2, which is a specific example of solidified piece SL1. Solidified piece SL2 is formed by solidifying molten metal made of an aluminum alloy. Gas pockets SL2b, SL2b, SL2b, SL2b, SL2b, were confirmed on the underside SL2a of solidified piece SL2. It is presumed that gas pockets SL2b are gases generated from the release agent that have accumulated on the underside SL2a of solidified piece SL2. Gas pockets SL2b and the area corresponding to the main surface 1a of metal block 1 do not come into contact with each other because of the cavity created by gas pocket SL2b.

The specific example of the temperature measurement unit 5 shown in FIG. 5 has more parts for measuring temperature compared to the specific example of the temperature measurement unit 5 shown in FIG. 3 and FIG. 4. Therefore, when a large amount of gas accumulates on the underside of the solidified piece, similar to the solidified piece SL2, the specific example of the temperature measurement unit 5 shown in FIG. 5 can measure the temperature of the lower part of the metal block 1 with better accuracy compared to the specific example of the temperature measurement unit 5 shown in FIG. 3 and FIG. 4.

(Third Specific Example)
A specific example of the evaluation device 10 shown in FIG. 6 includes a thermoelectric element 5 c which is a specific example of the temperature measuring unit 5 , and a cooling block 6 .

Thermoelectric element 5c is, for example, a Seebeck element. The thermoelectric element 5c is connected to an electric circuit including a voltmeter, etc.

The cooling block 6 includes a main body 6a and a flow path 6b. The main body 6a may be provided so as to be capable of thermal conduction with the thermoelectric element 5c. The main body 6a is provided, for example, so as to be in close contact with the thermoelectric element 5c. The flow path 6b is connected to a cooling device (not shown) so as to be able to supply and discharge a cooling medium. The cooling device cools the cooling medium and supplies it to the flow path 6b. After the cooling medium removes heat from the main body 6a in the flow path 6b, it is discharged from the flow path 6b and returns to the cooling device. By performing these steps continuously, the cooling block 6 and the thermoelectric element 5c can be cooled.

The thermoelectric element 5c generates a voltage according to the temperature difference between the metal block 1 and the cooling block 6. It is preferable that the temperature difference between the metal block 1 and the cooling block 6 is 50°C or more, because this allows the thermoelectric element 5c to generate a sufficiently large voltage. The cooling block 6 is preferably cooled so that its temperature is 50°C or less than the temperature of the metal block 1. The voltage generated by the thermoelectric element 5c is measured using a voltmeter or the like, and the temperature of the lower part of the metal block 1 can be calculated based on this measured voltage.

In addition, the specific example of the evaluation device 10 shown in FIG. 6 can measure the temperature of a predetermined area on the underside of the solidified piece SL1. Therefore, the specific example of the evaluation device 10 shown in FIG. 6 can directly measure the temperature of the predetermined area itself on the underside of the solidified piece SL1, compared to the specific example of the evaluation device 10 shown in FIGS. 3 to 5. Since the specific example of the evaluation device 10 shown in FIG. 6 does not need to provide holes 1c and 1d at the bottom of the metal block 1, the heat transfer in the metal block 1 is more stable than the specific example of the evaluation device 10 shown in FIGS. 3 to 5. As a result, the specific example of the evaluation device 10 shown in FIG. 6 can measure the temperature of the bottom of the metal block 1 with better accuracy than the specific example of the evaluation device 10 shown in FIGS. 3 to 5.

(Example of evaluation results)
Next, an example of the evaluation results of the release agent using the above-mentioned evaluation method will be described with reference to FIG.

In the above-mentioned evaluation method, a specific example of the evaluation device 10 shown in FIG. 6 was used. In the above-mentioned evaluation method, a total of three types of oil-based release agents L1, L2, and L3 were evaluated. The application conditions of the release agents, the temperature conditions of the metal block, etc. were the same for all of them. The tensile force and the generated voltage were measured, and the results are shown in FIG. 7. This measured tensile force corresponds to the release resistance force.

As shown in FIG. 7, the measured tensile force of the oil-based release agent L1 and the measured tensile force of the oil-based release agent L2 are approximately the same value. Therefore, the film made of the oil-based release agent L2 has the same degree of releasability as the film made of the oil-based release agent L1, and is therefore excellent.

On the other hand, as shown in FIG. 7, the measured value of the generated voltage of the oil-based release agent L2 is higher than the measured value of the generated voltage of the oil-based release agent L1. Therefore, the film of the oil-based release agent L2 has better heat transfer to the mold than the film of the oil-based release agent L1. Therefore, the thickness of the film of the oil-based release agent L2 is considered to be thinner than the thickness of the film of the oil-based release agent L1. From the above, it is presumed that the oil-based release agent L2 has better heat transfer to the mold than the oil-based release agent L1 while having the same degree of release properties, and is therefore superior for actual casting.

As shown in FIG. 7, the measured tensile force of oil-based release agent L3 is higher than the measured tensile force of oil-based release agents L1 and L2. Therefore, the film made of oil-based release agent L3 has poor releasability compared to the films made of oil-based release agents L1 and L2.

As shown in FIG. 7, the measured voltage generated by the oil-based release agent L3 is higher than the measured voltage generated by the oil-based release agents L1 and L2. Therefore, the thickness of the film formed by the oil-based release agent L3 is considered to be thinner than the thickness of the films formed by the oil-based release agents L1 and L2.

Here, the releasability is affected not only by the performance of the film itself but also by the thickness of the film. One of the reasons why the releasability of the film made by the oil-based release agent L3 was low is thought to be that the film made by the oil-based release agent L3 was too thin, not the performance of the film itself. If the film made by the oil-based release agent L3 is too thin, it is thought that there is a major problem with the application of the oil-based release agent L3. Therefore, it is thought that by optimizing the application conditions of the oil-based release agent L3, the thickness of the film made by the oil-based release agent L3 can be increased, and as a result, sufficient releasability can be imparted to the film made by the oil-based release agent L3.

The present invention is not limited to the above-mentioned embodiment, and can be modified as appropriate without departing from the spirit of the present invention. The present invention may be implemented by combining the above-mentioned embodiment and examples thereof as appropriate. For example, in the above-mentioned embodiment 1 and its modified examples, the release agent is evaluated, but the lubricant may be evaluated. In the above-mentioned embodiment 1 and its modified examples, the evaluation device 10 includes a tensile force measuring device 4, but in the above-mentioned embodiment 1 and its modified examples, the evaluation device 10 may include a force measuring unit, for example, a push-out force measuring device.

10 Evaluation device 1 Metal block 1a Main surface (release surface) 1b Main surface 1c, 1d Hole 2 Cylindrical portion
3: Hot water supply guide 3a: Inlet 3b: Outlet 4: Tensile force measuring device 5: Temperature measuring section 5a, 5b: Thermocouple 5c: Thermoelectric element 6: Cooling block 6a: Main body 6b: Flow path SL1, SL2: Solidified piece ST1: Release agent application step ST2: Cylindrical part mounting step ST3: Molten metal supply step ST4: Solidified piece formation step ST5: Temperature and tensile force measurement step

Claims (3)

A metal block;
A cylindrical portion;
A force measuring unit;
A die casting release agent or lubricant evaluation device comprising:
The metal block has a release surface to which a release agent or lubricant is applied,
the cylindrical portion is placed on the release surface of the metal block so as to close a lower end of the cylindrical portion,
The force measuring unit pours molten metal into the inside of the cylindrical portion, solidifies the molten metal, and forms a solidified piece. Then, the force measuring unit measures the pushing force when the cylindrical portion is pushed out or the pulling force when the cylindrical portion is pulled until the solidified piece separates from the release surface of the metal block .
The temperature measuring unit measures the temperature of the lower part of the metal block at one time from when the solidified piece is formed to when the cylindrical part is pushed out or pulled,
The temperature measurement unit includes a thermoelectric element in contact with a lower portion of the metal block, and a cooling block in contact with the thermoelectric element .
Apparatus for evaluating die casting release agents or lubricants. The cooling block is cooled so that the temperature difference between the metal block and the cooling block is 50° C. or more.
2. The apparatus for evaluating a die casting release agent or lubricant according to claim 1 . a step of applying a release agent or a lubricant to the release surface of a metal block, placing a cylindrical portion on the release surface of the metal block so as to close the lower end of the cylindrical portion, pouring molten metal into the inside of the cylindrical portion and solidifying it to form a solidified piece, and then measuring a pushing force when pushing out the cylindrical portion or a pulling force when pulling the cylindrical portion until the solidified piece separates from the release surface of the metal block ;
measuring the temperature of the lower part of the metal block at one time from when the solidified piece is formed to when the cylindrical part is pushed out or pulled;
In the step of measuring the temperature of the lower part of the metal block at one time point from when the solidified piece is formed to when the cylindrical part is pushed out or pulled,
a thermoelectric element contacting a lower part of the metal block, and a cooling block being kept in contact with the thermoelectric element, the cooling block being cooled so that a temperature difference between the lower part of the metal block and the cooling block is 50° C. or more;
Evaluation method for die casting release agents or lubricants.

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