MOLD RELEASE AGENT ADHESION STATE EVALUATION METHOD, LUBRICANT ADHESION STATE EVALUATION METHOD, AND MOLD RELEASE AGENT ADHESION STATE EVALUATION SYSTEM

Description

RELATED APPLICATIONS

This application is a US National Stage, filed under 35 U.S.C. § 371, of International Application PCT/JP2023/029057, filed Aug. 9, 2023, and claims priority to Japanese Patent Application No. 2022-158330; the entirety of the above listed applications is incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a mold release agent adhesion state evaluation method, a lubricant adhesion state evaluation method, and a mold release agent adhesion state evaluation system.

BACKGROUND ART

Techniques for measuring a coating amount of a mold release agent have been disclosed (for example, Patent Literatures 1, 2, and 3).

SUMMARY

In performing machining using a mold such as casting or plastic working, it is important to cause a liquid (machining liquid) used for machining, such as a mold release agent or a lubricant, to adhere uniformly and evenly. For example, to ensure good productivity and enhance quality of cast products in die casting, it is required to evaluate an adhesion state of a mold release agent adhering to a mold as accurately and simply as possible. It is therefore an object of embodiments the present disclosure to provide a machining liquid adhesion state evaluation method and a machining liquid adhesion state evaluation system both capable of evaluating an adhesion state of a machining liquid adhering to a mold accurately and simply.

A mold release agent adhesion state evaluation method according to embodiments of the present disclosure is an evaluation method for an adhesion state of a mold release agent used for die casting and adhering to a mold, and includes: heating the mold; causing the mold release agent to adhere to a surface of the heated mold; acquiring an image data of appearance of the surface of the mold to which the mold release agent adheres; deriving an adhesion state of the mold release agent to the surface of the mold from color quantification information corresponding to the acquired image data of appearance, based on a correlation between previously acquired color quantification information and the adhesion state of the mold release agent; and outputting data concerning the derived adhesion state of the mold release agent. An evaluation method and an evaluation system according to embodiments of the present disclosure are also applicable to evaluation of an adhesion state of a lubricant for plastic working to a mold.

The mold release agent adhesion state evaluation method described in embodiments of present disclosure can evaluate an adhesion state of a mold release agent adhering to a mold accurately and simply.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating a portion of a die casting device for use in a mold release agent adhesion state evaluation method according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a mold release agent adhesion state evaluation system according to the present invention.

FIG. 3 is a schematic cross-sectional view illustrating a state where a mold release agent is caused to adhere.

FIG. 4 is a flowchart showing typical process steps in the mold release agent adhesion state evaluation method according to the first embodiment.

FIG. 5 is a schematic cross-sectional view illustrating a state where an image of a surface of a fixed mold and a surface of a movable mold is captured.

FIG. 6 is an image obtained by superimposing appearance image data on a three-dimensional image formed from a captured image, as an example of a captured image.

FIG. 7 is a graph showing a relationship between thickness and color quantification information.

FIG. 8 is a schematic view illustrating a state of thickness distribution of a mold release agent adhering to a surface of a movable mold.

DESCRIPTION

An evaluation method according to the present disclosure can evaluate an adhesion state of a machining liquid such as a mold release agent or a lubricant to be used by causing the machining liquid to adhere to a mold. A mold release agent adhesion state evaluation method according to the present disclosure is an evaluation method for an adhesion state of a mold release agent used for die casting and adhering to a mold, and the method includes: heating the mold; causing the mold release agent to adhere to a surface of the heated mold; acquiring an image data of appearance of the surface of the mold to which the mold release agent adheres; deriving an adhesion state of the mold release agent to the surface of the mold from color quantification information corresponding to the acquired image data of appearance, based on a correlation between previously acquired color quantification information and the adhesion state of the mold release agent; and outputting data concerning the derived adhesion state of the mold release agent. In addition, when the adhesion state of a lubricant applied to a mold for plastic processing was evaluated using the evaluation method according to the present disclosure, it was possible to evaluate the adhesion state of the lubricant in a similar manner and display the distribution of the adhesion state. The lubricants evaluated here are lubricants for plastic working that form a visible coating when applied to a mold.

In die casting, a molten metal is poured into a cavity formed by combining molds heated to a predetermined temperature and molded, and then, a product is removed from the combined molds, thereby producing a cast product. A mold release agent is applied to adhere to a surface of a mold by a method such as coating, spraying, or discharging in order to produce a cast product precisely with prevention of seizing between a molten metal and the mold and to smoothly remove the cast product from the mold. If the adhesion amount of the mold release agent is excessively large, the surface of the cast product might be colored or quality might degrade by vaporization of a component of the mold release agent or other reasons. If the adhesion amount of the mold release agent is excessively small or the adhesion amount of the mold release agent to the surface of the mold is uneven, precise manufacturing of cast products might be inhibited or removal of the mold from the cast products might be difficult. For these reasons, it is required to cause an appropriate amount of the mold release agent to adhere to the surface of the mold as uniformly as possible.

Here, it is important to grasp the adhesion state of the mold release agent, that is, whether or not an appropriate amount of the mold release agent uniformly adheres to the surface of the mold, from the viewpoint of good productivity and enhancement of quality of cast products. It is difficult to measure the thickness of an adhering mold release agent by visual observation or the like and to grasp the adhesion state of the mold release agent because the thickness is very thin and the color of mold release agents used to date is generally transparent as well as the mold is basically black. In particular, in a case where the mold has a complicated shape, it is not easy to check whether or not the mold release agent adheres to every corner. Further, in a case where the color of a coating cannot be distinguished from the color of the mold, it is also difficult to grasp the adhesion state of the mold release agent.

In conventional techniques, a coating formed by applying a mold release agent to a mold is transparent and cannot be visually recognized, and thus, the adhesion state of the mold release agent is grasped by mixing a fluorescent agent in the mold release agent and irradiating the resulting mixture with ultraviolet rays to observe excited fluorescence, grasped by tactile sensation using a mold release agent incorporating powder, or grasped by measuring an emissivity.

However, with these techniques, since a substance other than the mold release agent component is mixed in the mold release agent, the mold release agent may exhibit an adhesion behavior different from that of the original mold release agent, and it is difficult to strictly grasp the adhesion state of the mold release agent. In addition, if a substance for measuring the thickness remains on the mold after the measurement, the substance might cause a problem, and thus, the mold needs to be sufficiently cleaned.

Embodiments of the present disclosure relate to a mold release agent for a die casting mold with high releasability and high heat resistance. This mold release agent includes a solvent and an organic acid salt and has a property of forming a white coating when applied to a mold. A mold release agent adhesion state evaluation method according to the present disclosure is suitably applicable to a mold release agent that can be visually recognized after application. This mold release agent does not require any foreign substance to be mixed in order to measure the thickness, and the adhesion state of the mold release agent itself can be evaluated. For example, in a case where the mold release agent includes an organic acid salt, when the mold release agent is applied to a mold, the solvent evaporates so that a white coating is thereby formed on the surface of the mold. Such a white coating has excellent visibility, and a remaining portion of the mold release agent can be easily recognized from the appearance of the mold. In this case, when image data of appearance of the surface of the mold is acquired, the adhesion state of the mold release agent can be easily derived through the step of driving the adhesion state of the mold release agent from color quantification information corresponding to the acquired image data of appearance, based on a correlation between the previously obtained color quantification information and the adhesion state of the mold release agent. Then, data concerning the derived adhesion state of the mold release agent is output, and the adhesion state of the mold release agent adhering to the surface of the mold can be accurately evaluated. In this method, the mold release agent is used without mixing any additives into the mold release agent, and thus, handling of the mold release agent is simplified. Thus, this mold release agent adhesion state evaluation method can evaluate an adhesion state of a mold release agent adhering to a mold accurately and simply. Although the mold release agent including the solvent and the organic acid salt is mentioned as an example in the above description, the present disclosure is applicable without limitation as long as a machining liquid such as a mold release agent or a lubricant that forms a visible coating after application is used.

In the mold release agent adhesion state evaluation method, the step of acquiring the image may include the step of acquiring a three-dimensional image of the mold to which the mold release agent adheres. Many molds for die casting have complicated shapes, specifically have a large number of uneven shapes and large undulations, for example. For such a mold, a three-dimensional image of the mold is acquired so that information on a more desirable adhesion state of the mold release agent can be thereby obtained. Specifically, for example, it is possible to easily grasp whether or not the mold release agent reliably adheres to the inner part of the mold with a complicated shape, whether or not the mold release agent is accumulated in detail while die casting is repeated multiple times, or the like. This enables more accurate evaluation of the adhesion state of the mold release agent.

In the mold release agent adhesion state evaluation method, the image data of appearance may include a color image. With this method, the adhesion state of the mold release agent can be derived in consideration of information on the color image. This enables more accurate evaluation of the adhesion state of the mold release agent.

In the mold release agent adhesion state evaluation method, the data concerning the adhesion state of the mold release agent may be data corresponding to a thickness of the mold release agent. With this method, the adhesion amount of the mold release agent, that is, the thickness of the mold release agent, can be precisely derived. This enables more accurate evaluation of the adhesion state of the mold release agent.

In the mold release agent adhesion state evaluation method, the color quantification information may be lightness, hue, chroma, chromaticity, or color saturation. With this method, the adhesion state of the mold release agent can be derived by utilizing lightness or other information. This enables more accurate evaluation of the adhesion state of the mold release agent.

In the mold release agent adhesion state evaluation method, the step of outputting the data may include the step of displaying the three-dimensional image of the mold and distribution of the adhesion state of the mold release agent in association with each other. With this method, distribution of the adhesion state of the mold release agent can be visually grasped by comparing with the three-dimensional image of the mold. This enables easier evaluation of the adhesion state of the mold release agent.

In the mold release agent adhesion state evaluation method, the step of outputting the data may include the step of generating and outputting image data displayed in different colors depending on a thickness of the mold release agent derived as the adhesion state of the mold release agent. With this method, a difference in thickness due to a difference in color from the generated image can be visually recognized easily. This enables more efficient evaluation of the adhesion state of the mold release agent.

In the mold release agent adhesion state evaluation method, a mold release agent that can be visually recognized after application is suitably used. The mold release agent includes a solvent and an organic acid salt, for example. The solvent may include water and may include a basic compound. The organic acid salt may include a carboxylic acid compound expressed by the following formula (1). In the formula (1), R1 represents an alkanediyl group having a carbon number of 2 or more and 4 or less, a vinylene group, or a benzene group, and x represents 2 or 3. The carboxylic acid compound may include at least one compound selected from the group consisting of succinic acid, adipic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, and trimellitic acid. Such a mold release agent is excellent in releasability, lubricity, and other properties.

Since this mold release agent includes the organic acid salt, the mold release agent can reliably remain as a white coating on the surface of the mold when the solvent evaporates. This further ensures a grasp of a region to which the mold release agent adheres, and enables more accurate evaluation of the adhesion state of the mold release agent.

A lubricant adhesion state evaluation method according to the present disclosure is a lubricant adhesion state evaluation method for a lubricant used for plastic working and adhering to a mold, and includes the steps of: heating the mold; causing the lubricant to adhere to a surface of the heated mold; acquiring an image data of appearance of the surface of the mold to which the lubricant adheres; deriving an adhesion state of the lubricant to the surface of the mold from color quantification information corresponding to the acquired image data of appearance, based on a correlation between previously acquired color quantification information and the adhesion state of the lubricant; and outputting data concerning the derived adhesion state of the lubricant.

The lubricant adhesion state evaluation method described above can evaluate an adhesion state of a lubricant adhering to a mold accurately and simply.

An evaluation system according to the present disclosure can evaluate an adhesion state of a machining liquid such as a mold release agent or a lubricant to be used by causing the machining liquid to adhere to a mold. A mold release agent adhesion state evaluation system according to the present disclosure is a mold release agent adhesion state evaluation system for a mold release agent used for die casting and adhering to a mold. The mold release agent adhesion state evaluation system includes: an image data acquiring unit that acquires image data of appearance of the mold; a deriving unit that derives an adhesion state of the mold release agent to a surface of the mold from color quantification information corresponding to the image data of appearance of the mold acquired by the image data, based on a correlation between previously acquired color quantification information and the adhesion state of the mold release agent; and an output unit that outputs data concerning the adhesion state of the mold release agent derived by the deriving unit. An evaluation of an adhesion state of a lubricant adhering to a mold for plastic working conducted by the evaluation system according to the present disclosure enabled an evaluation of the adhesion state of the lubricant and displayed distribution of the adhesion state. The lubricant used in the evaluation is a lubricant for plastic working that forms a visible coating when applied to a mold.

This mold release agent adhesion state evaluation system can evaluate an adhesion state of a mold release agent adhering to a mold accurately and simply.

In the mold release agent adhesion state evaluation system, the image data acquiring unit may include a 3D scanner. The image data acquiring unit may acquire three-dimensional image data of appearance of the mold by capturing an image by the 3D scanner. The output unit may provide a display by superimposing the adhesion state of the mold release agent on the three-dimensional image of the mold. With this configuration, a three-dimensional adhesion state of the mold release agent can be easily grasped. This enables easier evaluation of the adhesion state of the mold release agent.

A mold release agent for die casting will be specifically described as an example of an embodiment of a machining liquid adhesion state evaluation method and a machining liquid adhesion state evaluation system according to the present disclosure with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

First Embodiment

First, an overview of a die casting device for use in a mold release agent adhesion state evaluation method and a mold release agent adhesion state evaluation system according to a first embodiment of the present disclosure will be briefly described. FIG. 1 is a schematic cross-sectional view illustrating a portion of the die casting device for use in the mold release agent adhesion state evaluation method according to the first embodiment of the present. FIG. 1 shows a state where molds described later are opened. FIG. 2 is a block diagram illustrating a configuration of a mold release agent adhesion state evaluation system according to the present disclosure. The system may be integrated as one device or may be configured by combining a plurality of devices. An evaluation system 51 and a die casting device 11 may be integrated.

Description will be given with reference to FIGS. 1 and 2. The mold release agent adhesion state evaluation system 51 according to the present disclosure is used together with the die casting device 11 illustrated in FIG. 1, and includes an image data acquiring unit 28, a deriving unit 53, and an output unit 54. The image data acquiring unit 28 acquires image data of appearance of a mold described later. The deriving unit 53 derives an adhesion state of a mold release agent to a surface of the mold from color quantification information corresponding to the image data of appearance of the mold acquired by the image data acquiring unit 28, based on a correlation between previously acquired color quantification information and an adhesion state of the mold release agent. The output unit 54 outputs data concerning the adhesion state of the mold release agent derived by the deriving unit 53. The configuration of these components will be described later.

The die casting device 11 includes a fixed mold 13, a movable mold 14, an injection sleeve 15, and an injection piston 16. The fixed mold 13 is fixed. On the other hand, the movable mold 14 is movable relative to the fixed mold 13. A direction of movement of the movable mold 14 is a direction indicated by arrow D or the opposite direction. When the fixed mold 13 and the movable mold 14 are brought into contact with each other, a cavity 17 is formed. The injection sleeve 15 has a hollow tubular shape, is located in the fixed mold 13, and has its open end communicate with the cavity 17. The injection sleeve 15 has an injection port 18 through which a molten metal is injected into the injection sleeve 15. The injection port 18 penetrates the injection sleeve 15 in the radial direction thereof. Through the injection port 18, the molten metal, that is, a metal such as molten aluminum, is injected into the injection sleeve 15. Although a surface 25 of the fixed mold 13 and a surface 26 of the movable mold 14 are illustrated in a simplified manner for ease of understanding, specifically, a complex uneven shape is formed on the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14.

The injection piston 16 injects the molten metal into the mold, specifically the cavity 17 formed by bringing the fixed mold 13 and the movable mold 14 into contact with each other through the injection sleeve 15. The direction in which the molten metal is injected is a direction indicated by arrow D in FIG. 1. The injection piston 16 includes a plunger chip 21 and an injection rod 22. The plunger chip 21 is located in the injection sleeve 15 and is brought into contact with the molten metal to push the molten metal into the cavity 17. The injection rod 22 includes a portion coupled to the plunger chip 21 and projects to the outside of the injection sleeve 15. Application of a lubricant to an inner wall surface 19 of the injection sleeve 15 reduces friction between an outer diameter surface 24 of the plunger chip 21 and the inner wall surface 19 of the injection sleeve 15 in pushing the plunger chip 21, and smoothly moves the plunger chip 21.

Next, process steps in fabricating a cast product using the die casting device 11 will be briefly described. First, the fixed mold 13 and the movable mold 14 are heated to a predetermined temperature beforehand, and then, the movable mold 14 is moved in the direction of arrow D in FIG. 1 so that the fixed mold 13 and the movable mold 14 are opened as illustrated in FIG. 1. Then, a mold release agent is applied to adhere to the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14. FIG. 3 is a schematic cross-sectional view illustrating a state where a mold release agent is caused to adhere. Referring also to FIG. 3, in causing the mold release agent to adhere to the surface 25 and the surface 26, a mold release agent discharging member 27 that discharges the mold release agent is used. The mold release agent discharging member 27 is of a spray type, and is configured to discharge the mold release agent to the surface 25 and the surface 26 from a discharge port. The mold release agent is discharged from the mold release agent discharging member 27 and adheres to the entire surfaces 25 and 26.

Thereafter, the movable mold 14 is moved in the opposite direction to arrow D to be set in a closed state. Subsequently, the injection rod 22 is moved in the direction of arrow D. Then, the molten metal in the injection sleeve 15 is pushed out from the injection sleeve 15 to fill the cavity 17. This state is kept for a predetermined time so that the molten metal is solidified. Thereafter, the movable mold 14 is moved in the direction of arrow D to be set in a state where the molds are opened. Then, a cast product attached to the fixed mold 13 or the movable mold 14 is removed. In this manner, a product as a cast product is obtained. In this case, since the mold release agent adheres to the surface 25 and the surface 26, the cast product can be easily removed. Thereafter, the mold release agent is applied to adhere to the surface 25 and the surface 26 again, and a similar cast product is produced.

Here, the mold release agent used in this example will be described. As an example, the mold release agent includes a solvent and an organic acid salt. In this embodiment, the solvent is water. The mold release agent may include a basic compound. In this embodiment, the mold release agent includes water, adipic acid, terephthalic acid, and sodium hydroxide.

In production of a cast product using the die casting device 11 as described above, it is significantly important to grasp an adhesion state of the mold release agent to the mold accurately and simply. A mold release agent adhesion state evaluation method will now be described. FIG. 4 is a flowchart showing typical process steps in the mold release agent adhesion state evaluation method according to the first embodiment. Referring to FIG. 4, in the mold release agent adhesion state evaluation method according to the first embodiment, a mold heating step is performed as a step (S10). In this step (S10), a heater (not shown) located inside of the die casting device 11 or at a predetermined position near the die casting device 11 is controlled. Then, the fixed mold 13 and the movable mold 14 are heated to a temperature at which casting can be performed. In this case, for example, both the fixed mold 13 and the movable mold 14 may be entirely heated by continuously manufacturing several cast products as trial casting.

After the fixed mold 13 and the movable mold 14 have been heated to the predetermined temperature, a mold release agent adhesion step is performed as a step (S20). In this step (S20), the mold release agent discharging member 27 is used to cause the mold release agent to adhere to the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14. In this step, the mold release agent described above is used.

Thereafter, as step (S30), a drying step is performed. This step (S30) is performed by blowing air to the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14. At this time, the solvent included in the mold release agent evaporates. Then, a component of the organic acid salt remains on the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14. That is, the component of the organic acid salt in the adhering mold release agent remains as a white coating on the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14.

Subsequently, as a step (S40), an image shooting step is performed. In this step (S40), an image of the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14 is captured by the image data acquiring unit 28. In this embodiment, the image data acquiring unit 28 includes an appearance image capturing device (color module camera) and a 3D scanner. Here, as an example, the appearance image capturing device is incorporated in the 3D scanner, and an appearance image of the molds and a three-dimensional image are captured at the same time. A general 3D scanner can be used, but a handy type is suitable for capturing an image of the molds having an uneven shape without modifying the die casting device 11. FIG. 5 is a schematic cross-sectional view illustrating a state where an image of the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14 is captured. Referring to FIG. 5, in image shooting, the image data acquiring unit 28 is located between the surface 25 and the surface 26, for example, and images are captured by moving the location or tilting the image data acquiring unit 28 at various angles. In this case, images of the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14 are captured from various locations and angles. The image data acquiring unit 28 captures images with different image shooting locations manually or by automatically moving a table to which the image data acquiring unit 28 is fixed. In this manner, a three-dimensional image of the molds to which the mold release agent adheres is acquired. As an example of the image data acquiring unit 28, the appearance image capturing device (color module camera) and the 3D scanner are mounted. That is, the appearance image capturing device incorporates a color module camera and a light source (LED) to capture a color image of the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14. Examples of the color module camera includes a CMOS and a CCD. The light source emits light as a flash at image shooting to be thereby hardly affected by external light and maintain a constant color saturation of the image. The 3D scanner is a non-contact type incorporating two cameras and an infrared light source, and measures a distance from a subject by a passive method to capture a three-dimensional image of the molds. With the use of infrared light, a shape can be accurately measured without being affected by external light. In this manner, the color image of the surfaces of the molds to which the mold release agent adheres and the three-dimensional image of the mold are acquired. Appearance image data and three-dimensional image data are stored in a memory or the like in a state where the image shooting locations are associated with each other. In the above-described example, the image data acquiring unit 28 is moved to capture an image of the entire surfaces of the molds, but an image of a predetermined location may be captured by fixing the image shooting location.

Subsequently, as a step (S50), an image processing step is performed. In this step (S50), from the captured images, an appearance image, and/or a 3D image, that is, a three-dimensional image of the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14, is created. In this case, since the three-dimensional image is captured by the 3D scanner included in the image data acquiring unit 28, the three-dimensional image of the surface 25 of the fixed mold 13 and the surface 26 of the movable mold 14 can be precisely created. The following description will be directed to an image of the surface 26 of the movable mold 14. Of course, the same holds for the image of the surface 25 of the fixed mold 13 as for the image of the surface 26 of the movable mold 14, although the uneven shape or other features are different. FIG. 6 is an image obtained by superimposing appearance image data on a three-dimensional image formed from a captured image, as an example of a captured image. Referring to FIG. 6, at the surface 26 of the movable mold 14, a mating surface 31 and a cavity surface 32 located inside the mating surface 31 are located. FIG. 6 shows that a region 34 around a center 33 of an upper portion of the cavity surface 32 and many regions 35 in the surface of a lower portion of the cavity surface 32 are intensely white. On the other hand, FIG. 6 also shows that a region 36 around the region 34 at the upper portion of the cavity surface 32 and a region 37 at the right of the center of the cavity surface 32 hardly include white areas. This image shows the three-dimensional shape and appearance information at the same time, and thus, it is possible to grasp distribution of adhesion states of the mold release agent easily. The three-dimensional image and the appearance image may be displayed separately.

Thereafter, as a step (S60), an adhesion state deriving step is performed. In this step (S60), in the obtained three-dimensional image, regions to which the mold release agent adheres are represented in white. Color quantification information is acquired from the appearance image data, and an adhesion state is derived using the color quantification information. The color quantification information is information in which the color is quantified based on indexes such as lightness, hue, chroma, chromaticity, and color saturation. In deriving the adhesion state, the following correlation line is used. A correlation is acquired for each mold release agent. Here, as an example, a thickness is derived as an adhesion state. FIG. 7 is a graph showing a relationship between thickness and color quantification information. In FIG. 7, the abscissa represents thickness (μm), and the ordinate represents color quantification information (lightness L*). In FIG. 7, a line 41 indicated by a continuous line is a calibration curve. That is, the line 41 is obtained by plotting thicknesses measured in previously causing the mold release agent to adhere and L* values at the individual thicknesses as circles and connecting the plotted circles by an approximate curve. When the captured image is measured with a colorimeter, color quantification information such as lightness (L* value) corresponding to the image is acquired. The thickness is measured by, for example, a non-contact thickness sensor. With the calibration curve 41, the thickness in each region can be precisely derived from the L* value in the region. That is, the step of deriving the adhesion state of the mold release agent includes the step of deriving the thickness of the mold release agent based on the color quantification information acquired from the image data. It is sufficient that the color quantification information to be used is an index having a correlation with the adhesion state of the mold release agent, and lightness (L* value), chromaticity a* value or b* value, and other values can be used, for example. That is, the color quantification information to be used is selected depending on the type of the mold release agent. The step of deriving the adhesion state includes the step of deriving the adhesion state from the color quantification information in accordance with the image data acquired in the image shooting step, based on a correlation between previously measured image color quantification information and the adhesion state of the mold release agent. The data concerning the adhesion state is information concerning adhesion of the mold release agent, and is, for example, information corresponding to the thickness, the adhesion amount, whether the adhesion amount is large or small, whether or not the adhesion amount exceeds a reference value, variations of the adhesion amount. The information corresponding to the thickness may be a numerical value of the thickness, and a display form is not limited as long as the information concerns the thickness, such as information indicating the thickness by a level, whether or not the thickness is large or small, whether or not the thickness exceeds a reference value, or a variation of the thickness. The data concerning the adhesion state may be derived as distribution on the mold, or only adhesion information at a predetermined position may be derived. For example, adhesion information may be acquired by capturing an appearance image of the mold at a position where the mold release agent is unlikely to adhere. The correlation between the color quantification information and the adhesion state may be represented in a form other than the calibration curve. The derivation of the adhesion state is performed using the deriving unit 53 included in the mold release agent adhesion state evaluation system 51. The deriving unit 53 is, for example, a control device that is included in the mold release agent adhesion state evaluation system 51 and controls the entire operation of the mold release agent adhesion state evaluation system 51.

FIG. 8 is a schematic view illustrating a state of thickness distribution of the mold release agent adhering to the surface 26 of the movable mold 14. Referring to FIG. 8, in an image 29, a three-dimensional image is displayed in different colors depending on the thickness of the mold release agent. In FIG. 8, colors are assigned according to a thickness scale. For example, the color is displayed in black when the thickness is 0 μm, and colors are assigned stepwise or continuously from cold color (blue) to warm color (red) as the numerical value of the thickness increases. By visually recognizing the image 29 shown in FIG. 8, it is possible to easily evaluate whether the mold release agent appropriately adheres to the surface or not. This output is performed using the output unit 54 included in the mold release agent adhesion state evaluation system 51. The output unit 54 is, for example, a display or a printer that is included in the mold release agent adhesion state evaluation system 51 and performs display of an image or the like in response to a signal from the control device.

In the mold release agent adhesion state evaluation method according to the present disclosure, the mold release agent including the solvent and the organic acid salt is used as an example of a mold release agent that can be visually recognized after adhesion. The thickness of such a mold release agent can be measured using the mold release agent itself, and any foreign substance is not mixed in the mold release agent. The organic acid salt included in the mold release agent can remain as a white coating on the surface of the mold by separating the solvent, for example. Such a white coating has excellent visibility, and a remaining portion of the mold release agent can be easily recognized from the appearance. Then, in acquiring an image of the surface of the mold, the adhesion state of the mold release agent can be easily derived from the acquired image through the step of deriving the adhesion state of the mold release agent. Then, data concerning the derived adhesion state of the mold release agent is output, and the adhesion state of the mold release agent adhering to the surface of the mold can be accurately evaluated. In this method, the mold release agent is used without mixing any additives into the mold release agent, and thus, handling of the mold release agent is simplified. Thus, this mold release agent adhesion state evaluation method can evaluate the adhesion state of the mold release agent adhering to the mold accurately and simply.

With the mold release agent adhesion state evaluation method according to the present disclosure, no impurities are added to the mold release agent in order to evaluate the adhesion state, and thus, the mold does not need to be cleaned after measuring the thickness. Thus, in the middle of manufacturing products as cast products, an adhesion state of the mold release agent in the middle of manufacturing of products can be evaluated by, for example, image shooting by the image data acquiring unit 28. For example, this method is effectively employed especially in periodically evaluating the adhesion state of the mold release agent in a mass production state. That is, an optimum adhesion amount of the mold release agent in each region and an optimum adhesion method for the mold release agent for obtaining the optimum adhesion state are arbitrarily determined in accordance with the shape of the mold, casting conditions, the capacity of a peripheral facility, and others. In addition, by performing the mold release agent adhesion state evaluation method according to the present disclosure during manufacturing of cast products, the adhesion method and conditions of the mold release can be efficiently examined.

In this embodiment, the step of acquiring an image includes the step of acquiring a three-dimensional image of the mold to which the mold release agent adheres. Many molds for die casting have complicated shapes, specifically have a large number of uneven shapes and large undulations, for example. For such a mold, a three-dimensional image of the mold is acquired and the position at which the thickness was measured and information concerning the thickness are visualized in association with each other so that more detailed information on the adhesion state of the mold release agent can be thereby obtained. That is, distribution of the information corresponding to the thickness is visualized by superimposing information corresponding to the thickness on the three-dimensional image in the display. Accordingly, adhesion information on the mold release agent can be grasped for a wide range of the mold. Specifically, for example, it is possible to easily grasp whether or not there is a portion to which the mold release agent does not adhere in the mold with a complicated shape, whether or not the mold release agent reliably adheres to the inner part of the recess, whether or not the mold release agent is accumulated in detail while die casting is repeated multiple times, or the like. This enables more accurate evaluation of the adhesion state of the mold release agent.

In this embodiment, the image data of appearance includes a color image. With this method, the adhesion state of the mold release agent can be derived in consideration of information on the color image. This enables more accurate evaluation of the adhesion state of the mold release agent.

In this embodiment, data concerning the adhesion state of the mold release agent is data corresponding to a thickness of the mold release agent. With this method, the adhesion amount of the mold release agent, that is, the thickness of the mold release agent, can be precisely derived. This enables more accurate evaluation of the adhesion state of the mold release agent.

In this embodiment, the color quantification information is lightness, hue, chroma, chromaticity, or color saturation. With this method, the adhesion state of the mold release agent can be derived utilizing hue or other information. This enables more accurate evaluation of the adhesion state of the mold release agent.

In this embodiment, the step of outputting the data includes the step of displaying the three-dimensional image of the mold and distribution of the adhesion state of the mold release agent in association with each other. With this method, distribution of the adhesion state of the mold release agent can be visually grasped by comparing with the three-dimensional image of the mold. This enables easier evaluation of the adhesion state of the mold release agent.

In this embodiment, the step of outputting the data includes the step of generating and outputting image data displayed in different colors depending on a thickness of the mold release agent derived as the adhesion state of the mold release agent. With this method, a difference in thickness due a difference in color from the generated image can be visually recognized easily. This enables more efficient evaluation of the adhesion state of the mold release agent.

A mold release agent adhesion state evaluation system according to the present disclosure is a mold release agent adhesion state evaluation system for a mold release agent used for die casting and adhering to a mold. The mold release agent adhesion state evaluation system includes: an image data acquiring unit that acquires image data of appearance of the mold; a deriving unit that derives an adhesion state of the mold release agent to a surface of the mold from color quantification information corresponding to the image data of appearance of the mold, based on a correlation between previously acquired color quantification information and the adhesion state of the mold release agent; and an output unit that outputs data concerning the adhesion state of the mold release agent derived by the deriving unit.

This mold release agent adhesion state evaluation system can evaluate an adhesion state of a mold release agent adhering to a mold accurately and simply.

In the mold release agent adhesion state evaluation system, the image data acquiring unit may include a 3D scanner. The image data acquiring unit may acquire three-dimensional image data of appearance of the mold by capturing an image by the 3D scanner. The output unit may provide a display by superimposing the adhesion state of the mold release agent on the three-dimensional image of the mold. With this configuration, a three-dimensional adhesion state of the mold release agent can be easily grasped. This enables easier evaluation of the adhesion state of the mold release agent.

Other Embodiments

In the embodiments described above, the imaging device that captures the appearance image of the mold is incorporated in the 3D scanner, but may be separately disposed. In the case of capturing no three-dimensional image, the 3D scanner is unnecessary. Although the color image is acquired as the appearance image of the mold in the above embodiment, the present disclosure is not limited to this example, and a monochrome image at a wavelength suitable for indicating properties hue, lightness, etc.) of the mold release agent after adhesion may be acquired. In the case of acquiring a three-dimensional image, an image including planar positional information and information in the thickness direction of the mold is obtained, and thus, it is possible to evaluate the adhesion state of the mold release agent in more detail. However, the present disclosure is not limited to this example, and two-dimensional image may be acquired.

In the embodiments described above, step S30 shown in FIG. 4 includes the drying step, but the drying step may be omitted, for example, depending on the mold release agent to be used.

The evaluation method and the evaluation system according to the present disclosure are also applicable to evaluation of an adhesion state of a machining liquid such as a lubricant or a mold release agent that forms a visible coating when applied to a mold or the like, in a manner similar to the mold release agent for die casting described above. Examples of the machining liquid include a non-graphite-based lubricant for plastic working. For example, the non-graphite-based lubricant for plastic working includes an organic acid salt such as a carboxylic acid compound, and forms a white coating when applied to the mold (lubricant adhesion step). Then, appearance of plastic working mold and color quantification information is acquired by the image data acquiring unit (image data acquiring step), the adhesion state of the lubricant is derived based on a correlation between previously acquired color quantification information and an adhesion state of the lubricant (adhesion state deriving step), and a result thereof is output (data output step). Thus, the evaluation method and the evaluation system according to the present disclosure are suitably applicable.

It should be understood that the embodiments disclosed here are illustrative and non-restrictive in every respect. The scope of the present disclosure is defined by the claims and is intended to include any modifications within the scope and meaning equivalent to the claims.

DESCRIPTION OF REFERENCE NUMERALS

• • 11 die casting device, 13 fixed mold, 14 movable mold, 15 injection sleeve, 16 injection piston, 17 cavity, 18 injection port, 19 inner wall surface, 21 plunger chip, 22 injection rod, 24 outer diameter surface, 25, 26 surface, 27 mold release agent discharging member, 28 image data acquiring unit, 29 image, 31 mating surface, 32 cavity surface, 33 center, 34, 35, 36, 37 region, 41 line (calibration curve), 51 mold release agent adhesion state evaluation system, 53 deriving unit, 54 output unit.