JP5488500B2 - Hardness testing machine - Google Patents

Description

  The present invention relates to a hardness tester for measuring the hardness of a test piece.

  As such a hardness tester, for example, a Vickers hardness tester for measuring the Vickers hardness or Knoop hardness of a test piece is known. In such a hardness tester, an indenter that applies a test force to the test piece to form an indentation on the surface thereof, a mounting table that is placed opposite to the indenter and places the test piece, and a plurality of test pieces on the test piece An XY stage that sequentially moves the test piece to form an indentation at the measurement point, a plurality of objective lenses for observing the test piece, and any one of these objective lens and indenter facing the measurement point And a revolver that switches so that The indentation formed on the test piece is an eyepiece for the operator to observe the test piece image that has been enlarged through the objective lens, and a monitor for displaying the test piece image that has been enlarged by the objective lens. Observe using.

  When performing a hardness test, when forming a plurality of indentations for a single test piece, the hardness of the test piece around the indentation due to the formation of the indentation is changed to a hardness test by changing by work hardening. In order to prevent the influence, it is necessary to keep the center-to-center distance between the indentations at a certain level or more. For this reason, in JIS (Japanese Industrial Standards) Z2244 (Vickers Hardness Test-Test Method), in the case of steel, nickel alloy, titanium alloy, copper and copper alloy, the distance between the centers of the indentations is the diagonal length of the indentations. In the case of light metal, lead, tin, and alloys thereof, the distance between the centers of the indentations is set to be 6 times or more the diagonal length of the indentations.

  Similarly, when the hardness test is executed, it is necessary to keep the distance from the indentation to the edge of the test piece at a certain level or more. In the above JISZ2244, in the case of steel, nickel alloy, titanium alloy, copper and copper alloy, the distance between the indentation and the edge of the test piece shall be 2.5 times or more of the diagonal length of the indentation, and light metal, lead In the case of tin and alloys thereof, the distance between the centers of the indentations is determined to be at least three times the diagonal length of the indentations.

  Patent Document 1 discloses a method for measuring hardenability in consideration of such a distance.

JP 59-85818

  In order to check whether the distance between the centers of the indentations meets the conditions specified in JIS, after measuring the size of the larger one of the adjacent indentations and measuring the distance between the centers of the indentations Furthermore, it is necessary to perform a complicated operation of calculating whether or not the distance satisfies a condition defined in JIS, and the confirmation cannot be easily performed. Regardless of whether a sufficient distance between the indentations can be secured, especially when a large number of hardness measurements are performed on a single specimen, the distance between the centers of the indentations satisfies the conditions specified in JIS. It is extremely difficult to determine whether or not. This is a problem that occurs not only in the distance between the centers of the indentations but also in the distance between the indentation and the edge of the test piece.

  The present invention has been made to solve the above problems, and an object thereof is to provide a hardness tester capable of appropriately maintaining the distance between the centers of the indentations or the distance between the indentations and the edge of the test piece. And

  The invention described in claim 1 provides a test force for the test piece by placing a test stand on which the test piece is placed, an indenter for forming an indentation on the surface of the test piece, and raising and lowering the indenter. In a hardness tester comprising: a load mechanism to be applied; a camera for photographing an indentation formed on the surface of the test piece; and a display unit for displaying an image of the surface of the test piece taken by the camera. Indentation recognition means for recognizing the position and size of the indentation formed on the test piece placed on the mounting table, the hardness of the test piece placed on the mounting table, and the next indentation on the test piece The size of the impression formed next on the test piece based on the input part for inputting the position and test force when forming the test piece, and the hardness and test force of the test piece inputted by the input part Prediction means and the indentation recognition means Based on the recognized position and size of the indentation formed on the test piece and the position and size of the indentation formed on the test piece next predicted by the prediction means, the indentation was formed on the test piece. And determining means for determining whether or not the distance between the indentation and the indentation formed on the test piece is equal to or greater than a necessary distance.

The invention according to claim 2 is the invention according to claim 1, wherein the coordinate position when the next indentation is formed on the test piece is (x, y) and any of the test pieces formed on the test piece. The coordinate position of the indentation is (xi, yi), the size of the indentation d formed on the test piece next predicted by the prediction means, or the size of any indentation di formed on the test piece. When the larger size is D and the coefficient determined by the material of the test piece is n, the determination means compares the distance L1 represented by the equation (1) with n · D. Then, it is determined whether or not the distance between the indentation formed on the test piece and the next indentation formed on the test piece is a required distance or more.
L1 = [(x−xi) ² + (y−yi) ² ] ^0.5 (1)

  The invention according to claim 3 is the invention according to claim 2, wherein a circle with a radius n · d centered on the coordinate position (x, y) and a center of the coordinate position (xi, yi). The image processing unit is further provided for displaying the circle having the radius n · di on the display unit.

According to a fourth aspect of the present invention, in the second aspect of the present invention, when the current coordinate position is (xc, yc), the coordinate position (x, A position where y) is a coordinate (x, y) at which f (x, y) represented by Expression (2) is minimized among coordinates (x, y) where L1 is not less than n · D. Setting means is provided.
f (x, y) = [(x−xc) ² + (y−yc) ² ] ^0.5 (2)

  The invention according to claim 5 is a mounting table for placing the test piece, an indenter for forming an indentation on the surface of the test piece, and raising and lowering the indenter to give a test force to the test piece. In a hardness tester comprising: a load mechanism to be applied; a camera for photographing an indentation formed on the surface of the test piece; and a display unit for displaying an image of the surface of the test piece taken by the camera. Edge recognition means for recognizing the position of the edge of the test piece placed on the mounting table, hardness of the test piece placed on the mounting table, and when forming the next indentation on the test piece An input unit for inputting a position and a test force, and a prediction means for predicting the size of an indentation to be formed next on the test piece based on the hardness and test force of the test piece input by the input unit And the end of the test piece recognized by the edge recognition means And the distance between the edge of the test piece and the next impression formed on the test piece based on the position of the test piece and the position and size of the impression formed on the test piece next predicted by the prediction means Is provided with determination means for determining whether or not the distance is equal to or greater than the necessary distance.

The invention according to claim 6 is the invention according to claim 5, wherein the coordinate position when the next indentation is formed on the test piece is (x, y), and the coordinates of any edge in the test piece are set. When the position is (xej, yej), the size of the impression formed on the test piece next predicted by the prediction means is d, and the coefficient determined by the material of the test piece is m, the determination means Compare the distance L2 represented by the formula (3) with m · d, so that the distance between the edge of the test piece and the indentation formed on the test piece is equal to or greater than the required distance. It is determined whether or not.
L2 = [(x−xej) ² + (y−yej) ² ] ^0.5 (3)

  According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the image processing unit further includes a circle having a radius m · d centered on the coordinate position (x, y).

The invention according to claim 8 is the invention according to claim 6, wherein when the current coordinate position is (xc, yc), the coordinate position (x, A position where y) is a coordinate (x, y) at which f (x, y) represented by Expression (4) is minimized among coordinates (x, y) where L2 is equal to or greater than m · d. Setting means is provided.
f (x, y) = [(x−xc) ² + (y−yc) ² ] ^0.5 (4)

  According to the first and second aspects of the present invention, it is possible to easily determine whether or not the distance between the centers of the indentations is appropriate. For this reason, the distance between the centers of the indentations can be properly maintained, and an accurate hardness test can be executed.

  According to the third aspect of the present invention, since the area where the center distance of the indentation is inappropriate is displayed in advance, it is possible to easily set the position where the hardness test is executed next from the appropriate area. It becomes.

  According to the invention described in claim 4, the coordinate position (x, y) when the next indentation is formed can properly maintain the center-to-center distance of the indentation, and the test should be executed initially. It is possible to automatically set the position in the vicinity of the determined position, and the hardness test can be executed accurately and quickly.

  According to the fifth and sixth aspects of the present invention, it is possible to easily determine whether or not the distance between the indentation and the edge of the test piece is appropriate. For this reason, the distance between the indentation and the edge of the test piece can be properly maintained, and an accurate hardness test can be executed.

  According to the seventh aspect of the present invention, since the region where the distance between the indentation and the edge of the test piece is inappropriate is displayed in advance, the position where the hardness test is performed next can be easily performed from the appropriate region. It becomes possible to set.

  According to the invention described in claim 8, the coordinate position (x, y) when the next indentation is formed can properly maintain the distance between the indentation and the edge of the test piece and It is possible to automatically set the position near the position where the test is to be executed, and the hardness test can be executed accurately and quickly.

1 is a schematic diagram of a hardness tester according to the present invention. 3 is a schematic diagram of a load mechanism for applying a test force to the indenter 21. FIG. It is a block diagram which shows the main electrical structures of the hardness tester which concerns on this invention. It is explanatory drawing which shows typically a mode that an indentation is formed in the test piece 100 with the indenter 21. FIG. 3 is a plan view showing indentations formed on a test piece 100. FIG. It is a flowchart which shows each process of the hardness test by the hardness tester based on this invention. It is a flowchart which shows each process of the hardness test by the hardness tester based on this invention. It is a schematic diagram which shows the some circle displayed on the display part 18 with the test piece 100 and its edge 101. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a hardness tester according to the present invention.

  The hardness tester includes a table 11 and an XY stage 12 as a mounting table that is placed on the table 11 and on which a test piece 100 is mounted. The XY stage 12 is for moving the test piece 100 in the X direction (left-right direction in FIG. 1) and the Y direction (direction perpendicular to the paper surface in FIG. 1). The XY stage 12 is provided with a motor 13 for moving the test piece 100 in the X direction and a motor 14 for moving the test piece 100 in the Y direction. The XY stage 12 is configured to move up and down by the action of the lifting handle 15.

  The hardness tester includes an eyepiece 16 for visually observing the test piece 100, a camera 17 for photographing the test piece 100, and a CRT for displaying an image of the surface of the test piece 100. A display unit 18 and an input unit 19 such as a keyboard for inputting various data are provided.

  Further, the hardness tester includes an indenter 21 that forms an indentation by pressurizing the test piece 100, a load mechanism that will be described later for applying a test force to the indenter 21, and a plurality of objective lenses 22, 23. And a revolver 20 that rotates while supporting the indenter 21 and the objective lenses 22 and 23. The revolver 20 rotates about an axis that faces in the vertical direction by operating the knob 26.

  FIG. 2 is a schematic diagram of a load mechanism for applying a test force to the indenter 21.

  The load mechanism includes a lever 32 that can swing around a shaft 31. A pressing portion 35 is disposed at one end of the lever 32. The pressing portion 35 is configured to press a contact portion 37 attached to an end portion of the indenter shaft 36 connected to the indenter 21 as the lever 32 swings. A permanent magnet 33 is attached to the other end of the lever 32. An electromagnetic coil 34 is disposed outside the permanent magnet 33. The permanent magnet 33 and the electromagnetic coil 34 constitute a voice coil motor. This voice coil motor becomes an electromagnetic load mechanism, and by controlling the current flowing through the electromagnetic coil 34, the test force applied to the test piece 100 by the indenter 21 can be controlled.

  FIG. 3 is a block diagram showing the main electrical configuration of the hardness tester according to the present invention.

  This hardness tester includes a control unit 50 that controls the entire apparatus. The control unit 50 is connected to the camera 17, the display unit 18, the input unit 19, and the electromagnetic coil 34 of the load mechanism described above. In addition, the control unit 50 includes an indentation recognition unit 51 that recognizes the position and size of the indentation formed on the test piece 100, an edge recognition unit 52 that recognizes the position of the edge of the test piece 100, and The distance between the prediction portion 53 that predicts the size of the indentation formed on the test piece 100, the indentation formed on the test piece 100 and the next indentation formed on the test piece 100, and the end of the test piece 100 A determination unit 54 that determines whether the distance between the edge and the indentation formed on the test piece 100 is equal to or greater than a necessary distance, and an edge having a predetermined radius centered on each indentation is displayed on the display unit 18. The distance between the image processing unit 55 and the impression formed on the test piece 100 and the next impression formed on the test piece 100 and the distance between the edge of the test piece 100 and the next impression formed on the test piece 100 are as follows. Next, when the required distance is not exceeded, the test piece 100 And a position setting unit 56 for setting the position of the indentation to be formed.

  FIG. 4 is an explanatory view schematically showing how the indentation 21 forms an indentation on the test piece 100, and FIG. 5 is a plan view showing the indentation formed on the test piece 100.

  When executing a Vickers hardness test as a hardness test, a diamond indenter 21 whose tip is a regular quadrangular pyramid is pushed into the surface of the test piece 100 by a depth h by the action of the load mechanism shown in FIG. After releasing the test force, the diagonal length d of the indentation (indentation) formed on the surface of the test piece 100 (or the average value when the diagonal lengths dx and dy orthogonal to each other are different) is measured. The Vickers hardness is proportional to the value obtained by dividing the test force by the surface area of the indentation assuming that the bottom surface is square and the apex angle is the same pyramid as the indenter 21.

  Next, each step of the hardness test using the above-described hardness tester will be described. 6 and 7 are flowcharts showing each step of the hardness test using the hardness tester according to the present invention.

  When performing the hardness test, first, the expected hardness of the test piece 100 to be tested is input (step S1). Next, the position (x, y) where the indentation is formed is input in order to execute the hardness test (step S2). Further, the test force for executing the hardness test next time is input (step S3). These inputs are performed when an operator inputs predetermined data using the input unit 19. However, the next position of the indentation may be automatically input instead of being input by the operator.

  Next, an entire image of the test piece 100 is acquired (step S4). In this case, the test piece 100 is moved in the XY direction together with the XY stage 12 by the action of the motors 13 and 14, whereby the entire surface of the test piece 100 is photographed by the camera 17 and an image of the entire surface of the test piece 100 is acquired. To do. In addition, when the area | region which performs a hardness test does not cover the whole surface of 100 of a test piece, you may make it acquire only the image of the one part area | region of the surface of the test piece 100. FIG.

  Next, the position of the edge of the test piece 100 is recognized by performing image processing on the entire image of the test piece 100 (step S5). This edge position recognition is performed by the edge recognition unit 52 shown in FIG. Further, by performing image processing on the entire image of the test piece 100, the coordinate position (xi, yi) and the size di of the indentation already formed on the test piece 100 are recognized (step S6). Here, when a plurality of indentations are formed, (i = 1, 2, 3,...). The recognition of the position and size of the indentation is performed by the indentation recognition unit 51 shown in FIG. Here, the size di of the indentation indicates an average value of the diagonal lines dx and dy shown in FIG.

  Then, the image processing unit 55 displays a circle of radius n · di centered on the coordinate position (xi, yi) of the indentation on the display unit 18 together with the image of the test piece 100 (step S7). Here, n is a coefficient determined by the material of the test piece 100, and is 3 for steel, nickel alloy, titanium alloy, copper and copper alloy, and 6 for light metal, lead, tin and their alloys. Become. This makes it possible to recognize an approximate area that is inappropriate for the next execution of the hardness test.

  Next, the prediction unit 53 predicts the size d of the impression formed on the test piece 100 based on the hardness and test force of the test piece 100 input by the input unit 19 (step S8). Then, the predicted indentation size d formed on the test piece 100 is compared with the indentation size di already formed on the test piece 100 (step S9). The size is set to D (step S10). In addition, when there are a plurality of impressions already formed on the test piece 100, this comparison is performed for each impression.

  Then, the image processing unit 55 adds the circle having the radius n · d centered on the coordinate position (x, y) to the circle having the radius n · di centered on the previously displayed coordinate position (xi, yi). The circle is displayed on the display unit 18 together with the image of the test piece 100 (step S11).

  FIG. 8 is a schematic diagram showing the plurality of circles displayed in this way together with the test piece 100 and its end edge 101. This figure shows the case where the material of the test piece 100 is steel, nickel alloy, titanium alloy, copper and copper alloy.

  As shown in this figure, the test piece 100 is formed with indentations of sizes d1, d2, and d3, and circles with radii of 3d1, 3d2, and 3d3 are displayed in the previous display step (step S7). Yes. In addition to these, a circle with a radius of 3d centered on the coordinate position (x, y) is displayed on the display unit 18 together with the image of the test piece 100 (step S11). In this case, as will be described later, when any of the circles and the indentation arranged at the coordinate position (x, y) overlap, or a circle with a radius of 3d and a size of d1, d2, d3. If the indentation overlaps, the coordinate position (x, y) is an inappropriate position for the next execution of the hardness test.

  In the above description, 3d, 3d1, 3d2, and 3d3 circles are displayed in order to prevent the distance between the indentations from being below a certain level. When considering the distance between the position (x, y) forming the edge and the edge 101 of the test piece 100, a circle with a radius of 2.5d centered on the coordinate position (x, y) is displayed. That's fine. As described above, in the case of steel, nickel alloy, titanium alloy, copper, and copper alloy, as described above, the distance between the indentation and the edge of the test piece 100 is set to 2.5 of the diagonal length of the indentation. This is because it is determined to be more than double. Here, 2.5 corresponds to a coefficient m described later. In this case, as will be described later, when the circle and the edge 101 of the test piece 100 overlap, the coordinate position (x, y) is determined to be an inappropriate position for the next execution of the hardness test. It will be.

  Next, the determination unit 54 compares the distance L1 represented by the following formula with n · D, so that the indentation already formed on the test piece 100 and the next indentation formed on the test piece 100 are compared. It is determined whether or not the distance is greater than the required distance (step S12). This determination is performed for each indentation when there are a plurality of indentations already formed on the test piece 100 as shown in FIG.

L1 = [(x−xi) ² + (y−yi) ² ] ^0.5

  In this step S12, when n · D is L1 or less (step S13), the distance between any indentation already formed on the test piece 100 and the next indentation formed on the test piece 100 is JIS. It is over the default value defined in.

  In this case, the determination unit 54 continues to compare the distance L2 represented by the following formula with m · d, so that the indentation formed on the edge 101 of the test piece 100 and the test piece 100 next is determined. It is determined whether or not the distance is greater than the required distance (step S14). Here, when a plurality of edges are formed, (j = 1, 2, 3...). Further, m is a coefficient determined by the material of the test piece 100, and corresponds to the above n. This m is 2.5 for steel, nickel alloy, titanium alloy, copper and copper alloy, and 3 for light metal, lead, tin and alloys thereof.

L2 = [(x−xej) ² + (y−yej) ² ] ^0.5

  When m · d is equal to or less than L2 in step S14 (step S15), the distance between the edge 101 of the test piece 100 and the indentation formed on the test piece 100 is equal to or greater than a predetermined value defined in JIS. It will be. In this case, OK display is performed on the display unit 18 (step S16), and the process ends.

  On the other hand, when n · D is larger than L1 in step S12 described above, the distance between any indentation already formed on the test piece 100 and the next indentation formed on the test piece 100 is JIS. Since it is smaller than the predetermined default value, NG display is performed on the display unit 18 (step S17). Even when m · d is larger than L2 in step S14 described above, the distance between the edge 101 of the test piece 100 and the indentation formed on the test piece 100 is smaller than a predetermined value defined in JIS. Therefore, NG display is performed on the display unit 18 (step S17).

  In these cases, the position setting unit 56 in the control unit 50 resets the coordinate position (x, y) when the next indentation is formed. At this time, when the coordinate position of the current indenter 21 that is the coordinate position where the indentation is to be formed at the present time is (xc, yc), the coordinate position (x, y) is the minimum of f (x, y) represented by the following expression among the coordinates (x, y) where L1 is n · D or more and L2 is m · d or more. The processing ends after setting the coordinates to be converted.

f (x, y) = [(x−xc) ² + (y−yc) ² ] ^0.5

  Thereby, the distance between the center of the indentation and the distance between the indentation and the edge of the test piece 100 can be properly maintained, and the next indentation is located at a position near the position where the test is initially performed. The coordinate position (x, y) at the time of forming can be automatically set, and the hardness test can be executed accurately and quickly.

  In the above-described embodiment, when n · D is larger than L1 or m · d is larger than L2, the coordinate position (x, y) when the next indentation is formed by the action of the position setting unit 56 is used. ) Is reset, but only the NG display (step S17) is performed, and then the operator forms the next indentation while referring to the plurality of circles displayed on the display unit 18 in step S11. The coordinate position (x, y) may be reset.

  In the above-described embodiment, the distance between the indentation already formed on the test piece 100 and the next indentation formed on the test piece 100 is greater than the necessary distance by comparing n · D and L1. Whether or not the distance between the edge 101 of the test piece 100 and the indentation formed on the test piece 100 is equal to or greater than the required distance by comparing m · d and L2. Judging. However, only one of these may be determined.

  Further, in the above-described embodiment, the entire surface of the test piece 100 is photographed by the camera 17 to obtain an entire image of the test piece 100, and this is subjected to image processing, so that the indentation already formed on the test piece 100 can be obtained. Although the coordinate position (xi, yi) and size di and the position of the edge of the test piece 100 are recognized, by using the result of the hardness test performed on the same test piece 100 before that, You may make it recognize the coordinate position (xi, yi) and magnitude | size di of the indentation already formed in the test piece 100, and the position of the edge of the test piece 100. FIG.

  Further, in the above-described embodiment, the same values as those defined in JIS are used as the values of the coefficient n and the coefficient m, but the error of the predicted value d of the size of the next indentation by the prediction unit 53 is used. As the values of the coefficient n and the coefficient m, those larger than those specified in JIS may be adopted.

DESCRIPTION OF SYMBOLS 11 Table 12 XY stage 13 Motor 14 Motor 15 Lifting handle 16 Eyepiece 17 Camera 18 Display part 20 Revolver 21 Indenter 22 Objective lens 23 Objective lens 26 Knob 31 Axis 32 Lever 33 Permanent magnet 34 Electromagnetic coil 50 Control part 51 Indentation recognition part 52 Edge recognition unit 53 Prediction unit 54 Judgment unit 55 Image processing unit 56 Position setting unit 100 Test piece

Claims (8)

A mounting table for mounting the test piece, an indenter for forming an indentation on the surface of the test piece, a load mechanism for applying a test force to the test piece by raising and lowering the indenter, and the test piece In a hardness tester comprising: a camera that shoots an indentation formed on the surface; and a display unit that displays an image of the surface of the specimen taken by the camera.
Indentation recognition means for recognizing the position and size of the indentation formed on the test piece placed on the mounting table,
An input unit for inputting the hardness of the test piece placed on the mounting table and the position and test force when the next indentation is formed on the test piece;
Based on the hardness and test force of the test piece input by the input unit, predicting means for predicting the size of the impression formed on the test piece next,
Based on the position and size of the indentation formed on the test piece recognized by the indentation recognition means, and the position and size of the indentation formed on the test piece next predicted by the prediction means, the test is performed. A determination means for determining whether the distance between the indentation formed on the piece and the indentation formed on the test piece is equal to or greater than a necessary distance;
A hardness tester characterized by comprising: The hardness tester according to claim 1,
The coordinate position when the next indentation is formed on the test piece is (x, y), and the coordinate position of any indentation formed on the test piece is (xi, yi). Next, D is the larger size of the size d of the indentation formed on the test piece or the size di of any one of the indentations formed on the test piece, and the coefficient is determined by the material of the test piece. n,
The determination means compares the distance L1 represented by the formula (1) with n · D, so that the distance between the indentation formed on the test piece and the indentation formed on the test piece is A hardness tester that determines whether or not the required distance is exceeded.
L1 = [(x−xi) ² + (y−yi) ² ] ^0.5 (1) The hardness tester according to claim 2, wherein
An image processing unit that displays a circle of radius n · d centered on the coordinate position (x, y) and a circle of radius n · di centered on the coordinate position (xi, yi) on the display unit Hardness tester further equipped with. The hardness tester according to claim 2, wherein
When the current coordinate position is (xc, yc),
The coordinate position (x, y) when the next indentation is formed on the test piece is expressed as f (2) among the coordinates (x, y) where the L1 is equal to or more than the n · D. A hardness tester provided with position setting means for setting coordinates (x, y) to minimize x, y).
f (x, y) = [(x−xc) ² + (y−yc) ² ] ^0.5 (2) A mounting table for mounting the test piece, an indenter for forming an indentation on the surface of the test piece, a load mechanism for applying a test force to the test piece by raising and lowering the indenter, and the test piece In a hardness tester comprising: a camera that shoots an indentation formed on the surface; and a display unit that displays an image of the surface of the test piece photographed by the camera.
Edge recognition means for recognizing the position of the edge of the test piece placed on the mounting table;
An input unit for inputting the hardness of the test piece placed on the mounting table and the position and test force when the next indentation is formed on the test piece;
Based on the hardness and test force of the test piece input by the input unit, predicting means for predicting the size of the impression formed on the test piece next,
Based on the position of the edge of the test piece recognized by the edge recognition means and the position and size of the indentation formed on the test piece next predicted by the prediction means, the edge of the test piece And a determination means for determining whether or not the distance between the indentation formed on the test piece is equal to or greater than a necessary distance,
A hardness tester characterized by comprising: The hardness tester according to claim 5, wherein
The coordinate position when the next indentation is formed on the test piece is (x, y), the coordinate position of any edge in the test piece is (xej, yej), and the predicted position is predicted by the prediction means. When the size of the indentation formed on the test piece is d and the coefficient determined by the material of the test piece is m,
The determination means compares the distance L2 represented by the expression (3) with m · d, so that the distance between the edge of the test piece and the indentation formed on the test piece is the required distance. Hardness tester that determines whether or not it is above.
L2 = [(x−xej) ² + (y−yej) ² ] ^0.5 (3) The hardness tester according to claim 6, wherein
A hardness tester further comprising an image processing unit that displays a circle of radius m · d centered on the coordinate position (x, y) on the display unit. The hardness tester according to claim 6, wherein
When the current coordinate position is (xc, yc),
The coordinate position (x, y) when the next indentation is formed on the test piece is represented by f ((4)) among the coordinates (x, y) at which the L2 is equal to or more than the m · d. A hardness tester provided with position setting means for setting coordinates (x, y) to minimize x, y).
f (x, y) = [(x−xc) ² + (y−yc) ² ] ^0.5 (4)

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