JP2019152486A - Method and device for correcting design tolerance - Google Patents

Abstract

To provide a method and a device for correcting design tolerance, capable of simply correcting the design tolerance of workpiece measurement items.SOLUTION: A method for correcting design tolerance includes: an analysis step of analyzing an average value and variation of the measured data obtained by measuring workpiece measurement items with a shape measuring machine; a setting step for setting a target value as an index for determining a tolerance width of the design tolerance after correction; and a tolerance correction step of correcting each of the upper limit tolerance which is the upper limit value of the design tolerance and the lower limit tolerance which is the lower limit value of the design tolerance based on the analysis result in the analysis step and a target value set in the setting step.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a design tolerance correction method and a correction apparatus for correcting a design tolerance of a measurement item of a workpiece measured by a shape measuring machine.

  For example, various parts (products) of the cylinder block and the cylinder head are strictly managed by the manufacturer in terms of shape and size. The shape and dimensions of each part of this part are determined according to the tolerance class defined by the Japanese Industrial Standards (JIS), or according to the manufacturer's internal regulations. ) Are specified respectively. For this reason, manufacturers use one-dimensional coordinate measuring machines to measure one or more measurement items (shape measurement, dimension measurement, etc.) of workpieces that are parts, and design measurement data for each measurement item. It is inspected whether it is within the tolerance range.

  In such a three-dimensional coordinate measuring machine, measurement is performed for each measurement item by contacting the probe with the workpiece while displacing the position and orientation of the probe according to a measurement program in which measurement items (measurement points, etc.) relating to the workpiece are defined. (See Patent Document 1).

Japanese Patent Laying-Open No. 2015-222196

  However, when production of parts (workpieces) starts by a manufacturer, etc., it may be necessary to widen the design tolerances because it is not possible to process the parts that fall within the assumed design tolerances, or the quality of the parts can be reduced with the assumed design tolerances. It becomes necessary to narrow the design tolerance because it is found that it cannot be secured. In this case, it is necessary to correct the design tolerance for each measurement item of the part defined in the measurement program based on the accumulated result of the measurement data for each measurement item of the past part.

  In this case, since it is necessary for the user to determine the correction amount of the design tolerance from the measurement data accumulation result for each measurement item of the part (work), this determination takes time. As a result, there arises a problem that the design tolerance cannot be easily corrected.

  Furthermore, in addition to the workpiece measurement items, the above-described measurement program may define design tolerances or the like determined for each measurement item. As a result, when measuring each workpiece measurement item using a three-dimensional coordinate measuring machine, whether or not the measurement data obtained for each measurement item is within the design tolerance range is displayed on the measurement image. An alarm can be displayed on the measurement image when the measurement data is outside the design tolerance range.

  However, in this case, correction of the measurement program is required in accordance with the correction of the design tolerance. However, correction of the measurement program requires specialized skills, and no one can easily correct it. Further, when the measurement program is corrected, it may take time to search for the corrected portion, it may take time to check the operation after the correction, or a mistake may occur. As a result, there arises a problem that the maintenance cost of the measurement program increases. Therefore, there arises a problem that the design tolerance cannot be easily corrected.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a design tolerance correction method and a correction apparatus capable of easily correcting design tolerances of workpiece measurement items.

  A design tolerance correction method for achieving the object of the present invention is a design tolerance correction method for correcting a design tolerance of one or a plurality of measurement items of a workpiece measured by a shape measuring machine. An analysis step that analyzes the average value and variation of the measurement data obtained by measuring the measurement items, a setting step that sets an index value that serves as an index for determining the tolerance range of the corrected design tolerance, and an analysis in the analysis step Based on the result and the target value set in the setting step, there is a tolerance correction step for correcting an upper limit tolerance which is an upper limit value of the design tolerance and a lower limit tolerance which is a lower limit value of the design tolerance.

  According to this design tolerance correction method, design tolerances (upper limit tolerance and lower limit tolerance) can be automatically corrected.

  In the design tolerance correction method according to another aspect of the present invention, in the setting step, a magnification for the variation analyzed in the analysis step is set as the target value, and in the tolerance correction step, the variation is set as Q and the average value is A. And the magnification is α, the corrected upper limit tolerance is UC, and the corrected lower limit tolerance is LC, the corrected upper limit tolerance is calculated by the equation UC = A + (Q × α) / 2, and after correction Is obtained by the formula LC = A− (Q × α) / 2. Thereby, the design tolerance can be automatically corrected.

  In the design tolerance correcting method according to another aspect of the present invention, in the analysis step, a peak-to-peak value that is a difference between the maximum value and the minimum value of the measurement data or a standard deviation of the measurement data is obtained as a variation.

  A design tolerance correction method according to another aspect of the present invention includes an accumulation step of accumulating measurement data obtained by measuring a workpiece measurement item by a shape measuring machine in an accumulation unit, and in the analysis step, the accumulation unit The average value and variation of the measurement data stored in Thereby, the design tolerance can be corrected based on the accumulated result of the past measurement results.

  The design tolerance correction method according to another aspect of the present invention includes a display step of displaying a control chart on the display unit based on the measurement data stored in the storage unit and the upper limit tolerance and the lower limit tolerance. Thereby, the design tolerance (upper limit tolerance and lower limit tolerance) after correction can be recognized by the user.

  A design tolerance correction apparatus for achieving the object of the present invention is a design tolerance correction apparatus for correcting a design tolerance of one or a plurality of measurement items of a workpiece measured by a shape measuring machine. An analysis unit that analyzes the average value and variation of measurement data obtained by measuring the measurement items, a setting unit that sets an index value that serves as an index for determining the tolerance range of the corrected design tolerance, and an analysis result by the analysis unit And a tolerance correction unit that corrects an upper limit tolerance that is an upper limit value of the design tolerance and a lower limit tolerance that is a lower limit value of the design tolerance based on the target value set by the setting unit.

  The present invention can easily correct design tolerances of workpiece measurement items.

It is the schematic of the measurement system which performs the measurement regarding the 1 or several measurement item of a workpiece | work. It is a block diagram which shows the structure of a control apparatus and a management apparatus. It is a block diagram which shows the structure of the management apparatus main body. It is the schematic of a measurement data storage part. It is explanatory drawing which showed an example of the management chart produced | generated for every measurement item by the management chart production | generation part. It is explanatory drawing for demonstrating the specific example of the calculation of the correction | amendment upper limit tolerance and the correction | amendment lower limit tolerance by a tolerance correction | amendment part. It is a flowchart which shows the flow of the measurement process of the workpiece | work by a measurement system.

[Overall configuration of measurement system]
FIG. 1 is a schematic diagram of a measurement system 10 that performs measurement (such as shape measurement and dimension measurement) on one or a plurality of measurement items of the workpiece 9. As shown in FIG. 1, the measurement system 10 includes a plurality of three-dimensional coordinate measuring machines 12, a plurality of control devices 14, and a management device 16.

  Since the plurality of three-dimensional coordinate measuring machines 12 have the same configuration, here, one three-dimensional coordinate measuring machine 12 will be described as an example. In this embodiment, it is assumed that the types of workpieces 9 to be measured by the three-dimensional coordinate measuring machines 12 are the same.

  The three-dimensional coordinate measuring machine 12 corresponds to the shape measuring machine of the present invention, and includes a table 18, a carriage 20, a probe head 22, and a probe 24. Each three-dimensional coordinate measuring machine 12 drives the carriage 20 and the probe head 22 by a drive mechanism (not shown) to bring the probe 24 into contact with the workpiece 9 while displacing the position and posture of the probe 24. The coordinate values (coordinate values in three axis directions orthogonal to each other) at the measurement location are acquired. In addition, since the detailed structure of the three-dimensional coordinate measuring machine 12 is a well-known technique, specific description is abbreviate | omitted here.

  A plurality of control devices 14 are provided for each three-dimensional coordinate measuring machine 12. In addition, since the some control apparatus 14 is the same structure, it demonstrates taking the case of one control apparatus 14 as an example here. The control device 14 is an arithmetic processing device such as a personal computer, for example, an arithmetic circuit including various arithmetic units including a CPU (Central Processing Unit) or an FPGA (field-programmable gate array), a memory, and the like; Various functional circuits. The control device 14 is connected to the corresponding three-dimensional coordinate measuring machine 12 by wire (or wireless connection is possible).

  The control device 14 performs measurement control for each measurement item of the workpiece 9 by the three-dimensional coordinate measuring machine 12 and calculation of the measurement data 26 for each measurement item of the workpiece 9. Further, the control device 14 is connected to the management device 16 by wire (or wireless connection is possible). Here, the measurement items of the work 9 are defined at least the measurement location (measurement position) in the work 9 and the measurement content (shape, dimensions, etc.).

  The management device 16 is an arithmetic processing device such as a personal computer, and is connected to each control device 14. The management device 16 manages (accumulates) measurement data 26 for each measurement item measured by each three-dimensional coordinate measuring machine 12. Moreover, the management apparatus 16 corrects the design tolerance of each measurement item of the workpiece 9 as will be described in detail later.

[Configuration of control device]
FIG. 2 is a block diagram showing the configuration of each control device 14 and management device 16. As shown in FIG. 2, in addition to the three-dimensional coordinate measuring machine 12, an operation unit 30 and a display unit 31 are connected to each control device 14. For each control device 14, the measurement or the like of the workpiece 9 by the three-dimensional coordinate measuring machine 12 is controlled according to an input operation to the operation unit 30.

  Each control device 14 includes a controller 32, a storage unit 34, a data processing device 36, an information output circuit 37, an interface 38, and a correction circuit 40. In addition, since each part from the controller 32 of each control apparatus 14 to the correction circuit 40 is fundamentally the same structure, each part of one control apparatus 14 is demonstrated here.

  The controller 32 drives the carriage 20 and the probe head 22 by a drive mechanism (not shown), and causes the probe 24 to contact the workpiece 9 while displacing the position and posture of the probe 24, thereby measuring the coordinate measuring machine 12. Perform measurement for each item. At this time, the controller 32 drives the carriage 20 and the probe head 22 based on the measurement program 28 read from the storage unit 34 to cause the three-dimensional coordinate measuring machine 12 to perform automatic measurement of the workpiece 9. Thereby, the measurement for each measurement item is automatically executed by the three-dimensional coordinate measuring machine 12. The controller 32 can also perform manual measurement for driving the carriage 20 and the probe head 22 in accordance with a manual operation input to the operation unit 30.

  At the time of automatic measurement, the controller 32 executes the measurement program 28 stored in the storage unit 34, thereby measuring the coordinate measuring machine 12 based on a plurality of measurement items defined in the measurement program 28. Perform measurement for each item.

  In the measurement program 28, a plurality of measurement items are defined according to the type of the workpiece 9, that is, the measurement location for each measurement item, the measurement order of each measurement location, the posture of the probe 24 for each measurement location, and the like. . The measurement program 28 defines a design tolerance that is predetermined for each measurement item (measurement location). The measurement program 28 is described on the assumption that correction (correction of design tolerance) is performed by a correction circuit 40 described later, and has, for example, a description portion in which the design tolerance is changed.

  When the measurement for each measurement item is executed by the three-dimensional coordinate measuring machine 12, the data processing device 36 sequentially acquires the coordinate value of the contact point of the probe 24 from the three-dimensional coordinate measuring machine 12 via the controller 32. Thus, measurement data 26 that is a measurement result for each measurement item is calculated. Then, the data processing device 36 stores the measurement data 26 for each measurement item in the storage unit 34 and outputs it to the interface 38.

  Further, the data processing device 36 displays the design tolerance for each measurement item on the display unit 31 based on the design tolerance for each measurement item defined in the measurement program 28, or includes the measurement data 26 for each measurement item. When an out-of-design tolerance range occurs, an alarm indicating that fact is displayed on the display unit 31. In addition, about an alarm, you may perform the audio | voice display (audio | voice output) using a speaker etc. which are not illustrated.

  The information output circuit 37 extracts information on the name, measurement item, and design tolerance from the measurement program 28 in the storage unit 34 before the measurement of the workpiece 9 by the three-dimensional coordinate measuring machine 12 is started. The measurement program information 29 is output to the interface 38.

  Note that the timing of outputting the measurement program information 29 by the information output circuit 37 is not particularly limited, but in this embodiment, the information output circuit 37 uses the information output circuit 37 in accordance with the correction timing by a tolerance correction unit 63 of the management device 16 described later. The measurement program information 29 is output.

  The interface 38 is connected to a management device 16 (to be described later) by a wired connection (or wireless connection is possible) via a LAN (Local Area Network) or the like, and exchanges various information and data with the management device 16.

  Specifically, the interface 38 outputs the measurement data 26 for each measurement item input from the data processing device 36 and the measurement program information 29 input from the information output circuit 37 to the management device 16. Each interface 38 outputs tolerance information 67 (see FIG. 3) input from the management device 16 to the correction circuit 40. The tolerance information 67 indicates a new design tolerance for each measurement item, which will be described later in detail.

  The correction circuit 40 accesses the measurement program 28 in the storage unit 34 based on the tolerance information 67 input from the management device 16 via the interface 38, and is corrected by the measurement program 28, that is, defined by the measurement program 28. Correct the design tolerance for each measurement item. As described above, since the measurement program 28 is a description premised on the correction by the correction circuit 40, the correction circuit 40 corrects the design tolerance by correcting the corresponding description portion in the measurement program 28. It can be done easily.

[Configuration of management device]
The management device 16 corresponds to a design tolerance correction device according to the present invention. The management device 16 accumulates measurement data 26 for each measurement item input from each control device 14 and stores later-described tolerance information 67 for each control device 14. And output. The management device 16 includes a management device main body 42, an operation unit 44, and a display unit 46. The operation unit 44 is, for example, a keyboard and a mouse, and is used for inputting an operation instruction to the management apparatus main body 42. The display unit 46 performs various displays including a management chart 72 (see FIG. 3) described later under the control of the management apparatus main body 42.

  FIG. 3 is a block diagram illustrating a configuration of the management apparatus main body 42. As illustrated in FIG. 3, the management apparatus main body 42 includes an interface 50, a management control unit 52, and a storage unit 54.

  The interface 50 exchanges various information and data (measurement data 26, measurement program information 29, tolerance information 67 and the like) described above with the interface 38 of each control device 14.

  The management control unit 52 includes, for example, various calculation circuits including a calculation unit (CPU or FPGA) and a memory. This management control unit 52 is based on a management program 56 stored in the storage unit 54, stores (accumulates) the measurement data 26 input from each control device 14, corrects design tolerances for each measurement item, Various controls including output control of the tolerance information 67 for each control device 14 are performed. The management control unit 52 functions as a storage control unit 58, a management chart generation unit 60, a tolerance correction unit 63, and a display control unit 66 by executing the management program 56.

  The storage control unit 58 acquires each measurement data 26 from the interface 50 every time measurement data 26 for each measurement item is input from each control device 14 to the interface 50, and the measurement data storage unit in the storage unit 54. 70 is stored (accumulated).

  FIG. 4 is a schematic diagram of the measurement data storage unit 70. As shown in FIG. 4 and FIG. 3 described above, the storage control unit 58 accumulates the measurement data 26 obtained from the interface 50 in a state where both the type of the work 9 and the type of the measurement item can be identified. Store in the unit 70. Thereby, every time each three-dimensional coordinate measuring machine 12 performs measurement for each measurement item, the output of the measurement data 26 for each measurement item from each control device 14, the acquisition of each measurement data 26 by the interface 50, The storage control unit 58 repeatedly stores each measurement data 26 in the measurement data storage unit 70. As a result, the measurement data 26 for each measurement item is stored in the measurement data storage unit 70.

  Note that the storage method (storage method) of each measurement data 26 in the measurement data storage unit 70 is not limited to the example shown in FIG. 4, and at least identifies both the type of the workpiece 9 and the type of the measurement item. You may change arbitrarily if possible.

  FIG. 5 is an explanatory diagram showing an example of a management chart 72 generated for each measurement item by the management chart generation unit 60. As shown in FIG. 5 and FIG. 3 described above, the control chart generation unit 60 is based on the measurement data 26 in the measurement data storage unit 70, and the measurement data 26 plotted in time series (period) for each measurement item. Is generated. The horizontal axis of the control chart 72 is not particularly limited as long as it indicates a temporal change in the measurement data 26 of each measurement item, and may be changed to, for example, the “production lot number” of the workpiece 9.

  The symbol “C” in the drawing is a center line corresponding to the average value of the measurement data 26 for each measurement item, and the symbol “UC” in the drawing is an upper limit value of the design tolerance determined for each measurement item. The upper limit tolerance (upper specification limit) is indicated, and the symbol “LC” in the figure indicates the lower limit tolerance (lower specification limit) that is the lower limit value of the design tolerance defined for each measurement item. Furthermore, the symbol “W0” in the figure indicates the tolerance width of the design tolerance that is the width between the upper limit tolerance UC and the lower limit tolerance LC for each measurement item.

  The initial values of the upper limit tolerance UC and the lower limit tolerance LC for each measurement item are determined by the design tolerance for each measurement item included in the described measurement program information 29. Even if the initial value of the upper limit tolerance UC and the lower limit tolerance LC for each measurement item is set according to the tolerance class defined by the Japanese Industrial Standards (JIS) or the tolerance class prescribed by the manufacturer's internal regulations, etc. Good. In this embodiment, an upper limit tolerance UC and a lower limit tolerance LC are corrected by a tolerance correction unit 63 described later.

  The symbol “UP” in the drawing indicates the upper management limit of the measurement data 26 for each measurement item, and the symbol “LP” in the drawing indicates the lower management limit of the measurement data 26 for each measurement item. And the code | symbol "W1" in a figure, ie, the width | variety of the upper management limit UP and the lower management limit LP shows the management limit defined for every measurement item. Therefore, based on whether or not the variation of the measurement data 26 for each measurement item is within the control limit, it is possible to determine whether or not the size and shape of the workpiece 9 corresponding to each measurement item are in the management state. it can. The management limit W1 (upper management limit UP and lower management limit LP) for each measurement item is determined within a range of ± nσ (n is an arbitrary natural number) with respect to the center line C, for example, for each measurement item. .

  The management chart generation unit 60 stores a management chart 72 for each measurement item in the storage unit 54. Then, each time new measurement data 26 is stored (accumulated) in the measurement data accumulation unit 70, the management chart generation unit 60 manages the management diagram 72 in the storage unit 54 corresponding to the measurement item of the new measurement data 26. Update.

  The tolerance correction unit 63 corresponds to the analysis unit and the correction unit of the present invention. The tolerance correction unit 63 determines the type of measurement item based on the measurement program information 29 input from each control device 14 via the interface 50 or the like. The tolerance correction unit 63 corrects the design tolerance for each measurement item, that is, corrects the upper limit tolerance UC and the lower limit tolerance LC based on the following first to third conditions. Hereinafter, the corrected upper limit tolerance UC is abbreviated as “corrected upper limit tolerance UC”, and the corrected lower limit tolerance LC is abbreviated as “corrected lower limit tolerance LC”.

  Note that the correction by the tolerance correction unit 63 is performed, for example, before the measurement of the workpiece 9 by each three-dimensional coordinate measuring machine 12 is started. The timing of the correction is not particularly limited. For example, when the type or manufacturing lot of the workpiece 9 to be measured by the three-dimensional coordinate measuring machine 12 changes or when each three-dimensional coordinate measuring machine 12 is started. There may be. When the type of the workpiece 9 to be measured does not change, the correction by the tolerance correction unit 63 may be performed periodically (for example, once a day).

  The first condition is the average value and variation of the measurement data 26 for each measurement item. For example, when the design tolerance (tolerance width W0) of this measurement item is set narrow with respect to the variation (variation width) of the measurement data 26 of an arbitrary item of the workpiece 9, the workpiece 9 that falls within the design tolerance is set. It cannot be manufactured or processed. In this case, it is necessary to correct the upper limit tolerance UC and the lower limit tolerance LC so as to widen the design tolerance (tolerance width W0). For this reason, the tolerance correction unit 63 analyzes the average value and variation of the measurement data 26 for each measurement item before calculating the correction upper limit tolerance UC and the correction lower limit tolerance LC for each measurement item.

  The second condition is a magnification set for each measurement item by an input operation to the operation unit 44 (corresponding to the setting unit of the present invention), and is a magnification that serves as an index for determining the tolerance width W0 of the design tolerance after correction. (Corresponding to the target value of the present invention). For example, when the magnification for each measurement item is set to 10 times, a tolerance width W0 that is 10 times the variation of the measurement data 26 is secured for each measurement item. By adjusting the magnification, for example, when the quality of the workpiece 9 is not ensured with the tolerance width W0 of the design tolerance for each current measurement item, the tolerance width W0 of the design tolerance for each measurement item can be narrowed. For this reason, the tolerance correction unit 63 calculates the correction upper limit tolerance UC and the correction lower limit tolerance LC for each measurement item based on the magnification set for each measurement item via the operation unit 44.

  The third condition is the number of rounding digits after the decimal point of both the correction upper limit tolerance UC and the correction lower limit tolerance LC for each measurement item calculated by the tolerance correction unit 63. This third condition is also set for each measurement item by an input operation to the operation unit 44. Note that the third condition may be omitted as appropriate.

  The tolerance correction unit 63 analyzes the measurement data 26 in the measurement data storage unit 70 to obtain an average value of the measurement data 26 for each measurement item, and as a variation of the measurement data 26 for each measurement item, A peak-to-peak value (hereinafter abbreviated as PP value) or standard deviation, which is the difference between the maximum value and the minimum value, is obtained. The tolerance correction unit 63 then calculates the correction upper limit tolerance UC for each measurement item based on the average value and variation (PP value or standard deviation) for each measurement item and the magnification for each measurement item set by the operation unit 44. Calculate the corrected lower limit tolerance LC.

  Specifically, when the average value of the measurement data 26 for each measurement item is A, the variation Q of the measurement data 26 for each measurement item, the PP value is W, the standard deviation is σ, and the magnification is α, the tolerance is The correction unit 63 calculates the correction upper limit tolerance UC and the correction lower limit tolerance LC using the following [Equation 1].

  FIG. 6 is an explanatory diagram for describing a specific example of calculation of the correction upper limit tolerance UC and the correction lower limit tolerance LC by the tolerance correction unit 63. In FIG. 6, “correction method 1” uses the PP value (W) as the variation for each measurement item, and “correction method 2” uses the standard deviation (σ) as the variation for each measurement item. Further, the upper limit tolerance UC before correction is set to +0.1, and the lower limit tolerance LC before correction is set to −0.1.

  As shown in FIG. 6 and FIG. 3 of the description, in the correction method 1, the tolerance correction unit 63 sets the PP value of the measurement data 26 to W = 0.028, for example, and sets the average value of the measurement data 26 to A = 0.01. When the magnification is α = 10, “+0.15” is obtained as the correction upper limit tolerance UC and “−0.13” is obtained as the correction lower limit tolerance LC based on the above equation (1).

  Further, in the correction method 2, the tolerance correction unit 63 sets the standard deviation of the measurement data 26 to σ = 0.015, sets the average value of the measurement data 26 to A = 0.01, and sets the magnification to α = 3 (3σ). In this case, “+0.0325” is obtained as the corrected upper limit tolerance UC, and “−0.0125” is obtained as the corrected lower limit tolerance LC based on the above equation (1).

  Next, the tolerance correction unit 63 rounds the correction upper limit tolerance UC and the correction lower limit tolerance LC for each measurement item calculated using the above [Equation 1] to the rounding digits after the decimal point set in the third condition. To do. Thereby, the correction of the design tolerance (upper limit tolerance UC and lower limit tolerance LC) for each measurement item by the tolerance correction unit 63, that is, the calculation of the corrected upper limit tolerance UC and the corrected lower limit tolerance LC is completed. Then, the tolerance correction unit 63 outputs the calculation result of the correction upper limit tolerance UC and the correction lower limit tolerance LC for each measurement item to the display control unit 66 as tolerance information 67. Further, the tolerance correction unit 63 outputs the tolerance information 67 to each control device 14 via the interface 50.

  The correction circuit 40 of each control device 14 determines the design tolerance (upper limit tolerance UC and lower limit tolerance LC) for each measurement item with respect to the measurement program 28 in the storage unit 34 based on the tolerance information 67 input from the tolerance correction unit 63. ) Is corrected.

  Returning to FIG. 3, the display control unit 66 displays the inspection result table display screen obtained by appropriately statistically processing the measurement data 26 for each measurement item stored in the measurement data storage unit 70, the second condition and the third described above. Various screens including a condition input screen and a display screen of the management chart 72 for each measurement item are displayed on the display unit 46.

  Further, when displaying the management chart 72 (see FIG. 5) for each measurement item on the display section 46, the display control section 66 is based on the tolerance information 67 input from the tolerance correction section 63 described above. Display the correction upper limit tolerance UC and the correction lower limit tolerance LC.

[Operation of measurement system (management device)]
FIG. 7 is a flowchart showing the flow of measurement processing of the workpiece 9 by the measurement system 10 having the above-described configuration (corresponding to the design tolerance correcting method of the present invention). As shown in FIG. 7, first, each three-dimensional coordinate measuring machine 12, each control device 14, and the management device 16 are activated (steps S1A and S1B).

  Next, an administrator of the management device 16 performs an input operation of the second condition (magnification for each measurement item) and the third condition (number of rounding digits for each measurement item) on the operation unit 44 of the management device 16. . Thereby, the second condition and the third condition are set for the tolerance correcting unit 63 of the management control unit 52 of the management device 16 (step S2A, corresponding to the setting step of the present invention).

  On the other hand, after starting each 3D coordinate measuring machine 12 and each control device 14, the information output circuit 37 of each control device 14 extracts the measurement program information 29 from the measurement program 28 in the storage unit 34 and outputs it to the interface 38. (Step S2B). Thereby, the measurement program information 29 output from each control apparatus 14 is input into the tolerance correction | amendment part 63 of the management apparatus 16 via the interface 50 grade | etc., (Step S3A).

  The tolerance correcting unit 63 that has received the input of the measurement program information 29 determines the type of measurement item of the workpiece 9 to be measured by each three-dimensional coordinate measuring machine 12 based on the measurement program information 29 (step S4A).

  Next, the tolerance correction unit 63 analyzes the average value and the variation (PP value or standard deviation) with reference to the measurement data 26 of the workpiece 9 stored in the measurement data storage unit 70 for each of the determined measurement items (step) S5A, corresponding to the analysis step of the present invention). Thereby, the first condition described above is also determined.

  Then, the tolerance correction unit 63 calculates the above [Equation 1] based on the analysis result of the average value and variation (PP value or standard deviation) for each measurement item and the magnification for each measurement item set by the operation unit 44. Is used to calculate the corrected upper limit tolerance UC and the corrected lower limit tolerance LC for each measurement item. After this calculation, the tolerance correction unit 63 rounds the calculation results of each correction upper limit tolerance UC and correction lower limit tolerance LC to the number of rounds after the decimal point set in the third condition. Thereby, the correction of the design tolerance (upper limit tolerance UC and lower limit tolerance LC) for each measurement item by the tolerance correction unit 63, that is, the calculation of the corrected upper limit tolerance UC and the corrected lower limit tolerance LC is completed (step S6A, the tolerance of the present invention). Equivalent to the correction step).

  When the calculation of the correction upper limit tolerance UC and the correction lower limit tolerance LC for each measurement item is completed, the tolerance correction unit 63 outputs the tolerance information 67, which is the calculation result, to the display control unit 66. Further, the tolerance correction unit 63 outputs the tolerance information 67 to the interface 50 (step S7A). As a result, the tolerance information 67 is output to the correction circuit 40 of each control device 14 via the interface 50.

  The correction circuit 40 of each control device 14 has a design tolerance (upper limit tolerance UC and lower limit tolerance LC) for each measurement item with respect to the measurement program 28 in the storage unit 34 based on the tolerance information 67 input from the management device 16. Correction processing is performed to correct (steps S3B, S4B).

  Next, the controller 32 of each control device 14 reads the measurement program 28 from the storage unit 34 and executes it (step S5B). As a result, for each control device 14, the controller 32 causes the three-dimensional coordinate measuring machine 12 to perform the measurement of the workpiece 9 regarding a plurality of measurement items determined by the measurement program 28 (step S6B).

  Further, when measurement of the workpiece 9 by each three-dimensional coordinate measuring machine 12 is started, the data processing device 36 of each control device 14 calculates the measurement data 26 for each measurement item, and the calculated measurement data 26 is stored in the management device 16. (Step S7B).

  At this time, the data processing device 36 causes the display unit 31 to display design tolerances (correction upper limit tolerance UC and correction lower limit tolerance LC) for each measurement item defined in the measurement program 28, or in the measurement data 26. When an out-of-design tolerance range occurs, an alarm indicating that fact is displayed on the display unit 31.

  Each measurement data 26 output from each control device 14 is input to the interface 50 of the management device 16. Then, the storage control unit 58 stores (accumulates) each measurement data 26 in the measurement data storage unit 70 in a state where both the type of the work 9 and the type of the measurement item can be identified as shown in FIG. (Step S8A, corresponding to the accumulation step of the present invention).

  Subsequently, the management chart generation unit 60 updates the management chart 72 in the storage unit 54 corresponding to the new measurement data 26 in response to the new measurement data 26 being stored in the measurement data storage unit 70 ( Step S9A). Then, when a display operation of the management chart 72 regarding an arbitrary measurement item of the workpiece 9 is executed by the operation section 44, the display control section 66 reads out the management chart 72 corresponding to the display operation from the storage section 54, and displays the display section. 46 (step S10A, corresponding to the display step of the present invention).

  At this time, the display control unit 66 displays the correction upper limit tolerance UC and the correction lower limit tolerance LC in the control chart 72 based on the tolerance information 67 input from the tolerance correction unit 63 described above. Thereby, the correction upper limit tolerance UC and the correction lower limit tolerance LC are displayed on the display unit 46 so as to be identifiable.

  Hereinafter, the design tolerances (upper limit tolerance UC and lower limit tolerance LC) for each measurement item are optimized by repeatedly executing the processing of each step.

[Effect of this embodiment]
As described above, in the present embodiment, the design tolerance (upper limit tolerance UC and lower limit tolerance LC) for each measurement item is corrected based on the variation of the measurement data 26 for each measurement item and the magnification set for each measurement item. It can be done automatically. As a result, the design tolerance can be easily corrected.

  Further, in the present embodiment, since the measurement program 28 can be automatically corrected due to design tolerances, a skill that is familiar with the correction of the measurement program 28 is not required, and the time required for the correction of the measurement program 28 and after the correction This eliminates the time required for checking the operation and prevents the measurement program 28 from being mistakenly corrected, thereby reducing the maintenance cost of the measurement program 28. As a result, the design tolerance can be easily corrected.

[Others]
In the above embodiment, by displaying the control chart 72 on the display unit 46, the tolerance information 67 (the correction upper limit tolerance UC and the correction lower limit tolerance LC) calculated by the tolerance correction unit 63 is displayed on the display unit 46 in an identifiable manner. However, the method for displaying the tolerance information 67 on the display unit 46 so as to be identifiable is not particularly limited, and any method may be used.

  In the measurement system 10 of the above embodiment, a plurality of sets of the three-dimensional coordinate measuring machine 12 and the control device 14 are provided, but the three-dimensional coordinate measuring machine 12 and the control device 14 may be a set. That is, the measurement system 10 of the present invention may be a stand-alone system including a set of the three-dimensional coordinate measuring machine 12 and the control device 14. In this case, the management program 56 described above is installed in the control device 14, and the control device 14 also functions as the management device 16 of the above embodiment. That is, the correction of the upper limit tolerance UC and the lower limit tolerance LC and the correction of the measurement program 28 may be performed by one apparatus.

  In the above-described embodiment, the three-dimensional coordinate measuring machine 12 and the control device 14 are provided separately, but both may be integrated.

  In the above-described embodiment, the magnification (α) is set as an index value serving as an index for determining the tolerance width W0 of the design tolerance after correction. However, the tolerance width W0 of the design tolerance after correction is set using another index value. May be determined. In the above-described embodiment, the magnification (index value) for each measurement item is set by an input operation to the operation unit 44. However, the setting method is not particularly limited, and other than the operation unit 44 is used. Settings may be made.

  In the above embodiment, the measurement data storage unit 70 is provided in the management device 16, but may be provided outside the management device 16 of the measurement data storage unit 70, for example, a server or database on the Internet. .

  In the above-described embodiment, the case where each three-dimensional coordinate measuring machine 12 measures the same type of workpiece 9 has been described as an example. However, the type of the workpiece 9 measured for each three-dimensional coordinate measuring machine 12 is the same. The present invention can be applied without this.

  In the above embodiment, the three-dimensional coordinate measuring machine 12 has been described as an example of the shape measuring machine of the present invention, but various shapes (straightness, roundness, surface roughness, dimensions, and the like) of the workpiece 9 according to the measurement program. If it is various shape measuring machines which measure shape etc., it will not be limited in particular.

10 ... Measurement system,
12 ... 3D coordinate measuring machine,
14 ... Control device,
16 ... management device,
26: Measurement data,
28 ... measurement program,
40 ... correction circuit,
42 ... management device body,
44 ... operation unit,
46 ... display part,
52 ... Management control unit,
58. Storage control unit,
60 ... control chart generator,
63 ... Tolerance correction unit,
66 ... display control unit,
70: Measurement data storage unit

Claims (6)

In a design tolerance correction method for correcting the design tolerance of one or more measurement items of a workpiece measured by a shape measuring machine,
An analysis step for analyzing an average value and variation of measurement data obtained by measurement of the measurement item of the workpiece by the shape measuring machine;
A setting step for setting a target value as an index for determining a tolerance width of the design tolerance after correction;
Based on the analysis result in the analysis step and the target value set in the setting step, the upper limit tolerance which is the upper limit value of the design tolerance and the lower limit tolerance which is the lower limit value of the design tolerance are corrected, respectively. A tolerance correction step to
A method for correcting design tolerances. In the setting step, a magnification for the variation analyzed in the analysis step is set as the target value,
In the tolerance correction step, when the variation is Q, the average value is A, the magnification is α, the corrected upper limit tolerance is UC, and the corrected lower limit tolerance is LC, the corrected 2. The design tolerance correction according to claim 1, wherein the upper limit tolerance is obtained by a formula UC = A + (Q × α) / 2 and the corrected lower limit tolerance is obtained by a formula LC = A− (Q × α) / 2. Method.   The method for correcting a design tolerance according to claim 1 or 2, wherein, in the analysis step, a peak-to-peak value, which is a difference between a maximum value and a minimum value of the measurement data, or a standard deviation of the measurement data is obtained as the variation. . A storage step of storing the measurement data obtained by measuring the measurement item of the workpiece by the shape measuring machine in a storage unit;
4. The design tolerance correction method according to claim 1, wherein in the analysis step, the average value and the variation of the measurement data accumulated in the accumulation unit are analyzed. 5.   5. The display step of displaying a control chart on a display unit based on the measurement data stored in the storage unit and the upper limit tolerance and the lower limit tolerance corrected in the tolerance correction step. Method for correcting design tolerances as described in the paragraph. In a design tolerance correction apparatus for correcting design tolerance of one or more measurement items of a workpiece measured by a shape measuring machine,
An analysis unit for analyzing an average value and variation of measurement data obtained by measuring the measurement items of the workpiece by the shape measuring machine;
A setting unit for setting a target value as an index for determining a tolerance width of the design tolerance after correction;
Based on the analysis result by the analysis unit and the target value set by the setting unit, the upper limit tolerance which is the upper limit value of the design tolerance and the lower limit tolerance which is the lower limit value of the design tolerance are corrected. A tolerance correction unit;
Design tolerance correction device comprising:

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