JP2006239846A - Nc machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an NC machining device capable of more easily measuring a shape of a work after machining. <P>SOLUTION: This NC machining device is furnished with a touch sensor a head end part TSS of which is energized in a specified direction and free to slide in the specified direction and the head end part TSS of which outputs a signal concerning a distance moved in the specified direction in parallel and a control means. The control means 30 forms a measuring shape data continuously measuring a shape of s surface of a work W in accordance with a direction moving the touch sensor TS and speed and the signal from the touch sensor TS output in accordance with the shape of the surface of the work W by pressing the head end part TSS of the touch sensor TS from the specified direction on the surface of the work W. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an NC machining apparatus (numerically controlled machining apparatus).

Conventionally, an NC processing device (numerical control processing device) processes various parts or products such as a mold of a resin molded product. For example, in the case of a mold, the NC machining apparatus creates a concave or convex mold by processing the surface of the workpiece. When inspecting the shape of a workpiece after processing (in this case, a mold), generally, an inspection operator uses various highly accurate measuring instruments such as calipers to measure the dimensions of various positions on the workpiece. Measure and inspect.
In addition, as a method of measuring various positions on the workpiece using the NC machining apparatus, the workpiece after machining using the touch sensor attached to the spindle of the NC machining apparatus according to the conventional technique described in Patent Document 1 is used. The coordinates on the surface are measured. An NC program creation method for automatically creating NC program data from the measured coordinates has been proposed.
JP-A-5-108130

When inspection of a workpiece after machining is performed by an inspection operator using a measuring instrument such as a caliper, it is very troublesome. In addition, the accuracy of the inspection result may vary depending on the skill level of the inspection operator.
Further, if the conventional technique described in Patent Document 1 is applied, it is conceivable to inspect the workpiece after machining by measuring the coordinates of various positions on the workpiece after machining by the touch sensor. However, in the method described in Patent Document 1, the distance in the depth direction at one point on the surface of the workpiece (the Z-axis direction in FIG. 11 of Patent Document 1) can be measured, but the horizontal direction (in FIG. 1). The distance in the X-axis direction and the Y-axis direction) cannot be measured. Moreover, it takes a very long time to measure various positions one by one by the operator's operation. For this reason, it is difficult to measure the shape of the workpiece after processing with the technique described in Patent Document 1.
The present invention has been made in view of such points, and an object of the present invention is to provide an NC machining apparatus that can more easily measure the shape of a workpiece after machining.

As means for solving the above-mentioned problems, the first invention of the present invention is an NC machining apparatus as described in claim 1.
The NC processing device according to claim 1 is an NC processing device including a touch sensor that measures the shape of the surface of a workpiece on the machine and a control unit, and the touch sensor includes a tip portion of the touch sensor. Is urged in a predetermined direction, the tip portion can slide in the predetermined direction, and a signal relating to a distance by which the tip portion has moved in parallel to the predetermined direction can be output.
The control means continuously moves the touch sensor based on a measurement program for measuring the shape of the surface of the workpiece, and presses the tip of the touch sensor from the predetermined direction against the surface of the workpiece, Based on the direction and speed in which the workpiece is moved and the signal from the touch sensor output in accordance with the shape of the workpiece surface, measurement shape data obtained by continuously measuring the workpiece surface shape is created.

The second invention of the present invention is an NC machining apparatus as set forth in claim 2.
An NC processing apparatus according to a second aspect is the NC processing apparatus according to the first aspect, wherein the control means performs a filtering process on the measurement shape data to correct the measurement shape data.

The third invention of the present invention is an NC machining apparatus as set forth in claim 3.
The NC processing device according to claim 3 is the NC processing device according to claim 1 or 2, wherein the control means stores the measurement shape data in accordance with a speed when the touch sensor is moved. The area is divided into a plurality of areas, and the measured shape data is corrected by applying a filter process to each divided area using a filter constant corresponding to the speed when the area is measured.

The fourth invention of the present invention is an NC machining apparatus as set forth in claim 4.
The NC processing device according to claim 4 is the NC processing device according to any one of claims 1 to 3, wherein the control means moves the touch sensor at different speeds with respect to the same location on the surface of the workpiece. The measured shape data is corrected based on the plurality of measured shape data.

The fifth invention of the present invention is an NC machining apparatus as set forth in claim 5.
The NC processing device according to claim 5 is the NC processing device according to any one of claims 1 to 4, comprising storage means in which target shape data including dimensions of the workpiece after processing is stored, The control means corrects the measured shape data based on the target shape data stored in the storage means.

The sixth invention of the present invention is an NC machining apparatus as set forth in claim 6.
An NC machining apparatus according to a sixth aspect is the NC machining apparatus according to any one of the first to fifth aspects, comprising storage means for storing allowable error data relating to the shape of the surface of the workpiece, and the control means. Determines the quality of the processed workpiece based on the measured shape data and the allowable error data stored in the storage means.

If the NC processing device according to claim 1 is used, for example, in a state where the touch sensor provided on the spindle is pressed against the workpiece, the spindle is moved in a direction perpendicular to the pressing direction, for example, and the touch sensor is moved on the surface of the workpiece. It is possible to continuously measure the shape of the surface of the workpiece using a signal that is output according to the shape (surface irregularities etc.) (measurement shape data as a continuous shape rather than measuring the position of each point) Can be created). Thereby, it can measure in a very short time compared with the method of measuring many points one by one.
Thereby, the shape of the workpiece | work after a process can be measured more easily.

  In addition, according to the NC machining apparatus of the second aspect, various noises (for example, natural vibration of the NC machining apparatus, etc.) superimposed on the continuously measured shape data are appropriately removed by filtering. can do.

  In addition, according to the NC machining apparatus of the third aspect, it is possible to more appropriately remove noise. For example, when the touch sensor is vibrated by the natural vibration (mechanical vibration, etc.) of the NC processing device, the measured shape data is measured when the touch sensor is moved at a speed V and when the touch sensor is moved at a speed V / 2. The interval (shape) of the waveform due to the vibration appearing in (1) changes (see FIG. 5A). Such noise can also be appropriately removed by changing the filter constant according to the speed when the touch sensor is moved.

  In addition, according to the NC machining apparatus of the fourth aspect, it is possible to more appropriately remove noise. For example, when the touch sensor is vibrated by the natural vibration (mechanical vibration or the like) of the NC processing apparatus, when the touch sensor is moved at the speed V, the same is true when the noise waveform of the interval a is superimposed on the measurement shape data by the natural vibration When the touch sensor is moved at a speed V / 2 with respect to the location, the noise waveform with the interval a / 2 is superimposed on the measurement shape data by the natural vibration (see FIG. 5B). In this way, it is possible to appropriately detect and remove noise that changes according to speed.

  In addition, according to the NC processing apparatus of the fifth aspect, it is possible to remove an abnormal measurement value that cannot be removed even by filtering using the target shape data (ideal shape) stored in advance. For example, if the surface shape does not change smoothly with respect to the movement direction of the touch sensor, and there is a steep unevenness, the output from the touch sensor may not follow the change in shape and may be abnormal. is there. Such an abnormal value can be appropriately removed.

Further, according to the NC machining apparatus of the sixth aspect, the accuracy of the workpiece machined by the NC machining apparatus can be appropriately determined using the NC machining apparatus.
For this reason, even if it is not a skilled worker, the workpiece | work after a process can be test | inspected appropriately.

The best mode for carrying out the present invention will be described below with reference to the drawings.
● [Appearance of NC processing equipment and characteristics of touch sensor, etc. (Figs. 1 and 2)]
FIG. 1 shows a schematic external view of an embodiment of an NC processing apparatus 10 of the present invention. 2A shows a schematic external view and a schematic characteristic diagram of the touch sensor TS, and FIG. 2B shows a schematic configuration of the NC processing apparatus 10 shown in FIG.
An NC machining apparatus 10 according to the present invention includes a main shaft 20 that can be moved in three orthogonal directions (X axis, Y axis, Z axis), and a tool K (machining means) provided on the movement of the main shaft 20 and the main shaft 20. And a control means 30 for controlling the drive. The movable direction is a direction from the main shaft 20 toward the workpiece W (in the case of FIG. 1, the Z-axis direction) and a direction perpendicular to the direction (in the case of FIG. 1, the X-axis direction or the Y-axis direction). What is necessary is just to be able to move in at least two directions.

The spindle 20 can be provided with (attached to) at least one of the tool K and the touch sensor TS. As shown in the example of FIG. 1, the spindle 20 includes a spindle 20 of a type in which the tool K or the touch sensor TS is attached to the tool K or the touch sensor TS, and the spindle 20 is replaced with the touch sensor TS. A spindle 20 of a type in which a tool K and a touch sensor TS are attached to each head part on the spindle 20 having a plurality of head parts and the head part facing the workpiece W can be freely changed is also included. Both types of spindles 20 can “select and provide (attach) at least one of the tool K and the touch sensor TS”.
The control means 30 includes an input means 30a for inputting an instruction from the operator, an output means 30b for displaying an input state, a machining state, etc., a machining program (NC program or the like) for machining the workpiece W, and the workpiece W. The storage means 30d (refer FIG. 2 (B)) in which the measurement program (NC program etc.) for measuring the shape of this is memorize | stored is provided. In the schematic configuration shown in FIG. 2B, various interfaces (between the touch sensor TS and the CPU 30c, between the input means 30a and the CPU 30c, etc.) are omitted.

When the spindle 20 is provided with the tool K, the control means 30 (CPU 30c of the control means 30) can machine the workpiece W fixed to the table TB based on the machining program stored in the storage means 30d. is there.
When measuring the shape of the surface of the workpiece W on the machine, the touch sensor TS is pressed against the workpiece W in the direction from the main shaft 20 toward the workpiece W (in the case of FIGS. 1 and 2, the Z-axis direction). Note that “on-machine” means on an NC machining apparatus. The tip portion TSS of the touch sensor TS is biased in the pressing direction (in the case of FIGS. 1 and 2 in the Z-axis direction) by an elastic member such as a spring, and can slide in the pressing direction. The touch sensor TS pressed against the workpiece W is set in a direction perpendicular to the pressing direction (in the case of FIG. 1, the X-axis direction or the Y-axis direction, or the combined direction of the X-axis direction and the Y-axis direction) in a predetermined direction. When moved at a speed, the tip TSS moves in parallel to the pressing direction according to the unevenness (surface shape) of the workpiece W. The touch sensor TS outputs a signal related to the distance (stroke amount) that the tip TSS has moved according to the unevenness (surface shape) of the workpiece W (see FIG. 2A).

  When the spindle 20 is provided with the touch sensor TS, the control means 30 (the CPU 30c of the control means 30) controls the spindle movement means 22 based on the measurement program stored in the storage means 30d and performs machining with the tool K. The tip portion TSS of the touch sensor TS is pressed against the surface of the workpiece W (pressed from a slidable direction), and the touch sensor TS is moved in a direction perpendicular to the pressing direction. And the control means 30 (CPU30c of the control means 30) changes the shape of the workpiece | work W based on the direction and speed which moved the touch sensor TS, and the signal from the touch sensor output according to the unevenness | corrugation of the workpiece | work W. Measurement shape data measured continuously can be created.

● [Example of how to create measurement shape data (Figure 3)]
Next, FIG. 3 shows an example of measurement shape data created by measuring the surface of the workpiece W after processing. In the example of FIG. 3 (A), the surface of the workpiece W after processing is formed in a shape in which a substantially rectangular parallelepiped portion is left substantially at the center and the periphery thereof is cut into a concave shape.
For example, the control means 30 presses the tip portion TSS of the touch sensor TS against the point A in FIG. 3A and moves it at the speed V to the point B along the X-axis direction, and the moved speed and direction and the touch sensor TS. It is possible to create measurement shape data as shown in the example of FIG. The control means 30 knows itself about the X coordinate and the Y coordinate of the main shaft 20 that is moving, by moving the main shaft 20. Further, the Z coordinate of the tip portion TSS of the touch sensor TS can be converted based on the Z coordinate of the spindle 20 and a signal from the touch sensor TS.

Similarly, the control means 30 presses the tip portion TSS of the touch sensor TS against the point C in FIG. 3A and moves it at the speed V to the point D along the Y-axis direction. Based on the signal from the sensor TS, it is possible to create measurement shape data as shown in the example of FIG.
These “measured shape data obtained by continuously measuring the surface shape of the workpiece W” are created in a plurality of directions at a plurality of locations on the workpiece W, and the created plurality of measured shape data are measured positions and If arranged according to the direction, the shape of the workpiece W can be three-dimensionally represented as shown in FIG.

● [Correcting the created measurement shape data (Figs. 4 and 5)]
Next, an example of a procedure for correcting the measurement shape data created by the control unit 30 measuring the surface of the workpiece W will be described with reference to FIGS. 4 and 5.
In step S <b> 10, the control unit 30 receives a signal from the touch sensor TS while moving the touch sensor TS, and determines the Z coordinate with respect to the movement position (X coordinate and Y coordinate) of the tip end portion TSS of the touch sensor TS as the Z of the spindle 20. It calculates | requires based on the coordinate and the signal from touch sensor TS. By performing this process while moving the touch sensor, measurement shape data on the surface of the workpiece W can be continuously created. Here, in many cases, various noises are superimposed on the signal from the touch sensor TS, and it is preferable to remove the superimposed noise to improve the reliability of the measurement shape data.

The noise superimposed on the touch sensor TS includes, for example, natural vibration (mechanical vibration or the like) of the NC processing apparatus 10. This mechanical vibration is always generated while the NC machining apparatus 10 is in operation.
In step S20, in order to remove the influence of this mechanical vibration, the created measurement shape data is filtered. For example, processing is performed by a low-pass filter, a band-pass filter, or a notch filter having a cutoff frequency of about several hundred Hz.
In the graph of the measurement shape data shown in the example of FIG. 4, both the horizontal axis and the vertical axis are distances, but it is only necessary to perform the filtering process on the assumption that the horizontal axis (in this case, X axis or Y axis) is the time axis. (All are common to the following filter processes).

Further, as described above, processing may be performed with a fixed filter constant (cutoff frequency or the like), or processing may be performed with a variable filter constant. For example, when the vibration of the touch sensor TS is generated at a predetermined cycle S due to the natural frequency of the NC processing apparatus 10, the touch sensor is moved at a speed V, and the touch sensor is moved at a speed V / 2. In some cases, the noise waveform is different. Accordingly, the area of the measurement shape data is divided and stored in correspondence with the speed when the touch sensor TS is moved (for example, the area A moves at a speed V, the area B moves at a speed V / 2, etc.). . Then, the measured shape data is corrected using a filter constant corresponding to the speed when the data in the area is measured for each divided area.
For example, as shown in FIG. 5 (A), when the natural frequency is M [Hz] and the touch sensor TS is moved at a speed V [mm / sec] in the region A, the measurement shape data has an interval a. When the natural vibration is superimposed, noise is removed in the region A by a bandpass filter (or notch filter) that removes noise at the interval a. In the region B, when the touch sensor TS is moved at a speed V / 2 [mm / sec], the natural vibration is superimposed on the measurement waveform data at an interval a / 2. In this region B, correction for removing noise may be performed by a bandpass filter (or notch filter) that removes noise at an interval a / 2. The intervals a and a / 2 can be obtained from the natural frequency M and the speed V or V / 2 which are known in advance.

As another filtering process, the same location on the workpiece W can be measured and corrected a plurality of times at different speeds. In this case, the natural frequency may not be known in advance.
For example, as shown in FIG. 5B, when the touch sensor TS is moved in the region A at a speed V [mm / sec], it is assumed that a vibration waveform having an interval a appears in the measurement shape data due to the natural frequency. Further, when the touch sensor TS is moved in the same region A at a speed V / 2 [mm / sec], according to the natural frequency, a vibration waveform with an interval a / 2 appears in the measurement shape data. Since the waveform based on the shape of the workpiece W is constant regardless of the speed, the control unit 30 can determine that the vibration waveform is not a shape of the workpiece but a noise waveform due to the natural vibration of the touch sensor TS. it can. (In the same place, a waveform whose interval changes corresponding to a change in speed at which the touch sensor TS is moved is determined as a noise waveform)
In this case, correction may be performed to remove noise by a bandpass filter (or notch filter) that removes the vibration waveform at the interval a or the vibration waveform at the interval a / 2 from each measurement shape data.
In addition, vibration waveforms appearing at the same interval even when the speed is changed at the same location have a high probability of being the shape of the workpiece W, and can be determined not to be noise. Thus, when the same part is measured at different speeds, various corrections can be made.

Further, a noise component that cannot be removed even by the filter processing described above is also conceivable.
In step S30, the measured shape data is corrected based on the target shape data (three-dimensional shape data or the like) of the processed workpiece W stored in advance in the storage means 30d. The target shape data is stored in advance in the storage unit 30d.
For example, there may be a case where an abnormal value that does not exist in the actual workpiece W and is significantly different from the target shape due to some abnormality exists in the measured shape data (C portion in FIG. 4). The control means 30 compares the target shape data with the measured shape data, and corrects an abnormal value whose difference is larger than a predetermined value based on the target shape data. In such a state, the tip portion TSS of the touch sensor TS cannot follow the change in shape at a position where the tip portion TSS of the touch sensor TS suddenly moves in the pressing direction (moves rapidly in the Z-axis direction). Sometimes it happens.

In step S40, the quality of the workpiece W after machining is determined based on the allowable error data stored in advance in the storage unit 30d and the measured shape data subjected to the correction described above. In addition, the allowable error data is stored in advance in the storage unit 30d.
When the measured shape data is within the allowable error range based on the allowable error data, the control means 30 determines that the processed workpiece W is a non-defective product and outputs a display to that effect to the output means 30b. To do. If the measured shape data deviates from the allowable error range, it is determined that the processed workpiece W is not a non-defective product, and a display to that effect is output to the output means 30b.
In addition, since the shape of the processed workpiece W is measured using the NC processing apparatus 10 that processed the workpiece W, the touch sensor TS provided on the spindle 20 is replaced with the tool K when it is determined that the workpiece W is not a good product. It is possible to rework the workpiece W for machining correction, which is very efficient.

The NC processing apparatus 10 of the present invention is not limited to the appearance, configuration, processing method, and the like described in the present embodiment, and various changes, additions, and deletions are possible without changing the gist of the present invention.
Note that the numerical values and the like used in the description of the present embodiment are examples, and are not limited to these numerical values and the like.

1 is a schematic external view of an embodiment of an NC processing apparatus 10 of the present invention. FIG. 2 is a diagram showing a schematic appearance and characteristics of a touch sensor TS and a schematic configuration of the NC processing apparatus 10. It is a figure explaining the example of the method of producing measurement shape data. It is a figure explaining the example of the procedure which correct | amends measurement shape data. It is a figure explaining a mode that the natural vibration of touch sensor TS appears in measurement shape data as a noise waveform of the period according to movement speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 NC processing apparatus 20 Main axis | shaft 22 Main axis | shaft moving means 30 Control means 30a Input means 30b Output means 30c CPU
30d storage means K tool (machining means)
TB table TS Touch sensor TSS Tip W Work

Claims (6)

An NC machining apparatus having a touch sensor and a control means for measuring the shape of the surface of a workpiece on the machine,
In the touch sensor, the tip of the touch sensor is urged in a predetermined direction, the tip is slidable in the predetermined direction, and a signal related to the distance the tip moves in parallel to the predetermined direction. Can be output,
The control means continuously moves the touch sensor based on a measurement program for measuring the shape of the surface of the workpiece, presses the tip of the touch sensor from the predetermined direction against the surface of the workpiece, Based on the moved direction and speed, and a signal from the touch sensor output according to the shape of the surface of the workpiece, create measurement shape data that continuously measures the shape of the surface of the workpiece.
NC processing device characterized by that. The NC processing device according to claim 1,
The control means corrects the measurement shape data by performing a filtering process on the measurement shape data.
NC processing device characterized by that. The NC processing device according to claim 1 or 2,
The control means divides the measurement shape data into a plurality of areas corresponding to the speed when the touch sensor is moved, and a filter constant corresponding to the speed when the area is measured for each divided area. To correct the measurement shape data by performing a filtering process for each divided area,
NC processing device characterized by that. The NC processing device according to any one of claims 1 to 3,
The control means corrects the measurement shape data based on a plurality of measurement shape data obtained by moving the touch sensor at different speeds with respect to the same location on the surface of the workpiece.
NC processing device characterized by that. The NC processing device according to any one of claims 1 to 4,
Comprising storage means for storing target shape data including the dimensions of the workpiece after machining;
The control means corrects the measured shape data based on the target shape data stored in the storage means;
NC processing device characterized by that. The NC processing device according to any one of claims 1 to 5,
Comprising storage means for storing tolerance data relating to the shape of the workpiece surface;
The control means determines the quality of the processed workpiece based on the measured shape data and the tolerance data stored in the storage means.
NC processing device characterized by that.

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