JPH05253800A - Machining center provided with inspecting function for working accuracy of work - Google Patents

Abstract

PURPOSE:To simply inspect working accuracy of the whole of a worked work, in a machining center provided with the inspecting function of working accuracy of a work. CONSTITUTION:Whether a displacement quantity obtained by contactedly moving a tracer head on a worked work following to a measuring program is within the limits of a prescribedly set allowable value or not, is monitored by means of an accuracy inspection part 18 so as to inspect the working accuracy of the work. The displacement quantity beyond the limits of the allowable value and the present position is stored in a disqualified position memory part 18a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machining center having a machining accuracy inspection function for a machined workpiece having a three-dimensional free curved surface such as a die.

[0002]

2. Description of the Related Art When machining a workpiece having a three-dimensional free-form surface such as a die, an NC machining program is created from a model or drawing using a digitizer or CAD as shown in FIG. The machining according to the above is performed in a machining center with a high-speed machining function. Then, in the case of inspecting whether or not the machined work has been machined according to the command value of the NC machining program, conventionally, the point probe at the command point is measured by the touch probe attached to the machining center, or the machined work is tertiary The measurement is performed by resetting it on a dedicated measuring device such as the original measuring machine.

[0003]

In the above-described inspection of the machining accuracy by the touch probe, it is possible to measure only at a limited number of points, so it is confirmed whether or not the workpiece is machined within a certain allowable range. Can't
There is a drawback that the dimensional accuracy of the entire work cannot be guaranteed. In addition, in the inspection of the processing accuracy by the measurement-dedicated device, the above-mentioned drawbacks are solved, but there is a drawback that a large number of man-hours are required for resetting the work. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a machining center having a workpiece machining accuracy inspection function capable of easily inspecting the machining accuracy of a machined workpiece as a whole. It is in.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a machining center having a machining accuracy inspection function for a workpiece, which is capable of mounting a tracer head for detecting a displacement amount in place of a tool mounted on a spindle. The above object of the invention is
Inspection of the machining accuracy of the work by monitoring whether the displacement amount obtained by contact-moving the tracer head on the processed work according to the measurement program is within a preset allowable value range. It is achieved by providing an inspection means for performing the above-mentioned inspection, and a storage means for storing the amount of displacement outside the range of the allowable value and its current position.

[0005]

In the present invention, it is ensured that the difference between the tool diameter during machining and the stylus diameter during tracing by the tracer head is within a certain allowable value range, and Inspection is possible.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an example of a machining center having a function of inspecting the machining accuracy of a work according to the present invention. The machining center has a digitizing function in addition to the high-speed machining function. The first processor 101 that manages the entire system and displays the setting of data, and calculates the high-speed NC, and in particular, sets the command trajectory and feed rate so that the machining trajectory error is within the specified error amount (tolerance amount). The multi-processor configuration is composed of the second processor 102 that performs the control operation (tolerance operation) and the third processor 103 that performs the scanning operation. This makes it possible to disperse each processing and increase the speed. The outputs of these processors are supplied via the system bus 104 to the respective control units for the X, Y, and Z axes (addition of axes (also referred to as 4 axes) if necessary) and D.I. U. It is sent to a drive unit 10 composed of a (drive unit) to drive each axis.

FIG. 2 is a block diagram showing a detailed example of a machining center having a function of inspecting the work precision of the present invention shown in FIG. 1. In the case of digitizing, the machining machine 1 is used.
The tracer head 20 is mounted on the spindle 1. The scanning control data SD interpreted by the program interpretation unit 5 is sent to the scanning sequence control unit 8,
A scanning command SSC for one line is generated and sent to the scanning speed calculation unit 9. Then, the scanning speed component SV of each axis of the processing machine 11 is calculated according to the scanning command SSC for one line and sent to the drive unit 10, and the scanning is performed by controlling the locus and the feed speed according to the command of the digitizing program. Be seen.
The displacement amount DP of each axis of the processing machine 11 is detected by the displacement amount detection unit 13 and fed back to the scanning speed calculation unit 9, and scanning is performed by appropriate servo control.
The current position P of each axis obtained by scanning
The P and the displacement amount DP are read by the tolerance processing unit 14, the data is compressed, and the data is sent to the program creating unit 15.
Processing program PR is created and floppy disk 1
It is output to the outside in the form of high-speed communication 17 such as 6 or optical fiber.

Next, when performing high-speed machining, the tool 19 is mounted on the spindle of the processing machine 11. The NC machining program PR read from the floppy disk 3 is stored in the program storage unit 4, further read by the program interpretation unit 5, and interpreted according to the parameter PM read from the operation panel 1 via the parameter storage unit 2. The interpreted machining data MD is sent to the coordinate calculation unit 6, the coordinate value SS is calculated according to the parameter PM read from the operation panel 1 via the parameter storage unit 2, and the coordinate value SS is sent to the function generation unit 7. Then, the function SF is generated. And
The function SF is sent to the drive unit 10, and high-speed machining is performed by controlling the trajectory and the feed speed as instructed by the NC machining program PR. The current position PP of each axis of the processing machine 11 is detected by the current position detection unit 12 and fed back to the function generation unit 7 and the drive unit 10 to perform high-accuracy high-speed machining by appropriate servo control. When the machining accuracy of the machined work is to be inspected, the NC machining program PR is used as it is as a measuring program, the tracer head 20 is mounted on the spindle of the machining machine 11, and contact movement is performed. The current position PP and displacement amount DP of each axis obtained by the contact movement are read and monitored by the accuracy inspection unit 18, the displacement amount DP is compared with a preset allowable value, and the displacement amount exceeds the allowable value. The current position TO is stored as a reject in the reject location storage unit 18a.

An example of the operation of such a configuration will be described with reference to the flowchart of FIG. An NC machining program is created by the digitizing function (step S1), and the NC machining program is stored (step S2). Tracer head 2 mounted on the spindle of processing machine 11
0 is removed and the tool 19 is attached instead (Step S
3). Machining is executed by the high-speed machining function based on the NC machining program (step S4). After processing, remove the tool 19 mounted on the spindle of the processing machine 11,
Instead, attach the tracer head 20 (step S
5). NC used during processing by digitizing function
The tracer head 20 is brought into contact with the processed work according to the processing program and moved (step S6).

Then, it is judged whether or not the amount of displacement obtained at that time is within a preset allowable value range (step S
7) If the displacement amount is within the permissible value range, the machining accuracy is passed (step S8). If the displacement amount is outside the permissible value range, the machining accuracy is rejected (step S9), and all the processes are ended. .. For example, as shown in FIG. 4A, the center locus of the tool (radius Rc) with respect to the work is set as a broken line. The tracer head stylus (radius R
When s) is moved in contact with the work, the center locus of the stylus becomes a chain line as shown in FIG.
Therefore, the tracer head always generates a displacement amount of (Rs-Rc). Therefore, when the displacement amount from the tracer head is E and the allowable value is ε, it is determined that the machining accuracy is acceptable if the displacement amount E is within the range of Equation 1, and the machining accuracy is rejected if it is outside the range. be able to. The displacement amount E at this time is the displacement amount E of the axis obtained from the tracer head.
It is calculated by the equation 2 by x, Ey, and Ez.

[0011]

(1) (Rs-Rc) -ε <E <(Rs-Rc) + ε

[Equation 2] In the above-described embodiment, NC is used as the measurement program.
Although the machining program is used, it is also possible to shorten the measurement by using a program created by thinning the machining line as shown in FIGS. 5A and 5B.
At this time, the control device side of the machining center may automatically thin the lines according to the identification marks placed at the breaks of the respective processing lines. An example of this identification symbol is a sequence number (N **
* Command), auxiliary code (M ** command), or a dedicated mnemonic code, etc. can be considered. FIG. 6 is a block diagram showing another detailed example of the machining center having the function of inspecting the working accuracy of the work of the present invention, corresponding to FIG. 2, and the same components are designated by the same reference numerals and the description thereof will be omitted. This machining center cannot create an NC machining program, but can inspect a machined work.

[0012]

As described above, according to the machining center having the function of inspecting the machining accuracy of the workpiece of the present invention, the machining accuracy of the entire workpiece can be inspected without resetting the workpiece after machining, so that the inspection efficiency can be improved. Can be significantly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a machining center having a function of inspecting a work machining accuracy according to the present invention.

FIG. 2 is a block diagram showing a detailed example of the machining center of the present invention shown in FIG.

FIG. 3 is a flowchart illustrating an operation example of the machining center of the present invention.

FIG. 4 is a diagram for explaining a method of determining machining accuracy by the machining center of the present invention.

FIG. 5 is a diagram for explaining a measuring program used in the machining center of the present invention.

FIG. 6 is a block diagram showing another detailed example of a machining center equipped with a workpiece machining accuracy inspection function of the present invention.

FIG. 7 is a diagram showing a conventional inspection procedure for machining accuracy of a work.

[Explanation of symbols]

 18 Accuracy inspection section 18a Rejected part storage section

Claims (3)

[Claims] 1. A machining center in which a tracer head for detecting a displacement amount can be mounted instead of a tool mounted on a spindle, and is obtained by contacting and moving the tracer head on a machined workpiece according to a measuring program. The inspection means for inspecting the machining accuracy of the work by monitoring whether or not the displacement amount is within a preset allowable value range, and the displacement amount outside the allowable value range and its current position A machining center having a machining accuracy inspection function for a workpiece, which is provided with a storage means for storing. 2. A machining center having a workpiece machining accuracy inspection function according to claim 1, wherein the measuring program is a machining program used for machining the workpiece. 3. A machining center having a workpiece machining accuracy inspection function according to claim 1, wherein the measuring program is a program in which machining lines created based on a machining program used for machining the workpiece are thinned out.