JPS6031617B2 - Machine tool dimension control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dimensional control method using an in-process control mechanism and a post-process control mechanism of a machine tool.

Conventionally, the dimensions of workpieces being machined one after another are continuously inspected by an in-process control mechanism, the inspection results are transmitted to the control mechanism of the machine tool core, and the cutting operation of the grinding wheel is automatically controlled. There are known ways to do this.

However, with only this control method, the zero point of the gauge fluctuates due to temperature changes in the machining fluid, wear and temperature characteristics of the gauge itself, and this causes variations in the final finished dimensions of the workpiece, resulting in machining defects.

In view of these problems, the applicant first decided to use a post-process control machine to process the processed workpieces one by one or several pieces at a time.
While cleaning and cooling in a circulating manner to maintain exactly the same measurement conditions, the finished dimensions of the workpiece are remeasured using the maskter and the same inspection side, and the results are compared with a predetermined zero point standard. This signal is transmitted to the in-process mechanism as a zero point correction feedback signal to ensure that the zero point of the in-process mechanism is always maintained in the correct state, and also to deal with the dimensions of the master that change due to the influence of the constantly changing atmosphere, etc.
While removing these influences through washing liquid and cooling, they are transmitted to the post-process control mechanism itself, and the zero point of the post-process control mechanism itself is not affected by changes in the conditions that change one after another.
A system that automatically controls the workpiece dimensions during machining under the correct conditions by always setting them correctly, so that all workpiece dimensions after machining are always within a certain standard range. had applied.

The purpose of this invention is to improve this system.Even if the finished dimensions of the workpieces are within the tolerance, the variation in them is managed as small as possible from lot to lot, and the occurrence of defective workpieces is significantly reduced. In case of deviation, of course, when reaching a predetermined variation level within the tolerance (machined Ney value ± standard value), a zero point correction feedback signal is not only issued to the in-process control mechanism, but also a zero point correction feedback signal is sent to the in-process control mechanism. The present invention provides a method for automatically controlling workpiece dimensions by issuing a zero point correction feedback signal to an in-process control mechanism even when the deviation does not reach the above-mentioned variation level. The configuration of the present invention will be described below with reference to system configuration drawings showing embodiments. Note that although the processing Nely value will be explained here as the tolerance median value, the value can be shifted as necessary. The grinding wheel of a machine tool used in the system of this invention includes an in-process control mechanism, a post-process control mechanism that outputs a feedback signal to constantly correct the zero point of this in-process control mechanism, and a master in this post-process control mechanism that constantly controls all The cutting operation is controlled so that all workpieces are always machined to the same dimensions by keeping the workpieces under the same conditions and by a mechanism that corrects the zero point of the post-process control mechanism by itself.

That is, the system of the present invention includes a machine tool control mechanism A,
An in-process control mechanism B that continuously inspects the dimensions of workpieces being machined one after another and transmits the results to the machine tool control mechanism A, and an in-process control mechanism B that continuously inspects the dimensions of workpieces being machined one after another and transmits the results to the machine tool control mechanism A, and inspects the machined workpieces one by one or multiple pieces. A post-process control mechanism C that performs comparative measurements with the master and re-measures each time, and outputs a zero-point correction feedback signal to the in-process control mechanism B; and a zero-point correction mechanism D that outputs a signal to self-correct the zero point of this post-process control mechanism C.
It consists of

In addition, the middle part of the system configuration drawing is the grinding wheel, and C is the master. The control mechanism A of the machine tool has a control section 3, and controls the cutting operation of the grinding wheel mouth to the workpiece based on information transmitted from the in-process control mechanism B, which will be described later.

Imp. The process control mechanism B sends the in-process gauge head 1 and the machine tool control mechanism A the dimensions of the workpiece being machined, which are transmitted by the in-process gauge head 1.
It consists of an in-process instruction control section 2 that transmits information as information, and a meter section 2' whose zero point is always corrected in response to a zero point correction feedback signal from a post-process control mechanism C, which will be described later. The post-process control mechanism C includes a post-processing gauge head 4 that compares and measures each processed work piece or multiple pieces with a master piece, and washes and cools the work pieces and the master piece, and constantly A post process transmits a zero point correction feedback signal to the above-mentioned in-process instruction and control unit B based on the detection results from the circulation path 6 for both measurements under the same measurement conditions and the post process gauge head unit 4. The meter section 5' is configured such that its zero point is constantly corrected in response to a correction signal from a master zero point correction mechanism D, which will be described later. Finally, the master zero point adjustment mechanism D determines the zero point of the post-process gauge head 4 and the post-process The arithmetic circuit unit 7 compares and calculates the previous post-processing zero point stored in the zero-point memory circuit 72, and when the value has changed, the meter unit 5' of the post-processing instruction and control unit 5
The zero point correcting device 7 is configured to correct the zero point of the zero point and at the same time store the new corrected zero point in the post-process zero point storage circuit section 72. In addition, in the drawing 4,
Both indicate that the same post-processing gauge head section 4 is used for workpiece measurement and for master measurement, and although there is actually one gauge head, for convenience of explanation, two gauge heads are used. It is illustrated separately. This invention consists of the above-mentioned structure, and its operation is as follows. Namely, Imp. The gauge head section 1 is a differential transformer type detector that continuously measures the workpieces being machined one after another and detects their dimensions, and its output is as follows.
displayed on the meter 2' of the in-process instruction control section 2. When the measured value of the in-process gauge head 1 reaches a predetermined value, for example, zero, the in-process instruction and control section 2 outputs an electrical signal, which is transmitted to the control section 3 of the machine tool to control the grinding wheel opening. It is controlled to stop the operation and move backward. Next, the finished workpiece is
After being washed and cooled, the post-process gauge head section 4 inspects all the pieces or, if necessary, a plurality of pieces at a time.

The measured value is then stored in the post-processing instruction and control section 5. The results are used to issue a zero point correction feedback signal to the in-process control mechanism using the method described below. First, as shown in Figure 2, the zero point correction feedback signal is an F unevenness signal (third correction signal) that corrects deviation from the tolerance median value where the workpiece dimension is the machining Neley value, and deviation from the tolerance median value. ±FB to correct this if
L, signal (second correction signal) and ±FBL2 to correct it when it deviates from the tolerance critical value, that is, when it is NG.
It is composed of three types of signals (first correction signal).

Next, these three types of zero point correction feedback signals are
This message is issued when the workpiece size is as illustrated in FIG.

What is shown in FIG. 3a is one side (side or e side) of the tolerance median value (zero point) where N workpiece dimensions stored in the post-processing indicator tube control unit 5 are consecutively processed Nellie points. In the same way, when the average value of N is biased to one side from the tolerance median value, Figure 3 C shows the same number of N values or the number of values biased to the e side is larger than N/2. This is the case.

In the case of FIG. 3, control is performed to correct the zero point in the negative direction. In this case, although the third correction signal has been described, the same applies to the second correction signal as well. Then, this zero point correction feedback signal is sent from the post-process instruction and control section 5 to the in-process instruction and control section 2.

In other words, the zero point is corrected by using the FBS signal or FBL signal (small amount of correction), depending on the deviation from the tolerance median value to the side or e side, or the amount of deviation from the tolerance median value. Either FBL2 signal (large correction amount) is automatically transmitted. still,
The count number N of the number of workpieces explained above, F uneven signal, F
The amount of correction by the BL, signal and FBL2 signal and the ±reference value can be set arbitrarily depending on the type of machine tool or workpiece. Further, the master is checked by the zero point adjustment device 7 for each measurement, and the status of the change is transmitted to the post-processing instruction control section 5.

In Fig. 4, the processed workpiece is re-inspected by the post-process gauge head section 4, and based on the results, the post-process instruction control section 5 sends the above-mentioned second and third signals, that is, the median tolerance value. 1 shows a circuit for generating a correction signal at a reference value within the tolerance and a circuit for generating a correction signal at a reference value within the tolerance.

That is, in the circuit shown in FIG.
, is set to OFF. However, when it is 0N, a 10FBS signal is output, and when it is OFF, a -F mother signal is output. A determination pulse is turned on to determine whether it is a 10F spot or -FBS at each measurement timing. If, for example, the Neli level is in the state of 10F Satoshi when the discrimination pulse turns ○N, that signal is input to C as a count input of the distribution number detection power counter of 10F spots. - When the level is FBS, the same aircraft enters C2, and is counted in either C or C2 at each measurement timing. The discrimination pulse signal is connected to a count input of a sample quantity counter C3 to count the number of measurements. C,,
Assume that the counter of C2 is set to n. A sample number counter C3, which is counted every time the measurement is performed, is set to m samples, and the counters C, , C2 are reset and cleared every m samples. Counters C, , C2 restart counting from zero, and the counter of C3 is simultaneously reset to zero and starts counting the number of measurements again. If the counter C or C2 counts up to n by the time the counter counts up to the number of measurement items m, or when the counter counts up to m, the f correction signal corresponding to the one that is counting up is output. For example, if m=9 pieces and n=6 pieces are set, a correction signal will be output if the counter of C or C2 reaches n=6 pieces while measuring 9 pieces.
Further, the circuit shown at the beginning of FIG. 4 is set so that a signal of 10 FBL or 1 FBL is turned ON when the ±level of the tolerance reference value with respect to the median tolerance value of the gauge of the post-process control circuit is applied.

The relationship between 10FBL and FBL cancels each other out, and 10F
If BL, is ON, -FBL, is OFF, or vice versa.

Also, if it is within the standard value, neither is ○N. C4・C5
is a detection counter for exceeding the tolerance standard value, and when it counts up to n, fb, . generates a signal. When the discrimination pulse that is output at each measurement timing turns ON, a count input is input to -FBL, or 10FBL, which are in the ON state, and conversely, a reset input is input to the counter in the opposite direction. If the dimensions are within the reference value, both counters are reset. That is, when n pieces of measured workpieces are detected in the same direction exceeding the tolerance reference value, a signal fq is output. As explained above, the present invention provides a dimension control system for a machine tool equipped with an in-process control mechanism that detects the dimensions of a work being machined and controls the machine tool, and a post-process mechanism that corrects the zero point of the in-process control mechanism. A control method, wherein the feedback correction signal generated by the post-process control mechanism is a first correction signal output when the finished workpiece dimension deviates from ± tolerance critical value, and a tolerance median value set within the tolerance critical value. It consists of a second correction signal that is output when it deviates from the reference value, and a third correction signal that corrects the deviation of the soil from the median tolerance value within the above ± reference value, and the second correction signal and the third correction signal are If the N machined workpieces for which at least one of the correction signals of If the deviation from the standard value or the median tolerance value occurs, one or a combination of these will be issued if the majority of the N machined workpieces deviate from the standard value or median tolerance value. Therefore, with the system of the present invention, it is possible to manage variations within tolerances as small as possible, significantly reduce the occurrence of defective workpieces, and extremely easily and reliably adjust the zero point of the in-process gauge head. can be corrected, and machine tools can be automated and unmanned.

In addition, measurement errors due to processing heat are automatically corrected, so
It is easy to maintain a predetermined machining accuracy of the machined workpiece. Furthermore, it is possible to set the feedback system optimally and accurately depending on the type of machine tool and workpiece.

[Brief explanation of drawings]

FIG. 1 is a block diagram system configuration diagram according to the present invention. FIGS. 2 and 3 are drawings showing the relationship between the measurement results and zero point correction in FIG. 1. FIGS. 4A and 4B are drawings showing correction signal circuits, respectively. A...
Machine tool control mechanism, B...in-process control mechanism, C...post-process control mechanism, D...
...Zero point adjustment device for master, 1... Gauge head section for in-process, 2... Indication and control section for in-process, 2'... Meter, 3... Control section of machine tool,
4... Gauge head section for post processing, 5...
・Post-processing instruction and control section, 6... Washing machine, A... Work, Mouth... Grinding wheel, C... Master. Figure 3 Figure 1 Figure 2 Figure 4

Claims (1)

[Claims] 1. A dimensional control method for a machine tool equipped with an in-process control mechanism that measures the dimensions of a workpiece being processed and controls the machine tool, and a post-process mechanism that corrects the zero point of the in-process control mechanism, the method comprising: The feedback correction signal generated by the process control mechanism is the first correction signal, which is output when the finished workpiece dimension deviates from the ± tolerance critical value, and the feedback correction signal, which is output when the workpiece finish dimension deviates from the tolerance median ± reference value set within the tolerance critical value. a second correction signal that corrects deviation from the median tolerance value within the ± reference value, and at least one of the second correction signal and the third correction signal If the measured N machined workpieces continuously deviate from the above reference value or tolerance median value, the average value of the finished dimensions of the N machined workpieces will deviate from the above reference value or tolerance median value. A dimensional control method for a machine tool, characterized in that when a deviation occurs, an alarm is issued in one of the cases where a majority of the N machined workpieces deviate from the reference value or the tolerance median value, or a combination thereof. .