JPH069787B2 - Dress interval automatic setting method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for automatically setting a dressing interval for efficiently processing a grinding machine.

Conventional technology In grinding machines, dressing is properly performed to maintain sharpness because grinding efficiency decreases due to clogging of the grindstone, falling of abrasive grains, etc. The timing of this dressing is based on the grinding volume discharged by machining, and was left to the workers on site depending on empirical data and the condition of the machined surface.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The diameter of the grindstone of the grindstone gradually decreases depending on the dressing, and the wear and load of the abrasive grains increase as compared with the case of the large diameter, and it is necessary to shorten the dressing interval. This dressing interval also changes depending on the material of the abrasive grains and the material of the work piece, and in some cases it may be grinding beyond the dressing time, or dressing can be done even though it is still grindable due to the difference in sharpness. There is a problem that the processing accuracy is affected and it is difficult to perform efficient grinding.

The present invention has been made in view of the above problems of the conventional technique, and an object of the present invention is to provide a dressing interval automatic setting method that performs dressing at an appropriate time and has good processing accuracy and processing efficiency. To do.

Means for Solving the Problems In order to achieve the above object, the present invention provides a maximum load W _max of a wheel drive motor during rough / rough grinding of trial grinding before lot grinding, and a time T until reaching this load. And the workpiece diameter Do at this load is calculated in advance, and the time T
When the maximum load W _max is reached within the time T but the workpiece diameter Di at the time T does not reach the workpiece diameter value Do, it is determined that the grinding wheel is clogged, and within the time T, the maximum load W _max is reached. When the workpiece diameter Di at the time T does not reach the workpiece diameter value Do, the abrasive grains are judged to have fallen off, and the grindstone is dressed after finishing.

Action For the maximum load of the stored trial grinding result, the time to reach the maximum load, and the reduced workpiece diameter at the maximum load, the maximum load occurrence time during grinding, the workpiece diameter at the stored maximum load time, and When the conditions are found by comparing the above, the dressing interval is set as the dressing interval before the next process.

Embodiment An embodiment of the present invention will be described below with reference to FIG.

Headstock center 1 and tailstock center 2 in a known grinder
A measuring head 3 of a direct automatic sizing device for measuring the size of the workpiece W supported by the measuring head 3 is provided on a table (not shown). The workpiece diameter is input to the CNC device 15. Further, a grindstone shaft 8 having a grindstone 6 rotatably supported by a grindstone headstock 5 on a grindstone stand (not shown) and a pulley 7 attached at the rear end is a pulley 1 of an output shaft of a motor 9 on the grindstone stand.
It is connected to 0 with a belt. A digital watt meter 11 that can detect even a small change in the motor load is interposed in the power supply circuit of the motor 9.

The CNC device 15 for controlling the grinding machine uses the data obtained by trial grinding of the workpiece to be machined, that is, the maximum load W _max , the time T from the start of grinding to the maximum load, the workpiece diameter Do at the maximum load, and the rough cutting. memory 17 for storing inputting the write end Teisun径_{D 1} MDI16, entered in MDI16 data _{W max,} T, Do, the D _1, compared with the load Wi in maximum load _{W max} and the grinding of the memory 17 Load comparison circuit 18, the grinding time comparison circuit 19 for comparing the current time t from the time counter 12 that integrates the time from the start of grinding of the memory 17 and the time T until the maximum load of the memory 17, the maximum of the memory 17 A workpiece diameter comparison circuit 20 for comparing the workpiece diameter Do under load with the workpiece diameter Di after the lapse of time T until the maximum load, the workpiece diameter D ₁ at the end of rough grinding and the current workpiece diameter Di. Compare Workpiece diameter comparator circuit 21, T> t output of grinding time comparison circuit 19, a load comparator circuit 18
W _max ≤ Wi output, Di ≤ Do output of the workpiece diameter comparison circuit 20 at maximum load, and D of the workpiece diameter comparison circuit 21
AND gate 22 that outputs when the condition of ₁ <Di output is satisfied, T> t output of grinding time comparison circuit 19, load comparison circuit path 1
8, W _max > Wi output, Di ≧ Di output of the workpiece diameter comparison circuit 20 at the maximum load, rough workpiece finishing fixed diameter D ₁ from the workpiece diameter comparison circuit 21 and D ₁ <of the current workpiece diameter Di D
An AND circuit 23 that forms an AND condition with the i output, and an AND gate 24 that outputs the current diameter Di of the workpiece when a signal is input when the work grinding time t reaches the maximum load time T Is included.

Next, the operation will be described with reference to FIGS. 1 and 2.

When the size of the workpiece to be ground, the grinding allowance, and the grinding conditions are determined, the grindstone 6 is first dressed. Then, several workpieces are ground and rough grinding is completed.
The average value of _max , the time T until the maximum load is generated, and the workpiece diameter Do at this time are obtained. The values W _max , T, Do and D ₁ are input via the MDI 16 and stored in the memory 17. If this input is followed, the workpiece W is supported between the centers 1 and 2 and grinding is started. When the actual grinding is started, the time counter 12 measures the time, the tracing stylus 3 of the automatic sizing device outputs the momentary diameter dimension of the workpiece W to the amplifier 4, and the amplified output is input to the CNC device 15. A load is input from the watt meter 11 to the CNC device 15.

In the load comparison circuit 18, the maximum load W _max stored in the memory 17 is compared with the load Wi during grinding to obtain W _max.
The output is output to the AND gate 23 while> Wi.
_{When max} ≦ Wi, the output is output to the AND gate 22.

The grinding time comparison circuit 19 compares the time T until the maximum load stored in the memory 17 with the grinding time t of the time counter 12 up to the present time, and AND gates 22 and 2 only during T> t.
3 is output. Further, when T = t, it is output to the AND gate 24.

In the workpiece diameter comparison circuit 20 at maximum load, the reduced workpiece diameter Do stored in the memory 17 and the actual dimension Di measured by the automatic sizing device output from the AND gate 24 when T = t are compared. AND gate 22 when Di ≧ Do,
23, and a signal to continue grinding is output regardless of the load while Di <Do.

The workpiece diameter comparison circuit 21 compares the rough grinding end fixed dimension D ₁ stored in the memory 17 with the diameter D ₁ of the workpiece being ground, which is the output of the amplifier 4 of the automatic sizing device, and when D ₁ <Di. The output is output to the AND gates 22 and 23 so that the determination is not performed during the dense grinding or the finish grinding.

When the acid condition of the AND gate 22 is satisfied, it is determined that the grindstone is clogged, the cutting amount is reduced by a predetermined amount until the workpiece diameter becomes D _1, and after finishing grinding, Dressing is performed before the next grinding.

When the AND condition of the AND gate 23 is satisfied, it is determined that the abrasive grains have fallen off, and the cutting depth is increased by a predetermined amount until the workpiece diameter D ₁ is reached. Dressing is done before grinding.

Actually, the depth of cut after the conditions of 22 and 23 are increased and the increase in decrease is small because the remaining amount of grinding is very small. Dressing is performed after the end.

Effects Since the present invention is configured as described above, the present invention has the following effects.

Appropriate dressing can be performed, productive and efficient grinding can be performed, and a sufficiently satisfactory dressing cycle time can be maintained. Furthermore, stable processing accuracy can be maintained.

[Brief description of drawings]

FIG. 1 is a control diagram of the present invention, and FIG. 2 is a diagram showing trial grinding data. 11-Watmeter 3-Measuring element 4-Amplifier 12-Time counter 17-Memory 18-Load comparison circuit 19-Grinding time comparison circuit 20-Workpiece diameter comparison circuit at maximum load 21-・ Workpiece comparison circuit

Claims (1)

[Claims] 1. A maximum load W _max of a grindstone drive motor during rough / rough grinding of trial grinding before lot grinding, a time T until this load is reached, and a workpiece diameter Do at this load. When the maximum load W _max is reached during the time T during grinding but the workpiece diameter Di at the time T does not reach the workpiece diameter value Do, it is determined that the grinding stone is clogged, and within the time T When the maximum load W _max has not been reached and the workpiece diameter Di at the time T has not reached the workpiece diameter value Do, it is determined that the abrasive grains have fallen off, and the whetstone is dressed after finishing processing. Automatic setting method.