JPH0624694B2 - Grinding machine controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a grinder that grinds a work by a grindstone supported at the tip of a grindstone shaft, and in particular, it is difficult to measure the working dimension during grinding. The present invention relates to a control device that controls a cutting completion position of a work.

[Prior Art] Conventionally, a so-called sizematic grinding machine has been well known, which is configured to finish one machining when a cutting feed is performed up to a preset cutting completion point. In this type of sizematic grinding machine, for example, when performing the grinding by the skip dress method, the grinding conditions (the sharpness of the grindstone, etc.) are different between the previous time and this time due to the clogging of the grindstone, etc. Even if the feeding is performed accurately, there is a problem that the dimensions of the work are varied.

In this regard, Japanese Laid-Open Patent Publication No. 56-62757 proposes a method of detecting the wear state of the grindstone and further performing correction feed from the cutting completion point according to the wear amount.

Certainly, the amount of wear of the grindstone is an important factor in accurately controlling the machining size, but this alone does not accurately detect the position of the grindstone's machined surface.

That is, for example, when the sharpness of the grindstone becomes dull due to the clogging of the grindstone, even if the workpiece is cut and fed to the cutting completion point, the grinding is not performed up to the scheduled point and it is received by the deflection of the grindstone shaft. It is possible that the situation is merely described.

[Object of the Invention] An object of the present invention is to uniformly and accurately control a machining size of a work by accurately controlling a cutting completion point according to a grinding condition.

Therefore, the present invention focuses on the workpiece stock removal that basically defines the grinding conditions, detects the workpiece stock removal, and integrates the stock removal during skip dressing to determine the stock removal stock value. If it is considered that the cutting sharpness of the grindstone has deteriorated due to an increase in the machining allowance integrated value, the cutting feed is further performed from the cutting completion point when the sharpness of the grindstone is good. The cutting feed is performed up to the processing size to be finally obtained.

[Advantages of the Invention] According to the present invention, it is possible to make uniform the machining dimensions of a workpiece in a plurality of grindings between dressing of a grindstone, and to improve machining accuracy.

The present invention is particularly advantageous for machining a workpiece in which the dimension of the workpiece being machined cannot be measured by an in-process gauge.

[Embodiment] An embodiment of the present invention will be specifically described below with reference to the accompanying drawings.

As shown in the overall system configuration in FIG. 1, the traverse grinding apparatus includes a spindle 2 that holds a workpiece 1 by a chuck, a cutting table 3 that feeds the workpiece by cutting, a grindstone 4 and a grindstone shaft 5.
A machining head 6 that is replaceably attached to the tip of the machine, a grindstone table 7 that moves the machining head 6 back and forth in the axial direction, and a dressing device 9 that dresses the grindstone 4 with a dress diamond 8.
Is configured as a basic component.

The cutting motor 10 for cutting and feeding the cutting table 3 includes:
It is controlled by the cutting feed controller 11.

For this cutting feed control, a gauge 12 for measuring the inner diameter of the workpiece 1 before and after machining is provided.
Is output through the gauge amplifier 13 to the stock removal calculation circuit 14
It is designed to be input to.

The stock removal calculation circuit 14 is provided with a changeover switch 15
The gap eliminator device 16 provided for the processing head 6 is also connected, and when a contact signal is output by the gap eliminator device 16,
In response to this, the changeover switch 15 is changed over to the gauge amplifier 13 side, and thereafter, the machining allowance ΔD (j) is calculated from the output difference between before and after machining of the gauge 12.

Instead of providing the gauge 12, it is possible to detect the stock removal of the work by using the position detector normally built in the cutting motor 10.

The machining allowance ΔD (j) detected by the machining allowance calculation circuit 17 for each machining is input to the machining allowance integration calculation circuit 17, and the dressing allowance integration calculation circuit 17 performs a dressing operation until the next dressing is performed. During this period, the machining allowance ΔD (j) that is input each time machining is completed is sequentially integrated and the integrated value is obtained. Is output to the cutting feed control device 11.

As shown in FIG. 2, the cutting feed control device 11 determines the next cutting completion point Sc according to the following formula according to the stock removal integrated value I _R with respect to the initially set cutting completion point Sco. Is calculated.

Sc = Sco ± α · I _R α is a control constant given experimentally.

This will be described more specifically. Now, assuming that the machining allowance integrated value I _R increases stepwise by machining the first to fourth workpieces as shown in FIG. 3, the cutting completion point Sc
As shown in Fig. 4, it is gradually modified as the number of machining increases (Sc ₁ → Sc ₂ → Sc ₃ → Sc
₄ …), the required processing dimensions will be secured regardless of the number of processings.

In this case, it is considered that the corrected value should be experimentally obtained in relation to the stock removal accumulated value.

The above control is reset by the dress completion signal,
Again, the control as shown in FIGS. 3 and 4 is repeated.

In the above embodiment, the cutting completion point Sco is controlled to a preset fixed value, and the cutting completion point Sc until the next dress is controlled. However, the wear of the dress diamond and the reduction of the grindstone diameter are taken into consideration. Then, the cut completion point Sco itself can be gradually corrected.

The wear of the dress diamond causes deterioration of the surface quality due to abnormal detachment such as peeling when dressing the whetstone, and becomes a long-term factor that reduces the sharpness of the whetstone.

Further, the reduction of the diameter of the grindstone causes the grinding to be performed by line contact, which is a factor for improving the sharpness of the diameter of the grindstone. The correction due to the change in the diameter of the grindstone is reset every time the grindstone is replaced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system configuration diagram showing an embodiment of the present invention, FIG. 2 is a flow chart diagram showing a calculation flow of the system,
FIG. 3 and FIG. 4 are graphs showing changes in the stock removal integrated value I _R and the corresponding cut feed correction patterns. 1 ... Work, 3 ... Cutting table, 4 ... Grinding stone, 5 ... Grinding stone axis, 6 ... Grinding head, 7 ... Grinding stone table, 9 ... Dressing device, 11 ... Cutting feed control device, 12 ... Gauge, 14 ... Stock removal calculation Circuit, 17 ... Stock accumulating arithmetic circuit, 18 ... Cutting completion point arithmetic circuit.

Claims (1)

[Claims] 1. A grinder control device for controlling the size of a workpiece by stopping the machining when the cutting feed is performed to a predetermined position, and stopping the machining at the cutting completion position. A cutting feed device, a grindstone correcting device that corrects the grindstone after processing the work, a skip number detector that detects the number of processed workpieces after the grindstone correction, and a work allowance detecting means that detects the allowance of the work. A work allowance detection accumulator that sequentially integrates the work allowances detected by the work allowance detection means between skips after the grinding wheel is corrected, and a cutting feed that increases the cutting completion position as the integrated value of the work allowance increases. A control device for a grinding machine, comprising: a control device.