JPS62102975A - Grindstone dressing device for grinding machine - Google Patents

Abstract

PURPOSE:To keep the surface roughness of a work substantially constant by controlling the dressing speed for a grindstone in consideration of various elements relative to the surface roughtness of the work surface. CONSTITUTION:A table position control device 11 for controlling the table position through control of actuation of a motor 10 for driving a grindstone table 7 is provided with a dressing speed arithmetic circuit 12, and at dressing, the feeding speed of the grindstone table 7 is determined and controlled by the dressing speed derived from the circuit 12. In order to obtain the dressing speed, there are provided first a roughness gauge 13 for detecting the surface roughness of the work 1 which has been machined and a roughness pattern arithmetic circuit 14 for obtaining the changing inclination (pattern) of roughness through input information of the update dressing count, whether or not the grindstone has been exchanged and whether or not the dressing diamond has been exchanged.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a grinding wheel correction device for a grinding machine.

[Prior Art 1] In a grinding machine that uses a grindstone to perform surface processing such as internal grinding of a workpiece, in order to ensure the sharpness of the grindstone, the surface of the grindstone is dressed using a modification tool such as a dressing diamond.

Conventionally, this type of grinding wheel correction device detects the grinding wheel diameter,
A grinding wheel correction device for a grinding machine has been proposed in which the dressing speed, that is, the correction speed is controlled according to the diameter of the grinding wheel (Japanese Patent Publication No. 7825/1983).

(Refer to Japanese Patent Application Laid-Open No. 157951/1983). Needless to say, the purpose of modifying a grinding wheel is to ensure the sharpness of the grinding wheel and to control the roughness of the machined surface of the workpiece to below the required value, but it does not affect the surface roughness of the workpiece. The contributing factors are various and interrelated.

From this point of view, the surface roughness of the machined surface of the workpiece is measured,
A method in which the machining speed is controlled according to the surface roughness l (see Japanese Patent Laid-Open No. 58-20277Q), and a feed-pack control system for the machining speed using bossage (see Japanese Patent Laid-Open No. 55-42155). etc. have been proposed, but
For example, by simply controlling the machining speed, it is not possible to completely deal with changes in the sharpness of the grindstone, the diameter of the grindstone, the dressing condition, etc., and it is not necessarily possible to control the surface I11 constant.

[Objective of the Invention 1 The object of the present invention is to manage the surface roughness to a desired value by controlling the correction speed for the grindstone in consideration of various factors related to the surface roughness of the machined surface of the workpiece. It is.

[Configuration 1 of the Invention] Therefore, the present invention provides a grinding wheel correction device that corrects the grindstone by relatively moving a correction tool in the width direction of the grinding wheel, and A surface roughness measuring device that measures the surface roughness of a machined surface of a workpiece, a processing number detection device that detects the number of processing steps on the workpiece, a grinding wheel diameter measuring device that detects the diameter of the grinding wheel that decreases due to correction of the grinding wheel, and a workpiece. A grinding wheel correction speed control device that measures the surface roughness of the machined surface of the machine and controls the correction speed of the grinding wheel according to the wear condition of the correction tool at that point and the diameter of the grinding wheel so that the surface roughness is approximately constant. It is characterized by having the following.

[Effects of the Invention] According to the present invention, it is possible to optimally control the correction of the grindstone according to the wear condition of the correction tool and the diameter of the grindstone, and the surface roughness of the workpiece can be kept almost constant by appropriate correction of the grindstone. can be managed.

[Embodiment 1] Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings.

As shown in FIG. 1, the grinding machine includes a cutting table 3 that feeds the main shaft 2 that holds the workpiece 21 in a chuck, a grinding wheel 4 that is supported by a grinding wheel 5, and a grinding wheel 6 that supports the grinding wheel 4. 6
A grindstone table 7 for feeding the grindstone 4 in the axial direction, and a dressing device 9 for dressing (correcting) the grindstone 4 with a dressing diamond 8 are provided.

Table position control device 11 that controls the table position through drive control of the drive motor 10 of the grindstone table 7
In contrast, in this proposal, a dressing speed calculation circuit 12 is provided,
During dressing, the feeding speed of the grindstone table 7 is determined by the dressing speed calculated by this circuit 12, and is controlled to that value.

In order to calculate this dressing speed, first, a roughness gauge 13 is provided to detect the surface roughness of the workpiece 1 after machining is completed, and this surface roughness and the number of dressings up to now are measured.
A roughness pattern calculation circuit 14 is provided which calculates a change tendency (pattern) of roughness by using as input information whether or not the grindstone has been replaced and whether or not the dressing diamond 8 has been replaced.

Here, we will specifically consider changes in the surface roughness of the machined surface of the workpiece.

Figure 3 (a) shows the surface roughness R of the machined surface with respect to the number of grinding operations when dressing is performed at a constant dressing speed for each grinding process.
This diagram schematically shows changes in F.

As shown in FIG. 3(a), the surface roughness RF is short,
It changes depending on medium- and long-term fluctuation factors.

The short-term factor is due to the reduction in grinding wheel diameter due to dressing.
As the diameter of the grinding wheel decreases, a so-called sticking phenomenon occurs,
Gradually increase the surface roughness RF.

The mid-term factor is due to the replacement of the grindstone, and when the grindstone is replaced, the surface roughness Rp decreases by a further level.

Furthermore, the long-term factor is due to the wear of the dressing diamond 8 itself; as the dressing diamond 8 wears out, a type of peeling phenomenon called abnormal shedding occurs on the grinding wheel surface during dressing, and as a result, the grinding wheel surface becomes rough. This worsens the surface roughness RF of the workpiece.

This wear of the dressing diamond 8 progresses gradually, and the surface roughness deteriorates gradually over a long period of time.

Then, when the dressing diamond 8 is replaced, the surface roughness will be significantly improved at that point.

As a result of the combination of these short-, medium-, and long-term fluctuation factors, the third
As shown in Figure (a), the surface roughness RF changes.

FIG. 2 is a flowchart showing a method of calculating the change pattern of surface roughness as explained in FIG. 3(a) and setting the dressing speed \"C based on the calculation result.

First, the surface roughness change pattern RF is calculated using the following equation.

RF-α・n-β・k×γ・n...(1) Here,
6... Number of processes until the dressing diamond is replaced (number of dressings) k... Number of grinding wheel replacements until the dressing diamond is replaced α... Influence coefficient on surface roughness due to reduction in grinding wheel diameter β... Before replacing the grinding wheel Accompanying decrease in surface roughness n...Influence coefficient on surface roughness due to wear of the dressing diamond In the above equation, n and k are updated each time the dressing diamond is replaced.

Next, in the next step, based on the surface roughness change pattern RF determined by the above equation, the current dressing speed Vc is calculated by the following equation, with the initial setting value of the dressing speed being \"0.

\'c"～"o (1-RF) -(2)(
The dressing speed calculated using the formula 2) is as shown in FIG. 3(b), and is set as a result of superimposing short, medium, and long-term fluctuations corresponding to the surface roughness change pattern RF.

The thus set dressing speed \pa c is manually input to the table position control device 11 described above during dressing, and the device 11 controls the drive motor 10 so as to achieve the input dressing speed Vc.

As a result, as shown in FIG. 3(c), the surface roughness 3Rp of the machined surface of the workpiece can be kept almost constant.

In addition, Nanako Headquarters Zone 13 is set up as a post zone.
has the role of monitoring the result of the above-mentioned dressing speed control, and if the detected surface roughness worsens (in this case, it can be determined that there is some abnormality cause).

As described above, according to the present invention, the dressing speed is set so that the surface roughness of the machined surface of the workpiece can be controlled at a constant level by taking into account short, medium, and long-term fluctuation factors in the surface roughness of the machined surface of the workpiece. , the surface roughness can be maintained at a desirable constant value.

[Brief explanation of drawings]

Figure 1 is a system configuration diagram of a grinding machine according to the present invention, Figure 2 is a system configuration diagram of a grinding machine according to the present invention.
The figure is a flowchart showing the dressing speed calculation method according to the present invention, and FIGS. 3(a), 3(b), and 3(c) show a surface roughness change pattern, a dressing speed setting pattern, and a surface roughness obtained as a result of control, respectively. These are graphs showing the 1... Workpiece, 2... Main spindle, 3... Cutting table, 4... Grinding wheel, 5... Grinding wheel spindle, 7...
- Grinding wheel chifur, 8... Dressing diamond, 9... Dressing device, 11... Chiful position control device,
12...Dressing speed calculation circuit, 13...Surface roughness zone, 148...Roughness pattern calculation circuit.

Claims (1)

[Claims] (1) A grinding wheel correction device that corrects the grinding wheel by relatively moving a correction tool in the width direction of the grinding wheel, and a grinding wheel correction device that corrects the grinding wheel by relatively moving a correction tool in the width direction of the grinding wheel, and A surface roughness measuring device for measuring, a machining number detection device for detecting the number of machinings on a workpiece, a grinding wheel diameter measuring device for detecting the diameter of the whetstone that decreases due to grinding wheel correction, and a surface roughness measuring device for measuring the surface roughness of the machined surface of the workpiece. In addition, the present invention is characterized by comprising a grindstone correction speed control device that controls the correction speed of the grindstone according to the wear condition of the correction tool at that time and the diameter of the grindstone so that the surface roughness is approximately constant. Grinding machine grinding wheel correction device.