JPS6025653A - How to dress grinding wheel - Google Patents

Abstract

PURPOSE:To make continuous dressing attainable without intermitting a grinding job, by dressing a grinding wheel in a way of feeding a grinding coolant and air to space between the grinding wheel and a work on the basis of a signal out of a resistance detection device when grinding resistance reaches the tolerance limits. CONSTITUTION:As a criterion for the need of dressing a grinding wheel, a current value for grinding resistance tolerance limits of a driving motor for a grinding wheel shaft 14 is predetermined and stored in a comparator device in advance. When the current value of a motor 1 for driving the grinding wheel shaft 14 become larger than this criterion, a slurry feed pump 13 and a stirring motor 11 are operated whereby slurry is fed to where it should be, while a grinding coolant feed pump 8 is stopped. This slurry 10 is harder than a binding agent and consists of free grain being equal in hardness to or lower than a ground coolant and a grinding coolant. When the current value becomes below the setting value, feed of the slurry is stopped and grinding is therefore reopened. Thus, continuous dressing can be done without intermitting a grinding job.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention detects the dressing period by measuring the grinding resistance, and applies a grinding fluid containing free abrasive grains between the grinding wheel and the workpiece. The present invention relates to a method of dressing a diamond grinding wheel without interrupting the grinding operation.

[Background of the invention]

The dressing method of a diamond grinding wheel using free abrasive grains that has been proposed in the past involves installing a dressing grinding wheel facing the diamond grinding wheel, and supplying free abrasive grains such as alumina or a grinding fluid containing abrasive grains between the two grinding wheels. be. In these methods, a dressing grindstone is specially provided and a mechanism for moving the dressing grindstone is provided, resulting in problems such as a complicated structure. Furthermore, the method for detecting the dressing time and whether or not it is necessary to interrupt the grinding operation are not clearly discussed.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a method for dressing a diamond grindstone with high efficiency without interrupting the grinding operation.

[Summary of the invention]

Grinding of hard and brittle materials such as silicon carbide and silicon nitride is carried out using a diamond grindstone, but the key to this work is how effectively to dress the grindstone to improve grinding efficiency.

The present invention detects the dressing time by measuring the grinding resistance, and supplies a grinding fluid containing free abrasive grains between the grinding wheel and the workpiece to perform dressing without interrupting the grinding operation. It is characterized by

[Embodiments of the invention]

One embodiment of the present invention is a grinding machine (
Diamond grindstone 1. attached to a grindstone rotation drive shaft 14 (not shown). A workpiece to be ground by the diamond grindstone 1 2. A grinding machine table 3 for reciprocating the workpiece 2 in the axial direction and at right angles to the grindstone rotation drive shaft 14. Grinding fluid and slurry supply nozzle 4 for supplying the grinding fluid 7 and slurry 10 to the contact surface between the diamond grinding wheel 1 and the workpiece 2. An air nozzle 5 that blows air from both sides of the diamond grinding wheel 10 onto the contact surface between the diamond grinding wheel 1 and the workpiece 2, a grinding liquid tank installed outside the grinding machine, and a grinding liquid supply pump 8. Slurry tank9. Stirring motor 11 having stirring blades 12 provided to prevent sedimentation of abrasive grains in slurry
and a slurry supply pump.

Figure 3 below describes the dressing method for diamond grinding wheels used for grinding hard and brittle materials such as silicon carbide and silicon nitride.
This will be explained with reference to.

A workpiece 2 fixed on a reciprocating grinding machine table 6 is ground by a rotating diamond grindstone 1 while a grinding fluid 7 is supplied between the workpiece 2 and the diamond grindstone 1. As the grinding work progresses, the contact surface of the diamond abrasive grains 1a fixed to the outer periphery of the grinding wheel with a binder 1b such as resin or copper is worn out or destroyed, and the cutting edge of the diamond abrasive grains 1a is It slows down and becomes a state of verbal performance. When vibration occurs, grinding efficiency is significantly reduced and grinding resistance increases. In order to restore the grinding efficiency, the abrasive grains 1a must be sharpened and redressed, that is, dressed, as appropriate by scraping off the binder 1b.

An increase in grinding resistance can be easily detected by measuring the load current of a grindstone shaft driving electric motor (not shown).

The necessity of dressing is determined by comparing a preset current value (tolerable limit of grinding resistance) with the measured value of the motor current, and if the measured value is larger than the set value, dressing is necessary. Slurry supply pump 13 and stirring motor 1
1 operates to supply the slurry 10, and at the same time, the grinding fluid supply pump 8 stops. Slurry 10 supplied for dressing consists of grinding fluid and free abrasive grains 15. The free abrasive grains 15 are harder than the binder 1b and have a hardness equal to or less than that of the work material 2, and the abrasive grain diameter is equal to or less than the diameter of the diamond abrasive grains 1a. The diamond grindstone 1 is dressed by scraping off the binder 1b by free abrasive grains 1a in the slurry. After dressing has been carried out for a certain period of time, the grinding resistance is measured, and when the measured value (current value) becomes less than the set value, the slurry supply pump 15 is stopped.
At the same time, the grinding liquid supply pump is activated to supply the grinding liquid 7 to the grinding liquid nozzle 4. Thereafter, the above process is repeated until the grinding work is completed. In order for this dressing to be performed effectively, the slurry 10 must be uniformly supplied to the contact surface between the diamond grindstone 1 and the workpiece 2. By ejecting air from the air nozzle 5 having a small-diameter air ejection hole 16, dispersion of the slurry 10 is prevented and uniform supply is achieved.

According to this embodiment described in detail above, by measuring the grinding resistance, the diamond grindstone can be effectively dressed without interrupting the grinding operation.

〔Effect of the invention〕

Examples of the effects of the present invention are shown below. The silicon carbide ceramic was ground using a diamond grindstone (grain size: 120, binder: resin) with a cutting depth of 10 μm per pass. Grinding resistance (load current value of the grinding wheel drive motor) 1 at the start of grinding is 4A, and the current value when the total depth of cut is 30 is 6A.
Met. As mentioned above, this increase in current value is due to the vibration of the abrasive grains. Next, grinding was performed by supplying a grinding fluid mixed with silicon carbide powder having a particle size of 260, and as a result, the current value was restored to 4.5A. In other words, the effect of Kenpo dressing was observed.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram showing one embodiment of the present invention, and Fig. 2 is a diagram showing the principle of an embodiment of the present invention.
The left side view of the figure and FIG. 6 are block diagrams showing the operation of the present invention. 1 Diamond whetstone, 1a...Diamond abrasive grains,
1b... Binder, 2... Workpiece, 6... Grinding machine table, 4... Grinding fluid and slurry supply nozzle, 5
...Air nozzle, 6.Grinding fluid tank, 7.Grinding fluid, 8.Pump, 9.Slurry tank, 10.Slurry, 11.
- Stirring motor, 12... Stirring blade, 13... Slurry pump, 14... Grindstone drive shaft, 15... Free abrasive grains,
16...Air exhaust hole. 1st mouth 3 block

Claims (1)

[Claims] 1. A dressing method for a grinding wheel using a hard material such as diamond as abrasive grains, and a means for measuring the grinding resistance generated between the workpiece and the grinding wheel, and a grinding fluid containing free abrasive grains made of a hard material. When the grinding resistance reaches the allowable limit, the grinding resistance A grinding wheel dressing method 0 characterized in that the grinding wheel is dressed by supplying a grinding fluid containing free abrasive grains and air between the grinding wheel and the workpiece according to a signal from a means for measuring the