JPS59110562A - Cup-shaped grindstone - Google Patents

Abstract

PURPOSE:To planish a mirror surface with a high speed by bonding diamond abrasive grains etc., to base metal into a cup shape by means of a resin bond and forming the tip part of a grindstone layer into a triangular cross section having a relief angle, in the cup-shaped grindstone for a hard brittle material, etc. CONSTITUTION:A grindstone layer 9 is formed by bonding diamond abrasive grains or cubic boron nitride abrasive grains to grindstone base metal 8 into a cup shape by means of a resin bond. The tip part 10 is left behind by about 1- 2mm. in its width during its burning process, and thereafter it is shaved by a rough diamond file, etc., toward the grindstone internal periphery side so as to leave behind it by about 0.2-1.00mm.. At the same time, the grindstone layer 9 is ground off giving a relief angle of about 2-5 deg.. Thereafter the deflection of the grindstone edge surface is removed by means of a metal diamond grindstone, as well as the tips of the abrasive grains are flattened by allowing the diamond abrasive grains to be projected, and reducing the cutting edge interval of the abrasive grains. Accordingly, the contact area of the grindstone with a workpiece is reduced with the contact arc reduced, facilitating the elimination of chips. Thus, it is possible to planish a mirror surface with a high speed.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a cup-shaped grindstone for grinding hard brittle materials, semiconductors, metals, etc. to predetermined dimensions and sizes using a grindstone. .

Structure of the conventional example and its problems Figure 1 shows grinding using a cup-shaped grindstone, in which a workpiece 2 is placed on a table 1, and the height of the wheel 3 relative to the table 1 is kept constant. A linear grinding surface is obtained on the workpiece 2 by keeping the grinding surface constant and driving the wheel 3 or table 1 over a moving distance at a predetermined feed speed.・However, the conventional method of obtaining a straight grinding surface on the workpiece is not to move the spindle, but to move the slide table on which the workpiece is placed. The grindstone used for grinding will be explained. The conventional cup-shaped grindstone is composed of a grindstone layer 4 and a base metal 5, as shown in FIG. 2. Grinding wheel layer 4 contains diamond abrasive grains and a bonding agent.

Generally, the parts 6 and 7 of the grinding wheel layer 4, which are made of additives and are involved in the workpiece, are flat and have a wide width. However, in the case of flat and wide ri as described above In this case, the contact area between the workpiece and the grinding wheel is large, making it difficult to remove chips, and it is also difficult for the grinding fluid to flow in, resulting in a large amount of heat generated during grinding, which causes chatter and the workpiece to fall off, and the grinding surface deteriorates. It does not become a mirror surface, chips occur, and the surface roughness, flatness, or processing distortion becomes deep, making it impossible to obtain the desired product characteristics. Furthermore, since the contact resistance is large, the torque of the spindle that rotates the grinding wheel must be increased, and for workpieces where dimensional accuracy is important, where the abrasive grains often fall off, the abrasive grains wear out and fall off, and the feed setting value may be reduced. Even if mechanical feed is applied, the cut may not be made, and the workpiece may not be completed to the desired dimensional accuracy, and the workpiece must be reprocessed after being measured, resulting in repeated steps. The required number of shears reduces processing efficiency and increases costs.

In addition, the grindstone can be flat-cut between the grindstone and the workpiece when resetting, and the grindstone has a good sharpness and has a long life without chipping.

Structure of the Invention In the present invention, the optical end of the grindstone layer is left in a tone of 0.2 to 1.0, and has a shape with a relief angle inclined at 2 to 6 degrees toward the inner circumferential side of the grindstone layer. It has the unique effect of improving the sharpness of the whetstone, improving surface roughness and flatness, and extending the life of the whetstone.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows the shape of the grindstone in the first embodiment of the present invention. In Fig. 3, the whetstone is a diamond whetstone, 8 is the whetstone base metal, and the whetstone layer 9 is $200.
0 to #3000, the tip 10 of the uncut whetstone layer 9 is left about 1 to 2 mm during firing, and then a coarse diamond file or an electroplated grindstone of about #600 is used to move the tip 1o toward the inner circumference of the whetstone. The grinding wheel layer 9 is ground down so as to leave about 0.2 to 1.0 degree of clearance, and the grindstone layer 9 is ground down with a clearance angle of about 2 to 5 degrees, so that the diamond abrasive grains protrude.

After that, a metal diamond whetstone of about $200 to #400 is brought into contact with the whetstone tip 10, and the whetstone is installed to eliminate runout on the end face of the whetstone, protrude the diamond abrasive grains, reduce the gap between the cutting edges of the abrasive grains, and adjust the abrasive grain tip. so that a flat surface appears. By this forming, the contact area between the diamond layer and the workpiece becomes smaller, and the contact arc also becomes smaller, making it easier to remove chips and facilitate the inflow of grinding fluid. Furthermore, wear and drop of abrasive grains are reduced, dimensional accuracy is improved, and machining efficiency is also improved. FIG. 4 shows the waviness of the machined surface of ferrite by a conventional grindstone and the waviness of the machined surface by the grindstone forming method of the present invention.

As can be seen from FIG. 4, with the grindstone forming method of the present invention, the waviness of the machined surface is reduced from north to λ. In addition, while there is chipping of 5 to 10 μm in conventional grindstone processing, the grindstone forming method of the present invention has no chipping, the machined surface condition is very good, and the processing speed is more than 7 times higher, increasing processing efficiency. Improved. Furthermore, compared to conventional grindstones, the polishing cycle has been increased by more than three times.

As a second embodiment, a grindstone shape as shown in FIG. 5 is also possible, in which a portion of equal thickness is provided at the tip of the grindstone to prevent changes in the contact area between the grindstone layer and the work piece due to wear of the grindstone.

In Fig. 5, reference numeral 11 is a grinding wheel base metal, and the thickness of the tip of the grinding wheel layer 12 is set to be the same to prevent changes in the contact area between the grinding wheel and the workpiece due to grinding wheel wear, and to prevent variations in the machined surface due to changes in the contact area. can. Although the explanation has been made using diamond abrasive grains, similar effects can be obtained by using cubic boron nitride abrasive grains.

In order to exceed the effects of the invention, the present invention has a grinding wheel with a tip of 0.2 to 1.
This is a method of forming a triangular whetstone with a clearance angle of 2 to 6 degrees toward the inner circumference of the whetstone.This whetstone enables high-speed mirror polishing and improves product performance. It is possible to supply large quantities of this product, and its practical effects are outstanding.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional cup-shaped grindstone, Fig. 2 is a sectional view of the same main part, Fig. 3 is a sectional view of a cup-shaped grindstone according to the first embodiment of the present invention, and Fig. 4 is a sectional view of a conventional cup-shaped grindstone. FIG. 6 is a graph showing the waviness of the machined surface of the grindstone according to the first embodiment of the present invention, and FIG. 6 is a cross-sectional view of the cup-shaped grindstone according to the second embodiment of the present invention. 8.11 Grinding wheel base metal, 9,12... Grinding wheel layer. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 4 Figure 5 - 30″l

Claims (1)

[Claims] Diamond abrasive grains or cubic boron nitride abrasive grains are bonded to a grindstone base metal in a cup shape with resin bond, and the tip of the grindstone layer bonded to the grindstone base metal is left with a roughness of 0.2 to 1.0, and the inner periphery of the whetstone is A cup-shaped whetstone with a triangular cross section and a relief angle of 2 to 60 mm toward the side.