Grinding characteristics of PCD and PCD tool sharpening technology (3)

(3) The tool holder of the machine tool has high-precision rotation function and on-line detection device. Because the PCD material is hard and brittle and wear-resistant, the tool tip is usually designed in an arc shape to reduce the amplitude of the relative vibration of the tool and the workpiece. In order to realize the machining of the cutting edge arc, the tool holder of the machine tool should have a high-precision turning function and an on-line detecting device for the size and quality of the tool nose arc radius. This avoids the positioning error caused by multiple clamping and can double the processing efficiency.

5 Grinding process of PCD and PCBN tools

5.1 Selection of sharpening process One of the purposes of cutting tool sharpening is to obtain cost-effective cutting edge quality, and the key to good quality is the choice of sharpening grinding wheel size. The finer the grain size of the grinding wheel, the smaller the cutting edge of the cutting edge, and the lower the grinding efficiency. For this reason, according to the accuracy and use of the cutting edge of the tool (see Table 1) or its failure degree (see Table 2), the PCD cutting tool sharpening process is divided into three processing stages: coarse, fine and fine. According to the specific situation, the reasonable sharpening process can greatly improve the processing efficiency.

Table 1 Classification according to the accuracy and use of the cutting edge

No.—edge cutting precision—optional sharpening wheel particle size—use a thick—0.05mm—230/270#～320/400#—roughing b fine—0.02mm—M20～M40—semi-finishing c fine—0.005mm —M5～M10—Finishing Table 2 Classification by blade failure degree (re-grinding tool)

Serial number - degree of failure - optional sharpening wheel particle size - remarks a thick - cutting edge damage 0.5mm - 230 / 270 # ~ 320 / 400 # - or electric machining b fine - cutting edge collapse 0.3mm - M20 ~ M40

c fine - cutting edge wear 0.1mm - M5 ~ M10

Roughing requires less edge and can be machined or ground. High electrical processing efficiency, suitable for processing complex tools, such as drill bits for printed circuit boards, forming cutters for cutting laminate flooring. Grinding processing can choose coarse-grained grinding wheel. When grinding, the contact area is large, the grinding force is high (300~400N), and the excess machining allowance can be quickly removed. The fine-grained grinding wheel is used for fine machining, and the contact area is small when sharpening. Low grinding force (100 ~ 200N), less heat generation, but low material removal rate. This stage is mainly to improve the cutting edge quality by grinding and polishing. Finishing is in the middle of both.

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