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英国Dormer公司过去用氧化铝砂轮磨微型钻头的螺旋沟和钻尖,废品率达70%。为了解决磨沟和磨尖问题,该公司采用了特殊酚酫结合剂的立方氮化硼砂轮,目前,废品率已降低到约3%。砂轮由一对0.33马力的电动机驱动,磨削时用冷空气或CO_2冷却。磨沟时用直径4英寸的碟形砂轮,立方氮化硼磨粒浓度为75,转速4350转/分。磨尖用6A2杯形砂轮,立方氮化硼磨粒浓度为100,转速5000转/分。钻头毛坯用M42高速钢制成,经淬火和回火,硬度约为HV900,毛坯先经过无心磨削。在直径0.15毫米的毛坯上用
Dormer Dorchester used to grind the helical grooves and tips of micro-drill bits with alumina grinding wheels to a level of 70%. In order to solve the problem of grinding grooves and sharpening, the company used a cubic boron nitride grinding wheel with special phenolic binder. At present, the rejection rate has been reduced to about 3%. The wheel is driven by a pair of 0.33 horsepower electric motors, cooled with cold air or CO 2 while grinding. Grinding groove with a diameter of 4 inch dish wheel, cubic boron nitride abrasive particle concentration of 75 rpm 4350 rev / min. Sharpening with 6A2 cup-shaped wheel, cubic boron nitride abrasive particle concentration of 100, the speed of 5000 rev / min. Drill rough with M42 high-speed steel, the quenched and tempered, hardness of about HV900, the rough first through the centerless grinding. Used in the 0.15 mm diameter blank