SCIENCE AND TECHNOLOGY ENGLIAH FOR MECHANICAL ENGINEERING he generating drive between cutter and workpiece does not involve a rack or leadscrew since only circular motion is involved. The tool and workpiece move tangential typically 0.5 mm for each stroke of the cutter. On the return stroke the cutter must be retracted about I mm to give clearance otherwise tool rub occurs on the back stroke and failure is rapid. The speed on this type of machine is limited by the rate at which some 50kg of cutter and bearings can be moved a distance of l mm. The accelerations involved require forces of the order of 5000 N(0.5 Ton) yet high accuracy must be maintained leadscrew丝杆SCIENCE AND TECHNOLOGY ENGLISH FOR MECHANICAL ENGINEERING The generating drive between cutter and workpiece does not involve a rack or leadscrew since only circular motion is involved. The tool and workpiece move tangential typically 0.5 mm for each stroke of the cutter. On the return stroke the cutter must be retracted about l mm to give clearance otherwise tool rub occurs on the backstroke and failure is rapid. The speed on this type of machine is limited by the rate at which some 50kg of cutter and bearings can be moved a distance of 1 mm. The accelerations involved require forces of the order of 5000 N (0.5 Ton) yet high accuracy must be maintained. leadscrew 丝杆