Challenge: To end grind printed circuit board carbide drill blanks used by a major tool manufacturer to qualify the blank before fluting. The existing method relied on a batch process where parts were placed, a stack at a time, into a fixture and surface ground. Control over the length was highly dependent upon the setup of each batch in the machine, and length adjustment and perpendicularity were cumbersome to adjust for small diameter parts. Existing machines on the market were extremely large in comparison to the small diameter of the part to be processed, and were very expensive.
Solution
Glebar’s DD-7 double disc machine, configured with a bowl feeder, loaded the blanks into a vertical carriage plate faster than 1 part per second. Two opposing, controlled grinding wheel slides with 0.1 micron position accuracy maintained the gap between the parts, insuring length control. A post grinding contact gauge insured that better than 0.00015” perpendicularity and length accuracy was maintained at a high rate of less than 1 second per part. Changeover to larger diameter parts was a simple operation of exchanging the carrier plate using 4 bolts and adjusting the gap on the grinding wheel slides. Additionally, the move from a batch process to a continuous, unattended process increased productivity and throughput in the cell dramatically.
