Q. We make small, arched, spring steel pieces that are 2 × ¼ inches from 0.022-inch stock. The arch height is 0.22 to 0.24 inch. We debur the edges in a three-foot bowl vibrator using 3/8-inch angle cut cylinders. The deburring cycle is three hours, and we remove the parts using a handheld magnet; the parts are degaussed prior to inspection. The process is acceptable, but the problem is that the parts stack together in the vibrator, and about 15 percent of them have to be reprocessed. We add a grit to help to break up the stacks. Before we were adding the grit, the rework rate was about 30 percent. What changes can we make to improve this operation? P.J.
A. Parts stacking together is a serious problem with some thin parts. You are luckier than most, however, because the answer for you may be part-on-part processing. The parts themselves are the deburring media in this technique, and the action is assisted by adding abrasive compounds that aid the deburring action and help separate parts that tend to stick together.
The procedure is to fill the machine with parts (no media) and wet them down with the cleaning/inhibiting compound while the machine is running. Then turn off the compound and sprinkle about ½ lb/cu ft of abrasive compound around the mass. When necessary, add enough liquid compound solution to keep the load from drying and sprinkle in a little more abrasive compound. When adequate deburring is achieved, turn on the liquid compound and rinse until the parts are clean.
Should you desire to continue using media, I suggest using ½-inch WEJ (aka TriCyl, V-Cut Cylinder, etc.) media for faster edge deburring.