Deburring with Dry Products

Q. We make our products from acrylic impregnated wood. The average size is 2 x 4 x ¼ inches. We machine by conventional methods that include milling, drilling and turning. This leaves some light burrs along the cut edges, and we want to remove the burrs without damaging the glossy finish. We have a tabletop bowl vibrator and a two-cu-ft tub vibrator. We have tried corncob, wood chips and small plastic cones. The cob and chips did the deburring in eight hours. We cannot, however, devote that much machine time. The plastic cones deburred adequately in 30 min but left a satin finish. Someone suggested putting polishing rouge in the cobs, but we don’t want to leave any coating or residue because our products are children’s toys. We are extremely careful to avoid anything potentially harmful if a child puts it in his mouth. Do you have any suggestions for a media or process? Thanks for your help. J.B.

 

A. You are absolutely right to avoid any compound that might remain on the surface. A totally dry treatment will be the best way to go. Many soft woods are finished in vibratory machines using light agricultural media such as wooden pegs, corn cob and walnut shells. The time cycles are often less than an hour in these applications because of the soft wood. Impregnated woods, however, are very hard even though they are made from soft woods. They are harder than the densest natural wood.

The question becomes how to speed up the dry process when using something like wood pegs. The answer lies in some of the higher energy finishing machines that accelerate the action between parts and media. Spin finishing, centrifugal barrel finishing and centrifugal disc finishing do just that. The latter is my choice because of lower initial cost and because they are easier to load and unload.

My recommendation is to begin with a manufacturer of wood pegs designed for mass finishing. (I referred my caller to one manufacturer.) They may already have experience with similar products, and if not, will get you started with some media recommendations and a referral to equipment manufacturers experienced in dry processing.