Page 38 - MetalForming April 2016

Dos and Don’ts of
Mass Finishing
Follow these tips to optimize your surface-finishing operations.
Mass finishing as a mechanical surface-finishing method has been around since the mid- 1950s. But because it is a largely empir- ical process, mass finishing is still one of the least-understood, under-appre- ciated manufacturing technologies. Many manufacturing engineers still consider mass finishing as low-tech, and pay little attention to properly set- ting up and optimizing their surface-
finishing operations. The results usually are higher overall finishing costs, high- er scrap rates and a lot of unnecessary rework. Don’t make those mistakes.
More Than Meets the Eye
The first mass-finishing vibratory machines were used exclusively for simple deburring operations on mass- produced parts, mainly in the auto- mobile industry. In the beginning no one thought about defined edge- radiusing, precise surface-roughness readings, pre-plate finishes or mirror- image polishing. Today, mass-finish- ing systems can produce practically any surface finish, from simple debur- ring to high-gloss polishing, on practi- cally any kind of workpiece.
Yet for many, mass finishing remains a vibratory bowl filled with some “rocks.” Not true. It embodies a com- plex system with multiple elements that must be perfectly matched to each other (see Table 1). Only the ideal matchup of these elements guarantees ideal finishing results.
Figs. 1 and 2—Fin- ishing of parts such as small chain links (above) requires only a small finish- ing machine, but large parts, such as bearing rings with diameters greater than 100 in. (right), require finishing in large rotary vibratory machines.
36 MetalForming/April 2016
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