03-09-2012, 12:35 PM
Factors to Consider in Mass Finishing
1Mass Finishing.pdf (Size: 778.41 KB / Downloads: 264)
Introduction to Mass Finishing
Management needs to know how a high quality metal finish can be achieved, how to select proper specifications
for a given service and how to control the release of products to insure that they meet the standards. At the same
time management must be confident that this know-how is based upon sound engineering principles and
incorporates a reasonable factor of safety.
Since finish quality is related to surface condition, it is logical to review surface preparation and improvement by
mass or bulk finishing methods. Mass finishing can economically enhance the utility, attractiveness, and value of
the metal, plastic, ceramic or other parts manufactured for industrial or consumer use. While mass finishing
processes do not guarantee that the final finish on a product will be a high-quality finish, they do improve
surface properties, upgrade product quality, and enhance the image of the finishing industry. Edge, corner,
surface finishing, including the removal of burrs, defects, and sharp edges, improves part appearance, handling
safety and prepares surfaces for subsequent coating. Other benefits include easier assembly, improved operating
performance, increased strength (in part by elimination of surface stress concentrations), and longer product life.
By imparting compressive stresses to the surface, fatigue strength can be improved. Mass finishing processes can
develop active metal surfaces—usually with random scratch patterns. On such metal surfaces it is possible to
react chemicals, electroplate, adhere paint, anodize, phosphatize, chromate or color efficiently.
Design for Mass Finishing
Design of a metal product affects finish quality and can influence deburring and finishing cost. Many of the
design factors applicable to parts to be mechanically polished and electroplated need not be considered for the
mass finishing operation alone. These systems are flexible so that parts of almost any shape can be processed,
weight and size permitting. However, review of part design by those knowledgeable in deburring can cause
relocation of webs, hole size changes, etc., where such changes have no effect on part function. Finishing cost
reductions can be substantial. Designers can well keep in mind the fact that part surfaces and edges will be
deburred, deflashed, radiused and / or refined by media of some type. Therefore, is possible, part dimensions,
and contours involving holes, fillets, edges and significant surfaces should be such that media can reach the
surfaces to accomplish the desired result efficiently. Parts to be electroplated after mass finishing are, of course,
subject to the design considerations, including designation of significant surfaces.
Mass Finishing
Mass finishing is the processing of parts or components to be finished in a container, usually with abrasive or
nonabrasive media, water and compound. Action or movement of the container is created to cause media to
press and / or scrub against component surfaces, edges and corners, or components to rub against each other, to
remove burrs, radius edges and corners, improve surfaces, alter and / or enhance characteristics.
This Guide will review the principles of operation of the various mass finishing systems, discuss the equipment
involved, list the different media and finishing compounds used, and describe results that may be accomplished
by mass finishing processes. Mass finishing systems involve rotary barrels, vibratory tubs and round bowl
machines, and spindle finishing machines.