New Vibratory Finishing Compound Wearing Down Too Fast
Q. We recently changed our vibratory finishing compound and soon noticed that our ceramic media was wearing down considerably faster than before. This results, not only in higher media costs, but also in a deposit of media dust on the parts. What component of the compound causes this accelerated media wear and could it also harm machine parts such as the urethane liner? J.K.
A. Ceramic media is a fired ceramic product, invulnerable to chemical degrading by a normal cleaner. Even the strong acids used in special vibratory processes do not degrade the media. Automatic dish wash soaps are much stronger cleaners than anything you would expect to find in a vibrator and they do not damage ceramic dishware. The phenomena you observe are the result of much better cleaning by the new compound or much less lubricity than the old compound or both. When media gets dirty or glazed, it can last a long time. It also does a poor job of deburring. Actually, you can really benefit from the new compound by reducing your time cycles (increasing productivity) and you can probably go to longer life media that will still debur better than the old media. See this column in the October 1996 issue for a discussion of glazed media. The second part of your question concerns damage to the urethane liner. The answer is the same as before. Nothing in normal finishing compounds (except abrasive compounds) will cause undue wear to the urethane liner. The new compound is keeping the media sharper only slightly increasing liner wear.
It has been shown that the inexpensive chemically accelerated vibratory surface finishing (CAVSF) process can reduce the average surface roughness.
When choosing vibratory media, understand the size, shape, starting roughness condition and metallurgical structure of the part.
Choice of equipment, media and compounds has a major impact on your finishing applications.