Dry Mass Finishing Vibratory Processes
Is it possible to run a dry vibratory deburring process for steel parts?
Q. We are currently deburring our steel parts in a wet vibratory bowl process using a ceramic media. Our customer has instructed us to run a dry process. Is this possible?
A. Dry processes in vibratory machines are being developed and are progressing. There is a urethane-based, pre-formed media that runs fairly clean and works pretty well. The process works better when it is combined with a dust collector that removes the fine particles produced by the process.
Any dry media can load with oils, dirt and metal oxidation particles reducing the media’s effectiveness.
The ceramic media you’re currently using, when run dry, will scratch your part’s finish a bit more. The media will eventually load and become dirty, possibly impregnating contaminants into your parts. It may also visually deteriorate your finish. You can try it, it might work for awhile, and your dirty media can be periodically cleaned.
Dry media processes with polishing abrasive impregnated into corn cob or walnut shells are being used for high-luster finishing. The impregnated dry media work well in high-energy centrifugal systems, spindles and drag machines. These media are simply replaced when no longer effective.
How to achieve an isotropic finish using a traditional vibratory bowl—and why you’d want to do it
When choosing vibratory media, understand the size, shape, starting roughness condition and metallurgical structure of the part.
Surface finish types for commercially supplied stainless steel sheet are detailed in various standards. ASTM A480-12 and EN10088-2 are two; BS 1449-2 (1983) is still available, although no longer active. These standards are very similar in that they define eight grades of surface finish for stainless steel. Grade 7 is “buff polished,” while the highest polish—the so-called mirror polish—is designated Grade 8