We are considering a metallic media for vibratory finishing our die castings. It is very expensive. The salesman, however, says it will “never” wear out. Can we count on that statement, or do you have other information? One more question, will this media adequately deburr our castings?
“Never say ‘never.’” my dad told me. If you figure on replacing 5% to 10% a year, you won’t be disappointed. There is some wear on metallic media. If you see hardened steel media that is several years old, you will see that it is smaller than the original size. Even more so, however, some media is lost during the normal operation. Look around any vibrator using metallic media and you will undoubtedly find some media on the floor. Also, some gets away with the parts. Not a lot is lost at any one time, but it adds up over the years. Another loss can be due to corrosion, if you use carbon steel media.
Recently, a company that promotes metallic media published some wear rate information. Their data shows the wear rate on hardened steel media as 0.01% of the weight per hour. This is 20% in a 2,000 hour year, a little higher than I would expect. Also, they published a wear rate of 0.014% per hour for cast aluminum media. Somewhere between my figures and those you should find the actual experience. When you apply these numbers to the cost of a volume of media, the cast aluminum will be about half as expensive to use as the hardened steel, and both are less costly than abrasive ceramic media.
Regarding deburring we always recommend sample processing before purchasing. Only you can judge the results.