Mechanical Finishing Q&A: Eliminating Large Machined Aluminum Part Damage in a Large Vibratory Tub
How can we eliminate our part damage with small, medium-cut, ceramic triangular media?
Q. We are running a large aerospace aluminum machined part in a large vibratory tub machine. We are getting part edge damage and occasional gouging, even when we run a single large part. We are using a small, medium-cut, ceramic triangular media. How can we eliminate our part damage with this media?
A. The ceramic media is much harder than your parts. When the part rotates, the media gets trapped between the sidewall and the part, gouging the edges as it rotates. Even a polyester plastic media will create the same problem because it is harder than the aluminum part you’re finishing.
Large aluminum or soft metal parts processed in a large channel tub have to be run with a synthetic plastic media. To eliminate part damage, use a synthetic plastic media that is softer than the aluminum.
Originally published in the February 2016 issue.
Consider these five variables to determine what fits your application.
Immersion tin and lead-free hot air solder leveling (HASL) coatings based on SnCu or SnAgCu alloys are widely used as surface finish materials for printed circuit boards (PCB). These coatings prevent the underlying copper from corrosion and preserve its solderability during lead-free assembly processes and for a long storage life of PCBs.
When choosing vibratory media, understand the size, shape, starting roughness condition and metallurgical structure of the part.