Reducing Processing Steps for a High Luster Finish
Q. We are brightening aluminum parts with six-millimeter microbrite-porcelain polishing balls. We first run a ceramic cut media to reduce our cutting lines and then we run a plastic media to smooth the roughness of the ceramic finish. This gives us a smooth finish to run the final microbrite for the bright finish. Is there a process that can eliminate one of our cut steps and how do we get a little brighter microbrite finish? –A.B.
A. There is a polyester plastic media, Z1-zirconium plastic that cuts almost like a ceramic but give you a smooth finish to burnish off of. You will have to run the Z1 cut cycle approximately 20 percent longer than the combined time of your current two cut cycles.
The Z1 weighs 100 pounds per cubic foot instead of the normal polyester plastic of 65 pounds. This combined with the zirconium abrasive will give you a good cut and finish.
To improve your luster, try a mix of three- and four-millimeter microbrite porcelain balls. This size mix gives a higher luster than a six-millimeter. Also try another burnishing compound; compound can make a big difference.
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.
It has been shown that the inexpensive chemically accelerated vibratory surface finishing (CAVSF) process can reduce the average surface roughness.