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Automated Scratch Brushing of Aluminum

The company I work for currently manually scratches aluminum extrusions. This is a very labor intensive process in some cases, depending on the size of the extrusion. We are looking at trying to repeat the randomness that we get with the manual scratch on with an automated machine. We have tried a couple of different options and both result in a straight line pattern. Does anybody have any suggestions?

Nicole Call
- Minneapolis, Minnesota, USA
2003

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Hi Nicole. Can you tell us the options you tried that resulted in straight line patterns? Nobody wants to try to answer only to be told: "We already tried that" :-)

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

We have tried a couple different nylon bristle brushes that resulted in a straight line look. The two different brushes had differing lengths of bristles so the amount of pressure required was different and therefore resulted in different patterns but both still straight line.

Nicole Call
- Minneapolis, Minnesota
2003

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Not sure how long these pieces are, but if they are extrusions, I take it they can be 10 or 20 feet? Also, if you are trying to include this surface finishing operation into the production or as a secondary continuation process then you will always get some kind of repeat pattern. About the only random pattern that will not be repeated is to put the parts into a long vibratory tub type mass finishing system; however, these machines are not exactly cheap. About the longest fixed size machine system is about 10' long but there are pass through systems that are longer. The only other way is to try abrasive blasting the parts at different angles by rotating the part or guns or both.

AF Kenton
retired business owner - Hatboro, Pennsylvania
2003

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Hi again. The most common way of scratch brushing aluminum is actually with one quick sandpaper "scritch" in a wide-belt sanding machine sometimes called a "Timesaver" (that's actually a brand name). Although the scratches run the same direction, they do vary in length, depth, and width. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 16, 2013