How to reduce rough edges on aluminium plates during laser cutting?

Hi,

It was first time of laser cutting steel and aluminum plates. I gave DXF files to a local laser cutting company which had a big industrial laser cutter.
The technician told me that accuracy range is around 0.1 mm and the quote was reasonable so I went ahead supplying 5 mm and 4 mm aluminum plates. Steel parts came out near perfection which was beyond my expectation - laser sharp, clean edges. Aluminum parts had visual artifacts and rough edges.

CAD file of one of the effector plates in RepRapPro Fisher 3D Printer.
The hole size is 2.8 mm.


I spent good hours to clean up rough edges and holes of the parts. Parts in below images are all 4 mm thickness.






Is there any way that improve laser cutting quality of aluminum plates?
One I have in mind is paint aluminum plates in non-reflective paint which sounds little silly.

Edited 1 time(s). Last edit at 03/13/2016 05:56AM by janpenguin.

... the quality will depend on used lasers (good ones are much more expensive), and experience od the technicians.

You can get better results in aluminium with waterjet-cutting ...

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Viktor
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When I worked for a place that did significant laser cutting, we ran most piceces by default through a "timesaver", which is a wide powerfed belt sander made for just such a purpose. If the parts were too delicate for this, we had folks hand deburr. Frequently a right angle die grinder and an open weave pad wheel. Never gave a customer burred parts. You also might specify on your prints "parts to be supplied clean and burr free".
Fwiw steel is frequently actually burned away in laser cutting by injecting oxy or other assist gas into the cut zone. Much less flows out molten, keeping edges cleaner. Aluminum doesn't respond the same, so you use air or nitrogen instead to blow the kerf free. Aluminum also has lower melting point which means more molten metal left.
Despite whatever people tell you, never depend on a laser for precise round holes. Lead in and out will always mess them up not to mention draft and material condition near the cut (never think you can tap laser cut holes in harder steels). Drill holes that need precision after the fact. You'll save on laser costs which rise with every pierce point in he material. If you don't have precision drill equipment have a drill jig made up with hardened drill bushings and use a drill press.

Edited 1 time(s). Last edit at 03/14/2016 04:53PM by Koko76.