On Friday 06 December 2013 13:18:03 Billy Huddleston did opine: > Burning wood, and etching metal are two different things. 30W lasers > have a hard time etching Aluminum without a special paste applied to > the part. I don't think a 2W laser diode will do much to a PCB except > maybe blacken it a bit. > > Thanks, Billy
Well good, that heads me off at the pass then, thank you. What I had in mind was to pulse it, maintaining the 2 watt average, but banging it with 200 watts for .5% of the time, 1 u-sec on, 100 off. The burners themselves do that for the duration of the pit being burned AIUI, but not quite that great a ratio since they can be on for about 90% of the time under certain encodings for several hundred microseconds. First purchase of course is a set of those narrowband sunglasses to match the diode used. I haven't scrapped any blue-rays yet, they are either not yet in wide use in recorders, or a much longer lasting technology. Fancy way of saying I don't have one in the "junque" pile, yet. ;-) So, ways and means to make a quick change spindle that cranks up a 100k rev dental tool may be in the next path explored. 2500 revs max with this one means I can't run more than about 2 ipm if I want clean cutting, at 5 I have to drop it on a sheet of 600 grit wet-r-dry, wet, and sand-cut the burrs off before I can turn it over to do the back side else they hold the board at random heights at random locations on the board, not very conducive to nice, just thru the copper etching. The bearings in this spindle are now fairly old, and take a beating from a hammer on the draw bolt head every time I change tools, so I am slightly amazed they haven't went tits up already, but asking for even 25 grand seems like a quick way to burn these up. I have a vision of something that I can interchange in the current quill mount by unclamping it, pulling the handle rack shaft out and pulling the existing quill, gearcase and motor out, which is something in the 10 cm diameter range. Also with the drive motor on top, but stolen from an old dremel perhaps. Either direct drive, or perhaps a gear up using pulleys and o-rings in the area above the head casting. But so far its in the what if stage. :) > On 12/06/2013 12:55 PM, Gene Heskett wrote: > > Greetings; > > > > On reading one article on the net about ripping up old dvd writers and > > using the nominally 2 watt laser diode to do some wood burning etc > > with them, it has occurred to me that there could possibly be a use > > for those diodes in 'etching' pcb's. The article showed one mounted > > in a gantry machine, burning wood, from a quite decent distance away > > from the wood, perhaps an inch or 2.5cm above the surface of the > > wood. The backblast didn't quite reach back up to the laser to dirty > > its lenses. > > > > So my question is, to someone who may have tried/done this, is can a 1 > > ounce layer of copper be burned away rapidly enough so as not to leave > > a burned, conductive path where the copper was? > > > > I ask because I have 3 or 4 old dvd writers that no longer write a > > usable disk, although the written area can be seen on the throwaway > > disk. Pack rat that I am, I haven't binned them yet. > > > > Cheers, Gene Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> If I were a grave-digger or even a hangman, there are some people I could work for with a great deal of enjoyment. -- Douglas Jerrold A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ Sponsored by Intel(R) XDK Develop, test and display web and hybrid apps with a single code base. Download it for free now! http://pubads.g.doubleclick.net/gampad/clk?id=111408631&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
