I actually use an inkjet printer with transparencies with very very good results at the moment - it was just a bit of a mad idea I suddenly had as I've been looking at building a 3 axis PCB drilling machine and this could easily be bolted on. Obviously exposing a whole board by laser would be a nightmare - the distance the head would have to travel would be lengthy. But ..... if you left most of the copper on the board and only exposed places where you definitely don't want copper then it becomes more feasible. Dom ----- Original Message ----- From: "Mike Harrison" To: "Microcontroller discussion list - Public." Sent: Tuesday, May 01, 2007 3:55 PM Subject: Re: [EE] Plotting an image via laser onto photoresist board > On Tue, 1 May 2007 07:14:21 -0700, you wrote: > >>> If photoresist boards can be "influenced" by these high powered lasers >>> then it could be a cheapish way of "printing" directly onto PCBs. >>> >>> Thoughts are to either have a rotary indexed table or maybe reverse >>> engineer a cheap laser printer and pass the board through using the >>> printer optics to raster print the image onto the board. >>> >>> Anyone know what happens to photoresist under a moderate power laser >>> beam ? >>> >> >>The laser from a DVD burner most likely won't have any effect on the >>resist. It's wavelength is about 650 nm, whereas the resist is >>sensitive to UV. You may have luck if you were to use the laser from a >>Blu-Ray burner, but that will set you back many hundreds of dollars. >> >>The guts from a laser printer won't cut it either, because they use a >>much lower power laser, and it's 780 nm, which is even further from >>the seisitivity of the PCB resist. In addition, the spot from the >>laser printer moves very fast across the surface, so will never stay >>in one place long enough to affect the resist, unless you were to >>write the same scan line many thousands of times before stepping on. >>It might be possible to istall the laser from a Blu-ray burner into a >>laser printer.. but then all the optics would be wrong and the beam >>would need to be refocussed and realigned somehow. >> >>I think a more promising route is to use a much higher powered laser, >>and find a positive acting resist that hardens with heat, or use a >>resist that the laser selectively ablates. I'm building such a system >>at the moment, using a CO2 laser, but it won't be functional for a few >>more months. > > Why bother ? I can't see any benefit in doing this - printing artwork on > tracing paper on a laser > printer and using a conventional UV exposure box will always be so much > quicker and cheaper. > Plenty of info here : www.electricstuff.co.uk/pcbs.html > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.467 / Virus Database: 269.6.2/782 - Release Date: 01/05/2007 > 02:10 > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist