[chbot] Laser Cutting

[Keith Colson]

Hi Volker

I think the reason you had to change your scale is your DXF file was 
output in inches. This requires an enlargement of 25.4% which matches 
your number well. I get a lot of people sending me files like that for 
cutting.

The cut width varies with plastic thickness. e.g. a very thin plastic 
will get a cut line of under 0.2mm where a thick piece will have a 0.4mm 
line width or kerf as we say. This all assumes the laser cutter is set 
up correctly. e.g. bed height, bed level, focus is correct etc. It has 
taken me some time to get all that right on my machine. The laser beam 
looks like an hour glass in energy density.

As for the dirty bottom on the work. You can put golf tee's in the 
honeycomb and rest your plastic on that. This makes for a clean cut as 
all the previous work does not get smoked and melted on to your work.

Yes, removing the top paper is a good idea otherwise it chars and takes 
time to remove afterwards. If you need any laser help just ask. I have 
modified my laser to cut at 45 degrees now. Pretty handy for light 
piping around 90 degree corners.
http://www.edns.co.nz/index.php/blog/laser-cutting-45-degrees/

Cheers
Keith