my hobby laser cutter - tombstones

[KTP]

Just to show that CO2 laser cutters need not be complicated or expensive

http://www.skyko.com/halloween/tombstones.jpg

These were cut out of 1 inch foam (fumes vented!) using a free 50 watt medical CO2 laser saved from going to the junkyard by me. I simply made a lens holder (znse lens 2.0" F.L. ebay $25) with a forced air nozzle and bolted it to the head of my cnc bedmill. I attached the articulated arm of the laser to the lens, put about 5-10psi coming out the nozzle and cut the foam as fast as my mill could move (about 120IPM at the time...faster now).

I have since collected several more scrap lasers...some working, some not, but have yet to find the jewel I really want...a Coherent Diamond or Synrad Firestar of sufficient wattage to cut thin steel...

One day maybe.

[CNCadmin]

Any pics of the machine?

[KTP]

Not really, well except I have this closeup pic of the lens nozzle...crude, but hey I cobbled this together in a couple of hours. The laser is not currently mounted to the mill (I am using the mill for milling )

http://www.skyko.com/shizlaser/shizlas2.JPG

[bunalmis]

@KTP

Can you send detailed photo of your laser tube?

http://www.skyko.com/shizlaser/shizlas2.JPG

[2muchstuff]

In what part of the states do you live in where they throw away lasers that big. I have a source of medical equipment that I scrap out but I have yet to come across any lasers. Maybe I need to move.

[KTP]

bunalmis: I don't have a photo at hand of the laser tube...it is somewhat of a pain to take the cover off the laser for that. It is your standard garden variety sealed 50 watt CO2 medical laser. It uses a transformer and a 3-500Z Eimac triode (Hams go ape over these, btw) instead of a switching power supply to regulate tube current. I have not tried to tap into that yet, rather I just put a relay into where the footswitch goes. Crude, but it works well for what I needed to cut at the time. Obviously if I want to do ultra high speed engraving I will need to figure out the triode circuit and where I can tap in a ttl signal to control the tube power. At the same time, I will need to move it off my Shizuoka mill, since the mill can only go around 400IPM at the most, and you really want to be at 2000IPM or faster for engraving.

2muchstuff: Seattle, WA....but I bet I could find a super cheap or free laser in just about any state in the US. Even if you have to pay a little (like $200 or so) for the laser, you can make this back up instantly on ebay selling the parts you don't use (I sold a znse beam combiner and some gold mirrors for $150).

[Ed_R]

Very nice work on teh tombstones, those look really sharp.
What's a regular laser cutter head run these days?And how do you control the depth of cut on those things?

[KTP]

Not sure what you mean by regular laser cutter head. If you mean a commercially produced nozzle with a lens and perhaps beam expanding optics, maybe $4000.00? from Coherent or somewhere.

If you mean the laser itself, a complete 50 watt laser system would run around $6000 to $10000 new from Synrad, Coherent, etc. for a nice compact all metal rf excited unit, to as low as $1000 for a Chinese made dc-excited glass tube and power supply (but that one may only last a few months as opposed to 10 years or more for the metal construction rf excited ones).

Not cheap when bought new. :-(

As for depth of cut control. In styrofoam...pretty much you cut all the way through and glue together cut layers to create the milled effect you see on my tombstones. In this case it is somewhat similar to a hot wire cutter I guess.

[Ed_R]

Very nice work still

[CNCRob]

The tombstones look great.