New Machine Build- A Few Questions From a Laser Rookie

[Clockwork]

I’m still in the design phase of building a laser machine. Decided to throw out a few questions here before I go down the wrong path.

Here’s what I have:

50W Chinese CO2 Laser tube

Power supply components consisting of a 45KV transformer with rectifiers – A 200K 100W oil filled Ballast resistor - .08uf smoothing capacitor with a 10M Ohm Bleeder resistor – Variac to control voltage to the tube 22-27KV

ZnSe Mirrors and adjustable lens assembly

Water pump and tubing

18 X !8 XY table operated by stepper motors and Gecko Drives.

Digital Milliamp Meter for laser current path and Digital Temperature Meters to measure water temperature going in and out of the tube.

Mach 3 machine control software.

TurboCADCAM and Bobcad/Bobart software

Questions:

I’m considering a mirror-less design that mounts the tube vertically on a fixed gantry. The laser would point straight down onto the moving XY table. The laser output will be a few inches above the work. ….. Any problem with mounting the tube vertical? Will I need the focusing lens at this short distance? What is the best/recommended method to hold the glass tube securely to the support housing?

Should I compensate for the amount of time it takes to turn the laser on and off?

Is there a recommended maximum temperature for the cooling water reservoir?

Will I need a fan to blow the smoke away?

Where can I buy the honeycomb material that makes up a laser worktable?

Is software available that will convert a picture file directly into motor movement and laser on/off commands?

Will this laser cut through hardwood 3/16 thick?

Thanks in advance

[MacGyver]

Originally Posted by Clockwork Questions: I’m considering a mirror-less design that mounts the tube vertically on a fixed gantry. The laser would point straight down onto the moving XY table. The laser output will be a few inches above the work. ….. Any problem with mounting the tube vertical? Will I need the focusing lens at this short distance? What is the best/recommended method to hold the glass tube securely to the support housing? Should I compensate for the amount of time it takes to turn the laser on and off? Is there a recommended maximum temperature for the cooling water reservoir? Will I need a fan to blow the smoke away? Where can I buy the honeycomb material that makes up a laser worktable? Is software available that will convert a picture file directly into motor movement and laser on/off commands? Will this laser cut through hardwood 3/16 thick? Thanks in advance

No problem with a vertical mounting other than the fact that you'll need some space for the focusing lens... and yes, you still need that.

Considering the amount of momentum you'll have to overcome for moving such a large table underneath the laser with any repeatable accuracy, laser turn-on time will be in the noise. Ignore it.

No specific max temp for the water, but you'll want it as cool as possible without creating condensation in the tube.

Blow the smoke away or foul your optics... your choice.

Mike Null from St. Louis Laser has some nice cutting grids for a very reasonable price.
http://www.stl-laser.com/

Software is available... Solustan is one, though it's not exactly inexpensive. Google is your friend here...

50W should cut through 3/16" without much of an issue, but you'll see quite a bit of charring. You may want to consider air-assist.

[ImanCarrot]

Be carefull cleaning any optics, there's a bit of a knack to it. Any scratches can cause localised heat build up which can fracture the optics. Oh and remember that Zinc Selenide is toxic in dust form. Oh and don't go near ZnSe with acids or alkalis, it gives off nasty gasses like Hydrogen Selenide or something (smells like garlic).