Its called a "beam combiner"
You've got the right idea and terminology . The combiner is a plate made of zinc selenide coated to transmit the co2 beam thru with little loss while completely reflecting the red diode or HeNe beam coming in at 90ยบ, therefore combining the two into one beam.
Just do a search for 'znse combiner' and you'll find several sources.
One note, if your on a tight budget ZnSe optics tend to be expensive. A common less expensive technique is to use a small regular mirror mounted to a solenoid actuated shutter that moves in and out of the beam path. The only difference in doing it this way is that you don't get the red dot while the laser is actually working (which is useless anyway!).
Laser.Tech
24"x48" 60 watt hobby system
I am building 24"x48" 60 watt system intended to cut 1/4 inch hardwood, balsa, depron, mylar and probably some veneers. I already did a CNC retrofit on a sherline mill and lathe setup, so making parts isn't a problem. I've come up with a fairly compact design, using common materials, with everything fitting inside of a 3.5'x5'x3' box. However, I'm a little worried about using flameable materials inside the box. I've got some left over ceramic tile to line the inside of the bed. I'm using aluminum drop ceiling grills for my 'honeycomb' bed. For etching thicker objects, I'm planning to adjust the table depth by varing the number of grills.
I'll use a dust collector to evacuate fumes, and a small compressor for an air jet. I'm worried the compressor will cause vibration, so I'm not sure how that will work out. I want the air jet to be strong enough to put out flames.
My laser is scheduled to arrive this Thrusday. :cheers: I should be test firing it this weekend.
I've won a small motorized beam expander/reducer on ebay. It should come next week. I don't know the focal length, but it was reportedly from a medical CO2 laser. I'm hoping there will be some markings on it that will help determine if it is suitable.
I want to put a flow switch on my coolant loop, but can't find anything reasonably priced.
Thanks again for the help. I've got a million more questions. I'll probably start a thread with my project log.