Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

Beam expander condencer for Coherent co2 laser tube model J-3-10.6 250W


New member
Apr 15, 2021
Hi all
need help to choose correct beam expander &condencer for Coherent tube 250w

we have build laser cutting machine with CO2 laser tube Coherent Diamond J-3-10.6 model 250w with pick power of 750w ,beam diameter of 8.5mm 1+-

we would like to coose beam expender and condencer which wont harm much the laser power and keep the beam shape and size up to 2.5meter long.

the laser tube installed on machine x bridge and having 3 reflect mirrors 35mm and focal lens 30mm

please advice what beam rate is sugested? 1\2 or 1\1.5 with condancing 1\2.5? what recomanded beam expender brand ?

the machine will be just for cutting and not engraving
cutting acylic from 3mm to 30mm

the focal lens we use is 2.5" and 5"

thanks in advance for your help

best regards



Well-known member
May 14, 2011
Rule of thumb is that it take 10W for ever 1mm of acrylic material you want to cut so you are a little under-powered for 30mm.
Depends on edge quality you want to achieve as well + other factors.

Would be a good idea to contact Coherent and ask for advice however if you are not the original customer/end user of record than you probably will not get a lot of support out of them.

Have a look at and contact these guys--pretty sure they can and will advise: https://www.ulooptics.com/beamexpanders-for-co2-lasers/

See the Trotec acrylic cutter video below--does almost a flame polished edge effortlessly/beautifully.
They have tips and ticks in their pdf guide here: https://www.troteclaser.com/fileadmin/content/pdf/News/us/acrylic-processing-guide.pdf

Hope that helps. Several factor involved--sorry I couldn't be more helpful, however, real experts at what you want to do can.
LPF is mostly hand held hobbyist lasers and related not production machinery oriented.

Last edited: