View Full Version : Laser power

John S
16-05-2009, 05:23 PM
So what power laser is needed to cut 2mm plastic.
Got an idea for some jigs and need something with virtually no tool diameter as I need sharp corners.

John S.

Lee Roberts
16-05-2009, 06:50 PM
Yep i also want this kind of info as i would like to cut 3mm ply. 100w Laser is about as far as i have got, do they have names ? should we be looking at a CO2 laser ?

Robin Hewitt
16-05-2009, 09:23 PM
should we be looking at a CO2 laser ?

I don't think you'll get 100W out of a diode :naughty:

Have you seen 80W ebay item: 150337719900 ?

"The tube,power supply,focus lens,reflection mirror in our E-bay store are all compatible"

How deep are your pockets? and, do check out the length before doing anything silly :biggrin:

John S
16-05-2009, 10:18 PM
Length isn't a problem even at 1 metre.
You don't move the tube, that stays fixed at the rear of the machine.
The laser fires along a plastic pipe onto a 45 degree mirror mounted on the end of the Y axis, it turns the beam 90 degrees to another 45 mirror on top of the Z then thru the focus lens which in that case is 50mm above the work.

Everything has to be spot on as regards lining up and focus but it's made easier if you build into the lens holders some some of micrometer steering mechanism.

I have been involved in setting up laser machines in the past, that part isn't a worry but we were operating with 3.5 to 5 Kw lasers and 2mm plastic was no problem, in fact 15mm steel wasn't a problem either :rolleyes:

What I want to know is what is the minimum power needed for cutting this material.

John S.

16-05-2009, 10:32 PM
So what power laser is needed to cut 2mm plastic.
John S.

Most of the commercial desktop style laser cutters (http://www.epiloglaser.com/zing_techspecs.htm) seem to start at about 30 or 40W CO2.

There's lots on the net about using solid state diodes from laser pointers or DVD burners, but these have barely enough power to cut paper. Black paper OK. White paper nope.

I found this (http://www.instructables.com/id/Zach-Radding-Homebrew-Laser-Cutter/) a while ago - the guy has built a couple of machines using CO2 tubes.

Lee Roberts
16-05-2009, 11:36 PM
I'v been looking on the net since i posted and i think for what i want to do 60w will be fine. Everything john said i'v just learnt on my searchs, dont know if i would want to take on the job of lining up John !?!

Thanks for the ebay item Robin, 340 sounds ok given the price of spindle's. Not to sure about the p&p cost tho ?

Lee Roberts
16-05-2009, 11:38 PM
Just found this: :link: (http://cgi.ebay.co.uk/50w-CO2-Sealed-Laser-Tube-Water-Cool_W0QQitemZ150343748684QQcmdZViewItemQQptZLH_De faultDomain_3?hash=item150343748684&_trksid=p3286.c0.m14&_trkparms=72%3A1688%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50)

john do you know of a better place to buy from ?

17-05-2009, 12:53 PM
A few watt diode will cut plastic depending on the colour of the plastic of course!!!!

2.4 watt IR should do the trick if 2mm Black plastic, Wont be fast though approx 200mm per min.

Have done it my self, wasn't difficult to set up laser cost about 100 from US ebay, Really easy to drive not like RF excited tubes or smaller diodes. I used an ATX PSU with a current limiting resistor.

Here is a pic of diode mounted onto an old Pentium 2 heat sink, The IR output is delivered by fiber optics to a colimator lens, So nice and easy to implement on Gantry router.



25-05-2009, 12:31 AM
there's a calculator utility you can download on these pages http://www.synrad.com/48series/48_50.htm
it's a windows exe but you can choose the material, thickness and co2 laser power - and it'l tell you the approximate cutting speed.

hopefully of some interest :smile:


26-08-2009, 09:53 PM
One word of caution concerning the synrad calculator. It is designed for high production speeds. For most, use it as very rough estimate of required power to the high side. The other variables are the amount you focus down the beam, the losses through manipulation optics, the beam divergence, and the type of assist gas used. Very hard to generalize exact requirements. There goal is to sell the most powerful system they can, not the least.

As I work with 60-250w Yag, KTP, and CO2 lasers daily, their are many ways to skin the cat. To get big powers out of 808nm diodes is still cost prohibitive for high powers. The best solution in my opinion at this time is CO2 for plastics. Rips through any plastic very well. Acrylics, and polycarbonate's come out with a beautiful edge. If you do intend to cut plastic beware. Gasses released are deadly. Special attention need be used to assure if your evacuation system goes down, the laser shuts off. Here is some low density material I was using to debug a system I am developing. Enjoy!