Ok,
Here we go. My home built CNC laser powered by a 30 watt RF ULSinc laser.
Got the order from my other half for a laser for her Scrapbooking shop but the shop is too small and she can't work the thing so I am relegated to using it for her :-)
It can sometimes take over 3 hours to cut 1mm thick 4 inch high letters in chipboard for an alphabet with numbers and special characters. Gets REALLY boring in the end but I still find it interesting to watch for special jobs.
Rich.

YouTube - Home Built laser

very cool!

Very Impressive. Do you have a build log here on the zone?

Jason

Yep, I do. I started one ages ago but never got around to finishing it off. I will have to do that oneday. Just search on my nickname and you will find it.
Rich.

very cool

Hi,

Wow, well I must say thank you for the video, and posting details of the construction of your project on the forums for others to learn from, I am wondering though and a little concerned about the possibility of some of the laser light reflecting from the aluminium angle iron below the material being cut?.

Darren.

Impressive!
My incompetent question - how many watts (and type of laser) will be needed to cut max. 0.2mm steel sheet (actually silicon steel)?
Regards,
Herbert

Hey Dazza,
The beam is pretty straight throughout the path until it goes through the lens where it's focused to a very small dot then when it exits it expands. The aluminium does reflect the beam but because it's not a mirror surface it destabilizes it so it probably goes all over the place. The surface of the table is brushed martensitic stainless steel which also sends the beam all over the place.
I usually sit a few feet away and have had no problems with reflected beams but I still keep my polycarbonate glasses on just in case. You only get 1 chance with an eye. :)

Hey Herbert,
I haven't cut steel and my only laser is the 30 watt one I have but if I would take a guess at it after all the info I have read I would say that a 150 to 200 watt would be the way to go. You could probably cut it with less power but it would be like cutting through a tongue depressor with a magnifying glass. You could probably do it but you would fall asleep waiting for it to finish the cut.
YAG lasers seem to do a much better job than CO2 but CO2 lasers are readily available from time to time on eBay. There is currently a Synrad 400 watt laser on there for $40K

If I had more money I would not get anything less than a 60 watt laser for my type of work as the 30 watt does take a lot more time to cut things and leaves a charred edge that you have to brush off after. 60 watt would do it faster and probably not leave a charred edge due to the speed of the cut. The slower you cut the more it tends to burn the edge. Air assist is mandatory.
If you only want to engrave granite or marble then 10 watts is enough and there are 2 Firestar lasers for sale on eBay right now for less than $1000 US each.
Hope this helps
Richard.

Thanks for reply, MonoNeuron,
Yeah, found out one YAG, output power around 200mJ ...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=120279726109&ssPageName=STRK:MEWA:IT&ih=002
and this kind of Chinese unit http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=270252661863&ssPageName=STRK:MEWA:IT&ih=017
Seems at first I need to study and make it clear for myself - what is what and how works, before to start with lasers.
Regards,
Herbert

Impressive!
My incompetent question - how many watts (and type of laser) will be needed to cut max. 0.2mm steel sheet (actually silicon steel)?
Regards,
Herbert
Sounds like you are wanting to cut your own stator plates :)

What would It take laser wise to cut through say 1/4" MDF wood?
Thanks

Hi Kram,
I would get an 80 watt laser to do this. The big problem with MDF is the glue which is harder to burn through than the wood. As I have said before on some other post, you could probably do it with less but it would take an awful long time and really burn the edges but with more power you can cut a lot faster with less charring and be a lot more productive. I wish I had a 100 watt laser now and I will get one as soon as I get married, finish off the renovations, go on my honeymoon and sove up the $22,000 they want for one.
(looks like I won't be getting one for a while) :-)

Someone with an 80 watt laser may want to chime in here and give us a more complete answer and let me know if I am wrong. Wish I had one to test :-)

Rich.

I am so totally impressed by your knowledge and creativity. WOW! I want to build one too! Can one use a laser from like a cd or dvd burner just to etch designs in wood or ivory gun grips or that type of thing? I mean instead of cutting all the way through? Thanks for your time and response...Your video was really neat to watch.:):cheers

Sounds like you are wanting to cut your own stator plates :)

Hm? Seems we acquaintanced - nice to meet you ;-)
Yes, I want to cut stator plates ... among other things,
I want to buy good enough Laser - all the rest Im able to build myself.
cheers,
herbert

Thank you for your response.. I have a better under standing about the power needed to cut through MDF.
Just a note the MDF I am using is not the dark colored version also called masonite I am using the light colored version that has the feel of compressed paper.

Thank you again great job on your machine.
Mark

Can one use a laser from like a cd or dvd burner just to etch designs in wood or ivory gun grips or that type of thing? I mean instead of cutting all the way through? Thanks for your time and response...:cheers

Hi Rose,
There are a lot of videos on YouTube where people are using DVD lasers to burn things. They seem to do a good job for the size and you probably could use them for burning designs into wood etc albeit at a very slow pace.
Once you have built one of them you are always after more power because of the time frame it takes to cut/engrave. Sometimes it takes an age.
I hope you are a patient person but then again it won't cost you $40K like it does here for a basic laser table.
Cheers from Rich.

Hi Kram
If you take a piece of MDF into (or send) one to a laser cutting service then they may be able to tell you exactly how much power and what speed it takes to cut the stuff.
With my 30 watt laser I can pierce holes in thin MDF but it is very different when cutting and probably a more powerful air compressor would be a benefit as well to blow the carbon away from the cut. Probably something in the order of 30-40 psi. Mine only puts out about 10 psi (if that)
I will try a few experiments when I get the time as I am off on Holidays in a few days.
regards
Rich.
P.S. Have you been to Synrads website and checked out their applications sections.?
http://www.synrad.com/search_apps/Default.htm

I guess you can work out the cut depth by dividing the drilling rate by the feed rate. Drill rate is calculated at:

http://alumni.media.mit.edu/~yarin/laser/physics.html

but quite a few thermodynamic properties to look up for your material. Boiling point or melting point of 3/4" pine anyone?!?!?!?

Im looking into upgrading my CNC router to a laser just because the router is so freaking slow. I wonder of you could use fibre optics rather than mirrors to direct the lightfrom the laser diode to the gantry.