Mahalo Tweakie,
I was just wanting to know how the cooling system worked out with the CO2 Laser. Does it keep the laser cool during long run times or duty cycle work? I live in Hawaii where the ambient temperature is over 80 deg Fahrenheit. I'm thinking that I may have cooling problems with my new machine, what do you think? Should I build/buy some sort of refrigeration/water cooling system Kinda like what a saltwater fish tank would use?
Thanks Josh

Hi Obal,

My current DotG post processor is attached. This is for ‘dot mode’ operation of both laser and impact magnet and will produce three lines of GCode for each ‘dot’ (the laser / magnet is only fired when the X axis is stationary).

If it is of interest, there is some more information (in English) relating to the use of DotG here http://hobbycncart.com/forum/61-146-1

Tweakie.

Hi Josh,

As you have seen I am using a ‘closed loop’ water cooling system with a forced air radiator as the heat exchange element. This type of system will only cool the tube to ambient air temperature but, for me, works just fine within the UK where our (ambient air) temperature rarely exceeds 25 deg.C.
From tests carried out (with a glass tube CO2 laser) the maximum efficiency is achieved with a tube temperature of  around 7 to 8 deg.C so in some circumstances it may be an advantage to consider active cooling with a refrigerated device such as a ‘beer chiller’ or purpose built cooling unit. The down side to this is that relative humidity has to be taken into account because condensation forming on the output coupler lens can cause premature failure just as condensation on the outside of the glass tube could compromise the electrical insulation of the high voltage electrode connection (as an example - the condensation that forms on the outside of glass of a cold beer).

In reality, it should never be necessary to drive a CO2 laser at it’s absolute maximum power output but I think you should be aiming to maintain a nominal water temperature between 10 to 20 deg.C during operation.

Hope this helps.

Tweakie.

Tweakie,
Thanks you brought up a good point that I didn't think about, condensation. I was so focused on cooling the fluid below 25 Deg.C. I didn't take that into account. Especially here in Hawaii where the humidity is high during the summer months. I think you are on to something with the "beer cooler" looks like I will be insulating the Laser tube housing, pumping chilled air as well as chilled fluid.
I could see it now "Laser by Day, Beer Cooler by Night"

Thanks

Joshua

 

Most of the beer coolers I have seen have multiple circuits so it could be 'laser by day' and 'cold beer by day' (sort of multi-tasking).

Tweakie.

Hey Tweakie,
quick question, do you know if a sealed Co2 laser 200w can cut metal?
Do you know which metals and what thicknesses?

Thanks
Fernando

Hi Fernando,

With the right lens yes it will cut metal but only very thin stuff and not all types / compositions (the shorter wavelength YAG lasers are usually used for metals).

Sorry but this is not an area in which I have practical experience so cannot give any more detailed information.

Tweakie.

Tweakie,

I seem to remember I saw some manufacturer of small CNC CO2 laser machines which claimed they cut metal (SS if I recall) up to 1mm with something like 80W. They had a video as well. I'll see if I can find the link.

Dan

Can't find this now, but here is a similar one:

http://www.youtube.com/watch?v=e9BvPeAmuvc

May be I was wrong about the 80W, but it's still way lower than we thought.

Dan

Thanks guys