Chinese Laser - Overburn

[Christohper Rett]

I bought one of THOSE Chinese lasers (40W-CO2-Laser-Engraving-Cutting-Machine). I am having trouble cutting through material without excessive burning/fires. I have tried all kinds of soft wood and plywood (paper thin through 1/4"). No problem generating enough power to cut through but is causing fires/burn marks. Power seems to be the only adjustment that I can make. there is a speed adjustment in the software that does not seem to make a difference. I put a small desk fan inside the machine and it seems to make a small difference. Maybe I need a larger fan? Most of the stuff I make is for miniature gaming and the pro's all use MDF/HDF. Maybe that is the secret but I cannot find a local or online supply of the material!

Any ideas?

Thanks,
Chris

[Bill George]

Are you using air assist to the nozzle? How good is your exhaust fan and system?

[Christohper Rett]

I am not using air assist and have only the stock exhaust fan at the moment which I suspect is lame. Sounds like air/cooling is the solution? Where do I get the most bang for my buck in upgrades? Keep in mind that I only spent $400 bucks on the whole system. THANKS!

[Jerome Stanek]

air assist is the way to go. if you have a compressor add air to the head

[Christohper Rett]

does anyone sell a kit? or do I need to figure out how to cobble one together?

[Bill George]

does anyone sell a kit? or do I need to figure out how to cobble one together?

Both my Chinese and ULS machines came with air assist. Check with your supplier.

Never mind this is one of those K40 machines, so what you are reading on here 95% does not apply to yours. I do think some of the machines came with a manual dial control for power.

If you want support on your laser head over to lightobject dot com. He has a whole section devoted to those machines, with upgrades suggested. You will soon find out the upgrades will cost a lot more than you counted on to make a working laser.

[David Somers]

Christopher,

Everyone's suggestions about adding air assist are spot on. This post is just to give you some background on what you are looking at.
Your blower's function is to remove smoke and fumes from your lasers case and blow it either outside or through a filter where most of the harmful products are removed. It is not Air Assist.
Air Assist is sometimes as simple as a powerful aquarium air pump and hosing that delivers air to the laser. You will either see an aquarium style air hose going down alongside your laser tube, or it will plug into an inlet on the side of the laser tube below where the lens is. Both types will have a small valve that will control how much air passes through the tube. The latter type of air assist will deliver air into the tube below the lens and it will blow out through the bottom of the lens tube cone. The idea in both cases is to make sure fumes soot and smoke from your job is not making it up into the lens tube where it will coat the lens and cause problems (like a cracked lens eventually.) It is also there to provide enough air to prevent flare ups on flammable materials like wood. And it is there to blow any smoke and soot away from the kerf or engraving area. Smoke and soot between your object and the lens cone reduces the effectiveness of your laser beam as it cuts or engraves.

That is the system everyone is referring to.

Incidentally. For taking care of flareups you will find a simple water mister works great most of the time. If you are cutting you do not take your eyes off the laser for even a moment. If you need to run to the restroom pause the laser. Fires happen fast. The spritzer will take care of almost all of them if you are watching. Beyond that, a more serious fire can be dealt with with a standard ABC style fire extinquisher, but by using those you will incur a tremendous cleanup job after. You might want to look at a simple CO2 extinquisher. Works great on the things that get put in a laser and leaves no residue to clean up after.

Hope that helps!

Dave

[Bert Kemp]

also with out air assist and a good exhaust system your lens and mirrors will get dirty real fast and if you don't keep them clean they will be useless pretty fast. The softwood and mdf create a lot of soot and residue clean your lens daily if your cutting a lot.