Having just delivered four lasers to customers here in December - it seems that people do not understand the importance of having air assist in their cutting.
Yes, you can cut fine without. Once or twice. But…
Air assist is having a stream of air blowing out from under the lens towards the material - the air is blowing out of the same nozzle as the laser beam.
The air assist aids by:
- Removing smoke from the cut - making more energy hit the target area and less dissipate in the smoke
- Drastically reduce the build up of gunk and smoke on the focus lens.
It is 2) that is the most important one. Cutting regular plywood with a 40w laser - I observed about 4% diminished power per 10 minutes of cutting without air assist. Eventually, the lens will begin to heat up from the amount of energy dispersed on its surface. If not cleaned in time, the lens might shatter (had this happen once).
Air assist completely removes this build up of smoke and ash.
So what do You need off an air assist system?
I have worked with compressed air, which is great - but requires some type of compressor or pump. This is noisy and adds another item that needs to be turned on and maintained.
Recently I have started to add a simple 80mm computer fan, attached to a fan-shroud (3D printed) that funnels the air to a slender hose, that attaches to the lens nozzle. While this does not generate a huge amount of “blow” - lessening the effect of 1) above - it is easily adequate in keeping the lens free of build up.
While mocking around with the best way to implement this, I added a small divider, sending about 1/3 of the air out ABOVE the lens. This prevents dust from settling on top of the lens in through the laser reflector/ mirror opening - and keeps the top mirror from getting too dusted as well.
The 80mm fan is running off spare power from the PSU in the laser, so it turns on with the system. It is fairly silent.
There is still room for a lot of inventiveness in the laser designs, even tho’ the technology is fairly old.