aquarium airpump as air assist to protect lens

[Niklas Bjornestal]

Would it be useful to install an aquarium air pump to use as "air assist" when engraving, to protect the lens?

[Robert Walters]

I have an aquarium pump (one of those common dinky things) laying around and I didn't feel that had anywhere near the pressure nor volume to be useful for air-assist.

There are some beefier ones that look like they have heat sinks that are though, but you have to get one of the larger ones. But I don't believe they have a way to filter the incoming air either.

This 112W states 110L/m but reliability may be an issue:
amazon DOT com/Hydrofarm-AAPA110L-112-Watt-110-LPM-Commercial/dp/B002JPPFJ0/ref=pd_sbs_lg_1?ie=UTF8&refRID=1P4KAJTJ2PCEEVDJMAZ5

[Dave Sheldrake]

As an air assist the one above will be close to useless, to protect the lens though it will work fine.

cheers

Dave

[Robert Walters]

As an air assist the one above will be close to useless, to protect the lens though it will work fine.

cheers

Dave

What are you using/suggest for air-assist?

[Brian R Cain]

The volume and pressure of air you need for air assist will depend on the machine. In the case of Universal machines that air assist with optics protection, i.e the floor-standing ones, the air takes two paths. One path in unregulated on the machine and goes to the optics enclosures to provide positive pressure that will reduce the likelihood of fume and debris contaminating the optics, the other path is regulated on the machine and provides the air that goes through the cone to suppress flaming. It needs a compressor capable of delivering at least 4 CFM at around 30 PSI to do the job properly. Their desktop machines don't have optics protection, the air only goes to the cone. If you have a a small compressor, it probably won't do either of theses functions very effectively. The air also needs to be clean, dry and oil-free.

I've seen instances where a rogue dealer has sold these machines with a cheap airbrush type compressor that was frankly worse than useless. You could hold a lighted match under the cone and it would barely flutter. The risk of damaging your lens or setting fire to the machine isn't worth it. Another factor is that when the cone is fitted, it can created a vacuum that sucks fume into itself and onto the lens if there isn't enough air coming out of the cone to prevent this. Dirty lenses are inefficient and get hot, eventually cracking or burning the fume onto themselves so they can't be cleaned.

I've also seen instances where people have connected up garage type compressors and wonder why their lenses get contaminated with oil. Obviously other laser systems have different arrangements to the Universal machines but you still need to find out what the recommended air requirement is to be same.

[Keith Colson]

Hi Brian

That's interesting stuff on the Universal lasers. I don't have a lot of experience with my VLS6.60 yet. I run 20 PSI into the only air inlet it has as that's how it was set up from where I removed it from. Does that sound OK? Mainly cutting 1/4 " acrylic.

I did score a nice refrigerated air dryer in the deal so I know there are no vapours in my air supply. I was told that was a must. I have seen some DIY air dryers using car radiators that looked like they would help if you didn't want to spend the 4K on the dryer. Here is my dryer. It also has a couple of nice filters fitted to the in and out. It has a drain that goes outside for all the fluids.

290565

[Bill George]

A standard car radiator would never take over 15 psi without blowing up. Are you sure its not an Air Conditioning condenser, which might have oil inside and be pretty expensive.

[Keith Colson]

Good point, its the ac condenser from a car.
See this video (http://www.youtube.com/watch?v=fAOuuaNuJUo)

Cheers
Keith

[Brian R Cain]

Hi Brian

That's interesting stuff on the Universal lasers. I don't have a lot of experience with my VLS6.60 yet. I run 20 PSI into the only air inlet it has as that's how it was set up from where I removed it from. Does that sound OK? Mainly cutting 1/4 " acrylic.



The gauge on the machine tells you the pressure going to the cone. 20 PSI or slightly more will be fine, but you can set the regulator on the compressor higher to help protect the optics better. The max pressure you should have going to the machine is 50 PSI, otherwise you can blow the plastic hoses off inside the machine. The reason they let you have finer control of the air going to the cone is that if it comes out to high, you can end up blowing the pieces you cut out all over the place, possibly cutting through them if they land on a part of the sheet that's yet to be cut.

[Chuck Stone]

A standard car radiator would never take over 15 psi without blowing up. Are you sure its not an Air Conditioning condenser, which might have oil inside and be pretty expensive.

15psi shouldn't do any damage to a car radiator, that's well within the normal operating pressure.
In fact, the most radiator caps are rated at 13-16psi, at which time the cap allows fluid to drain
into the reserve tank. When the pressure drops again, the fluid is pulled back into the cooling
system. So 15psi is a normal operating pressure, it won't blow up. I might not push an old
radiator past about 25psi or so.. but even a can of Coke might be twice that high. It might leak, but
it isn't going to 'blow up' so we don't need to approach it wearing a Kevlar suit or anything.. ;-)