View Full Version : Choosing the right exhaust blower and air pump/compressor

Mike Lysov
12-13-2012, 5:03 AM
Hi guys,

I am getting a new 280W laser cutter that according to its manufacturer requires an air pump that can supply "Dry air, flow rate > 20L/min Gas pressure between 4 ~ 6 Kg (0.4 ~ 0.6 Mpa)."
How do I find one that will meet these requirements? I guess the small and quit ones used for airbrushing won't be sufficient because they cannot do more than 40PSI. What else I can look at apart from 10/20L tank compressor used for spray guns that is usually very loud? I need something that is not loud and can run at least 2-3 hours non stop.

And how can I calculate that some particular air compressor can deliver such pressure through 8mm hose all the time?

And regarding exhaust system, the laser comes with 8" outlet and 2HP blower with the same diameter both for inlet and outlet . Does it mean that I must run a hose outside that is at least 8" in diameter to get airflow working very good? What if I add reducer after the blower and run a 6" hose instead of 8"

From my experience with dust extraction it seems that suction gets weaker if an inlet diameter is reduced. At least with my 4" dust extractor and a CNC Router suction drops at the end because I use a 1.25" hose connected to a dust shoe. I would not reduce the inlet diameter but there is not enough room for 4" hose on the dust shoe.

john banks
12-13-2012, 7:41 AM
With that power, I would try to keep the exhaust 8" all the way, minimising bends and length and avoiding reducers, also go for smooth wall for better flow if you can. Regarding noise, you may want to look at how loud the 2HP blower is.

Re compressor, we use a noisy belt drive Chinese 3HP compressor which can manage 4-6 bar like you need with I think a 100 liter tank, but not sustain it through 10mm OD hose (about 12m length) with I guess most importantly a nozzle about 4mm diameter at the end, we can comfortably sustain 2-3 bar and find 2 bar is enough for cutting wood cleanly but we only have a 100W tube now 280W and most of our wood is only 1/4-3/8" thick. What are you planning to cut? We have 12m of hose to locate the compressor in a building behind so we and the neighbours can't hear it.

Can the manufacturer give you any guidance?

Mike Lysov
12-13-2012, 3:23 PM
Unfortunately I do not know how loud the blower is. It will be supplied with the laser. I have got two 1HP blowers and they are not loud at all.

All specs for the air compressor and the blower in the manual that I have got as a soft copy.
I am planning to cut wood up to 18mm.

They have provided some advice like "the air compressor should be commercial type" or "you cannot utilize your existing 4" hoses with 8" system" but it is just general information that do not cover specific questions or existing products on Australian market.

Thanks for your reply anyway especially on the exhaust system. I will make sure that all hoses at least 8" in diameter. However there is no way for me to build it without bends. There will be at least 2 or even 3 of them on its way to my house roof.

for my current 100W laser machine it seems that a mini vacuum oil-less pump is more than ok. It has been supplied with the laser and it can deliver 20L/m at 40PSI. Actually it does it so good that there is no or very little residue left at the front of material( I cut up to 9mm thick MDF).