I will follow up with my “as-stock” numbers next week once my flow meter arrives.
We have very different machines, but it’s a start.
Edit: My nozzle is actually better designed than I expected. Not optimal, but acceptable. Orifice is 2.82mm dia. Subjective testing with a petri dish filled with veg oil showed my diaphragm pump exhibits visible pulsing.
Edit2: OPT sells a nice 2.2mm nozzle for their diodes and recommends 10-15lpm flow rate for cutting. This equates to 10.96-16.45 M/sec or 35.96-53.97 Ft/sec.
I’m going to trust their recommendations…
That puts my target at 17-23 LPM for my 2.82mm nozzle.
Air stream size and quality (laminar/linear vs turbulent/divergent) will no doubt affect results but I’m not sure I have the space to improve that much on my laser.
I finally got around to measuring air flow vs pressure:
If you squint hard enough, it’s linear:
The compressor pushed air through fifty feet of 1/4 inch hose that AFAICT choked off the higher flow rates. You’d get better flow from a compressor next to the laser.
The fittings in the dual-flow plumbing drop a fair bit of pressure and would also restrict the higher flow rates.
Nice! I don’t have a pressure gauge that can measure nearly that accurate.
I’m still waiting on my flow meter. It was returned to sender before it got to me. Had to re-order. Sigh.
My original plan was use a dead simple single flow circuit with a single solenoid. I’ve since decided I’d like a constant purge going thru the nozzle to help keep the lens cover clean. So, I’ll be adding a bypass before the solenoid that runs thru a needle valve. Still damn simple, but will hopefully greatly extend service intervals.
My compressor is maybe 30 feet from the laser, but I’ll run 3/8” or 1/2” hose up to the enclosure, so pressure drop from the long run will be negligible at these flow rates.
Finally got my flow meter. Won’t have time to mess with until this weekend, but I did plug it in to see what the OE pump can manage.
It’s a bit less than 10 L/min at the center of the ball with pump at max speed. I have a comfortable amount of tubing (5mm ID). Less than 1m total currently. I could shorten it by a couple hundred mm, but it wouldn’t make enough difference to abandon the shop air plan.
6.67 m/sec current max velocity (at nozzle) vs a theo. target of about 14 m/sec.
I did massage the nozzle slightly and it made a small, but visible, improvement in flow cohesion. It’s just a cheap cast zinc/pot metal piece that had some flashing and sloppy edges/radii at the orifice termination. I reamed the ID and cut the end of so it’s a SHARP 90 to the flow axis. Tightened up the airstream a bit. Also sounds better. Lol.
