Hurricane 60 watt laser airflow inside the cabinet

[Bryan Rocker]

Good sunny afternoon fellow creekers. As I finish the repairs on this laser I have been cleaning it. The lack of air flow and lack of cleaning inside the machine, its a wonder they never had a fire. My question of the day is this. I know the machine has and warrants the need for a 6" exhaust duct. However, the way this machine is designed is that the 6" exhaust duct connects to a 2nd 6" opening that is designed in theory to remove dust, particles and smoke off the laser bed. I say in theory because the plenum goes from 6" round to 43 each 1 1/4" x 1/4" slots. The area is not even close. The slots come up to 13 square inches and that is generous since all the slots are rounded top and bottom. Six inch round ducting is around 28.3 square inches.

The real question is do any of you still have this plenum installed? Its tack welded on, not even removable. A real fire hazard if you ask me. I am leaning towards yanking it at a minimum.

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[Kev Williams]

I believe the theory behind the small slots is to equalize the negative pressure across all the slots, so they draw air evenly. I can't see the slots in the pics but I'll assume they span the width of the table?

And while I'm hardly an air-movement guru, I do know this much: I've run HF green blowers for 16 years, all using 4" ductwork, and they draw smoke like gangbusters. 4" ductwork works out to 12.56 sq inches, nearly identical to the area of your slots...

-My LS900 has a 4" duct intake, and the long slot behind the table that draws the smoke measures roughly 1/2" x 24" inches, for 12 sq. inches, and this machine very effectively draws smoke straight across the table from 20 inches away with the door and front of the machine wide open--

To flip the coin, my GCC, has a roughly 38" x 1/2" slot in front of a 4" duct behind the table, which is 19 sq. inches-- on the front of the machine in the same horizontal plane as the suction slot are a pair of intake slots of roughly the same size, idea being the air will flow across the top of the table. But my HF blowers can't draw enough air thru that large of a slot to create an appreciable air flow. The air MOVES obviously, and it DOES remove all the smoke, eventually, but rather than the majority of the smoke being drawn across the top of the table, about half the smoke just drifts around the cabinet, eventually finding it's way backwards.

So- in use, I would think those slots may work better than you might think!