Laser Exhaust Suggestions?

[Keith Winter]

Looking for blower suggestions on a two laser setup.

Our current setup works well for engraving but we're starting to cut more now, and I'm noticing smoke in the cabinet indicating I need more flow.

Here is our current setup: 4" duct 20 foot in from the window connected to blower then another 14 foot of duct, y adapter, then another 6 foot to each of the 2 machines. So about 40' of 4" duct total, in-port on laser is 4" as well. Here is the blower we're using: http://www.harborfreight.com/2-hp-industrial-5-micron-dust-collector-97869.html\

Can you guys A) suggest a better blower for the 2 laser setup we're doing that will get that smoke out quicker?

[Mark Sipes]

Are you running the 5 micron collector also... or just the blower

[Dan Hintz]

That length of 4" duct is probably killing you with losses... I'm guessing there are twists/turns in there, too, which are the real problem children. You main run is ideally 6", shrinking to 4"right at each machine. Then, make sure your flow (CFM) is high enough.

[Dave Sheldrake]

100 feet of 4 inch on a 1550 cfm max flow isn't going to make it :( will take a while to calculate the losses but a fan that size on a small diameter pipe like 4" over 100 feet, if you are getting 200 cfm at the end I'll be surprised

[Keith Colson]

Hi Keith

Check out my system
http://www.sawmillcreek.org/showthread.php?230406-My-extraction-system

I am only running only one laser and I have 8" pipes. 4" looks like about half what you need as suggested. Will your blower fit an 8" pipe?

Another good thing is to get an air flow meter. They are only $40 or so. You can measure it like shown in my picture. Personally I would run one blower per laser as it will be quieter and more efficient. If you have speed control like I documented that is a big advantage. You can overclock those motors for the smoky jobs, or run them quiet for other jobs.

Cheers
Keith

[Keith Winter]

Thanks for all the replies!

That is a great looking system Keith, I'll grab a meter too to measure! Mark I'm not sure even what the 5 micron collector is? I thought that was the bag which we don't use, we vent the other end out the window/wall

Some questions in response to you all:

1) My blower has a 6" port, each laser has a 4" port. I'd like to keep it two lasers per blower because I plan on adding another 2 lasers within the year. I don't want to have 4 blowers going :) but I can definitely upgrade the blower we have now if you think that's not enough? Suggestions?

2) If I moved up to a 6" pipe would that double my cpm? Should I just got ahead and go to a 8" vent even though it's only a 6" port on the blower, would I gain a significant cpm going from 6" to 8"?

3) Is it better to have to blower closer to the laser or in the middle between the in-take and output like we have it?

3)

[Keith Winter]

One more question in addition to above, what about upgrading to a unit like this? http://www.amazon.com/SHOP-W1687-3-Horsepower-Dust-Collector/dp/B001R23ST0 Would that be enough for our 2 current lasers + 2 more future lasers if I switched to 8" vent pipe and then 4" when it got to each machine? 40' length with 4 x 90 degree turns as assumed before?

[Bill George]

One more question in addition to above, what about upgrading to a unit like this? http://www.amazon.com/SHOP-W1687-3-Horsepower-Dust-Collector/dp/B001R23ST0 Would that be enough for our 2 current lasers + 2 more future lasers if I switched to 8" vent pipe and then 4" when it got to each machine? 40' length with 4 x 90 degree turns as assumed before?
Not at home right now and no reference books, but each 90 deg elbow is worth X ft of pipe. I am guessing at 25 ft per turn. Plus the friction loss in the straight pipe, flex duct has lot more loss. Your blower is more than likely rated at X cfm in free air, add some pipe, add some elbows and misl fittings and that rating in free air goes away pretty fast.
General rule of thumb I have see used is keep the intake side pipe as short and free of loss as you can.
I did not follow your link all the way, but if your using All laser machines at the same time, then the total cfm of the dust collector must equal what each machine needs. I wonder now if the 2800 cfm is a "free air" rating or what?