Second hose on exhaust system

[Andrea Weissenseel]

Hi all,

since my exhaust system only extracts from top of the material, I sometimes have problems with residue when cutting acrylic. Somebody told me to build a box with a hole and hook up a vaccum cleaner to also extract from the bottom of the table that would avoid the problem. Besides that my vaccum cleaner does not extract anything though my cutting table :( I'm also considered about the fumes. On my exhaust system I have 4 possibilities to install a hose, the large one is connected to the laser on the back of the exhaust there are 3 smaller holes to hook up a hose.

I wonder if I can hook up a second hose to the exhaust and connect it to my box

Thx for advice, Andrea

[Gary Hair]

Andrea - my fear would be that if the two hoses weren't pulling with the same power then one would end up being rendered useless. I think you would be better off moving a single exhaust to a place that works better than it does now. My laser, for example, has the exhaust in the rear panel, about level with the bed when I'm lasering thin materials. The intake is in the front panel in about the same position. I have a vector grid that is raised off the bed so that fumes flow over both the top and bottom of the material right into the exhaust.

Gary

[Andrea Weissenseel]

thank you Gary, my setup is like you described it. My grid is also raised, but the exhaust doesn't get the fumes from underneath

[Scott Shepherd]

There's no issue doing what you are suggesting. The Universal's have something very close to that exact thing. It's a big cutting grid box that sucks air through it, providing some downdraft exhaust. The Trotec's have a separate hose for their table, just as you are thinking about doing. So I'd say you'd be perfectly fine in doing that.

[Michael Kowalczyk]

use a blast gate on each of them. That's what I have and I can change the CFM on the back or from the bottom, based on materials. I cut a hole in the bottom of the table and the machine so I have a 4" hose connected to the table with a vacuum table on top and the regular extraction vent in the back above the table. I took an old dust collector motor with a turbine that has about 1900CFM coming down a 6" pipe and it has a TY on it that splits it into two 4" lines. 1 for the back vent and one for the table. Depending on your current vac's CFM you may need to upgrade if your smoke can not be instantly extracted when both vents are fully open, IMHO.

[Andrea Weissenseel]

Thank you all for your answers :) I found an intermediate solution in raising the cutting grid more, that way the extraction underneath got a lot better. Also I adjusted the air assist - I didn't pay attention to it for while, and I only a little breeze so both together already helped a lot. Eventually I still will attach that second hose, just have to think about where to make the hole in the laser either like Michael in the bottom of the table or in the back of the laser. Today I talked to a technician from the company where my exhaust is from, and he said it wouldn't make sense to extract from that cutting box he told me to just get a bigger exhaust system

Cheers, Andrea

[Mark Ross]

Did your system ever draw from underneath? We have two Epilog 36 EXT's and when the smoke and fumes hang around, it is an indicator that someone forgot that silly thing called preventative maintenance. We cut tons of acrylic and styrene and even the vapors will eventually clog all the piping to the point where the machine needs a good scrubbing. I would check with your machine manufacturer if it is supposed to draw from below as well. We replace our honeycomb vector cutting grids about 3-4 times a year because nothing will dissolve the residue, rendering the vector grids useless and worse, a fire hazard.

And yes we have tried oven cleaner (works but dissolves the aluminum grid), the green stuff, the purple stuff and the local dollar car wash.

[Richard Rumancik]

I think I would have to agree with Gary & Michael on this. A second blower results in two blowers in parallel. This can be done but it is quite an engineeering feat to get a stable operating system and is not generally recommended, especially when the blowers and path impedance are not identical. If you have a single blower with a "Y" drawing from two places on the machine, you will likely have a better chance of getting a stable flow. With 2 gates as Michael suggests you can control the ratio as required.

[Michael Kowalczyk]

Did you try Krud Kutter?

Do you need a honeycomb bed or would a Pin table be better? We have a honey comb that we rarely use now, 2 pin tables and an anodized aluminum vacuum table.

What size is your table?

Thanks and ...

[Andrea Weissenseel]

@Mark - it rather draws out of the cabin, than from top or bottom

@Michael, yes I need the honeycomb because of the thin materials I cut. My table size is 740x460mm . Do you cut on your vacuum table? What about reflection?