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Comment by alonmower | Hacker News Reader

I bought a combo laser cutter/3D printer a while back and ended up putting an enclosure around it and a dedicated dryer vent in my garage wall with a blower fan attached to it so the whole thing is at negative pressure. Few hundred dollars an a couple of hours of my life but I feel a lot more confident using it now.

I mostly did this because of the laser cutter (plywood can let out some horrible smells when cut), but it's nice to be able to do it for the 3D printer too. I know PLA is considered 'safe' but I figure better safe than sorry for these kinds of things. Hard to unwind damage that may take a long time to manifest.

The printer also has a CNC but I very quickly learned that I should _not_ run the blower fan when that's running. That was no fun to clean up.

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> I know PLA is considered 'safe'

But the article says:

> The toxicity tests showed that PLA particles were more toxic than the ABS particles on a per-particle comparison, but because the printers emitted so much more of the ABS - it’s the ABS emissions that end up being more of the concern

which is not very reassuring either way.

> The printer also has a CNC but I very quickly learned that I should _not_ run the blower fan when that's running. That was no fun to clean up.

As someone considering a dust extraction hood for a hobby CNC - what happened?

The fan is in the enclosure and wasn't strong enough to collect everything but it blew it around and coated everything in the enclosure. It also sprayed it around a decent amount of it outside on the side of our house (vs just venting the gases when using the laser or 3d printer).

I've seen some people set up vacuums that attach to the head so that dust is actually collected (and you get a filter in the vacuum to collect the dust). That seems like a better approach. I don't use the CNC very often so I haven't bothered. For now I just keep the fan off and occasionally stop the job to vacuum up the dust that's been produced with my shop vac.

Can i suggest using a 'wet trap' (or dust seperator), they work a treat and you can make your own, and are easy to setup.

Nice, will look into this!

I have a laser CNC, which has a built-in fan that is not quite strong enough to move both the smell and the particles out the exhaust system. I bought a pretty cheap dryer-vent blower fan and added it to the exhaust tube. With the addition of this fan, the particles and odor are sucked out sufficiently. Previously the smell of cut particle board and acrylic were so bad, I considered returning the machine.

The business-end of the exhaust tube sits outside a window, and has a reservoir for collecting debris that make it through the tubing--seems to also subdue the odor.

Nice, I have a pretty similar setup but don't have the reservoir, what are you using for that? My issue is that the CNC uses a drill bit so i get much bigger chunks/dust than the ultra fine particulate i get with the laser/3d printer

A bit of a hack, but I used one of those plastic cereal containers. Hose feeds into the lid, dust and particles goes into the water—whatever is leftover exists through an additional vent I made on the opposite side of the lid. Somewhat similar to a "bong" I suppose.

To your point, the laser doesn't produce particles that are the same size a brill bit would (larger pieces sit pretty on the bed until they are lifted away) but I reckon it might still help!

Just spitballing, but would a setup that swaps the dryer-vent-fan for suction on par with a Shop Vac be able to move those larger chunks? (add water to the Shop Vac's belly before using it as extra filtering)

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