So as far as fume extraction goes, I can confidently say I have a highly effective setup:
- Air intake plenum
- Fresh air supply
- Externally mounted impeller
- 6” flexible PVC ducting
- Effectively sealed laser machine
- Automated Intake and exhaust blast gates
The PVC ducting creates far less turbulence, is reliably sealed throughout, is much more durable, and does not crimp or get crushed. However, as much as I prefer the flexible PVC ducting over the foil garbage, I use it against my better judgement on the exhaust side of things (where some potential for combustible or burning material may come into contact with the ducting).
So the other day I was obsessively leveling my bed for no apparent reason or actual need… I digress.
I took note that sure enough, the small section of ducting attached to the bed port had holes burned into it! Hmmmmm. How and why? Although I knew it was possible, this was just too much.
So this is what I observed:
Anytime the laser head is directly over the upper third portion of the extraction port, if the laser fires through the material, it can shoot through the extraction holes and directly on to the ducting.
Well, I had been wanting to modify this port anyway to make the holes slightly larger (but not eliminate them completely). It’s important that some prevention on larger debris is in place to protect the impeller. So I expanded a number of holes on the port. Then I installed a small section of steel plate above the port to prevent the laser from being able to shoot through any of the upper section of holes and directly on to the ducting.
I also replaced the small section of ducting under the table with (yes) a new piece of that wonderful (but against my better judgment) PVC. However, as some additional mitigation, I started the ducting with a small section of 6” steel ducting this time.
Here is what that section of duct that I replaced looked like: