Ventalation issues with Hurricane Agnes/Gweike

[Jonathan Bowen]

So I move the entire laser and was pleasantly surprised that it traveled well. No alignment issues and I removed the tube to be extra safe. I've been running it in the new tabletop gaming store that I am integrating with. It's not open to the public yet but I have noticed that I'm still having a lot of ventilation issues. I upgraded to the green dust collector that most people recommend from harbor freight. So far it's been great. Lower pitch then the original one and it's a bit quieter. can't even notice I'm running the laser other then the air compressor that is in the bathroom temporarily and... the smell. It seems to be a design flaw in the cutter. As the scoop at the back doesn't draw a lot of the smoke away. I've toyed with the idea of ducting something under the honey comb to improve fume removal but I'm not sure how to do that. I've also thought about adding fans to the front grill so it pushed the fumes to the back and towards the scoop.

When cutting MDF I get a stream of smoke that come out the left side of the table and hangs for a bit before getting sucked towards the back of the machine and out. I'm a bit worried about debris getting on my lenses as well. I've been cleaning them a bit more lately to compensate.

Anyone deal with this issue and have any suggestions? I'd love to add some sort of draw from under the honeycomb. It is elevated a few inches but I'm just not sure how to go about it.

Thanks

[Dave Sheldrake]

Good idea Jon,

On my systems I have air ducted in via pipework to the front of the machines to allow a good cross flow direct the the outlet pipe. It also cuts down on heat losses from the warm air in the room being sucked out along with the smoke.

cheers

Dave

ps: the blower may be pulling more air than is being allowed in via the slots, if so then in a negative pressure situation the flow characteristics will be aweful

[Jonathan Bowen]

I'm still trying to figure out how to clean the airway. It's got a good bit of buildup in there. However, nothing fits in the slot and the hose connector goes directly into a right angle that leads up to the chamber for the air flow. I blew it out a bit with my air hose. I get the occasional dump of sentiment that rattles through the blower system.

I was losing power and noticed that my lenses are all really hot. I cleaned them and will start cutting again here shortly to see if the problem was fixed. I cut 4 or 5 sheets of MDF. Might have to start cleaning it after every cut till I get the exhaust situation resolved. I'm tempted to put a big hole in the side and reduce the 4" to 2" to run a scoop up to the table. However, I'm not sure the leasing company would be happy if I did that :) I'm also having some flame up issues because the air compressor isn't keeping up with the new 60 watt. I'm hesitant to go about the like 75% duty cycle its running now. I'm controlling the flow rate with a gate valve. I can still get some parts from a local supplier for it so I might just run it more and start saving for a better oil based system after it gives up the ghost. I still need to get it plumbed to the outside.

[Dan Hintz]

I was losing power and noticed that my lenses are all really hot.

If your lenses are getting hot and their not already caked with smut, you need to realign the beam... it's hitting the side of the holder. If it's getting hot and they're covered with smut, you have likely already cooked the lens.

[Jonathan Bowen]

Well I have full power for a bit but several sheets in I start to lose power. The mirrors are warm to the touch but cool down quickly and it cuts fine again. I double checked alignment and the second mirror doesn't seem to be hitting the holder. The burn spot is fully on the dime that I tape in place to do it. Checking the third mirror would be a pain but the beam seems to be hitting the lens without distortion that I can see. Do they just start to heat up over time due to small scratches and such? Never really looked into how they fail.

[Dave Sheldrake]

Expect about 50 to 60 degrees C if you are using Mo mirrors Jon and a little less if you use Cu's or Gold PVD silicon glass as a rough guide for the final head temperature (its a pretty big block of aluminium)

cheers

Dave

[Jonathan Bowen]

That is the normal case or the lenses going bad case? Just weird how I have full power for while but start to loss power if I run it for too long. Water temp is staying under 28C. I give it just a few mins rest and the lenses cool down then I get full power again.

EDIT: BTW its about 30 mins into cutting that the problem shows up then a slow reduction in power.

[Dave Sheldrake]

28 is too hot for a fatbody tube Jon, try to keep it within 20 to 22 degrees or you will lose power quickly.

cheers

Dave

[Jonathan Bowen]

I don't have a chiller. I just have a CW-3000. Starts about 22C I usually aim for less then 26C. Upgrading is on the agenda but it's gonna be a bit. I've eaten way too much in repairs to justify it for a bit. The tube is a 60 Watt from light object.

Edit: Well its lost most of it's power now... again. I triple checked the alignment and it seems fine. I emailed light object as the replacement power supply may have been from the same batch that had a problem with the voltage selector switch. So annoying.

EDIT2: Power loss seems to be from a loss mount on the 1st mirror. It shifted slightly and while I still had good reflection on the mirrors it seems to have shifted far enough to clip the side of the laser head cone. I think I'm still getting some clipping but its close to full power again. I might monkey with it a bit more not sure.