Flame issue:

[Corina Hibberd]

Hi folks. This mere hobbyist is looking for help/suggestions. Since moving home and my laser engraving machine, when I engrave and cut plastic sheets, shooting flames occur. Randomly when engraving but MAJORLY when cutting. The engraving result is OK but it doesn't cut right through the material and the heat/flames buckle the substrate. Not to mention the danger involved with shooting flames. This issue has only started since moving the machine. I've realigned the beams & adjusted the power & speed settings to no avail. Does anybody out there have any ideas for a solution? Thanks in advance :-)

[Matt McCoy]

Do you have air assist?

[Corina Hibberd]

Thanks for the reply Matt.
It's a cheap Redsail - LaserMate5.2.5
With regard to air assist, from what I can figure, in the settings there's a tick box option (Chinese terminology) "If Blowing". I can select yes or no. Flames occur for both options. I never had an issue before the machine was moved??

[Michael Henriksen]

Air assist is a separate air pump that directs air through the nozzle. Reduces smoke staining, speeds up cutting and prevents flame up. There is usually no air control solenoid in the machines so ticking the box in the software makes no difference. If you don't have an air pump or compressor connected then you don't have air assist.

[John Lifer]

Yep! I'll assume you have it packed up somewhere if you moved. Most of those provided with the Chinese laser are grapefruit ( or a bit larger) size silver aquarium pumps, most are similar to this.
https/www.alibaba.com/product-detail/Sunsun-ACO-008-138W-air-pump_60588185789.html?s=p

Please do not cut any more plastic and for that matter wood without it. First is major concern. The air will blow out flames, making things much safer, but not foolproof.

[Kev Williams]

From what I read, air assist has never been used...

Have you pulled the lens and tube out? If not do so, check to see of some bug got in there or some spider made a web or laid eggs, or whatever... If there IS anything in there it'll refract or otherwise mess with the beam. Also check the top side of the lens for something cooked onto the lens...

I once started my Triumph and a very hot miller flew out about 2 seconds later, that was weird

[Corina Hibberd]

You guys are amazing. I knew I came to the right place to learn. Yes there is an air pump, yes it was plugged in ... but the power supply wasn't working properly ... hence it wasn't actually running. All's well now & no flames happening. Thank you so much for your help. I now need to get the exhaust pump working properly. It doesn't seem to remove the fumes as well as it did.

[John Lifer]

It might need a bit of cleaning. And if any flex hose make sure it isn't collapsing. That's my I right now. I have 2feet of vlex outside and it bends and flattens. Reducing flow by 90%

[Doug Fisher]

If you have been using your machine without air assist, at this point you probably need to clean the lens on your laser.

[Corina Hibberd]

Thank you. Yes I cleaned the lens and nozzle when I rectified the air pump issue. I've re-positioned the flex hose with great results. The angle was a bit too severe. Thanks again for the advice guys.