Air Flow pushes the cut pieces in the way of the nozzle

[Philippe Lecomte]

Hi,

I'm currently doing a job where i cut a lot of small pieces on 5mm wood board.

When the job is running, sometimes, the air Flow pushes some of the cut pieces in the way of the nozzle when it's moving.

That's usually not a problem but i had a few big problems when the said cut piece move and went upright instead of standing flat then positionned itself in a hole.
When the laser nozzle hit the piece, it dragged the entire wood board with it, destroying everything in its way ! (Now, I know why you must ALWAYS stay around your laser when its running).

Is there a known trick to maintain the wood board chips flat when cut ?

I'm using magnets for larger pieces but i'm talking here of a multitude of <2 centimeters pieces.

Thanks in advance for the help.

Philippe

[Bill George]

Hi,

I'm currently doing a job where i cut a lot of small pieces on 5mm wood board.

When the job is running, sometimes, the air Flow pushes some of the cut pieces in the way of the nozzle when it's moving.

That's usually not a problem but i had a few big problems when the said cut piece move and went upright instead of standing flat then positionned itself in a hole.
When the laser nozzle hit the piece, it dragged the entire wood board with it, destroying everything in its way ! (Now, I know why you must ALWAYS stay around your laser when its running).

Is there a known trick to maintain the wood board chips flat when cut ?

I'm using magnets for larger pieces but i'm talking here of a multitude of <2 centimeters pieces.

Thanks in advance for the help.

Philippe

Don't know what kind of machine you use, but on my ULS and I imagine others also you can adjust the air pressure lower. The air regulator feeding the machine from the compressor is set at around 10 psi.

[Keith Winter]

To clarify are you talking about air assist or exhaust? Air assist you can adjust depending on your machine, you can also use a wider cone to slow down velocity.

Exhaust you can use blast gates to decrease air flow or dampened to attempt to direct the air flow more in your cabinet.

[John Bion]

Hi Philippe,
Could you possibly list your machinery in your signature, that helps with giving advice.
I have Chinese made lasers supplied by a large (LARGE) compressor, which is then regulated down to a maximum airflow (for the most demanding cutting work), prior to the machines. This in turn can be manually regulated by individual valves to each machine if the pressure is too high for any particular work.
I assume that the material you are working is thin, as thicker material will not blow out of position easily, unless tilting on a knife type table. What size honeycomb/knife/pin table do you have underneath - if you are throwing the small bits away then rather use a table that lets them fall (be blown) through, if you desire to retain the small bits, use a table that supports them well. Some plans you just know that at a certain point you have to tape a piece before finishing the cut.
Hope something in all that helps.
Kind regards, John

[Mark Taylor2]

Hi Philippe,
If you can, leave a small 'fret' between the stock and cut piece. I have to that for a lot of the items I cut for me. The 'fret' is simply a small area that's not cut. Depending on the wood, it's simple to use a hobby knife to cut it and release the part.

[Joel Ifill]

We tab parts if we are having issues and can deal with the tab, I've also tried various tricks using low tack tape or aerosol adhesives to non permanently glue the cutting piece to a backing that isn't cut.

[Keith Colson]

Yes, tab break outs are the trick. I am cutting 40K small parts right now and its the only way it would work. I use my portable vac to suck out all the scrap. There are over 1000 pieces per cut sheet. I also broke the sheet up in different colours so if the job fails or I want to continue work the next day I just stop the machine at a colour change.

Cheers
Keith

[Kev Williams]

Those nose cones are more trouble than they're worth to me. I took mine off the day after I got the machine running and haven't looked back.

But for those of you who think that's verboten, then how about taking your cone over to your belt sander and sanding down about 1/8" off the end. Air will still come out, the same air will cool the lens, plus the tip of the cone won't be so close to your work that it's in the way, AND the now wider hole will let more of your laser's beam out without interference...

Just remember to make a new focus dealybopper to account for the extra space! ;)

[Philippe Lecomte]

Hi,

Thanks for all theses tips, guys ! I've now a lot of experimentations to do in the next few days : Try to reduce the air pressure and to use the fret method...

As you may have seen, my english is not perfect (far from it actually) and i don't manage to catch what Joël and Keith try to explain. What does "We tab parts if we are having issues and can deal with the tab" means ?

Is a tab the small 'fret' between the stock and cut piece that Mark was talking about ?

As John suggested, i've updated my signature with some informations about my laser.

Thanks again,

Philippe