Cutting paper/card - Problems with Back burn

Evening all

I am trying out cutting some paper on my 60w CNC laser, I feel like I’ve got the settings at a point where it looks good but the next problem is back burn.

The top face that the laser initially cuts through looks great but the backside has black dusty scorch marks in areas.

The paper is currently laying flat on a honey comb mesh, any tips or tricks to eliminate this?



If your honeycomb has seen substantial use, it will have a heavy condensate from all the previous sappy cuts you’ve made. I recently dismantled my bed and soaked it for a while in laundry detergent and water, then blasted it with a pressure washer.

When the laser cuts through the material and hits the condensate, it burns and flashes upward to the workpiece.

I’m going to top the bed with a sheet of steel and use punk spikes on magnets to elevate the work. The steel will be easier to clean than the honeycomb.

Now you come to mention it the honeycomb is quite grimy, i didn’t think about all that residue being vaporized when the laser cuts through.

I’ll strip it down tomorrow and give it a good clean.

Thanks for the help.

For paper I use a stand-off grid made from heavy card.

It doesn’t reflect and allows good airflow.

Interesting, any chance of a photo the grid? just to give me some ideas.


It’s just a slotted box grid of card - Ill dig out the file.

Cardboard Paper Grid 2.5mm.lbrn (146.7 KB)


Sized for 2,5MM corrugated cardboard. I reuse old packing boxes.

12 x 12 grid, 300mm x 300mm, so it fits an A4 sheet, easily.

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Thank you for sending that over, i can see what you mean now.

That’s very handy as you can just make it as needed.


Honeycomb table cleaned and is like new! Wow

Hi Jeff

That looks brand new after cleaning, mine does not look like that.

The large flat stainless tray is perfect for cleaning in.