Question about the underside of the wood I cut

[kwmac]

So I attempted another project trying to learn about this, a set of laser cut earrings, easy enough, they turned out great on the top side. However, the under side was a bit charred and they took on the shape of the crumb tray, so they looked a little like a textured cheetah print on the bottom, lol. I used a piece of finished wood that I picked up at Michaels and it was relatively the same thickness as the proofgrade plywood, so that’s what I chose in my settings. What did I do wrong? Or will this always happen to the underside of a cut item?? Thank you!!!

[ekla]

The pattern you’re seeing is called flashback.
To consistently cut all the way through there is almost always a little bit. Masking your material before cutting (like the way PG materials come) and then peeling it off after will eliminate it from your final product.
If flashback is excessive then your speed is too slow and/or power is too high and you should adjust.

[eflyguy]

You can also lay your material over a different, sacrificial piece like cardboard or even paper. If you are making many items, it’s worth spending the time getting the settings correct to make something like that work.

[marmak3261]

It’s a bite, getting settings dialed in. For mission critical acrylic I do a sacrificial piece of cardstock like @eflyguy says. Now that you know the term, you can search for ways to mitigate it:

Flashback Underside Burns on Birch Plywood

Hi, I recently place an order for a Glowforge Pro and I’m planning on using this machine to cut through 1/8" birch plywood for a product I plan to sell. I understand that this machine comes with a crumb tray but I’m curious how well it prevents flashback or underside burns. I want there to be zero underside burns. Is it reasonable to expect this from this machine or should I look at an Epilog machine? Any advice wood be greatly appreciated. Kenny

[kwmac]

Ahhh, good to know! I masked the top side but not the underside
Thank you!!

[kwmac]

Thank you!

[kwmac]

I’ll definitely work on my settings as well as replying to all posts at once!
Thank you!

[Jessica.F]

Since this problem is being seen on materials that were purchased from another company, we can’t offer support for prints that don’t come out as expected. Materials may vary widely from piece to piece, even if they’re created by the same manufacturer. I’m going to move it to Beyond the Manual so other folks here can help. Should this happen with a print on Proofgrade materials, please open a new ticket in Problems and Support and we’ll help you right away!