Cleaning up burnt edges

[Annette Thomas]

Hello,
We are new to the engraving industry but have been in the garment, sign, and promotional products industry for 7 years. We do all our artwork in Coreldraw so we have good clean artwork. We are engraving then putting the cut line using a contour around the object. We are using 1/4" oak veneer sheets. We are using an Epilog 35 watt, using 5/100/500 settings. I have tried changing the speed but it will not cut through if I use 7 as speed.

After cutting, the edges are charcoaled. We are having a hard time getting the burnt edges cleaned up. The items are too small to sand off each time as they are keyrings so 2" is the max size. This is a detailed cut so the inside edges are almost impossible to get to. Any ideas of how to clean these up?

I have 2 pallets of this and did I mention it was free so I need to find a solution to what I have.

Thanks in advance,
Annette

P.S. Enjoying reading the posts here.

[Doug Bergstrom]

I found that it was difficult with many woods to avoid the burnt edges. Try using Baltic Birch, it cuts cleaner and engraves better. You can sand and finish easily.

[Vicky Orsini]

Maybe try lowering the power, speeding it up and cutting in multiple passes?

[George D Gabert]

Can you somehow put them on a rod and dip them in a sealer like polyurethane. This will seal the edges and put a nice finish on the parts

GDG

[Joe Pelonio]

I think it's a power issue, your 35 watt is not going to be able to cut oak faster, and that means char. With my 45 watt I cut 1/4" oak at speed 9-10 and the edge is black colored but not too charred. As Doug said, Baltic cuts easier/cleaner.

After cutting just spray with a clear like Krylon Crystal Clear Satin to seal the black from rubbing off.

[Richard Rumancik]

Annette, I hesitate to say it but I don't know if there is a lot you can do with settings. People say that even using nitrogen assist gas doesn't help much. I think the biggest factor for wood is having high enough power/speed to get through without charring, but as you have a fixed laser power and are using 100% speed there's no option for improvement here. When I do multiple passes I usually find the first pass leaves carbon, then the second pass burns brighter (due to carbon from first pass) making it deeper but worse for carbon residue.

If there is too much carbon to polyurethane over it, then you have to figure out how to remove at least the loose material. One possibility, and this assumes you have access to a small table-top sandblaster. Mask the rear with paper, then raster and cut normally (one setup). Remove parts, then clamp the graphic side against a flat surface to protect the graphic (could use a "reject" part as the flat surface and clamp it to match the contours of the good part) and then sandblast from the backside, which has paper on it. You might even find that you could get away without paper on the back.

Could you stack and clamp five or ten together and sandblast them all at once from the side? The clamp would make a nice "handle" to manipulate the parts during blasting. A little fixture to hold them in alignment while you clamp would be handy.

You would have to decide if it would work on the financial end.

[John Mimidis]

Try adjusting the frequency; don't just use the "auto" setting. Auto sets the rate at 5000pps. I use 2000-3000 on most woods.
HTH, John

[Annette Thomas]

I will try the adjustments. Since this is new to us, it's nice to have somewhere to post these questions. Sandblasting isn't really cost effective but dipping them in polyurethane sounds like a good idea. I will post my results after changing the settings.

Thanks.
Annette

[David Fairfield]

If you are cutting 1/4" oak with a 35 watt laser, I'd be surprised if there's a way to avoid those scortched edges. That's some pretty hard and thick material you've got there.

[Clint Lauricella]

Have never tried it on naked oak, but if you spray Pledge on it before lasering and worked it in, I've found you can wipe it off afterwards.

[Mike Null]

I agree with Vicki, faster speeds more passes. Try reducing the PPI as well. The resins in the glue may be the culprit.