I’ve been using a Creality Falcon 2 22w to cut veneers for geometric parquetry. I’m finding that despite everything fitting together very well at first, by the end of the job (potentially 100’s of shapes) i’m getting some gaps.
The pictures show an example of some walnut taped together. On a flat surface the join looks great but hold it up to the light theres a gap of easily 0.25mm there. These gaps are adding up and resulting in poor joins when there are hundreds of pieces tesselating together.
It looks like there are tiny fibres of walnut remaining that hold the two pieces apart, i’ve tried slowing the cut, cleaning the lens and testing focus but it’s not helping.
I do a lot of this type of laser work.
Every species and sample of veneer reacts slightly different to the heat and act of being cut.
Just like full thickness boards, veneers contain internal stresses that when release can cause dimensional changes. First thing to check is that the veneer is well supported and doesn’t shift or lift as the cut proceeds.
Woods that are more “fibery” or have distinct growth rings will leave uncut fibers where other woods will cut cleanly at a given power/speed.
Best solution for cuts I currently have found is single pass, raised above the laser bed, and air assist.
I haven’t tried that, but it could help.
For lumpy veneers (burls) that wont lay flat, I’ve had success by sandwiching the veneer berween two layers of glass to keep it flat (diode laser).
A better way to get a perfect straight line cut is with a proper veneer roller style “pizza cutter” or veneer saw. I also use a guillotine style paper cutter.
I know this isn’t what you need for most inlays with assorted shapes, but sometimes there are opportunities with some parts.
Often choosing a different wood or section of the veneer can yield better results.
I have the occasional issue with the veneers lifting, walnut can be tricky to keep flat so I have tried veneer softener/pressing to flatten it out but it didn’t really help that much.
I found oak to be a real pain when it comes to being fibery and have since given up on using it in future projects. Far too brittle too.
The glass trick sounds interesting! Hadn’t thought of that but movement in the veneer isn’t the issue here, it’s more about getting a super clean cut without any fibery edges.
I have yet to explore ‘real’ or traditional marquetry done with knives, maybe it could be worth a look…
My laser is a 10W, but I’ve found depending on the veneer I often change power from between 50% to 70% and often reduce speeds from 20mm/sec to 15.
Have you tried making several lower power passes?
Would multi passes work on veneer? In terms of settings all I have done is halve the speed in the hope it would clear the cut better and deal with the fibres. I could have a play with lower power and report back…
When dealing with “new” veneers (species or sheets), it’s always prudent to run a cut test. One pass is better IMO, in case the veneer flexes after the first cut.
20W should be able to do that easily, but trial an error is a sure way to learn the process.
So having done a bunch of tests I’ve found that low power multi passes are noticeably better. Doing 4 passes at 50% speed and 12% power, the joins are coming in much neater and I’ve halved my kerf width for maple and reduced walnut by a load too.
I guess the problem previously wasn’t so much about fibres not being cut, but more about excessive burnout on the cut itself from running at 100% power. Switching off air assist didn’t appear to make any difference.
Providing I can hold them nice and stable this looks like a bit of a win. Will have to see how it goes with a complete design.
Obviously I’ve 8x-ed the running time but that’s what a sudoku is for.
