What’s going on here? I’m not sure why the laser isn’t cutting correctly. It looks like it’s deep, then works it’s way to shallow. Thank you for all the help
Not seeing any cut lines there.
If you’re referring to the engrave depths, that’s the natural varying density of the wood grain. What material are you using?
I’m using a piece of fir. its actually cutting deep then working its way up to shallow almost flush with the material,
Yes, perfectly in line with the grain of the wood.
Again, it’s the natural variation of density in the material along the grain. There’s nothing wrong with the machine.
then how do I fix that?
Use a different material with a more uniform density.
ok well obviously. but what if that’s not possible? I have to use this material.
Modify the design so that a darker engrave works better. More “Black and white” than shades of grey.
A heavy score around all the individual elements might help, like a “cartoon”…
Don’t engrave as deeply?? There’s only so much you can do…
To quote one Mr Montgomery Scott… You canna change the laws of physics.
its also cutting deeper at the bottom of the design and lighter at the top. just sayin
Yes, again, due to the natural density of the wood as it changes. Fir, and pine, have naturally soft fast growth rings followed by hard, dense slow growth rings. The laser is cutting deeply into the soft, less dense areas and not as deeply into the harder, more dense areas. The density of the soft areas changes slightly at the visible linear feature in the wood about halfway through.
If you must use this material and you must get an even engrave, I would use a mechanical cutter. If you must use a laser, you would have to create a variable depth engrave map that would match the power of the laser engrave to the density of the wood. This will be very labor intensive and will require a lot of trial and error.
You may want to use the laser to lay out your cuts and then use something like a router or a chisel to do the actual wood removal. Or, you can use the part you already have and use a chisel or router to cut away the denser areas that weren’t removed by the laser.
This is one reason that the ProofGrade plywood is actually an engineered wood similar to particle board between two thin veneers of hardwood. This allows even engraving since the interior layer is of uniform density and engraves and cuts the same everywhere.
Yup. Here’s a portion of your image…
Note how the annual growth rings are wider toward the bottom and narrower towards the top. The wider rings will have a lower density than the tighter/narrower rings, and will engrave darker/deeper than the same settings in the denser region.
If you look carefully, you can even see the seasonal difference – each ring has a dense border between the next. This results in the see-saw engraving effect within each ring .
Exactly what @ben1 was describing.
If you turned your work piece 180 degrees, the light would be at the bottom and the dark at the top.
TBF it’s very cool looking, and would be almost impossible to do if you were trying!
If you stop thinking of it as an issue, will it work?
Thank you everyone. The lumber was reclaimed from an 1870s home my non profit (operation rebuild hope) is restoring to use as temporary housing for homeless veterans. Everyone who has supported us through donations and our volunteer of the year gets a plaque made from Bryans Home lumber. It was very important for us to salvage everything we could. I’ll have to be happy with the way it looks, and let the donors know each piece is unique…
One of the challenges is to try and line up the grain of the wood to fit the design. Bamboo does something similar and bamboo cutting boards will typically be horribly non-uniform across the different pieces glued together.
It can be a challenge, but the end result can be really neat.
This is one I particularly like:
Using the reclaimed boards makes a cool project even more meaningful. Perhaps making a little sign for display if they are given out at the same time or printout that goes with each plaque to explain how the variation in each plaque comes from the rings of the tree. A good wordsmith could tie it all in with growth, change, renewal etc that would turn this into a good thing. Either way, good luck with the project.
Thanks for the answer @eflyguy, that’s right. I’m going to close this thread - if the problem reoccurs, go ahead and post a new topic. Thanks for letting us know about this!