Hi all. I’m just about to chuck my laser into the nearest pond. I have an Ortur Master 2 Pro with an 80w (10w really) Lasertree laser. I only want to cut 2-3mm leather, at the minute anyway. I’ve done material tests which worked perfectly and cut cleanly, but when I use the settings to cut a big piece of leather it isn’t cutting through. I do use a sample off the same hide, dampen the leather and found I get neater cuts in the tests with the flesh side up, but I can’t get the darned stuff to cut on a ‘proper’ piece. The settings I’m using from checking the tests are 480mm/m and 65% and that cuts through perfectly… on the test. On the real piece, I can just about see the shapes on the back but nothing is cut. It is driving me potty!!
Any ideas please?
MORE POWER!!! - why stop at 65% Go for it turn it to “11”
MORE PASSES!! - natural material have variable consistency and moisture content. Plan on 25-50% more passes to ensure cutting across those variances.
Do not be afraid to push the envelope and go past what you see on the material test. At times, single line is a different result than a filled box.
HI Ann
I must begin by telling you I have no experience laser cutting leather as yet but after a conversation had here last week concerning moisture levels in wood I would ask, Is the leather piece that is for the actual job possibly much wetter than the test cut piece.
The laser will need more power to cut through any material the more moisture it holds due to having to evaporate the moisture as well as perform the cut.
Also, Is the focus absolutely correct on the piece where the cut is failing.
Other than that you could try just upping the power and reducing the speed and then adjust both to best outcome.
A pic of both pieces would be nice to see.
Thanks for your reply. I thought that the material test was designed so that you can see what the best settings will be? If not, there doesn’t seem much point to it if you still have to guess.
Thank you. I did wet the pieces at the same time, so they should have been at approximately the same moisture level hopefully. I finished the cut by hand and could see that the laser had only gone about halfway through the leather on the large piece, where the same settings cut really well through the test piece. It does all seem pretty random 
I would imagine that leather and wood could be similar in their randomness in density and absorption rate.
Just out of interest, were the test cuts small and local to each other…and the proper piece much larger with random cut depth along the line.
I guess I’m just a simple guy. I base my expectations on results. Rarely do I follow a food recipe to the letter, as I have my own personal preferences.
If I don’t get the results I want, then I start looking for one of the three variables to change. Speed, number of passes, or power level. For example my woodwork, I use 11 passes at 100% power at 1,000 mm per minute. It takes a long time, but I get a nice clean cut. Push the envelope, experiment to see what works.
You said you used a sample piece of leather? Was that a sample from the leather that you’re trying to engrave or cut, or was it sample included in the laser kit? We have to compare apples to apples.
Yes and no. One problem with the built in material test is the squares are pretty small by default. Depending on the speed range you’re testing in and the capabilities of your laser, the laser may not reach test speed in such a small square, giving false results.
In other words, if I try to test at 1,000 mm/min, the laser may only be able to achieve 500 mm/min in the 5mm space of a test square, so anything above 500 mm/min is a repeat of the 500 because the machine cannot achieve a higher speed in the space alloted. If I run 1,000 mm/min on a longer line, it can achieve full speed and because it is “actually” moving at 1,000 the cut will not be as deep.
In my opinion, the material test will get you in the proper range, but it’s only on a full size project that you can dial in the best settings.
I would be interested in seeing the results of your material test.
To expand on what @thelmuth said, the material test is adjustable. If you are making tiny parts, tiny squaers are okay. If you are making large parts, the laser can get up to the programmed speed, meaning it is now going faster and will not cut as deep in a pass.
If you are making large parts, set the material test for maybe 4 larger squares like 100mm (2”). Your test results will be closer to reality.
Ah - thank you, that makes total sense! The pieces I’m cutting aren’t huge, but obviously much larger than a 5mm square. Maybe the laser isn’t going in the pond just yet!
Thank you for the explanation, which makes sense to a newbie like me. Why do the laser user manuals never tell you what you really need to know?!
Yes, the real pieces were not huge but a lot bigger than the 5mm test squares. Now I know, I’ll try again with a bigger test.
The sample was from the same hide as th real job.
Your laser came with a manual?
Most of what I know about lasers and Lightburn comes from hours of youtube, reading on this forum, and experimentation. I cannot begin to imagine the amount of material I have rendered unusable during testing.
I think they assume nobody reads the manuals, so there’s no point in Too Much Information. 
Based on what we see around here, even the comprehensive LightBurn doc goes unread:
Do I see a “Lasers for Dummies” manuscript in somebody’s Word document list?
It would still take 10,000 hrs to understand it…and the first five years would still be the hardest!
I suspect it would be a 12 Volume set too. 