You know this, but to add clarity for the new folks… Set focus does a really great job at determining material height at a specific spot. But the GF uses that set focus height (material height) for the entire job. If a design is more than a few inches in size material flatness is a necessity. If the material is not exactly the same height across the project, cut thru may become a problem.
Yep. I use it multiple times to get good placement, then determine what is the most crucial focus point for the entire job. Sometimes I hit it right, sometimes I don’t. But, I’m getting better at judging it.
This takes way too long. If your placement is that critical, use a jig and get it right in one shot. 2 or 3 autofocuses is about as much time as one jig, and the jig is dead sure. Alternately, design your cuts to fit comfortably on your material and just don’t worry about the pennies in wasted materials. Life is too short.
(end opinion, carry on)
How is the camera on the GF able to determine the thickness of a material?
I am trying to find the correct settings for this particular leather. Before today I had always manually put in the thickness of the material that was in the crumbtray.
When I chose the set focus feature my leather was not cutting through. Dan the CEO posted this last April.
Two new changes to share…
Set Focus now sets the focus. (Surprise!) After you run Set Focus, it will use the height there for the focus distance. That means it will not run the autofocus at the start of your print, which means your print will run faster too.
If you’re using non-Proofgrade material, you no longer need to enter the thickness - and in fact, you shouldn’t. Just run Set Focus and it will take care of it for you, and allow you to print. We love you whether or not you’re using Proofgrade!
A red laser pointer in the head shoots a beam at an angle on the material. The head camera sees the elongated spot on the material and through the magic of math determines height of the material and therefore the focus point.
It shoots a laser (red dot) at an angle, then measures where it is, and uses pythagorean theorem to get the distance. Pretty simple math, elegant solution. Same trick that underwater ROVs use for rangefinding actually.
Look at the two red dots, they use one or both to figure out how far away things are.
It seems like these two questions have little to nothing to do with your follow ups about set focus. Yes, use set focus, but to answer these questions:
I will often run a 2nd cut, but not as a 2nd pass - I find that if I give it time to relax it’s more likely to cut the final bits. Yes I could slow down/add power, but that adds to the charring. Also those tiny stringy bits happen, you can run a lighter over them to burn them quickly, or a pair of scissors also works. You can run a “cleaning” cut with the laser, but unless they’re everywhere it’s kind of overkill.
Yes, there will be charring. You can put small pieces in a container/baggie of salt and shake it around and it’ll take the majority of it off - or you can use leather soap to clean it more manually.
Leather is persnickety - it’s natural, and has variations. You won’t run into knots, but you will run into scars
Just this evening I was cutting some leather. I ran the smallest piece I was going to use first…I didn’t use set focus…just chose med. PG leather from the drop down. It didn’t cut all the way through (I finished cutting it with an exacto knife). So, subsequent pieces I cut as thick PG leather and it worked just great. I did mask my leather with some light tack paper which helped keep charring at bay.
And, just as an aside…I’ve always heard about how stinky leather is and I was very surprised that it bothered me so little. So, either I have a good tight vent system going for me or I’m an oddity that doesn’t seem to hate the smell…or both. Good either way!
My problems started occurring when I was experimenting with the set focus but I did not have any bad smells from the cutting of the leather. As a matter of fact there was very little smoke from the cutting but a lot of charring.
I think what she is getting at is a second pass is when your settings designate two passes. The laser goes over the material with the same settings twice. A second cut is when you use one set of settings on a single pass. Then change your settings and do a second time around with these new settings. That way you could do a full power the first time and 20 power the second time.
I work with a lot of leather, usually 6-7 oz, but also from 1oz up to 10-12 & various types (though don’t put chrome tanned in the GF).
As others noted, leather chars when cut or etched. The laser is burning organic material–it also chars wood and paper, though often with those the soot blows off, but it “sticks” to the leather. And so I most often still hand cut as faster than cleaning the edges, but some of my designs I do like to cut, though often have to finish the cut by hand. And I always wash the soot off the edges or any etchings–don’t want my customers to get soot on their fingers!
Variation for cutting with a laser is not just due to the thickness with leather. It’s a skin, and different animals and different areas of the hide have different properties & densities. The back, shoulder & butt will be thicker & tougher than the belly. So what works great with one piece may not work as well with a piece taken from a different area of the same hide!
Also if there’s a scar in the skin, this is a dense area, even though you may not see it, it may cause a localized spot to not cut as deeply.
Also how it’s been tanned will affect cutting–some leathers have more oils and “stuffing”, though that is minimal with natural veg tan… And all leathers are split to desired thickness, but some are also pressed to final thickness, and this can also cause additional variation within the hide…
All in all, leather is great to work with, but expect to have to do some hand trim to finish the cut, and to clean the soot off the edges or any etched areas, so allow extra time for that. (I like bit of mild soap & water with soft toothbrush & get excess water off, and let leather air dry–laying flat or take the opportunity if thoroughly wet to mold it).