I’ve been messing around with some fairly basic geometric designs and decided to try to cut some using the thick draft board. After the job finished, I tried to remove the cut piece and noticed that it didn’t want to come loose. I applied gentle pressure to the interior of the piece (a fairly robust 4" x 4" cross shape) and the backing (not the paper masking) cracked and tore. Turning the entire sheet over, I noticed that the paper masking was not even cut all the way around the piece.
There are several things that could go into a cut not going through all the way.
Since this is Proofgrade, I assume you are using default Proofgrade settings. So that eliminates one problem of not using correct settings.
The thing to check is that your material is dead flat over the whole surface. One of the most common reasons for not cutting through is not having flat material. Proofgrade should be pretty flat right of the bat, but depending on the environment of the shop and how it is stored, it can quickly warp.
I would test out a new material always with some small shapes,like you are doing, but smaller and at the edges of the material, just to get a feel for how the material works. Proofgrade should work, but this early in the whole process of production units and mass shipping of Proofgrade and stills tweaking things under the hood, some caution is advised before committing to a full sheet of material.
That a pain to have this happen because it should just work. Once it doesn’t it really can make you nervous trying anything. That shouldn’t happen then, but seems to often enough to be an issue. Have you tried cutting a couple smaller shapes to see that it isn’t going through on them?
Here is the official response from this question to start on the troubleshooting path:
I have tried with a bunch of other shapes, including the founder’s ruler and some small Starwars models I found on the thingiverse. It seems to work perfectly with the the smaller bits and thinner draft board.
Anyhow, I ran this same job with a manual cut setting to make a second pass. That seems to work fine. It’s a nice, clean cut with no tearing.
I was hoping it was something I was simply doing wrong, as I am, admittedly, still something a noob when it comes to laser cutting. But maybe some of the default settings still need a small tweak.
I think he might have been referring to the quoted post I made from @vee, staff.
@GeoffreyD, I think testing is in order even for Proofgrade as you learn all the different variables that might affect a print. I’d work with a lot of cheap plywood or even cardboard just to see how designs behave. Shouldn’t be a problem, and most of the time isn’t, but trying to figure out a cautious way to approach things without burning through Proofgrade but still get things done. Sorry for you. Keep us posted with other things that you are testing.
I appreciate the consideration. Honestly, I don’t mind burning through a bit of material (ha!) as I come up to speed. I half expected to waste some material, honestly. In this case, I was specifically looking to see how the thick draft board performed (compared to the thinner draft board I had already been working with) so I really couldn’t have got at what I was looking for using cardboard. However, cheap plywood could, indeed, be an option!
Just a FYI: Flat is relative. When we say flat we mean dead flat to the crumb tray. Press on the material lightly to see if there is any place where it is not against the crumb tray. A few hundredths of an inch often makes the difference between cutting all the way through and not. I haven’t had a single piece of material in 6 months that was perfectly flat. Have to use magnets to hold the material to the bed every time.
Thanks for the clarification. What I have done to test whether material is ‘flat’ is to press the edges of the material firmly after placing it against the bed, looking for a raise or shift along the opposite edge. Obviously, I’m not going to find a 1/100" difference, but it has made me aware of [previously unseen] debris remaining on the bed. I’m not sure there’s anything more I can do?
That’s not sufficient for lasers. You need to do the press test in the field of the material to find places where the material is bowed up. In fact sometimes I’ll flip the material so the edges are the parts standing up because it’s easier to flatten the edges and not impact where you can place objects vs trying to work around magnets holding the middles down.
This very well may make a difference. Those tiny little pieces can make a big difference. I had a mis-cut in the same place on three different materials and I finally found a itty-bitty piece of plastic stuck in the honeycomb. You wouldn’t think .01 would matter, but it does. :-/ James is right too, it a tiny bow in the middle of the material that can mess things up as well.