Hi all - this sounds like some trouble I initially had, as well, and I wanted to add some (maybe only small) re-assurance.
I got my Shapeoko 3 XXL about 6 months ago and I now love it. I did have about 2 weeks of considerable doubt at the very beginning, related to some of the same issues the OP reported.
When I first got my machine assembled and started in doing some tests, I had some very frustrating issues connecting or keeping the connection the cutter. I can’t tell you all the steps I did, being so long ago, so unfortunately I can’t give any solutions, but I can tell you that, after upgrading to the latest GRBL and Carbide software and after some fiddling and back-and-forth with Carbide support (and a defective limit-switch which was swiftly replaced by Carbide), I now have a working machine which I really like.
Here are the quirks and limitations:
I often have to “reset” the controller board to get the cutter to connect. I used to keep the metal cover off the board so I could access the reset button. I used quotes around reset here because, more recently, I’ve found that I can flip the power off then quickly back to on, with the same effect as using the reset button. So, I’ve replaced the metal cover and now accomplish my “reset” by toggling the power switch (quickly).
the gantry move to back-right/home corner is really annoying. And seemingly unnecessary. I must be missing something.
tool changing sucks. Essentially, don’t even try because you’d need some kind of external tool to keep a new tool end at the same Z as the tool you’re changing from. The work-around (I believe this is corroborated by Carbide) is to just run separate jobs on the same piece. So, do your one job, keep everything in place, load a new job w/ the same zero, re-z-zero with a new cutter and run the new job. Repeat as necessary. Really, I think this could be a big area for improvement, especially with the auto-z-zero puck thingy that Carbide sells.
Default feeds or speeds seem really off, but I haven’t experimented extensively. But the ABS settings are clearly off; I kept melting/glomming around the tool within 30 seconds. I have the dial#/rpm sheet for the DeWalt and I think I set it to match the feed/speed chart. You definitely need to experiment with your own settings, the auto-settings don’t work (or didn’t for me). In the end, I dodged the issue, changed to polycarb material and haven’t experimented since.
Those are the biggy cons. The pros?
the tab feature works great. Kudos!
make really cool, large platform stuff on a budget!
the software works fairly well. I’ve yet to have a failed part because the software froze/crashed or whatever. Once you get used to Motion, you can zero quickly and be off and running. I was doing a run of 10 parts through it recently and kept clocking myself to see what the cycle time was and was kind of amazed (maybe I’m naive) at how fast I could cinch down a new piece of material, zero everything and get started… it was like 90 seconds.
The service is pretty darned good. I had problems with my system and someone there from Carbide responded right away and even sent a limit-switch kit that had failed. That person told me a lot of the same things as the OP heard, like “change your USB cable” and “try grounding the metal shield around the control board” and stuff like that, some of which I did but all of which didn’t seem to make a difference. It was the well-timed reset that did it for me. Which is essentially, whenever you see that “can’t connect to cutter” message, toggle the power toggle switch with maybe a half second between off and on. With possibly more than 1 try, it magically connects. Not that the service person identified that, but he did thrash around a lot to try to fix things.
In general, I love the machine. I love that I can easily create CAD, import the DXF and the Carbide software reliably creates the toolpaths. I’ve never had toolpath generation fail. It just works.
So, this user’s perspective of using the Shapeoko is “fun”/good rather than “hassle”/bad, which is quite an accomplishment considering the complication of CN routing. The first two weeks pointed to trouble, but after that, it was off the races. The biggest issues I now have relate to setting up material holding and chip management/vacuuming, not the software and not the operation of the machine (ie via Motion).
I hope that info helps.
Update: Carbide got in touch with me and told me how to fix the issue w/ the board, to get rid of the “reset” requirement. They also offered to swap out the board. Kudos to them for great service! (note: I haven’t tried the fix yet)