Hi all,
I have a 24 hour job that is divided into 5 different tool changes, which are saved as different toolpath files. Once I finish one and want to close shop for the night, should I leave the Shapeoko on and Carbide Motion up on the laptop? I was wondering if that would be a strain on the steppers. If I shut the Shapeoko down and leave Carbide Motion up on the laptop, will it remember the origin where I zeroed x,y, and z?
Thoughts on the best way to handle?
Thanks!
Jeff
Yes, stepper motors are weird and they work hardest when holding position, so the machine should not be left paused overnight (or longer than a brief break).
If you shut the machine down and restart it, the origin should be correct w/in the limits of the belt motion and the homing switch sensing — I’d suggest testing a small project in a piece of scrap first — also, having some feature which will be persistent which you can use as a sanity check will help for one’s peace of mind.
I’ve seen this mentioned before, but it describes a state, but not a problem. If you leave it on, what will actually happen to the motor that is bad for the motor?
It will furiously work to hold position w/ a potential for overheating.
Understood. It furiously holding its position is admirable. But if it does not overheat, is there any other problem with leaving it on?
Wear and tear focused on a pair of magnets is my understanding.
Thanks Will - that’s clearer now. Call me a terrible stepper motor employer, but I didn’t mind them working their hardest. Knowing it might kill them earlier will give me slight pause in the future 
I think what Will said is true about the stepper motors. However occassional 24 hour marathon jobs may cause wear by leaving the Shapeoko on but that is what it was made for. The stepper motors are inexpensive and could just be considered a maintenance item.
I would suggest you leave the machine and laptop on for the durration on rare occassions. The x y and z are persistant over power cycles. The homing cycle is not as percise for repeatability. If you were doing an advanced vcarve would your job tolerate being off a few thousands on each power cycle? The cumulative error could ruin your job.
Occassional abuse would be better than ruining your job on your fourth or fifth run.
Let it run and be safe on such a long project, just dont make a habit of it.
Makes sense Guy. Thanks for the response.
Most stepper drivers, that I know of, reduce current to the stepper motors after a period of time.
is this applicable to specifically the pause function or just being “on”
I’ve been leaving it on for days at a time just so I don’t need to reinitialize it when I want to use it.
In my scenario, I would finish a toolpath and just leave everything on until the next day and start a new toolpath within the same job. Carbide Motion would stay connected to the Shapeoko.
Yes, just being on locks the motors, causing them to work to maintain position.
Yes, I can see the issue with that.
I have found if you do this your z axis will lower
Not a lot but enough to see it in a 3D carve for sure as it happened to me
Now to be fair it could have been a humidity or temp change as I live in south Louisiana
Does this imply that using your shapeoko with a laser attachment is bad for the Z-axis stepper motor? I mean, it stays at the same height throughout all operations with the laser. And…for that matter…what about drag bits? [EDIT]: I take it back wrt drag bits…still using the Z motor. But the question re: Lasers still stands.
I would only be concerned about damaging stepper motors IFthey get so hot hat you can not comfortably touch them. On the other hand, if we were talking about servo motors, I would consider the wear and tear from them trying to hold position, as they tend to “dither” back and forth trying to keep the encoders in position.
I have stopped mine and closed everything down over night between tool paths, providing you do not move the board you are cutting when you start a new tool path it will go right back to the original setting do not re zero your machingr
After a power cycle on my machine, repeatability isn’t great. Seemingly a little worse after switching to the proximity switches. If I need to take a break from a job, I just let it idle along until I can get back to it.
I suppose it depends on what you’re working on. My work is generally large with respect to XXL, but has a lot of tiny engravings, small holes, and critical cut outs. After a disconnect, power cycle, pushing the gantry into the same hard stops - I am generally scrapping the piece if it was in the middle of a critical element or finishing pass. I can generally get a good zero, but the gantry can skew just enough to be visually evident.
Even if a stepper did happen to kill itself, they don’t seem like anything particularly special. $25 for a new one maybe? While I don’t have any long-term experience with stepper motors, the Servo’s on one of my big routers are over 25 years old, they pretty much hum along all day every day.
Since the job entails not just 5 different toolpaths, but 5 different cutting tools, then chances are any inaccuracy from the zero reset on reboot wouldn’t be relevant/noticeable.
For instance, since you have a PRO, chances are you’re using the BitSetter for every tool change. That itself uses a limit switch to set the Z-depth so it’s not 100% guaranteed that the depth is exactly right to 0.0001" (or whatever). But, I don’t see people complaining about BitSetter inaccuracies (right?).
Since these are different tools, chances are each tool is either cutting away more material than the last tool/toolpath or is cutting something different enough that there is not shared edge/seam that’s long enough to be visible. And even then, a little hand sanding to remove that 0.01" (or whatever) should be easy enough.
I posted about this some months ago. One suggestion was to use the Quick Position page to put the carriage into a known position, and then turn the machine off. When turning it back on, the reset to zero therefore starts from basically the same position every time, which might help make things even more repeatable.
If you’re really concerned about this, it’s easy enough to put a bit in and run some trials to see if running the same toolpath after shutdown/restart cuts any more material.