How to pause a set of prints overnight


#1

Hey all - I thought it might be helpful to ask this. I have a print that I need to do in separate chunks in order for the Glowforge UI to handle it. So I can print one chunk, then another without leaving the Glowforge app or opening the lid. Just ignore the old chunk and fire up the next. It’s working great, but I still have a few hours to go.

Can I leave the Glowforge app open overnight if I need to maybe NOT stay up until 4am? Will everything stay ready to go the next day or will it kick me out and force me to have to perfectly line things up on top of what I’ve already done? What should I expect to happen?


#2

You should be okay. There is a small risk of something happening to your session. But I’ve done exactly that for exactly that reason and everything was fine at 07:00 when I got back to it. :slight_smile:


#3

Maybe. The problem with trying something like that, is that after several hours, alignment can drift.

If it’s worth the risk, you can give it a shot.


#4

I don’t understand. Most likely because I don’t yet have my glowforge. Can you explain what you mean by ‘alignment may drift’? I would think X Y coordinated would be solid. No? Thanks.


#5

Thanks guys! I ended up leaving it with the button glowing, ready for me to stumble upstairs and hit go. Looks like it worked great. :slight_smile:


#6

I don’t understand it completely, but this has been a recommended best-practice since June…


#7

Thanks for sharing that! I’m currently rocking print 6 (ish/at least?) within the same area and have a couple more to go, and everything is looking good. So I’m guessing when he said “many” he meant it.


#8

I don’t think that applies to a machine sitting idle. I imagine it could sit idle for a week and, unless acted on by an outside force, the alignment would never change.


#9

The steppers do not have position encoders, so they use “dead reckoning”. Traditionally, the current position would be known by keeping track of how many steps they moved in each direction. If it misses a step, or there is a glitch in the code that keeps track of the current position, it doesn’t know and this causes alignment “drift”.

On the Glowforge, it works only slightly differently. The device itself does not keep count. It just plays back the steps it receives in the file it gets from the cloud (the cloud’s motion planner does all the math).

The GF stepper drivers have a home indicator (these are not limit switches, just internal step counters that can be set when the head is at the home position) that will give feedback to the processor to tell it they think the head has reached home. I don’t know if the current GF firmware verifies that the drivers indicate the head at the home position when the program finishes, though it is capable. Of course, neither would know if there were missed steps, so it wouldn’t make much difference.

All that being said, it should only experience alignment “drift” when it is actually moving. Sitting still shouldn’t cause any issues unless you bump the head.

EDIT: It appears my statement “The device itself does not keep count” was incorrect. The device does appear to keep count, as the return to home steps are not coming from the cloud.


#10

Love the new profile icon! Did you make that shirt or it existed off the shelf?


#11

I got it from Woot.

I’m a t-shirt addict.


#12

I’ve done exactly this before over the course of at least a week. The alignment was the difference between visually placing the preview and the actual cut made. That will drift, but the computer precision stays the same.


#13

Ooh. Purchased. That is awesome.


#14

I could not find when software updates get pushed to our forges, I’m guessing when we turn it on and it calibrates, since we don’t leave them on all night, usually. So I would hope it would not happen in the middle of the night while you are on pause, that could cause it to lose alignment? Dan, do the occasional software updates happen at forge boot up?


#15

Isn’t any pause that I’m aware of. As far as alignment goes, my unit maintains the same alignment after re-calibration. Only time it would be off is if the head or gantry struck something during a previous operation.


#16

If “on pause” you mean the machine is paused for cooling then no it won’t update then as it’s the middle of a job and Dan has confirmed it won’t interrupt a job.

But I think it requires a power cycle to initiate an update based on previous comments and guidance to power down & up to get an update.


#17

Firmware updates only occur during power-up, if I understand your question correctly.