when i am trying to trouble-shoot a failed print or simply wish to check the quality and progress of a print, using the pause print feature seems to be a great way to do so. The only issue is that its terribly difficult to actually see what is going on since the platform remains in the last position.
If the build platform were to raise up to the max height during a pause it would make checking a print much more easy and save time. the only issue i see with this feature is whether or not the machine is capable of accurately returning the platform to the last known position. Now i have to say i was kinda surprised that this wasn’t already a feature of the pause option. that being said, with my luck, its already built into the firmware and i missed something along the way.
That’s a good thought, John, and I’ll pass it on to our mechanical team. You’ve touched on the challenge yourself, however. As precise as our z-stage is, it’s challenging to return the build platform to precise point needed to avoid any artifacts once the print is restarted. This is also why we wait to complete a full layer before pausing – so we don’t interrupt the laser midstream.
I would think you’d end up with air bubbles at that layer (and a good chance of the print failing at that point,) if you pulled the bottom of the print out of the resin.
I’d vote for this, too … seems like just raising it about an inch gets the most recent layer clear of the resin. A little up-and-down dance once it’s back in the resin might do the trick to clear bubbles by generating resin flow around the part.
And then, once this feature is in place, the ability to selectively abort only the failed objects (and thereby stop cooking resin to the silicone) would be super.
With the Form 3, the only way I have observed to get it to raise up is to trick the machine into thinking it needs to add more resin. It raises the build platform while adding resin in order to allow the wiper to function.
Removing the cartridge during a print will cause the print to pause after the peel step, which can sometimes provide a better glimpse of the progress if it has printed at least 7-10 mm already.
Stepper motors and ball screws have been used in CNC since maybe back in the 1950s (maybe earlier, that’s the oldest machine I’ve ever seen). They are highly repeatable. If they weren’t, they’d be no good for CNC. My bench-top Taig CNC will move back and forth along all 3 axes all day long and always come back to the same spot (plus or minus maybe a half thousandth).
There are two factors that reduce repeatability, lost steps or high backlash. Lost steps happen if the stepper is overloaded, either asked to move too fast or the motion path is obstructed. Backlash can make the positioning system sloppy (it’ll move a little if you push/pull on it), but it also introduces an offset in the absolute position reference as a function of the direction of the current move relative to the previous move. If the next step is in the same direction as the last move, the backlash is “taken out” already and the motion stage moves exactly as far as it’s supposed to. If the move is the opposite direction of the previous move, the distance the stepper moves has to exceed the backlash before the motion stage will move.
The F3 build stage moves up a fair amount during the print to make room for the wiper to sweep. That move is much, much greater than any possible backlash that might be present (because that’s going to be very small or the printer wouldn’t work correctly). So it doesn’t matter if it moves even further, even all the way to the top of the stage. The increased distance contributes nothing to positioning error unless the stepper loses steps along the way. In which case, the machine is busted somehow, since if it’s working as designed that should never happen.
I also think this is an important feature to have. It lets people who are printing large projects to make sure the first 50-100 layers are working and holding. It sucks to see not find out hrs into the print that the first couple layers failed and you wasted resin letting it continue to print. We already pay a premium for resin it would be nice to be able to conserve as much of it as possible.
Implementation:
Tell your customers you will look into this feature and give an estimate date so we are not wondering when this will happen. Est 12/1/2021 - 02/01/2022 testing failure rate of feature.
Report back to your customers what you’ve found and if the feature is possible. If yes and you guys will implement the firmware give estimate on when we can expect the beta feature.
Make update live included with disclaimer!
Note: Implement a disclaimer that the feature is in BETA and that if we use it, we use it at our own risk to print failures and that Formlabs will not be held responsible for the failures or resin consumed by using the feature.
Also by using the feature we agree to sending anonymous data if the print still finished correctly or failed. This will help tune and move feature out of beta to final implementation.
Side note: All Chinese / cheaper printers support this feature with 0 problems and I can say the build quality of these machines are far less superior then our Form 3 and Form 3L.
Examples of printers I’ve used with 0 problems with this feature:
Phrozen Sonic Mini 4k
Phrozen Sonic Mighty 4K
Anycubic Mono X
Elegoo Saturn
I am aware these printers use different technology but if these companies can pull it off I’m sure Formlabs can!
Thank you for your time and if you need a small group to beta test this feature I would be happy to volunteer!
I observed that many suggestions are mentioned by Formlabs to be considered, but then there is no follow up. Shame, as many of these ideas could make our (customers) life easier.