Delayed Start (Again)

I saw this idea kicking around a while ago but I think it’s a great time to revisit it. I would love the ability to schedule a print to start with a specific end date in mind. My company owns a 3BL that we use for R & D purposes and I am only here 8-5pm Monday through Friday. Unlocking the ability to start prints and have them end when I am here the next work day would be a huge improvement for my workflow.

The response to this previously was that prints are fine in the printer if they sit, however in my experience this is not 100% accurate. I primarily print in Clear V4 on 50 microns and I have noticed if I don’t pull the print off immediately the viscosity of the resin can cure prematurely on the part. I like to schedule my prints to end when I am here to take them off immediately for that reason. The models that we are currently printing take around 40 hours so in order to schedule them properly I need to prime the printer, take my laptop home, and start the print late at night. It’s just not ideal.

I know other 3D printing companies already have this feature and would love to see Formlabs follow suit.



The resin won’t cure unless it’s exposed to UV. And near as I’ve been able to tell, it doesn’t “dry out” over time, either. It can’t be doing what you’re thinking it’s doing. I’ve left parts hanging from the build plate for days, and resin sitting in trays for over a year, don’t show any signs that the liquid has become more viscous or even partially cured.

My workflow is “run the job as soon as the design is completed, pull the parts from the printer when I get the time to do that no matter how long that time is”.

Do you have any pictures that can show the issue?

I can’t provide pictures of what we are printing but let’s just say it involves small channels with an internal diameter of around 4-6 mm. When the part sits over the weekend we have found channels occluded by resin. When we are able to take the print off immediately and flush with IPA we don’t have this issue. In our experiments with micro fluidics we ran into the same issue. The printer is in a dark room and away from light and if the resin was uncured it would wash away with IPA, correct?

None of these issues matter if I can schedule a 38 hour print to finish at 8 am on a work day.

Are you just swishing it around in the IPA to clean it? In my experience, purging internal passages requires the use of the squeeze bottle to force fluid through the passages…

My guess, the uncured resin that’s in the internal passages of your part, like the resin on the outside that forms drips at the lowest point on the print, pools over time. So instead of a thin uniform coating of resin on all the inside walls, you get a puddle at a low point. Those puddles can be harder to purge, for sure. But IPA squirted through the passage under pressure ought to blow them out.

It can’t be curing if there’s no UV so there’s got to be another explanation. :slight_smile:

I am squeezing IPA through it with a bottle and it is unaffected despite pressure. It’s clear resin so perhaps there is some laser scattering happening to resin that is pooling? I honestly don’t know. I just want a decent scheduler.

I have found that older open resins do not do as well leaving them in the printer as newly opened ones do. However, I also have found that the shape and size of the part being printed matter greatly in the ability to leave a print in the printer and still get a good print. Prints that are solid and do not have thin portions or small holes are much more robust and can remain on the printer for longer period of time before removal.

For example I was printing several 25mm squares that were about 1 mm thick out of Clear resin. I set the print up to run on a Friday and when I came in on Monday they all were warped. At first I thought it was a support issue but I ran the print again in the exact same way but removed the parts from the printer within an hour after the print completed and they were fine. So I have concluded that size does indeed matter. :slight_smile:

If you are working at the limit of small channels, it’s possible that sitting for a while might increase the viscosity or even cure a small amount more resin. Another possibility is that when the part is warm right out of the printer, the resin in the channel is lower viscosity, so getting the part a bit warm before trying to flush it, might help.

In any case, there is a sort of hack you can use to achieve your goal: Remote Print. It might involve starting a print at odd hours, though. The exact feature you are requesting is not very highly requested, so I don’t expect we will ship it soon.

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I would also vote for scheduled printing (and remote priming e.g. after a power cut when otherwise would have been primed)

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