Feedback (with Data): Estimated print times may or may not be accurate depending on resin and clicking the "refresh" button


Some resin print times are fairly accurate before clicking the “refresh” button next to the Print Time button, and some resin print times are fairly accurate after clicking the “refresh” button. Print times for those resins are extremely inaccurate in the opposite situation (clicking or not clicking the refresh button).

Problem Description:

I would really like to get reasonably accurate print time estimates from PreForm. Just this last week I experienced a huge frustration where I was preparing for a project demo, and I specifically printed with Durable Resin because PreForm said it would take 12 hours and 48 minutes, which would give me about 8 hours of buffer time to wash, cure, and test the part before the demo.

If it were an hour off, that wouldn’t be a big deal. But the print took nearly two times longer! It took about 22 hours instead of 12 ish hours!

That was quite upsetting, and also makes planning the working day difficult if I’m trying to choose which print job to perform based on what will be available to test out during the workday.

Data provided

The data below shows that:

  • Durable v2 Resin’s estimated print time prior to hitting the refresh button next to the “Print Time” in PreForm is reasonably close to the actual print time, whereas it is frustratingly incorrect after hitting the refresh button.

  • Grey Pro v1 resin’s estimated print time after hitting the refresh button is reasonably close to the actual print time, whereas it is significantly incorrect prior to hitting the refresh button.

PreForm v3.23.1
100 micron layer thickness on all parts
Layers Volume Resin Estimated Print Time Print Time After clicking refresh Actual Print Time according to Formlabs Dashboard
864 45 ml Durable v2 10h 15 min 3h 44 min 9 h 0 min
1406 163.07 ml Durable v2 22 h 45 min 12 h 48 min 21 h 39 min
458 70.06 ml Grey Pro v1 7h 45 min 3 h 33 min 4h 39 min
418 106.94 ml Grey Pro v1 8 h 15 min 3 h 24 min 4h 34 min

Please let me know if this data was helpful, and if you would like me to continue adding data points. If this is sufficient as-is, then I will only add data points when I use resins not already listed above.

The state of the printer at the start of the print is missing from this list. Both heating from cold and checking for an empty cartridge are included in the actual print time.

Overall I thank that the estimated print time gives a more reliable answer than the refreshed one.

Ah ok thank you for the feedback. Each of these prints were performed at least 4-6 hours after the previous print completed, so they all started from a “cold start”, if that’s the correct term to use. Priming was not performed in advance in any of these prints.

The print time estimate is only the time spent printing. But the actual print time includes the time spent heating and priming and filling. But that doesn’t explain a print that was estimated to take 11 hours but actually took 22. However, if the resin cartridge is empty, the printer takes extra time between layers to let the resin flow back after the peel. In that situation, the print times can easily double.