Print Time Accuracy

Am I the only one that notices that PreForm is pretty bad at calculating the print time for a build for the Form2 but pretty good at calculating it for the Form1+ ? Form2 calculation is typically 1 hour less than actual on the Form2 but pretty much right on for the same build on a Form1+. That is to say, the calculation is the same either way but the Form2 consistently takes longer to build.


I do not own a Form 1+ so I cannot comment on that. But from my experience, I too have noticed time estimates can be pretty far off. I posted about it once before and was told the wiper, resin sensing/dispensing, and even the pre-heating time (does that get calculated in the overall time?) all account for longer build times. Since the form 1+ doesn’t have a wiper or auto resin sensing/filling, perhaps they just need to adjust the software to better account for those factors?

I too saw some pretty drastic errors in the time calculation on my Form 2. I recently finished a print that Preform stated would be 15hr 50min and the nice email alerting me to a jobs completion totaled the job at 19hr 9min. My assumption was that preheat time was not figured in as Preform has no idea how warm the vat and therefore no idea how long the heating process will take, in my experience it take 15 ish min, to heat up (which tangentially begs the question, why cant we start the tank warming as soon as we fire up Preform), the other time suck I assume is tank refill. Preform does seem to have a calculation for wiping time as evident by the print time change if you move all parts closer to or farther from the wiper.

I stand corrected there sir! You are right on this.

Here was my suggestion to FL a while ago. This ability would give the printer a head start at warming up while the user imports, orients and builds supports for his/her item.

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Preheating does not seem to account for the vast inaccuracy.

I think the MAIN reason for the inaccuracy is the “resin sensing” and refilling. On my printer it can take up to 2 mins for it to sense, then dispense. If it has to do this a dozen times during a multi-hour print, it could easily add 30 min to the print time.

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This doesn’t account for it either. My latest print went +1:15 on a 3:45 calculation. That’s a 25% error. Maybe after heating, wiping and filling it all adds up but the bottom line is that my F1+ printed the same job within 1 minute of calculation.

Hmm, that is pretty far off. I could see how my theories could account for 10% or so, but being off by 25% …something else is going on there.

Maybe someone else can chime in with any other differences between the two printers that might account for the time Δ.

Experiencing the same. I had an 11 hour print, it took almost 13.5 hour to finish. The resin was warm at start.

Resin sensing takes long, and it is surprising to me that it has to sense the resin every time it needs to top up. The machine knows how much resin in consumes every x layers, so why not sense the resin every x2 or x4 layers and just dispense a few mil every x layers?

Got another one of those prints. Printing in flexible resin.

Duration according to preform: 9h40m so I expected it to be almost ready this morning as it is printing for 8h34m already.
The dashboard is saying: 5h14m remaining.

So the print time calculation is off by roughly 4 hours. That gets close to 50% off.

This is still a pretty big problem for us. I’m currently stuck at work because our print said it would finish 2 hours earlier than it is actually finishing. When you have multiple prints to do, it can really mess with your planning.

It would be nice for an improvement to the print time estimate. Hopefully Formlabs is working on it…???

Are Preform and the printer’s Formware up to date ? They recently made corrections to the print time estimate, I think it was around the big 17’ December update.

Things have been better on that front for me since, my last print took a bit more than 10 hours and Preform estimated 10h17’ so we’re spot on. It was a “shallow” print though, only 483 layers @0.1mm layer height, but the XY plane was full which is why it was quite long.

We updated everything yesterday, so we’re all good there. It was our first print with Grey Pro, so maybe it is just that. We’ll see how the next print in standard Grey goes.

I had a print yesterday that was estimated to take 3.5 hours, but ended up being over 5.5 hours (newest update installed), so there’s definitely something to this.

*edited to note that I was using Clear resin

I have a brand new machine and updated firmware installed. My prints are also considerably out from the estimate. Estimated 3.5 and took 4.5 if I recall correctly…it was certainly an hour out anyway.

Any thoughts on what is driving this? I plan to use the estimated print time as a basis for estimating print costs for clients and need it to be reliable.

The more layers there are, the greater the time discrepancy. So it has to do with the algorithm that calculates the time the build platform lifts and falls.

This is definitely an ongoing issue. Currently printing a big model on Form 2 in gray resin - initial estimate was 18 hours 34 minutes. I got in this morning to find it still had 1.5 hours to go (it’s been two hours since then, now it says 30 minutes). So total print time is actually more than 21 hours.

This has been a consistent issue - even since the latest firmware update.

I’m waiting for a print that was estimated at just over 12 hours and which is currently looking like it’ll finish in 14. It’s so consistently wrong that I just mentally add 2 hours to the estimate every time I print now.

Hi, I noticed those estimated time errors. These are my last prints:

Firmware Layers Resolution Volume Prevision Effective Diff Perc. error
1.17.7 579 50µm 1.9mL 01:52 02:58 01:38 58,93%
1.17.7 1211 50µm 86.6mL 04:56 06:34 01:38 33,11%
1.17.7 1425 50µm 102.6mL 06:35 08:32 01:57 29,62%
1.17.7 1333 25µm 10.3mL 04:40 06:38 01:58 42,14%
1.17.7 296 25µm 2.1mL 01:14 01:46 00:32 43,24%
1.17.7 310 25µm 25.7mL 02:40 03:07 01:21 16,88%
1.17.10 833 50µm 21.8mL 03:47 05:08 01:21 35,68%
1.17.10 1989 25µm 43.5mL 10:03 12:37 02:34 25,54%



The data doesn’t lie :joy::joy::joy: