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Why Are Simplify3D’s Time Estimates Always Wrong?

Many people who are into 3D printing use Simplify3D's commercial software, which is compatible with an extensive list of 3D printer brands and models and generates good instructions for good-quality prints.

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When printing 3D models, you need 3D printing software to translate your design into a set of instructions your 3D printer can understand. Many people who are into 3D printing use Simplify3D’s commercial software, which is compatible with an extensive list of 3D printer brands and models and generates good instructions for good-quality prints. But are Simplify3D’s print time estimates accurate?

Simplify3D’s time estimates are always wrong because print time is based on factors like acceleration, feed rates, and the speed of your 3D printer’s motors. And since 3D printers don’t share similar values, Simplify3D’s calculation can be off. The complexity of a project extends its print time, too.

In this article, we will talk about the various factors that affect print time. We will also discuss what Simplify3D users have experienced regarding the software’s time estimate and whether there is a way to fix inaccurate print time estimates.

What Affects the Accuracy of Time Estimates?

The kind of 3D printer and its settings, along with the complexity of the print and the filament material being used, can affect the accuracy of time estimates of Simplify3D’s designs. Many 3D printing enthusiasts admit that print time cannot be calculated accurately. 

To be more specific, actual print time depends on firmware, maximum acceleration, and feed rate factors. And the different capacities of a printer, combined with the various settings you have inputted, dictate the outcome of these factors. 

Meanwhile, the project’s complexity affects the movements and turns of your extruder when printing each layer, including the infill.

One user said that they use Simplify3D on three different printers and found that each printer has a different actual print time. With the Ultimaker 2+, for instance, the exact print time is around 20 to 25 percent more than Simplify3D’s estimated time. 

On the other hand, with the P3Steel, the actual print time is 30 to 40 percent, and with the Kodama Trinus, the printing time is very far from the calculated estimate.

In order to come up with an accurate computation of print time, the Simplify3D program has to have the support of the firmware. It has to collect data such as maximum acceleration, default acceleration, maximum feed rate, and jerk for each axis. This information is the main parameter of the printer’s acceleration and travel speed. 

Another user mentioned that some printers have values that won’t go beyond those sometimes referred to as firmware hard ceilings. According to another user, many 3D printers do have a maximum speed setting that limits any speed you dictate. 

So even if you increase the print speed ten times faster, it still won’t do anything to lessen the actual print time. What’s more, a 3D printer’s settings can limit acceleration or how much speed can increase. It so happens that the small and budget-friendly 3D printers have more settings limitations.

Simplify3D’s Time Estimates 

A lot of users complain about Simplify3D’s estimates on print time being off. This usually means that the 3D printer actually takes longer to print a project than the estimate indicated in the program. 

While some say that this difference between the time estimate and the actual print time is very significant, some say it’s not a lot or that it depends on the project.

For example, in Simplify3D’s community forum, some users said their prints take 10 to 20 percent longer than the software’s estimate, and those who said that Simplify3D’s time estimate is accurate most of the time for prints with single parts. 

There was also an instance when the software estimated a seven-hour print time for a 200-millimeter (7.87-inch) project, but the print was still at 28 percent after over seven hours. This meant a total of about 30 actual print hours.

Another user noted that people said the time estimate is off by some 20 to 50 percent in older posts. But this user’s actual print times are 25 to 33 percent longer than average, implying that Simplify3D’s time estimates have gotten better. 

This user also noted that Simplify3D’s 4.1.0 release note stated that they have greatly improved print time estimates by simulating the 3D printer firmware’s actual behavior for increased accuracy.

Yet another user explained that the error in time estimates is not likely to be linear. In this user’s case, the estimate is accurate up to an hour or so, but beyond that, the estimate can be high or low because the printer’s acceleration and jerk settings, as well as the complexity of the print, come into play.

Dealing With Inaccurate Simplify3D Time Estimates

If you find yourself constantly annoyed at the wrong time estimates that Simplify3D gives you when you are printing, you can employ some tactics to close the gap between the estimate and the actual print times. 

One is to take the average of actual print times for your last ten prints and divide it by their average estimated print times. This will give you the ratio that helps you identify the discrepancy as a more definite number, which will be the print time modifier. 

This number will serve as your guide for your next projects so you’d know how to adjust the program’s calculation, albeit mentally.

You can also try another solution shared by a user on Reddit that involves plotting data. 

Of course, another option is to take the estimates as nothing more than estimates. This means being flexible with your expectations. You can also visit Simplify3D’s community forum and search “time estimate” to get some ideas.

Many users have expressed that this problem would have been solved if Simplify3D allowed us to enter our print settings and other values so the program could factor these in when calculating print times.

Final Thoughts

Simplify3D’s time estimates are off the mark because they may not consider certain values, like acceleration and jerk, when calculating these approximations. These values vary from printer to printer and from one user’s customized settings to that of another user. 

The best way to deal with the discrepancy between estimated and actual print times is to plot them after each project, find out the trend, and derive your estimate based on this trend. 

Having nearly accurate estimates is important if you have several important projects lined up and can’t afford to waste time.

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About Ben

I started 3D printing since 2013 and have learned a lot since then. Because of this I want to share my knowledge of what I have learned in the past years with the community. Currently I own 2 Bambulab X1 Carbon, Prusa SL1S and a Prusa MK3S+. Hope you learn something from my blog after my years of experience in 3D printing.