How much additional time+money+skill required to get a Prusa Mendel kit printing as fast

How much additional time+money+skill required to get a Prusa Mendel kit printing as fast and accurately as an Ultimaker kit?

Most likely, more than you have and are willing to spend of at least one of those things, though it does make a difference where you get the Prusa kit.

@Whosa_whatsis Thanks. My impression is the Prusa is more for people that want to experiment with printers as much as printing.

@Brian_Low , once the prusa is dialed in, it pretty much stays there. I’d consider it a better learning tool than anything. While the ultimaker will spit out prints, etc quickly with very little troubleshooting – you also lose a lot of understanding about how these things function, what to do when things go wrong, how to identify certain artifacts in your print, etc.

@Brian_Low The Prusa (i1 / i2) can do accurate, but it can’t do fast without shaking itself apart. That’s the reason why the Mendel90 and Prusa i3 use sheet material over threaded rods.

Thomas, how fast is a “safe” speed for an i2?

That depends on the individual machine, but to get a decent quality i wouldn’t push it beyond 60mm/s, 2000mm/s² acceleration and 10mm/s-ish jerk (on the X axis, Y is fairly solid). Normal machines should be able to easily do double those values, but you’ll start seeing the printer’s top vertices rock left and right, creating overshoot / oscillation patterns on sharp corners of your prints. If you set jerk too high (assuming Marlin as your firmware) the printer’s frame might hit resonance on some infill patterns.

@Thomas_Sanladerer I’ve done 146mm/s on my prusa i2 without any detriment.

Yeah I’d add that a benefit of going with a Prusa over something like the Ultimaker is that you can not only learn more but improve on the base printer’s performance (substantially), more than you could a printer with a more fixed design.

Of course if your interest is primarily in the output, and the output of the Ultimaker makes your needs, then it might be the way to go.

@ThantiK @Jason_Gullickson Thanks, both good points. What mods and calibration were needed to get the Prusa i2 to 146mm/s?

@Thomas_Sanladerer Thanks for the info! So perhaps the prusa i3 will be easier to get moving fast.

Adding feet to the middle of the Prusa really helps - supporting the vertical smooth rods.

With feet I can run at 100mm/s without echoes, unless the print is really tall.

It took me three days to build the machine, and two days of rebuilds/upgrades to get it printing high quality. Total cost (including LCD and sdcard) was about $1k, although that was like a year and a half ago, nowadays you could do it for probably $750. Even cheaper if you self-source everything, I got a kit/build group along with mine.

I keep my travel at 250mm/s with no skips or anything, it’s just that parts have ridges around holes and corners if I print that fast. The machine is capable, though, and could be stiffened in various ways.

If you want to make a Prusa as fast as an ultimaker, go bowden - with a lightweight head you’d have a lot less vibration and could probably go up to 300mm/s before the extruder started having issues with filament viscosity.

@Brian_Low nothing. No mods. Straight Prusa Mendel.

I do get a little bit of a wave pattern around 90 degree corners though, but nothing so significant that it would affect the part.

@Paul_Chase It seems Bowden setups aren’t that common on Prusas. Why is that? They have a speed advantage and it seems like the software has reduced the stringing. Thanks for the details on your printer.

@ThantiK @Paul_Chase Sounds like you have your printers well tuned. Thanks for the info!

I’m planning to try out a dual-bowden setup on my Prusa once I get some of the basics (re) sorted out…

@Brian_Low Bowdens add complexity, without adding to print quality; they won’t affect the look of normal-speed prints, or at least I think they won’t once you get the bowden properly tuned. I’m playing with a bowden on my rostock now; it has issues with stringing and leaking, I’ve got to tune the retraction up. Maybe when I get it working I’ll think about upgrading prusa… the rostock is hella fast.