Fast microscope printing? Prusa i3 Mk4 with input shaping

Hi all,
Has anyone got a Prusa i3 Mk4 with the input shaping firmware? If so have you tried printing a microscope?

For those who don’t know, input shaping is a way to print much faster. Normally the speed it limited by the vibrations of the printer, fast prints tend to have clear “echos” or waves. Input shaping is a clever technique where the vibrations are modelled and the G-code is adapted very slightly to compensate. It can lead to much faster high quality printing.

I have not splashed out on a Mk4, but I have downloaded the profile for Slicer. As far as I can see it should be possible to print:

parts time
All parts for the high-res V7 microscope except the optics module, main body, and stand 4:32
Main body and stand (takes some fun rotating to get it to fit) 9:27
Optics module 0:33
Total 14:32

Factor in some dead time it looks like a microscope could be made in a day. I just worry how the main body will do printing so fast. I can believe that the resonances of the legs are as much of a problem as the resonances of the printer, and so the profile wouldn’t compensate properly. Would be interested to find out.

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I did a first try of just the upright separate z-axis on Friday. It was with the alpha3 firmware and standard input shaping settings. The surface quality on the optics dovetail was lumpy, it seemed to be over a bigger volume than one layer but I have not looked closely yet. It did not look good enough to fit the optics module. I had also used adaptive layer height.
There must be some settings I can try…

At ‘normal’ speed the MK4 is a little quicker, and so far I think it has much better surface than the MK3. Less obvious layering, but that may also be because the Mk3 is not new.

Cool, good to know you have one and are playing with this.

The department just got a Bambu Lab printer which has input shaping too… Just set a main body to print. Should take about 4:30 hours (in their normal speed - one can still go another two steps up speed wise)… can report back with photos when the thing is finished…


looks very nice! Printing other bits and putting another OF together over the ext weeks…



i did print the main body in just under 12 hours using a 0.6 nozzle while using print parameters like “dont cross parameters” which will prolong the print. Printer: Prusa MK3S



This post is old, but I wanted to share my thoughts without starting a new thread. Perhaps, it may help the internet traveler interested in building an OFM.

You don’t need an expensive printer. I built my 1st OFM using an $80USD monoprice mini printer because that was all I could afford. Currently, you can get a prusa XL or the incredible 5 color bambu lab carbon X1 for less than $2000. The popular ended 3 is perfect for the job. I upgraded mine with the direct sprite extruder to achieve better results.

PLA is the filament of choice. Current formulations are very good, reliable and easy to print. I personally use black esun PLA+. I have all of my printers dialed in for the best quality I can get using it. There are a lot of variables that influence the print quality. The slicer (cura, prusa, etc), PLA brand, PLA color, printer, nozzle, extruder, etc. all must adjusted accordingly.
I believe that the body should be PLA. All other parts can be done using ABS. However, ABS is prone to
Warping and shrinkage making the assembly complicated.

I print parts separately. Some massive printers like the prusa XL can accommodate all parts on the print plate. The advantage is that you have everything done in about 12 hrs. In my opinion filament layer adhesion may be compromised when you do this. The beginning of the layer will be cold and hard by the time the nozzle reaches the end of it. Enclosing the printer is not recommended for PLA. In addition, if the print fails, you lose all of the models. Even though my voron 300x300 can accommodate all, I currently print three times. The body, stand and drawer, and everything else.

What do you think? What do you do?


These looks great! 4:30 hrs? That is the F1 of 3d printers.

haha, yes, pretty fast, and since then, we built and tested the microscope, seems to be the same as others printed in slower settings.

Regarding your previous post on PLA:
Have you, or anyone else in the forum (I’ll check later if there is a thread about this) used other materials like PETG or ABS? reason I ask is I have been wondering about thermal stability in warm places… As some collaborators live in regions where temps can get quite high in summer (and have been getting higher in the past few years), I wonder up to which point PLA will keep stable?

Thanks @dgrosen! Nice to have a discussion of printers/printing.

I think speed really matters for those thinking about production for sale, but for the average microscope builder I totally agree that 3D printing is now reliable enough that the OpenFlexure works well on a low cost 3D printer.

This is a good point. I think the shrinkage of ABS is likely to be a killer, but PET-G is worth more investigation. Tech4Trade made microscopes with recycled PET filament, this worked but they had some issues with brittle prints, this tended to be due to moisture content during their own filament recycling process as far as I know.

In the past we have done some fatigue tests where the stage is cycled repeatedly for months. Doing this in different temperatures and humidities with different materials would be interesting. But also it is time and space consuming so would need budget.

In my opinion, UV light has more of an impact on PLA than either heat or humidity.

Thanks @j.stirling. I hope that my failures help others and that others assist me with theirs. :slight_smile:

I have tried PETG, it prints fine but I have not tested it extensively yet. I have one PLA and one PETG that are destined for testing in an incubator, but they have not made it there yet. In handling, the PET looks and feels more supple but there are some instances where it seems to have been more brittle and I have cracked parts.

There is a post on ABS, but resin printed using a mixture with a flexible resin mixed with ABS-like resin Nano Converter plate incompatible with RPi 3b - #3 by ashish_kumar_4