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Selecting a 3D printer

A project log for L2 Camera

Fully manual twin-lens reflex instant film camera

Vladimir GorsheninVladimir Gorshenin 11/19/2020 at 12:230 Comments

I have access to a pair of shared Prusa printers: an i3 MK2 and an i3 MK3 models. I've been using these printers for two years and not only learned how to print, but also how to calibrate the printers, do troubleshooting, maintenance and repair (shared hardware is severely abused). I printed with PLA, ABS, PETG, PET, TPE from variety of manufacturers. During all of that I was puzzled: why many 3D printing forums are full of questions describing issues? The description of my experience was "I just printed".

That was true until I decided to validate my design against another printer. I borrowed an Ender-3 printer with a glass bed from a colleague of mine. This is rather popular and common model of 3D printers.

Ender-3 turned out to be a crush-test to my design.

I note the following differences between the Prusa printers and the Ender-3:

  1. no auto bed leveling
  2. glass bed instead of PEI
  3. bowden extruder instead of direct one

The first two are, probably, the most crucial. I had to learn how to make bed leveling manually and how to make it properly. It took me two days. Filament has lower adhesion to glass, compared to PEI surface. In some cases it's an advantage. For example, when you remove prints after printing - you just pick the prints from the bed. In my case that was an disadvantage, because even PLA prints suffered warping. To mitigate it, I had to print with brims and remove them at post-printing.

But I was really surprised with another issue - so-called elephant foot effect. It's when the bottom layers of the print got shrunk. In this case it made harder two pieces of the camera body pieces to mesh properly. I encountered this issue for the first time in my experience and in happened with the Ender-3 printer. I had no such issue with Prusa printers. 3D printing forums suggest many reasons for that effect: high bed temperature, insufficient cooling, mechanical issues with the Z-axis, etc. In my case, I believe, it was a mixture of reasons.

I don't expect all of 3D printing enthusiasts interested in my project to switch to PEI-auto-bed-leveling printers in an instant. Therefore, I reworked my design and formed a set of recommendations for printing with the common goal to eliminate the aforementioned issues. All of these will be included into the release.

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