MK2S -> MK2.5 most recent upgrade experience  

MK2S -> MK2.5 most recent upgrade experience

Hello,

I was running my MK2/MK2S for two years. After purchasing MK3, enjoying removable bed and having comfort with all the recent updates I pulled a trigger for the MK2.5 upgrade. The kit arrived last week and I spent all my spare time to assembled it as fast as I could. It was fun as always. Here are my items which I had to take care of:

A side note first. I build MK2 kit myself, upgraded to MK2S myself and replaced already many broken cables on my printer. So I know already many weak points of this design and thinks to look for.

Preparation:
I printed all the parts which are in the MK2.5 upgrade package. Sliced it myself with 2 walls, 0.15 layer height and 50% gyroid infill. My idea is to have very rigid parts even I add more weight on the head. In worst case reducing the speed by 5-10mm/s should compensate any quality issues. In addition I also printed the Z-parts just in case something will go wrong.

Disassembly
Maybe the easiest part. Everything was straight forward like in the guide. I also removed/change the z-bottom/z-top parts with new PETG parts. The interesting thing are the used extruder head parts. It's interesting to see that ABS got brittle over time on the spots where it was exposed to heat. Let's see how PETG will handle that after one year usage.
I also changed the PTFE tube. Mine was already heavily used and I wanted to have it a little bit longer. 52mm (instead of 50mm recommended) is a sweet spot where it barely touches the gears. Should benefit a lot while printing TPU.

Assembly
No big surprises but still couple things to take care of.
* During insert of the x-carrage on the z-rods I lost some bearing balls. Good thing I saw it and replaced the two bearings the spare ones.
* Tightened the guide roll on the x-carriage. It had a little play from day one causing slight bend and squeeze of the belt from time to time.
* Replaced the x carriage belt. I still had original MK2 one which performed pretty well. I was impressed of only slight wear and tear. Anyway this was a good time to put a new one on
* As mentioned before, replaced the PTFE tube with new one which is slightly longer
* Replaced the part cooling fan. After two years it made some noise for the first couple layers. Perfect time to replace it
* Made sure the bed was roughly levelled. I had to put some washers already during the MK2S build and had to do the same thing for MK2.5 again. Nothing new to me and it pays off in the long run
* Made sure PINDA probe is high enough. My Z-height is -0.3 now and it should help against curving plastic
* Made sure the bond tech gears are perfectly aligned and fixed. I can see a big potential of mistakes for newcomers at this step

Results
* The Upgrade guide is really good. No surprises there, straight forward and good explained. The comments are also top!
* All parts fitted perfectly, no missing parts and all are working fine!
* Print quality has improved to my old MK2S! Maybe because of new parts and tweaks. But the most important thing, it got not worse!
* Removable bed is worth every penny. Don't want to miss that anymore
* My old MK2S S3D slicer settings worked perfectly fine on the new MK2.5. There is no need to tweak something. Default MK2.5 Slic3r settings are also working like a charm. Thumbs up on that!

Conclusion
I know the pain of early MK3 buyers. And I read about similar issues on the MK2.5. So I was ready to face it. But I was really impressed after the first print. The results are really good. Printed with PLA/PETG and ABS already. Especially I test printed some PLA small parts to see if I will get some clogging issues. I know this already from the early MK3 days, so I know how to check on this and reproduce the issue. I don't have it on my current MK3 and don't have it on my new MK2.5. PR did a good progress with new parts and settings.

Overall the upgrade was worth it. It feels like I got a new printer again for only $150. It includes the removable bed, new PINDA probe and silent NOCTUA fan. Print quality increased and I couldn't ask for more.

Thanks PR and the Prusa community for making the current/new and old products better. I'm Prusa customer for two years now and had never a feeling I bought a paperweight. All the money I spent for replacement parts and upgrades is still far away from the higher priced products.
I definitely can recommend the current MK2.5 upgrade!