Prusa Core One+ Upgrade

I have recently upgraded my Prusa MK3.9S 3D printer to Core One+. These are my notes and initial impression about this upgrade and Core One+.

A major point about this upgrade is it is not like any previous one. My first Prusa printer was MK3S, and I have always upgraded it since MK3S. All upgrades were slight modifications, maybe the most radical one was the introduction of Nextruder. However, Core One platform is totally different and it is an enclosed design. I think the ugprade is still reasonable, if you do not want to keep the MK3S platform, but if you want to keep it or if you can sell it, you can just purchase the full kit. It also makes sense to buy the full kit particularly if you do not have MK4S. From MK3.9S, I also had to buy new stepper motors (as used in MK4S) and because the steel rods had some wear, I also replaced them. So I have replaced a lot of components.

My initial impression of Core One+ is positive. I like the CoreXY design and the printer’s new form factor. Although I only print PLA, PETG and TPU, I like the enclosed design. The print quality is better than MK3.9S, but it is not surprising. My only concern of this printer is its maintainability and upgradebility. MK3S platform, being an open/not-enclosed design, is very easy to maintain, replace something, upgrade it etc. Being an enclosed build, I am not sure how easy it will be to modify the Core One platform printer.

For the people who would like to get the upgrade kit, I highly recommend you to check the conditions of the steel rods. If it is an old or used printer, it is probable they might show some wear and you might want to order new rods together with the upgrade kit. In addition to new rods, you might want new hotend, bearings and trapezoid nuts. I find the amount of plastic rivets supplied not enough. They are naturally enough for a build and there are some spares, but if you make a mistake and undo a panel, it might not be possible to re-use them, and the quantity of spares is not much. I recommend to buy an extra bag of plastic rivets.

Two small notes about the build; (1) the small black screws (not sure if all) are Torx. They can be lightly tightened with hex/allen keys, but they require a Torx driver to be properly used, so just be aware. (2) Z motors and the plastic parts mounted on the Z motors are not accessibly after mounting them into the base. So make sure they are built correctly.

I had two issues, one when building, second when calibrating it for the first time. The issue with building was the cable tie on the grid (of fans). I think the recommended position of the tie is way too close to the belt. It should obviously be OK as it is written on the manual but I dont feel comfortable with it. So I moved the cable tie slightly up (so it is not mounted on cable tie positions but on the grid). It is now impossible for belt to touch the grid or the tie. The issue with calibration was the filament sensor on the (right) side (panel). It did not pass the calibration. I did not understand what was the problem, so I did undo-ed it, check again and rebuild and it worked. I believe it was because a screw or two was too tight.

I have also purchased with the kit the advanced filtration kit (the HEPA filter). If you also do, check its instructions first, as you can also mount it during the build. Otherwise, you need to undo and redo a few things. If you are using the accelerometer kit, also do not forget to connect its cable between the WiFi module and the electronics.