Notes on the Prusa Core One

Last Update Sept 16, 2025

I have built many of the previous Prusa Kits, but for the Core One I ordered a pre-assembled version.  It has been running well since the first day I got it in January 2025. 

Notes for the MMU3 and the Core One  I have added the MMU3.

First impressions of the Core One

I am very happy with the Core One.  Prusa has stated the Core One is the platform for the next decade.  It has been working well since day one.  Improvements keep coming and hopefully it will last for many years.

Significant Details

• The Nextruder and 32bit Buddy board are transferred over from the previous MK4 series.  About half the parts of the MK4 can be used to upgrade to a Core One.
• It came with a Sock.
• It is an enclosure.  No enclosure needed for environmental controls.
• Y Foot is smaller since the Head now does X and Y movement.  The bed only moves in Z. 
• 32 bit hardware.  Room for more functions in the firmware. 
• Steel construction.  Significant that most parts are steel with a similar thermal growth.  Less warping and twisting of the machine as it heats up hopefully.   A better machine tool design than mixing aluminum and steel parts as in the MK series.
• The Core XY design with 2 belts and motors controlling the head is NOT more precise than the MK4S.  The belt errors add together.   It is a long discussion on machine design. Even Prusa admits that Core XY is not more precise than a "bed slinger"  It isn't noticeable since the servo 400 impulses per revolution is the same as the MK4.   This is a relatively course resolution of .08mm or .003" for XY when compared to machine tools.  But better than other 3D printers of this same class.  The Z is .02mm/.0008" resolution.  Servo resolution has to go up to 1200 impulses or more per revolution to improve XY resolution to meet the Z axis capability.
• It can be quieter.  
• You need an accelerometer.   Make sure the belts are properly adjusted.  Then use the Accelerometer to do Input Shaper Calibration and Phase Stepping Calibration.  Firmware 6.4.0 and above.
• Prusa Slicer 2.9.3 and above adjust the acceleration on small moves to reduce "noise/banging" on short moves.
• The base for new printer enhancements for years to come.  End of the line for MK4 improvements most likely.
• up to 55C environment temperature control.
• Up to 20% faster than the MK4s
• 30% more print volume. More Z, 270mm 10 mm more in Y
• Spool on the side saving space.
• 180 degree door, Left or right hinge mount.
• Vent slots for PLA/PETG
• The three Z axis servos are not controlled independently.  They are driven as if a single servo.   The buddy board can't support the extra servos.  A servo spliter board is used. 

Mods I have done for the Core One

Most of these mods do not directly effect the printing,   These are convenience mods I have made.

1. Important You need an accelerometer To do Phase Stepping and Input Shaper Calibration
2. Medium.  Purge Advanced Filtration for noxious filaments.  Along with the Slide Down mod.  Prevents using up the Hepa filter on filaments that don't need it.
3. Low   Insert based Belt Tensioners.   Long term life of the belt tensioner.
4. Preference  Fan cover for the heat sink fan.  Keep your fingers out of it.
5. Convenience.  Core One Buddy Camera.   Modified Camera Lid for better mount and angle.  Camera used with PruseConnect.
6. Convenience Tall squash ball feet so I could put drawers under the Core One
7. Convenience Drawers to go under the Core One.
8. Convenience Diamond Tip Nozzle.   I don't need to use a HF/CHF nozzle much.   I can use any filament in a diamond tip nozzle.
9. Convenience  Magnetized purge bin.  Hold all those bits of filament until you bring over a trash can.
10. Convenience  Dust covers, to keep these out of the corners.

This is significantly fewer important mods than I had with previous 3d printers.

USB thumb drive warning

The cheap USB sticks that come with the printer tends to have problems and are often replaced.  It is easy to get a good, quality replacement.   Make sure the new USB thumb drive is USB2, NOT USB3, 3+ etc. Through harsh experience I learned that a USB3 drive may cause severe problems with WIFI based file transfers.   This is what I use for Thumb drives. 

• 32GB or smaller
• Formatted for FAT32
• Allocation size when formatting, 4096, a personal preference for the 3D printers.

Improvements I would like to see

Better XY resolution.   .02mm equivalent to the Z axis.  Currently the Core One is .08mm XY resolution. 

Control all three Z axis Servos independently, for better bed leveling.

Direct support for USB3 and bettor Thumb drives.

Firmware:  Build progress picture should show progress in Z, or have the option to show it that way.

Slicer, support minimum move definition and then use the data to correctly fix Z moves and XY moves.

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