Update:
2021.07.16
$ New extrusion system(Prusa MK3S style 1:1 extruder, you can reuse BMG gears from previous versions of this printer)
$ New part for mk3s extruder (P-108-MINI-z-carriage-rear-for-MK3S-extruder.stl)

{
Removed:
MINI-z-carriage-rear.stl
P-110-MINI-extruder-section-with-ir-filament-sensor.stl

Added:
P-108-MINI-z-carriage-rear-for-MK3S-extruder.stl
P-110-MINI-MK3S-style-extruder-section-bmg-version-with-ir-filament-runout-sensor.stl
}

2021.07.13
$ New join-plate-with-Z-carriage + 95mm 3030 extrusion(Z-Axis Modification)
$ Adding front part cooling fan

2021.04.22
$ Set up sensorless homing
$ Lift Y carriage up by 5mm (spacers in the file section) to clear out front/back plate.
$ Z axis smooth rod (10mm) length changed from (321mm) to (330mm).
$ Upload new controller board case (rear cooling fan and LCD cable cut-out).

2021.03.12 Update part list.

2021.03.08 Upload new y front plate : the hexy plate.

2021.03.07
$ Scale up build area from 150x140 to 180x180
$ Part list updated.

2021.03.01 Upgraded to 32bit MKS Robin E3D.

Firmware Repo:
Marlin 2.0.6.1 for prusa mini custom build on MKS Robin E3D V1.1

Instructions&compiled_firmware Repo:
Wiring&Precompiled firmware for prusa mini custom build

Test run videos:
DIY mini printer

Inspired by:
Prusa-Mini DIY by @taufiq
Prusa Mini Extruder Section - BMG Version
Prusa Mini E3dv6 Hot-End
Prusa Mini Heatsink clone
Prusa Mini Z-Axis Modification

other useful component refers:
Prusa Mini Rubber Feet Upgrade
Vertical 2020/3030 Bearing Spool Holder
M3 Square Nut for 3030
M5 T-nut for 3030
Cable Tie Mounting Pad
Linear Rail Slot Covers 3030 Extrusion (for hide wire from Z motor)

Introduction

This is my version of Mini Prusa.The idea behind it was that after building my Prusa MK3s I realized that I have accumulated quite some spare parts over time,so there it is, A fully functional secondary printer built mostly from spare parts.

In doing so the size of the printer is W/H/D 330mm x 320mm x 350mm with a build area of 175mm(X) x 175(Y)mm x 120(Z)mm. (Bed size pre-defined in the firmware is 175175, but it can be scaled up to 180180).

I've tried out plastic extrusions on y-axis, it kinda works but was somewhat wobbly.
I wouldn't recommand plastic 3030 fot not being stable enough.

PS:

After setting up sensorless homing for TMC2209, remember to LOAD hard-coded defaults using "M502",then "M500" to save X&Y homing sensitivity to EEPROM.These two value will NOT be updated by flashing the firmware while migrating from normal machanical endstop system to the new sensorless homing system.

Custom Prusa Mini Parts List:

Printed Parts (exclude hotend assembly)

! Original Parts !

• 1x MINI-knob.stl
• 1x MINI-minda-holder-8mm.stl (or P-114-MINI-minda-holder-12mm.stl if you have a 12mm sensor)
• 1x MINI-x-carriage.stl
• 1x MINI-x-end.stl
• 1x MINI-y-belt-holder.stl
• 1x MINI-y-idler.stl
• 1x MINI-y-plate-front.stl (or P-115-MINI-hexy-y-plate-front.stl)
• 1x MINI-y-plate-rear.stl
• 1x MINI-z-carriage-front.stl
• 1x MINI-z-top.stl

! Custom Parts !

• 1x P-100-MINI-z-bottom-mks-robin-e3d-v1.1-case-Z-mod.stl
• 1x P-101-MINI-z-bottom-cover.stl
• 1x P-103-MINI-heatsink-fan-holder.stl
• 1x P-104-MINI-heatsink-clamp.stl
• 1x P-105-MINI-frontfan-holder.stl
• 1x P-106-MINI-join-plate-with-z-carriage.stl
• 1x P-107-MINI-Y-Extrusion-to-Z-extrusion-3030-Angle.stl
• 1x P-108-MINI-z-carriage-rear-for-MK3S-extruder.stl
• 1x P-109-MINI-lcd-display-128x64-box.stl
• 1x P-110-MINI-MK3S-style-extruder-section-bmg-version-with-ir-filament-runout-sensor.stl
• 1x P-111-MINI-y-carriage-with-spacer.stl([email protected])(! Print y-carriage with PETG or ABS !
  ! or it will sag and make contact with y-front/back-plate !)
• 4x P-112-MINI-y-carriage-bearing-strap.stl

Print settings:

• 3 Perimeters
• 4 top/bottom layers
• 0.2mm layer height
• 40% infill
• May require custom support(brushed support enforcer in prusaslicer works best)

Metal Parts:

X-axis

• 2x 279mm smooth rod (D=8mm)(x-axis rod)

Y-axis

• 2x 3030 extrusion (262mm)(y-axis 3030 extrusion)
• 2x smooth rod (D=8mm)(279mm)(y-axis rod)

Z-axis

• 1x 3030 extrusion (289mm)(z-axis)
• 1x 3030 extrusion (95mm)(Y-to-Z-Base)([email protected])(NEW!)
• 2x smooth rod (D=10mm)(330mm !!)
• 1x 8mm threaded rod (300mm)
• 1x T8 threaded rod lead screw(metal or POM)
• 1x Z Axis Trapezoid Motor Screw Nuts(POM Nuts) for Prusa i3 MK3s

E-axis

• 1x MK3S extruder gears kit

Fixings

• 2x M5x25 : Button head (y-end stop)

• 10x M5x16 : Button head

  • 2x (z-top to 3030)
  • 8x (front&back panel to 3030)

• 20x M3x10 : Socket head

• 5x M3 x12 Button head

• 6x M3x20 Socket head

• 6x M3x22 Socket head

• 8x M3 x25 Socket head

• 4x M3x30 : Socket head

• 30x M3 Square Nut

• 4x M3 hex nut (base box to 3030 extrusion)

Motors

• (X-axis)1x BIQU SY-17HS4401S stepping motor
• (Y-axis)1x BIQU SY-17HS4401S stepping motor
• (Z-axis)1x BIQU SY-17HS4401S stepping motor
• (E-axis)1x BIQU 17HS4023 stepping motor (or "pancake" motor)

Pulleys and belts

• 2 meters of GT2 belt (used in build and reserved as spare parts)

Linear Bearings

• 2 x LM10UUL 10mm Long Linear Ball Bearings (Z-axis)
• 5 x LM8UU 8mm Linear Ball Bearings (Y-axis(x3) + X-axis(x2))

Heated Bed components

• 1x Heated Bed 180 x 180
• 1x 100kohm NTC thermistor

Electronic System

• 1 x 24V 240W power supply
• 1x RepRapDiscount Full Graphic Smart Controller
• 1x Makersbase Robin E3D V1.1 control board
• 2x Makersbase TMC2208 V2.0 stepper drivers (E axis & Z axis)
• 2x Makersbase TMC2209 V2.0 stepper drivers (X axis & Y axis)
• 1x 5V NPN NC inductive proximity sensor (for bed leveling and Z homing)(using MT-det filament detection pins on the mks robin e3d v1.1)
• 1x (Y-axis)(Y MIN end-stop)Mechanical Limit Switches (End stop)
• 1x (X-axis)(X MAX end-stop)Endstop Limit Switches Plug Control with 24AWG Cable
• 1 x DC-DC LM2596S step down module
• 1x 1 Channel Way Optocoupler Isolation Module / Optocoupler

Cable and connector (Optional)

• 1x Dupont Connector 2.54mm, Dupont Cable Jumper Wire Pin Header Housing Kit

• 1x SN Crimp Pliers