Mini Bear - (DIY Build)

This is a bear-style 3d printer modified to fit a Prusa mini bed. This design has a custom linear rail y-axis, a motherboard case for an SK2 and Pi0, a PSU case for an HRP-300-24 (slimmer form factor), modified x ends for anti-backlash nuts, and a y-axis cable chain design for the y axis.

I opted to use an HRP-300-24 as the PSU as it is a slim enough form factor to not hang off the back, as well as provides enough amps for the smaller printer. I designed this in an effort to always be capable of upgrades it when new bear revisions are released. Because of this, I will not need to go through a mirroring effort. This was capable due to the cable chain design that runs the heated bed wires below the printer. 

The SKR2/Pi0 Case is slim to not hang off the back of the printer, and it can print on a standard Prusa mini bed.

Custom Sized Components Needed:

• 2 x 300mm - 2040 Extrusion
• 2 x 282mm - 2040 Extrusion
• 2 x 329mm - 2040 Extrusion
• 1x 220mm - 2040 Extrusion
• 2 x 290mm - Smooth Rod(Z Axis)
• 2 x 300mm - Smooth Rod(X Axis)
• 2 x 290mm Integrated Lead Screw Stepper Motor

Y-Axis Rail Assembly:

• 2 x MGN12 C Carriage(Y Axis)
• 2 x MGN12 C Rail 300mm(Y Axis)
• 4 x M3 12mm
• 4 x M3 6mm Countersunk Head
• 20 x M3 5mm (Users have found that 8mm works better)
• 20 x M3 T-Nuts
• 8 x M5 8mm (Users have found that 12mm works better)
• 8 x M5 T-Nuts

Cable Chain Assembly:

• 03-10-010-0 : igus Energy chain® Series 03 : 570mm
• 2 x M3 Threaded Inserts
• 2 x M3 8mm
• 1 x M5 8mm
• 1 x M5 T-Nuts

PSU Case:

• HRP-300-24
• 6 x M4 8mm
• 2 x M3 5mm
• 2 x M5 8mm
• 2 x M5 15mm

Motherboard Case:

• 60x60x25 Fan
• 18 x M3 Threaded Inserts
• 8 x M3 4mm
• 2 x M3 8mm
• 2 x M3 6mm
• 4 x M3 30mm
• 2 x 6mm(Diameter) 3mm(THK)
• 2 x 6mm(Diameter) 10mm(THK)

Prusa Bear Printer Design by gregsaun https://github.com/gregsaun/prusa_i3_bear_upgrade

Rail Holder Design - Small Modification from Chris Warcocki design https://github.com/codiac2600 

SKR2 Pi0 Case Inspiration/Remix from RC-CnC https://www.printables.com/social/21154-rc-cnc/about 

Y Axis Cable Chain Design Inspiration/Remix from VoronDesign https://vorondesign.com 

Please let me know if you have any questions or if something is incorrect such as bolt length/quantity. I encourage anyone to improve upon these designs, as this printer is a fun one!