The Rostock mini is a delta 3D printer based on the modified design of the original Rostock created by Johann. The printer is designed to have a smaller build volume allowing for a smaller, more compact, portable, and desktop friendly version of the delta RepRap design. Using OpenSCAD, the parametric nature of the design files allows for print surfaces to be configured that range from as small as the default 152x152 mm (6x6 inches) all the way to 300x300 mm (12x12 inches) or more. Further, construction parameters such as the length of the drive belts, diagonal rods, and a laser cuttable frame as well as the firmware parameters such as diagonal rod length and delta radius are all automatically calculated based on the size of the specified print surface.
As of October 11, 2012 this wiki is actively being edited so details and information will be changing over the next few weeks.
The modifications to this design were driven by three factors: to experiment with the delta configuration in a printer with a smaller physical footprint; to determine if the original Rostock design could be made more rigid (and thereby not need the heavy wood frame) if the vertical height was reduced considerably; and finally to design a sleeker, parametric lower and upper frame suitable for laser cutting in wood or acrylic.
While this design can be enlarged to fit an 8x8 or larger printbed, the vertical build height should be limited to maybe 8" to keep the frame rigid. Conversely, because of the torque needed to move the hotend platform, NEMA17 steppers are required making it difficult to scale any smaller than the Rostock mini default of a 6x6 printbed.
- Build volume: 152x152x192 mm (6x6x7.5 inches).
- Footprint: TBD.
- Print surface: 152x152 mm heated glass which never moves.
Bill of Materials
To see the how the Rostock mini is assembled, refer to the OpenSCAD file, Rostock_mini.SCAD, pictured above and available in the source files. Assembly begins by constructing each of the three towers, starting with the motor end, then the idler end, followed by the carriage, and then putting it all together to complete the tower. Next, assemble the end effector platform, assembling and attaching the diagonal rods as you go. Complete the mechanical assembly by attaching the motor ends of each tower to the lower frame before attachign the upper frame to the idler ends. Finally, install the electronics, mount the extruder, and complete the wiring. What follows is a brief overview of each of these assembly steps.
- Begin the motor end assembly by taping the four mounting holes for the lower frame with an M4 tap
- Drill each of the six M3 holes with a 7/64 or #35 drill bit
- Insert six M3x12 screws using fender washers and nuts but do not tighten
- Mount the NEMA17 motor using four M3x10 screws with washers or M3x12 ans washers with a cork gasket
- Attach 36-tooth timing pulley to the motor shaft
- Insert 8mm smooth rods into the top of the motor mount until just shy of the bottom of the opening
- Tap the two mounting holes for the upper frame with an M4 tap
- Drill each of the four M3 holes with a 7/64 or #35 drill bit
- Insert four M3x12 screws using fender washers and nuts but do not tighten
- Insert M8x30 screw through two 608ZZ bearings and one M8 washer and thread through the idler end until tight
- Tighten idler on the inside with a M8 washer and nut using a wrench and allen key