Drew's Rostock variant
by Ellindsey, published
This is a printer I am currently building based on Johann's amazing Rostock printer.
This design is modified to use Makerslide rail instead of smooth rod and linear bearings. I chose to use Makerslide partly because I found a pile of V-roller bearings at a junkyard for real cheap, but also because I thought the Makerslide would be more rigid and would allow me to hide wiring inside the channel.
This printer is also being designed to be a single self-contanied piece of furniture, with all wiring and electronic components hidden inside it as much as is possible. I intend to eventually equip it with Bluetooth, a SDcard reader, and a full LCD interface so it can print completely stand-alone.
The original version of thie printer didn't work bery well due to structural issues. I don't have access to a CNC mill or laser cutter or any other proper machine tools. I'm basically building this thing by hand with a table saw and power drill. The wooden structural parts for the original version weren't accurate enough, so I've redesigned it to be possible to build without haveing proper machine tools.
The revised version uses 3/8 inch threaded rod to make triangular frames at the top and bottom ends of the printer. The position of the rails can be finely adjusted by turning the nuts on the screws, so you can tweak it until everything is properly lined up after building it. The wooden frame is now reduncant, although I'm still using it to mount secondary parts.
Each drive axis is made from a lenght of Makerslide rail. I'm using three 666mm pieces (cut from a single 2000mm length) but the length could be changed for a larger or smaller print area.
The top ends of the rails each have a 5mm hole drilled in them, and one "railtopblock" part secured to the rail by a 5mm bolt and nut. This bolt also goes through an idler pully built around a 525 bearing. The rail top blocks also have pockets for the upper end travel limit microswitches, and channels for the wiring to those switches and other stuff on the top end.
The three top end blocks are joined to each other with three 3/8" threaded rods and nuts. The "topfoot" part allows you to mount an upper plate to the rods, which is convienent for somewhere to put the extruder drive, filament spool, lights, etc.
The bottom end of each rail has one "railbottomblock" part secured to it with a 5mm bolt and nut. Like the top, the bottom blocks are joined by 3/8" threaded rods, and the "bottomfoot" part lets you secure the rods to the bottom plate.
The rail bottom blocks have four thru holes for #10 bolts, with hexagonal pockets for #10 nuts. The two closer to the rail are to mount the motor blocks, with bolts that can be turned from above to adjust the belt tension. The two further away are for longer #10 bolts to support the plywood plate that supports the print bed. I use springs to support the bed support plate so that the print bed has some give to help prevent motor skips if the print head bumps into the printer part.
The "motormountblock" part has a mounting pattern for the motor, and a pocket for a 525 bearing to support the end of the motor shaft. Two #10 botls attach this block to the rail bottom block and can be turned from above to adjust the belt tension. I also put in slots that can be used to attach grounding wires to the motor face screws if desired.
The rail carriages are each made from one "carriagemid" and two "carriageside" parts. Each carriage side holds two V-groove bearings. Two #6 threaded rods go through the back side of the carriages to join the sides together. The drive belt is pressed through a groove in the carriage mid section, and then one #6 threaded rod and one M3 threaded go through the two sides and the center to join them together. Adjust the nuts until the piece slides smoothly but without any ability to shift sideways or rotate, and then lock-tite all the nuts.
Yes, I'm using a mixture of english and metric hardware. It's hard to find metric hardware around here, so I use english unless I specifically need to use a metric part.
The M3 threaded rod also goes through the two connecting rods on each carriage. The connecting rods are made from Traxxis rod ends and carbon fiber tubes.
The "headmainbody" part holds the three M3 threaded rods that secure the other ends of the connecting rods. It also has channels for wires and pockets for LEDs and three 20mm cooling fans. The mini J-head is secured in place with a little triangular wooden piece secured up inside the head main body with three screws. On top of this one "invertedextrudeclamp" and one "tighteningcone" secure the Bowden tube.
The extruder drive is a heavily modified Airtripper, which I'm not really happy with and intend to redesign.
I have stuck the original part from my first attempt in a zip file. I don't recommend using them, the new design works much better.