BrickRap

Project Description

A RepRap which is "back to the roots", in other words: Focus is not on printing speed or fancy features but on the capability to reproduce itself.

This shall be achieved by using "RepBricks" which are easily stacked together like the famous bricks for small children. Compatibility to commercial brick systems will even allow to build a BrickStrap using your childrens bricks.

Inspiration for this Project Comes from the following projects: Lego_RepStrap MendeLego LEGObot 3D Printer by matstermind and LegoStrap(which is quite empty...)

However I decided to use double sized bricks to lower the part count and increase ease of assembly.

Development Goals:

- Extremely low cost - Ultra-low vitamin count - Brick based construction (modular concept) - Compatibility of the bricks to commercial brick systems - Easy to build - Mother-Child principle: - BrickRap children have small printing area (just enough to print parts for growing) - Capability to grow in size by printing "growth parts" - Rack and Pinion drivetrain will make growing easier - Herringbone gears will drive the Rack and thereby self-center the drivetrain

Why use RepBricks?

While all the new developments are really great projects, they tend to be more and more professional. For most of them costly vitamins are required. In my personal opinion the idea of a self replicating machine is not the Focus of those high sophisticated machines. By using only a limited set of easily stackable "RepBricks" one could use parts from older designs for new machines (Maybe not only RepRaps). Furthermore the compatibility to Commercial bricks can lower the entry barrier for beginners, as a lot of People already own enough bricks to at least build the structural parts of BrickRap.

One limiting factor in the RepRap growth function is the Manual assembly. Using the Brick principle it is already possible to build assembly devices which could be used in the replication. Lego 3D-Drucker (german)

Mother+Child principle

The Mother in this context is a full size BrickRap with a printing area sufficiently big to print all used RepBricks. The child however is the smallest possible BrickRap, with a print area as small as one Standard (to be defined) "GrowthBrick". Using this principle a Baby BrickRap would produce the parts required for its growth on its own. In the meanwhile the MotherRap can produce more babies or help the Baby to grow.

Cost Reduction

One of the most important design goals for BrickRap is cost reduction. One example to achieve this is the rack and pinion carriage system for the printing plate. However with my current design there is a major drawback as the moving mass is increased by the fact that both (X and Y) motors are moving as the printing surface does. To overcome this I tried to use low weight cheap stepper motors. 28BJY-48 with a ULN2003 "driver". Connection to Ramps 1.4 was carried out using the free Pins at AUX4 and I managed to make the motor move using some modification of Repetier Firmware. However I am stuck there with some doubts how to redirect the signals from the dir/step protocol used with pollulu to the direct drive of the motor. As I completely fail in coding firmware this development is likely to be abandoned and I will go back to using Pollulu.

Development Status:

- conceptual work - a Picture of a model made of commercial bricks will follow soon.

This is the first model of BrickRap: The frame is quite stable this way. The Extrueer shall fit into the hole on the upside and be moveable only in Z-Direction (right now I have one Wades Extruder which nearly fits into the model, however work has to be done to reduce ist size). Therefore the printing table has to have 2 degrees of freedom. The racks are indicated by the pink bricks. The Motor Mounts are indicated by the orange bricks. The motors will have the herringbone gears directly on their shaft. (I hope printing resolution will anyway be not too bad. Something in the 0.5 mm range would be fine for my purposes)

For the rack and pinion drive I imagine something like Rack and Pinion for X-Axis by theodleif

ToDo [06-09-2013] - Wait for the last missing Pollulu for my WolfStrap to finally start printing.

- Create .stl for rack and pinion System which can directly be stacked on Standard double size brick.

- Create .stl for print optimized Brick (round Pins in the inside middle will be replaced by straight crossing lines)