RepRapMechanics

Mechanical Systems

The mechanical systems are the part of the RepRap machine that move either the print head, the build platform or both. Generally you have a motor which rotates and that rotation is either used directly as rotational movement, or it is converted into linear movement. The various forms of movement are discussed below.

Cartesian Robot (3-axis machine)

The Cartesian Robot is a very standard style of positioning system that uses the familiar X/Y/Z coordinate system. Basically, you have 3 linear axes: X, Y, and Z. A stepper motor controls each axis and can move it back and forth. One axis will generally be mounted on another axis, while the other axis is standalone. The build platform will be mounted on one axis, and the print head will be on the other. Common configurations are:

• Print head on X/Y assembly, build platform on Z axis
• Print head on Z axis, build platform on X/Y
• Build platform on X axis, print head on Y/Z

The RepRap project has developed two different Cartesian Robot machines:

• Darwin's 3-Axis System - print head on X/Y axis, build platform on Z. Made from RP parts and steel rod. Belt driven.
• McWire Cartesian Bot - McWire Cartesian Bot. Print head on Z, build platform on X/Y. Threaded rod driven.

Polar Coordinate Robot

see Polar

This style of printer consists of a turntable, an X axis, and a Z axis. The table rotates a build platform, the X axis moves a print head from the center of the table to the outside of the table, and a Z axis moves the print head up or down vertically.

The RepRap project does not currently support a particular polar robot, but we are excited to see several promising prototypes. See Polar for details.