Linear bearings can be used for linear motion AND rotational motion. This design uses linear bearings for both linear and rotational motion - simultaneously. While an X carriage can be traveling linearly on it's linear rod, the same rod can also be turning, driving a belt to simultaneously move the Y carriage on it's linear rod. This setup eliminates any movement of both the X and Y motors to achieve X/Y travel.
The left bottom motor runs a belt to the fuschia rod at the rear top. As that rod spins it drives two belts synced to the fuscia rod on the front. Those belts are also attached to the Y axis carriages so that this motor effectively moves the Y carriages along the yellow Y rods while rotating the fuscia X rods. LIkewise, the right rear motor can move the X carriage.
One of the problems with making this design compact (height-wise) was placing both the X and Y rods on the same level, which also placed the drive belts for both on the same path crisscrossing each other. That was solved using 20 tooth pulleys on one axis and 32 tooth pulleys on the other. These are driven pairs so tooth size is irrelevant since both axis drive pulleys are on the respective motors.
An SKP of the design can be downloaded HERE
Here is a cut-away view
Bi-Motion Box Printer
Design eliminates any movement of both the X and Y motors to achieve X/Y travel. It uses linear bearings for both linear travel and rotational movement.
- Build License:
- CC - Attribution NonCommercial - No Derivs - CC BY NC ND