Building a 3D printer is certainly a test of patience and will. When building a non-standard 3D printer it becomes easily apparent what kind of undertaking it may become.
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The gantry that was originally built was constructed of wood using draw slides as bearings. Threaded 1/4 – 20 rod is being used as the drive mechanism. After building the initial gantry and wiring up the X-axis and Y-axis several discoveries were made.
- Threaded rod if used as a ball-screw needs to be straight and free of any burrs. The easiest way to accomplish this is simply to run the corresponding die back over the threads. The feedrates that are achieved with ball-screws are far lower than its belt counterpart.
- The coupling used between the stepper motor and ball-screw needs to be flexible. Essentially using hose with hose clamps or any other means that allows for the two items to out of alignment. It is important to note that whatever you use that the backlash is kept to a minimum.
- The bearings used should be able to freely float from one end of the axis to the other. Draw slides are fine for the X-axis however a floating linear bearing for the Y-axis would be far better. This would insure any noise (bumps, rough, high spots) in the Y-axis bearing are not reflected in the print. The Z-axis can be either however insure that high feed rates don’t allow the Z-axis to flex while in movement.
- The bed that rides on the X-axis needs to be as flat as possible. If the material being used for the X-axis bed is not that flat you will find it difficult to zero the Z-axis against it. In other words make sure the X-axis bed surface is parallel to the Y-axis. This way the Z depth will be consistent regardless of where you are on the Y.
More to follow later in the week!!
Fecke – KJ4ZRZ