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Project:Cupcake-o-Matic: Difference between revisions
From London Hackspace Wiki
→Adding a Cantilever Z Axis
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===Adding a Cantilever Z Axis=== | ===Adding a Cantilever Z Axis=== | ||
[[File:cupcake_cantilever_z_axis.jpg|thumb|300px|A cantilever z-axis in laser cut acrylic.]] | [[File:cupcake_cantilever_z_axis.jpg|thumb|300px|A cantilever z-axis in laser cut acrylic.]] | ||
In order to move the extruder up and down in the z-axis the Cupcake CNC used a platform suspended on 4 M8 nuts on threaded rods. These threaded rods were linked together with a timing belt such that if the motor moved one step (1.8degrees) then all the threaded rods would rotate by the same amount. This meant you could get an accuracy of 0.00625mm per step. Unfortunately this was very slow and relied on the threaded rod being exactly straight which it rarely was. What would happen is as the z platform rose during a build one or more of the threaded rods would move in the x or y axes there by throwing off any precise accuracy in these axes. Another serious problem with this arrangement was the assumption that the 4 M8 nuts would always remain level and wouldn't jam. As a result the z axis platform would be wonky which didn't help when printing. | |||
To first fix this I printed a [http://www.thingiverse.com/thing:3091 Z-Wobble arrester without pin]. It replaces a nut on the z platform and allows the threaded rod to move back and forth without necessarily dragging the platform in that direction. This was fiddle to install as it required the removal of a nut trap on the platform and then the nut to be moved down a bit, whilst still leveling the bed. | |||
Replaced the 4 threaded rod suspended Z axis with a Thing-o-Matic inspired cantilever stage. | Replaced the 4 threaded rod suspended Z axis with a Thing-o-Matic inspired cantilever stage. | ||
