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garethky / Slice-Mosquito-Direct-Tool-Head

Models and Instructions for making a Mosquito/Bondtech direct drive toolhead for the E3D Tool Changer platform
GNU General Public License v3.0
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Investigate over tension and filament grinding #6

Open garethky opened 3 years ago

garethky commented 3 years ago

The current tension mechanism is easy to over tighten. This is in contrast to the MK3S and has a few causes:

  1. The leaver arm on the idler is longer, requiring less torque for the same force applied to the filament
  2. The Bondtech spring is shorter and stiffer, requiring fewer turns to apply the same force as the Prusa design.

The result is a very narrow difference between "just enough tension" and a loose screw. Unfortunately directly copying the Prusa design is not possible because the part cooling fan would block access to the spot where the tension bolt would go through the extruder. Another difficulty is finding a reliable source of longer springs.

Opening this issue to track ideas for a solution.

garethky commented 3 years ago

I've tried with the Prusa spring and it gives a wider adjustment ranger. For this revision I think we should give links to both parts and discuss the tradeoffs.

More extensive changes may have to wait for a future design.