Ultimate Stiffness Y Axis Tensioner and pulley for Wanhao Duplicator i3

thingiverse

The Y-axis of i3 machines has too much compliance, causing ringing artefacts - particularly noticeable when the printhead navigates sharp turns or corners. There are two primary sources of this compliance: 1. Spring-style belt tensioners, which inherently introduce compliance (a poor design choice). 2. The flimsy idler pulley mount, featuring a narrow base, tall geometry, and sheet metal mounting that rob rigidity. Existing solutions on Thingiverse eliminate the stock spring tensioner but fail to address the pulley flex issue, and running higher tensions puts additional load on the weak pulley mount. Frustrated with these inadequate solutions, I designed a complete tensioner system with maximum stiffness. It utilizes the conveniently positioned stock vertical flange as a longitudinal brace/web that provides extreme rigidity. This part offers several benefits: 1. The highest possible Y-axis stiffness and lowest associated ringing artefacts (I recommend combining this with reduced Jerk settings for optimal results). 2. Easy belt tensioning via adjustment screw. 3. Zero increase in moving mass of the Y-axis. Notes on installation: Two 3mm holes need to be drilled to allow the tensioner block to attach/brace onto the long sheet metal flange. This is best done while the block is in situ, ensuring correct alignment/placement of the holes. However, due to clearance, it's challenging to do this. The best method is to provisionally install in situ with thin double-sided tape attaching the block onto the flange. Then, the block and flange can be removed from the 3D printer as an assembly and easily drilled on the bench. This way, the holes will be perfectly positioned. Note that a nylock nut must be inserted into the arm to accept the tension adjuster bolt to prevent self-loosening.