Mendel X Axis Driving Modification

French Version

With original Mendel's x-axis design, carriage is drived by a belt which goes all around x-axis assembly. The belt passes on bearings at each corner of the assembly and this leads to carriage vibrations caused by belt teeth. Accordingly every printed part takes a tiny ondulation into X side, which is the indirect footprint of belt teeth.

This effect is sensitive with original X motor bracket, where belt passes on bearings by it’s back side. It is increased with alternative X motor bracket where belt passes on bearings by teeth side. Those two brackets also lead to an untimely belt wear, a little reduced with alternative X motor bracket.

The modification I describe avoids ondulation effect and belt wear, using a vertical belt positioning as with Prusa Mendel or Mendel90.

To print:

Fasteners (washers not included):

  • #2 M3x12 screws (motor attachment)
  • #2 624 bearings (right bracket free pulley, from old x-axis assembly),
  • #1 M4x35 screws (right bracket free pulley axis, length adapted pulley height),
  • #1 M4 nut (right bracket free pulley)
  • #2 M4x35 screws (attachment to carriage)
  • #2 M4x30 screws (original M4x40 screws replacement)
  • #4 M3x20 screws (belt attachment)

Left Bracket

Motor is horizontally fixed with two M3x12 screws.

Mendel modified left bracket, 3D model

Mendel modified left bracket, rear view, photography

HD pictogramLeft bracket rear view.

Right Bracket

Right bracket wears a return pulley which is the same as motor one, with two 624 bearings.

Mendel modified right bracket, 3D model

Picture of right bracket bearings and pulley assembly

HD pictogramBearings and pulley assembly.

Assembly order: bearing, bearing, washer, pulley, washer, nut. The shaft is an M4 screw and pulley's inner diameter is 5mm: the screw is surrounded by adhesive tape to bridge the gap.

The rounded housing is glued (yes it's bad…) after assembly.

Mendel modified right bracket, rear view, photography

HD pictogramRight bracket rear view.

Carriage Attachment

The two M4x40 screws on the top which set originals belt clamps (STL file) are replaced by M4x30 screws, the two bottom screws M4x35 only attach the belt clamp assembly.

Mendel modified carriage attachment, 3D model

Photo de l'accrochage modifié du charriot de la Mendel

HD pictogramCarriage attachment.

Download

STL files and OpenSCAD models — ZIP, 152 Ko.

• Publié le 09/02/2013 - modifié le 31/05/2013