Microbot Mechanical Design Guide

Microbot Mechanical Design Guide

posted in: Hardware, Microbots | 0

Wheels:

  • Outer Diameter: 10.6mm
  • Thickness: 2mm
  • O-ring groove diameter: 1.8mm
  • O-ring groove inner diameter: 9mm
  • Center mounting hole:  2mm diameter – ideally with .5mm D cut or wheel may spin on shaft

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Chassis: 

  • Starting Body Extrusion: 19mm width, 23.5mm length, 16mm height
  • Top Cutout subtraction: 17mm width, 21.5mm length, 8mm height – this should leave you with 1mm thick walls on all four sides
  • Motor hole size: 6.15mm diameter – motor is 6mm so 6.15mm gives us a little clearance
  • Motor hole position: center is 5.3mm from bottom of chassis, 6.25mm from Front/Back of chassis, depth 17.5mm
  • PCB mounting pattern dimensions: 13.4mm wide, 21.7mm long, 0.4mm hole depth, 0.8mm hole diameter
  • PCB mounting standoff: 1mm above chassis walls, 1.8mm wide

 

Motor Specs


Post 3D Printing Operations:

  • The PCB mounting holes must be drilled out as the print service does not allow full holes this small
  • Use .95mm carbide drill bit to drill holes to 4mm depth
  • Drill out idler wheel holes with .95mm carbide drill
  • Carbon steel M1 tap was not hard enough to tap the sintered stainless/bronze 3D print, the screws themselves however will thread into this .95mm hole.
  • If motor holes printed undersized (Shapeways metal prints produce thicker walls than model) holes must be drilled out to larger size
  • Use a #C (6.10mm) drill bit, 6.05mm hole size would be ideal, but using a 6mm drill bit seems to be too small for these motors which are around 6.04mm OD

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