Low Speed Friction Rig

Low Speed Friction Rig

Friction coefficient (the ratio of the force resisting motion to the applied load) is a key design parameter in all machinery with moving parts. Frequently published data for friction coefficients is difficult to find. Since friction is highly dependent on the contacting materials and the state of the interface (i.e. lubricated, dry, wet, contaminated etc.) it is usually best to measure friction under conditions as close to those of operation as possible.

Friction measurements are carried out on this Bowden & Leben type apparatus. It consists of a top specimen which is loaded against a counterface driven by a variable speed electric motor. It is possible to measure both static and kinetic coefficients of friction at low sliding speeds.

The frictional force between the specimen and the counterface causes the loading arm to push against a force transducer. Data is captured via an oscilloscope using simple PC software. Both static and dynamic friction coefficients can be measured.

 

Machine specifications:

  • The apparatus can be used to run tests conforming to ASTM standards that involve a block moving against a flat surface (eg. C 808, D 1894, D 3247 etc.).
  • Maximum tractional force: 140N
  • Maximum normal load: 800N
  • Typical contact pressures (conformal geometry): 1-15MPa
  • Temperature: up to 120 degrees C
  • Speed: 0.5mm/s to 5mm/s

Some Previous Applications:

  • Friction of novel polymeric composite bearing materials
  • Grip of a rubber coated inkjet paper feed roller
  • Friction of shoe/floor surfaces
  • Stick slip in auto seat latches
  • Friction in abrasive cleaning
  • Friction of writing instruments and the design of comfortable PDA writing surfaces
  • Water based lubrication of PVC window frame extrusions
  • Evaluation of motorway bridge bearing materials