Avoiding the stick-slip effect

Bornemann Gewindetechnik  GmbH  & Co. KG,  based  in Delligsen,  Lower  Saxony,  has  been  producing  threaded  spindles  and  screw  conveyors  for more  than 25 years.  One of their main products is ready-to-install trapezoidal spindle drives for heavy-duty lifting gear, as used to lift rail vehicles. Constant lubrication of  the load-bearing flanks of the thread profiles is essential for spindle lift drives, as insufficient  lubrication  can  lead  to  increased wear and overheating as well as  the  so-called stick-slip effect.

This occurs when two bodies are sliding past each other, and can happen because static friction is greater than dynamic friction. It usually disappears as soon as the two bodies are separated by an intermediary or lubricating agent.  The  problem is  often  a  result  of  the  spindle  design, for  example  if  there  are  no  lubrication pockets on the load-bearing flanks of the thread profile. Bornemann Gewindetechnik produces its threaded spindles using a whirl finishing process, which produces microscopic openings in the material surface, creating μ-sized  concave dips –  the so-called lubrication pockets.

Released by Bornemann Gewindetechnik (09/2010)