Robotic grinding application

Our customer manufactures hinges for plastic doors. Main parts are zinc-aluminum castings, powder coated according to end-users’ requirements. To achieve best paint quality, surface has to be ground.

Our system uses 3 infeed trays to feed the cell with parts. Trays were designed to accept all part variants. The robot uses a combined multi side gripper-multi part finger solution to grip all 3 parts. One of the parts has a very sensitive curved surface which requires stable pressure while grinding.

A belt grinder has been implemented with a belt specially designed for materials like zinc-aluminium alloy. This belt has great wear resistance, but it changes the thickness over the lifetime.  We added a numeric wheel to the controller where the user can manually select the wear level and the robot compensates by applying more force.

This robot cell uses combined outfeed solutions: two parts are placed on outfeed conveyor (earlier there was a passive slide), the third part is placed directly into a machine for drilling and thread cutting.


  • 3 different parts, all together 6 part variants
  • multi side – multi function gripper (inside, outside gripping with feedback)
  • automatic part variant identification system
  • advanced dual channel safety system with automatic gate locking
  • NACHI SA 166 robot with NACHI AR controller
  • manual belt wear compensation
  • tray based infeed
  • direct machine loading + outfeed conveyor
  • Cycle time per part: ~30-40 sec


  • Customer: T-DOTT Kft.
  • Project duration: ~3 months
  • Robot type: NACHI SA 166
  • Controller type: NACHI AR
  • Gripper: Schunk + custom design with Festo pneumatics
  • PLC system: OMRON
  • Safety system: OMRON
  • Grinding machine: GRIT FEIN
  • Technologies used: advanced NACHI programming, 3D CAD, CNC machining