High Force Indentation Apparatus With High Accuracy

The invention relates to an indentation apparatus ( 1 ) comprising a force frame ( 13 ) and a positioning frame ( 14 ). An indentation tool ( 5 ) is pressed into a work piece ( 7 ) in order to master a mould. The work piece ( 7 ) is supported by the base ( 6 ). An actuator ( 2 ) is mounted in the force frame ( 13 ). The actuator ( 2 ) and the indentation tool head ( 4 ) are connected with a rod ( 3 ). The rod ( 3 ) is fixed with flexible (swivel) joints ( 15 ) to said indentation tool ( 4 ) and said actuator ( 2 ) in order to physically decouple said force frame ( 13 ) and said positioning frame ( 14 ) from forces. Also a force sensor ( 9 ) is installed between the indentation tool ( 4 ) and the positioning frame ( 14 ). In order to keep the positioning frame unloaded, the balance force delivered by said force frame actuator ( 2 ) should be approximately equal to the indentation force. The signal of the force sensor ( 9 ) is interpreted by control electronics ( 10 ). The control electronics determine the force of actuator ( 2 ) such that the force measured at the force sensor ( 9 ) is approximately at zero level. In order to align actuator ( 2 ), rod ( 3 ) and indentation tool ( 4 ) axially, the actuator ( 2 ) will be moved as follower of the indentation tool head ( 5 ) movement.