Experiments

A fixture system for workpiece adjustment and clamping with/without its predeformation

Demonstrator overview

The objective of this case study is to reduce the setup time and increase the accuracy during clamping of large-scale flexible workpieces.
The objective is to control the clamping procedure in order to reach the specific workpiece position and deformation after clamping. It also covers the introduction of active damping to avoid the vibrations associated with the local low dynamic stiffness of the part and the clamping system.
The target workpiece will be a mechanical structural part (component of an assembly device) made of steel with 2500 mm in length and 1500 mm in width. This structural component is made by welding. Since the workpiece itself is compliant, the workpiece position setup and non-deformed or defined deformed clamping is the key issue.
The machining operations to control are the milling and drilling of workpiece components such as flanges. In this case, the precision of the workpiece is limited by the deformations suffered during clamping. The machining perfomance is also directly incluenced by stiffness of the clamping.
The solution is the development of modular active clamping systems for leveling the workpiece in support points and
the use of self-adjusted clamping units with integral force and position sensors with a closed loop control unit commanding the fixture elements based on the sensor’s information.

Description of the infrastructure

5-axis portal milling machine with a dedicated fixture (electro-mechanically actuated and with an automatic set-up)

Detailed description of the demonstrator

The demonstrator will consist of the development and implementation of a new type of a fixture system with these features:

  • integration of independent modular active clamping systems for leveling the workpiece in support points
  • integration of self-adjusted clamping units with integral force and position sensors with a closed loop control unit commanding the fixture elements based on the sensor’s information
  • shortening workpiece adjustment time and zero point setup during the so called scribe operation
  • increasing the process automation and the operator safety
  • providing a solution for quick, accurate and safe process

The demonstrator will detect workpiece deformations. It will change the fixture position to obtain a safe fixture of the part without its deformation.

INTEFIX