Clamping Devices
/ Holding Fixtures

Precise positioning of components on the fixture is extremely important for machining quality. Usually, features are present on the component (holes, recesses, precise stops...) which then find their counterpart on the fixture.

• CONVENTIONAL
  — Simple positioning
  — Positioning element is an integral part of the fixture
  — High repeatability
  
• UNIVERSAL
  + Positioning is a particular challenge
  + Suction cup positions are only of limited use as they are at fixed grid points
  + Auxiliary elements such as adjustable adapters or tools are necessary
  + Exception: MICADO OCTOPUS with individual positions

Milling quality is influenced by many factors. Primarily, the machine, milling tool, and cutting parameters used are decisive. Nevertheless, the clamping fixture also has a significant influence.

• CONVENTIONAL
  — Highest machining speeds possible
  — Large-area clamping prevents vibration & deformation
  — Clamping surface required close to the milling edge
  — Even overhang must be clamped
  
• UNIVERSAL
  + Fixture is highly process-critical
  + Few clamping points / small contact surface
  + Risk of deformation & vibration
  + Springback during drilling and vibrations can cause chatter marks or delaminations
  + Close coordination of fixture & milling parameters is necessary for a good and stable process

Net milling times refer to the periods during a complete post-processing operation for fiber composite components when the milling machine is actively cutting. It is important to note that, especially in the aerospace industry, production often operates with a batch size of 1. This means that two identical parts are never milled consecutively; instead, the process is always thought of in terms of shipsets. A shipset includes all components required later for the assembly of a sub-assembly.

• CONVENTIONAL
  — Reduced net milling times due to frequent retooling
  — Two work areas within the milling machine reduce downtime
  — Alternatively, pallet systems can be employed for external setup
  
• UNIVERSAL
  + No fixture change required - only automatic “reconfiguration”
  + Configuration time: a few seconds up to approx. 20 minutes (concept-dependent)
  + No handling of heavy fixtures required
  + No storage space consumed

High fixture availability is a prerequisite for reliable production planning. This heavily depends on the complexity and quality of the execution.

• CONVENTIONAL
  — Low risk of production downtime due to individual fixtures for each component
  — Repair and maintenance often possible in-house
  — High repeatability
  
• UNIVERSAL
  + Failure risk depends on complexity & quality
  + Many servomotors = high risk
  + Passive systems are significantly more reliable
  + Stocking spare parts highly recommended
  + Rapid response required in case of downtime

Costs are divided into investment and operating costs. Only by considering them over a specific lifespan can a valid comparison be made.

• CONVENTIONAL
  — Higher acquisition costs per component
  — Additional costs due to storage
  — Manipulation and handling increase effort
  
• UNIVERSAL
  + Generally lower acquisition costs per component, especially for large parts
  + Low storage costs
  + Significantly accelerated process