Reconfigurable tooling frames consisting of steel box sections and bolted friction clamps offer an opportunity to replace traditional expensive welded steel tooling. This well publicized reconfigurable reusable jig tooling has been investigated for use in the assembly of a prototype compound helicopter wing.
Due to the aircraft configuration, the wing design is pinned at both ends and therefore requires a higher degree of end to end accuracy, over the 4m length, than conventional wings. During the investigation some fundamental issues are approached, including:
Potential cost savings and variables which effect the business case.
Achievable Jig accuracy.
Potential sources of instability that may affect accuracy over time.
Repeatability of measurements with various features and methods.
Typical jig stability over 24hrs including effects of small temperature fluctuations.
Deflections that occur due to loading.
The cost benefit of reusable tooling in a low volume prototype scenario is examined followed by the design of the jig and location features to enable the accurate build and certification documentation to be completed. A prototype 4m test jig comprising of commercially available components and bespoke machined ‘pick-ups’ is presented.
Hardware and measurement process cost modelling is documented along with results for the positional and center-line concentricity setting accuracy that was achieved using a Leica AT901 laser tracking system.
Subsequent measurements over a 24hr period are also discussed along with potential sources of deviation in jig accuracy over time and with an applied load.