CAPAERO is exclusive distributor of West Coast Industries cold expansion products in Europe, Africa, Middle East, India and Russia.
Cold working tooling includes:
- Split Sleeve cold expansion tools - qualified by Airbus, Boeing and main OEM
- Split Mandrel cold expansion tools for production applications
CAPAERO developed a strong expertise in cold expansion processes. We are able to select the best solution to improve fatigue life of your components using Finite Element Analysis.
What is cold expansion and split sleeve process?
Split-sleeve cold working was developed in the early 1970's as a way to improve joint fatigue performance by expanding or compressing the material around the fastener hole.
In the split-sleeve process, this is accomplished by inserting a mandrel that has been prefitted with a disposable sleeve, through a fastener hole, and pulling the mandrel back through the sleeve. The internal surface of the sleeve is pre-lubricated with a special dry lubricant, protecting the mandrel from excessive wear, and reducing the amount of force required to pull the mandrel.
Split sleeve cold expansion is different from other processes like shot-peening : the compressive area around the hole is approximately 1 radius when shot peening offers only few µm depth compression.
Service Bulletin and maintenance operations
CAPAERO and WCI works closely to Airbus and Boeing customer services to provide dedicated toolkit to each service bulletin. WCI tooling is approved for all major aircraft manufacturer in the Structural Repair Manual (SRM). We provide engineering support and work closely to Airbus teams to support maintenance operations. We also support airlines and MRO centres to prepare operations. CAPAERO provides training sessions to operators and engineers working in maintenance of aero structure. The training is recognized by a personal certificate allowing to apply cold working procedures.
Split Mandrel process and automated coldworking
WCI developed an improved version of the split sleeve cold expansion process. The split mandrel process remove sleeve saving a lot of time and cost on large applications. Split mandrel is also the best process to be automatized. Boeing currently widely use split mandrel tooling. Airbus A380 wings are cold expanded with a split mandrel on a robot (see this publication).
CAPAERO can adapt standard expansion parameters to a special need based on stress or geometrical requirements. Special applications will be simulated with finite element analysis to predict stresses level and select the compression level needed.
CAPAERO can evaluate stresses level taking into account split effect on stresses repartition as shown on the picture. Then, expansion will be then tested on samples to confirm results matches customer needs.