Contactless Machining and Pre-Treatment for Bonded Repair

The surface preparation of damaged areas on composite parts is today a lengthy, cumbersome and delicate process, taking into consideration the detailed processing requirements specified in the SRMs. This is due to the need for the achievement of very specific and sometimes complex geometries (i.e. gradually increasing in diameter stepping or scarfing of the damaged area etc.) on a very strong and brittle material, such as carbon epoxy composites. Such processing is today achieved by means of high performance drilling equipment, fit on special (usually diamond coated) toolings that allow for delicate operations on the damaged structure.
Due to the hard carbon fibers the expensive tools wear out very quickly, causing a nonreproducible surface quality. Therefore, the high fatigue requirements for a successful repair process are often difficult to meet. Grinding contaminates fibers and the fabric structures with abrasive dust, therefore bonding by a repair patch doesn’t show high resistance. Resistance of CFRP components which are bonded using conventional methods decreases by up to more than 30% compared to the intrinsic fatigue resistance.
A novel laser based method enables effective ply-by-ply removal and surface pretreatment of CFRP for structural bonded repair, e.g. for adhesive bonding of clips and clamps or structural stepped bonding. The mechanical strength properties realized in the process allow superior structural bonding behavior e.g. for aviation industries.
 

BENEFITS

• Excellent cleaning and ablation results and speed
• Enhanced bonding strength
• Innovative robust diode-pumped laser technology
• Very low running costs (generally 1-3 €/h)
• No gas consumption, “Plug & Go”-technology
• Flexible application due to portable technology
• Maintenance free technology
• High reliability, no “human error” factor, potential for automation & certification

ECOLOGICAL EFFECTS

• No abrasives, no chemicals
• No waste except of removed CFAP plies
• Low noise application