EXPERT'S DIGEST ATL/AFP achieved results of the reinforcement trials. When joining different matrix materials it is important to ensure that the chosen process temperature fits to both joining partners. The more thermal stable material need to be fused without degrading the joining partner that is less thermal stable. Using an optical heating the absorption properties of the used material in respect to the used wavelength of the used laser system is important. Different Fig. 2: Tailored parts and tailored blanks via laser-assisted tape placement fiber-reinforcements can result in different optical absorption properties. The process can be The quality of the welding zone between the adapted to joining two materials with different base composite laminates and the placed reinforcement tape have evaluated have by a optical properties by adjusting the laser power mandrel peel test. The reinforcements have distribution via the setting of the laser angle. been produced with a lay-up rate of 300 The fact that the PA66/ GF blank could not mm per second. Figure 3 summarizes the be joint in the given test plan because of its low absorption degree in the near infrared spectrum, in conjunction with high welding temperature, high lay-up rate and limited available laser power. Welding a PA66/ CF tape on PA66/ CF blank at the same process conditions can be done with ease, since both joining partners absorb degree of 85% to 90% of the used laser energy close to surface. A good joint would be achieved by reducing the lay-up rate or by using more laser power. In addition the utilization of carbon black particles within laminate polymer for increased absorption is an option. Within »FibreChain« also the application of a CO2-laser system for tape placement is investigated, as due to its longer wavelength, the absorption of the laser radiation by the GFRP is higher even without carbon black particles. Combined forming and functionalization process The tailored thermoplastic composite sheets which have been produced by laser-assisted tape laying can be molded to the final shape in a thermoforming process. The stamp forming of thermoplastic composites is a fast process with cycle times shorter than 1 minute and is hence suitable for high-volume production. Fig. 3: Summarized results of reinforcement trials Expert's digest jec composites magazine Additive Manufacturing 97