Analysis and development of the laser cladding process

Sammanfattning: This thesis presents an investigation into the laser cladding process using CO2 and Nd:YAG lasers. The work is divided into four papers: Paper one is a literature review of the subject of laser cladding. This presents a general overview of the subject from a practical and theoretical point of view. Paper two is an investigation about the energy redistribution during CO2- laser cladding. Experimental absorption measurements by calorimetry were carried out to separate and analyse how much of the energy is lost by reflection etc. It was found that approximately 60% of the original laser power is lost by reflection. Paper three extends the work of paper two and compares the process efficiency of Nd:YAG and CO2 laser cladding. The energy redistribution during cladding has been analysed for both processes. The Nd:YAG laser cladding process was found to be considerably more energy efficient than CO2- laser cladding process. Paper four presents preliminary experimental results from two new processes; Laser casting and Laser clad-casting. Laser casting is a process similar to blown powder laser cladding but without the final product joined to the substrate. The substrate acts as a mould and the casting retains topological features of the substrate. Laser clad-casting involves the production of a clad layer between machined copper blocks. Clad tracks can therefore be achieved with large depth to width ratios and pre determined cross sections.