Environmentally friendly pulsed power applications for industrial processes

Summary form only given. The thermohydraulic shockwave source (THS) is used to investigate the technical and economical feasibility of new industrial applications based on intense pressure pulses/shocks. Two pilot applications are presented to demonstrate the possibility of shock wave-based processing, i.e. non-contact, ultra-pure grinding of (ceramic) powders, and removal of SMD (Surface Mount Devices) parts from PCBs (Printed Circuit Boards), respectively. The THS is scalable over a large scale, and adaptable in its shape and size to a large variety of applications. and will be described in detail in this contribution. It produces peak pressures of the order of 700 bars in a 6mm wide focal region. The application of intense pressure pulses to non-contact, ultra-pure milling and de-agglomeration of powders is presented in detail, including threshold process parameters. The grinding efficiency of the powder (in terms of surface area increase per unit energy consumed) increases strongly above a threshold pressure, indicating that a further decrease of the measured specific energy consumption of this process is feasible. Another example of applying shockwaves to industrial processes is the removal of SMD parts from PCBs. Application of a series of shocks to cemented or soldered connections results in crack formation and propagation within the bond region, and eventually to the removal of the SMD part itself. Processing is done in a liquid environment (i.e., degassed water, silicon oil, or hydrocarbons like alcohols), and can be used for either parts recycling, PCB repair, or process control in terms of online bond quality evaluation. Initial results are given concerning threshold parameters for soldered connections, statistics, and geometrical constraints. This process opens up a vast field of applications, in particular in the area of rapid on-line testing and quality control in a variety of industrial processes.