Plastic injection moulds An increasing application of laser beam hardening is the treatment of plastic injection moulds. The desire for an ever increasing service lifetime demands a hardening of the edges of the tools. Typical tools, either in segmented or monolithic form, can weigh up to ten tons or more. When in service, the high injection pressures (~ 1000 bar) can result in high wear on the entry and sealing faces, particularly if the plastic contains abrasive media. Wear of those regions results in parts with burrs on the edges, which often requires tedious removal by hand. Laser hardening is superior to flame or induction hardening since both of these techniques do not always produce the desired results and are limited in their application due to difficult geometries.