Waterjetting of carbon fibre reinforced polymers with recycled abrasive

Abrasive Waterjet Machining (AWJ) is a non-conventional materials processing technology that has gained popularity in machining Carbon Fibre Reinforced Polymers (CFRP). AWJ has many advantages over conventional machining processes as it does not produce a heat affected zone, produces low machining forces, is a cleaner technology and has low processing costs. A breakdown of process costs has demonstrated that abrasive accounts for 60% of total machining cost. Moreover, production of abrasive by stripping extremely large quantities of sand poses an environmental impact that could affect ecosystems. Abrasive recycling systems exist in the market and could reduce economic process costs and environmental impact; however the effect of recycling abrasive on cutting power and quality of CFRP has not been investigated. This article reports on experiments that were carried out, as part of the European-funded REFORM project, in order to characterise the effect of recycling abrasive in terms of morphology, machinability and surface quality characteristics (surface roughness and taper angle). Scanning Electron Microscope images of fresh and recycled abrasive were compared. A Design of Experiments (DoE) was devised to investigate the effect of machining with recycled abrasive. The results showed a changed in abrasive morphology and cutting performance.