A study of wear on focusing tubes exposed to corundum-based abrasives in the waterjet cutting process

Corundum-based abrasives are commonly used for cutting extremely hard materials like e.g. ceramics by means of abrasive waterjets. Due to a reduced lifetime of the used focusing tubes, this type of abrasive is only applied under special consideration of economic circumstances. The cutting centres which use this technology retain only a small amount of used abrasives because of the limited application of this grain type. Nevertheless, observing the disintegration of particles which have interacted with mostly advanced materials is of scientific interest. Garnet-based abrasives are commonly classified in different grain size classes after sieving to evaluate their recycling potential. Based on a feasibility study, this paper will present some results on achieved cutting data and also shows the geometrical change of the used focusing tubes which was realized by non-destructive examination. The mass loss factor of the used focusing tubes was calculated for different corundum materials and compared with the commonly used in AWJ machining abrasive, garnet. Additionally, cutting and recycling properties of the tested corundum-based abrasive was tested. The disintegration properties of the corundum-based abrasive were monitored by sieving and optical test methods. Particle identification after cutting process (grain or chip) was realized by energy-dispersive X-ray microanalysis (EDX). Finally, the results obtained were used to make a rough calculation for lifetime estimations of the focusing tubes related to the observed wear process.