Computer simulation of particle interference in abrasive jet micromachining

Solid particle erosion mechanisms of protective coatings for aerospace applications

“…Ghobeity et al [170] found that a Weibull radial probability distribution function was much more representative and agreed well with experimental values. In fact, they found that this probability function, combined with the measured linear radial decrease in velocity from the centerline of the jet outwards, predicted accurately the observed erosion wear scars produced by a cylindrical nozzle.…”

“…They found that the particle flux (feed rate per surface area) is a determining factor in predicting particle interference effects. In a more recent series of articles, combining experimental and modeling results, Papini, Spelt and coworkers [167,170,174,176,178,180] showed for normal incidence SPE that the erosion rates decrease for increasing WD because of an increased inter-particle collision probability when the volume between the nozzle outlet and the surface increases. Therefore, in order to optimize the testing methodology of our erosion test rig using the long aspect ratio nozzle, we present in Chapter 5 a study on the effects of feed rate and WD on the SPE of brittle bulk materials and show that particle interference effects can reduce erosion rates by as much as 40 %.…”

“…In the past 15 years, much work on the influence of process parameters on the shape of erosion scars has been done in the context of abrasion jet micromachining of glass for flat panel displays [69,71,167,[170][171][172][173][174][175][176][177][178][179][180][181]. In particular, the work of Papini, Spelt and coworkers [167,170,[174][175][176][177][178][179][180][181] has led to many interesting findings on the importance of working parameters such as feed rate and WD on the erosion process. As we will discuss in the next sections, the Gaussian profile of the wear scar has enabled us to measure the volume loss of eroded samples using a simple profilometry methodology and other results regarding particle interference effects have helped us to optimize our erosion testing methodology.…”

Analysis and modelling of particle velocities in micro-abrasive air jet

“…as a function of process and material variables [11]. A considerable amount of work has been conducted in recent years to develop simulation models for the AJM process [11][12][13][14][15]. These models can provide useful insight into the machining mechanism, and provide valuable guidance in selecting the process conditions.…”

Abrasive jet micro-machining of planar areas and transitional slopes in glass using target oscillation

“…The normalizing factor for t then becomes the time to erode the surface at x = 0 to the depth equal to the characteristic length. Ghobeity et al (2008) presented two methods to measure E * (x * ) for masked and unmasked samples, while Ghobeity et al (2007b) used a computer simulation to track the scattering and impact locations of virtual erodent particles to estimate E * (x * ) for masked samples. The two methods presented in Fig.…”