New model for the prediction of the machining depth during milling of 3D woven composite using abrasive waterjet process

Abstract

The goal is to study the influence of abrasive water jet (AWJ) machining parameters (jet pressure, traverse speed and scan step) on the cutting depth of 3D woven Carbon Fibres Reinforced Polymer (CFRP) composite. The original material linked to this non-conventional milling process has not been treated yet. The depths of cut were measured and characterized as a function of the machining parameters. Finally, two prediction models for the cutting depth are proposed and validated experimentally. An increase in cutting depth with the pressure and a decrease as the traverse speed and/or the scan step increase were observed. The first prediction model, based on the pocket depth measurements, has a mean error of 5%. However, the error increases (up to 23%) when the pocket becomes shallow (lesser than 1 mm). The second prediction model, based on the algebraic sum of elementary passes modelled with Gaussian bells, shows at first a mean error of 12%. A correction was performed depending on the erosion regime piloted by the depth of the elementary trench constitutive of the pocket. This enhancement, performed thanks to the primary jet diameters measurements with high speed camera, has improved the second model with a mean error of 5% (error < 16%).

A Comparative Study of Efficient Modeling Approaches for Performing Controlled-Depth Abrasive Waterjet Pocket Milling

“…As was aforementioned, the first model is based on the concept of elementary passes and kerf superposition, emphasizing the geometric representation of the pocket [21]. In this model, a Gaussian shaped curve is assumed to represent the incision profile of the kerf produced by a single straight pass of the jet, and then the elementary passes that are overlapped in the lateral direction are summed, creating the final shape of the cross-section of the pocket [21,33]. Although various authors consider different number of parameters for this model, in the present work, the term before the exponential (termed A) and another term in the exponential expression (termed B) are only considered for the sake of simplicity.…”

“…This model was also later successfully employed in challenging cases in order to determine the appropriate strategy for machining corners of the pockets [31] or to identify abrasion and erosion mechanisms [32]. Finally, Sourd et al [33] compared the use of a Gaussian model of elementary passes and a power law model during both slot and pocket milling of composite materials by AWJ. It was shown that the former helped the procedure of identification of erosion regimes and an appropriate correction was applied in order to improve its limitations in some cases and achieve sufficient accuracy.…”

Influence of abrasive water jet parameters on the surface integrity of Inconel 718

“…Several studies have proposed analytical models for the prediction of the milled pocket depth when machining composite materials and titanium alloys material [26,27]. In fact, the model proposed here for milling IN718 in function of the process parameters of the AWJ (pressure, traverse speed and step-over distance), is based on the equation ( 1) from previous literature work [26] related to the machining of composite materials or titanium alloys.…”

Research trends and future perspective in nonconventional machining of fiber-reinforced polymers: a review

“…In case of drilling, the laminate of the bottom surface was subjected to bending force; therefore, chips were generated. Sourd et al proposed two models of the depth of cut in AWJ milling of CFRPs by using pocket depth measurements and the algebraic sum of elementary passes [120].…”