An approach for using iterative learning for controlling the jet penetration depth in abrasive waterjet milling

Rabani, Amir; Madariaga, J. A.; Bouvier, Carl; Axinte, Dragoş

doi:10.1016/j.jmapro.2016.01.014

Cited by 40 publications

(23 citation statements)

References 30 publications

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“…We began by calculating non-straight trajectories for WJM. However, during the experimental tests it was found that the dynamics of the machine had a significant influence on the actual movement of the jet for these non-straight trajectories and the compensation techniques described in [ 25 , 28 ] for straight trajectories were ineffective. For this reason, just the values of the feed speed were optimized for these experiments and the jet performed straight passes in the x -direction.…”

Section: Resultsmentioning

confidence: 99%

“…The first experiment consists of etching the target surface defined in figure 8 . For this surface, the dynamics of the machine for one-dimensional trajectories can be accounted for using the technique described in [ 25 , 28 ]. The jet is moved using the proposed raster path method in the x -direction with the distance between two consecutive passes 0.2 mm.…”

Section: Resultsmentioning

confidence: 99%

“…The main reason is to avoid the influence of the dynamics of the machine. Although the dynamics can easily be compensated for ramps or simple trajectories [ 25 , 28 ], this compensation is very difficult when more complex trajectories are needed and the parameters of the controller are unknown. One possible strategy is to reduce the range of the feed speed so the values of the acceleration and jerk in the movement can be performed by the actual controller.…”

Section: Resultsmentioning

confidence: 99%

“…However, sometimes these parameters are not known or cannot be changed. Then, a simple solution can be applied to compensate this effect on the selection of the slope of a step profile [ 28 ]. When the dynamics of the machine cannot be identified and compensated, the approach presented here can still be used if the target surface is selected in such a way that high-frequency components are avoided [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

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Waterjet and laser etching: the nonlinear inverse problem

et al. 2017

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In waterjet and laser milling, material is removed from a solid surface in a succession of layers to create a new shape, in a depth-controlled manner. The inverse problem consists of defining the control parameters, in particular, the two-dimensional beam path, to arrive at a prescribed freeform surface. Waterjet milling (WJM) and pulsed laser ablation (PLA) are studied in this paper, since a generic nonlinear material removal model is appropriate for both of these processes. The inverse problem is usually solved for this kind of process by simply controlling dwell time in proportion to the required depth of milling at a sequence of pixels on the surface. However, this approach is only valid when shallow surfaces are etched, since it does not take into account either the footprint of the beam or its overlapping on successive passes. A discrete adjoint algorithm is proposed in this paper to improve the solution. Nonlinear effects and non-straight passes are included in the optimization, while the calculation of the Jacobian matrix does not require large computation times. Several tests are performed to validate the proposed method and the results show that tracking error is reduced typically by a factor of two in comparison to the pixel-by-pixel approach and the classical raster path strategy with straight passes. The tracking error can be as low as 2–5% and 1–2% for WJM and PLA, respectively, depending on the complexity of the target surface.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Waterjet and laser etching: the nonlinear inverse problem

et al. 2017

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“…AWJ is applied in many manufacturing processes. Classical machining technics like cutting and milling are studied, e.g., by Axinte et al [ 2 ] or Rabani et al [ 3 ]. Turning is one of the unusual machining processes and it was studied by Zohourkari et al [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Influence of Material Structure on Forces Measured during Abrasive Waterjet (AWJ) Machining

et al. 2020

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Material structure is one of the important factors influencing abrasive waterjet (AWJ) machining efficiency and quality. The force measurements were performed on samples prepared from two very similar steels with different thicknesses and heat treatment. The samples were austenitized at 850 °C, quenched in polymer and tempered at various temperatures between 20 °C and 640 °C. The resulting states of material substantially differed in strength and hardness. Therefore, samples prepared from these material states are ideal for testing of material response to AWJ. The force measurements were chosen to test the possible influence of material structure on the material response to the AWJ impact. The results show that differences in material structure and respective material properties influence the limit traverse speed. The cutting to deformation force ratio seems to be a function of relative traverse speed independently on material structure.

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