10.5061/DRYAD.6S48N
Bilbao-Guillerna, Aitor
University of Nottingham
Axinte, Dragos A.
University of Nottingham
Billingham, John
University of Nottingham
Cadot, Guillaume B.J.
University of Nottingham
Cadot, G. B. J.
University of Nottingham
Data from: Waterjet and laser etching: the nonlinear inverse problem
Dryad
dataset
2017
freeform etching
inverse problem
adjoint problems
2017-06-22T18:54:11Z
2017-06-22T18:54:11Z
en
https://doi.org/10.1098/rsos.161031
536339741 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
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.
RSOS PaperCompressed archive of all the Figures in the paper, the
measurement data used to generate them and the beam path data files used
in the experiments.