الفهرس 
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Abstract
In this investigation, an experimental study in cylindrical wire EDM
machining parameters is presented for both longitudinal and cross-feed turning
processes. At first, the design of a precise, flexible and corrosion resistant rotary
spindle is introduced. The spindle has been mounted on a conventional four axis
wire EDM machine to provide the workpiece rotation in order to generate free form
cylindrical geometries. Several experiments are conducted to investigate the
influence of six input variables: the depth of cut, gap, workpiece rotational speed,
pulse time-on, wire speed and interval time (factors) on the material removal rate
(MRR) and the average surface roughness (𝑅𝑎) (responses) as indicators of the
efficiency and cost-effectiveness of the process. In this investigation, two techniques
for design of experiments (DOE) were used. Stainless steel k316 is one of the
difficult-to-machine material, was used in this study. The experimental work was
done for longitudinal turning operation by changing one variable and keeping the
others constant to point out the effect of each of these variables on the six control
factors. In the pre-experiment, regression equations interpreting the relationship
between the six input variables and the material removal rate, surface roughness
have been deduced.
An L18 (21×35) Taguchi standard orthogonal array is chosen for the design of
experiments (DOE) for cross-feed turning process due to the number of factors and
their levels in the investigation. Mini tab Software version 16 was used to determine
the main effects of the process parameters. Analysis of variance (ANOVA) was
performed to find the dependent variables that affect the machining characteristics.
Regression analysis is performed to find out the relationship between the different
factors and responses. Signal to noise (S/N) ratio analysis is used to establish the
optimum condition.
Key words
WEDM, CWEDM, MRR, Ra, Taguchi’s L-18 Orthogonal array