Experimental Investigation on Geometric Error …
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2 Experimental Plan and Methodology of Present Work
In the present experimental investigation, influence of dummy sheet thickness (t d ),
step size (z), wall angle (ϕ), and feed rate (f ) on geometric error (in terms of rootmean-squared error) is studied. Table 1 represents the designated process parameters
and their levels. Box behnken design of experiments (BBD) is used to create experimental run order matrix. Totally, 29 experiments were performed. The experimental
setup is depicted in Fig. 2. The experimental investigation was done in the following
order:
1. Selection of sheet material, sheet thickness, and tool material.
2. Identification of major process parameters influencing geometric error.
3. Determination of range and level of identified and finalised process parameters.
4. Selection of appropriate response surface method (RSM) for designing the
experiments.
5. Conducting experiments as per obtained design matrix.
Table 1 Process parameters with their levels
S. No.
Process parameters
Unit
Level 1
Level 2
Level 3
1
Wall angle (ϕ)
degree
40
52.5
65
2
Step size (z)
mm
0.35
0.65
0.95
3
Feed rate (f )
mm/min
2200
3300
4400
4
Dummy sheet thickness (t d )
mm
0.51
0.71
0.91
Fig. 2 Experimental setup for SPIF with dummy sheet