Abstract:
Natural fiber reinforced composites (NFRCs) offers promising applications in the automotive
industry, particularly for interior components. However, the inherent heterogeneous and
abrasive nature of NFRCs presents significant challenges during the machining process,
especially drilling, leading to defects such as roundness error and delamination of fibers.
These drilling defects can hinder the practical use of NFRCs. To address these challenges,
this study focuses on the optimization of machining parameters for drilling hybrid sisal bamboo fiber reinforced epoxy composites filled with bagasse ash. The mechanical
properties characterization, including tensile, flexural, and impact strength tests, as well as
water absorption tests, were conducted on three compositions to determine the most suitable
hybrid composite for automobile interior applications. A series of drilling experiments were
carried out using the L16 orthogonal array, varying spindle speed, feed rate, and drill
diameter. The delamination factor and roundness error were measured using a digital
camera, ImageJ software, and a digital caliper. The experimental results were analyzed
using the Taguchi and Taguchi-GRA methods, and the optimum machining parameters were
determined as a spindle speed, feed rate and drill diameter of 1750 rpm, 10 mm/min, and 6
mm respectively. Among the three composites investigated, Composite three(C3) exhibited
the best properties, with tensile strength flexural strength, impact strength, and water
absorption rate of 66.22MPa, 272.44MPa, of 4.777kJ/m, and 3.27% respectively.
Verification tests confirmed the reliability of optimum parameters, with roundness error of
0.03 mm and delamination factor of 1.082. The findings of the study will contribute to
improving the drilled hole quality in the drilling of NFRCs, which is crucial for the practical
use of these particular NFRCs in the manufacturing of automobile interior parts.
