Parametric optimization of laser drilling of microwave-processed kenaf/HDPE composite

Abstract

The present work focused on the investigation of hole quality characteristics in laser-drilled kenaf/high-density polyethylene (HDPE) composites. Microwave-assisted compression molding was used to fabricate kenaf/HDPE composite with 20 wt% of the kenaf fiber reinforcement. The two input parameters pertaining to the experimentation were laser power and cutting speed. Kerf taper angle, heat-affected zone (HAZ), and surface roughness were investigated to evaluate the surface quality and accuracy of the holes generated through laser drilling on composite specimens. The assessment of HAZ was performed qualitatively through image analysis on scanning electron micrographs. Additionally, the effect of composite thickness on laser drilling was also investigated for 3-, 6.7-, and 10-mm composite specimens. The central composite design was used to plan the experiments. The kenaf/HDPE composite drilled at power 120 W and speed 2 mm/s shows a minimum kerf taper angle and surface roughness of 0.056° and 3.83 ± 0.19 µm, respectively. Regression model was obtained for the establishment of relation between input variable parameters and responses. Experimental results and predicted model results exhibited good agreement with each other as they provide error less than 5.35%. The analysis of variance was carried out to obtain the significance of the model chosen for optimization of the output values, that is, surface roughness and kerf taper.

Experimental Analysis of Heat-Affected Zone (HAZ) in Laser Cutting of Sugar Palm Fiber Reinforced Unsaturated Polyester Composites

“…Traverse speed rank came second in terms of effect on the HAZ, and its contribution increased with the thickness of the material. The minimum HAZ was recorded at minimum values of laser power in general, except for the case of 6 mm specimen thickness, where the optimum HAZ was recorded with a medium laser power value, which differs slightly from that recorded at the minimum value of laser power, and this is consistent with the results of the study conducted by Tewari et al [23]. The laser power parameter contributed the least to the influence on the HAZ with no clear proportion with material thickness variation, and this is consistent with what Tamrin et al [22] found.…”

“…Gas pressure provides the highest contribution to the influence on the HAZ, and the minimum HAZ responses are recorded at the higher value of assist gas pressure, which can be explained as an increase in the rate of cooling associated with the increase in gas flow rate due to the increase in its pressure. This result was contrary to what Tamrin et al [ 22 ], Renu Tewari et al [ 23 ], Jose Mathew. [ 30 ], and Dalibor Petković [ 32 ] found, as traverse speed had the most considerable effect on the HAZ in their studies.…”

“…The lowest values of the HAZ were obtained at the minimum values of laser power and the maximum values of traverse speed with minimal contributions of the rest of the input parameters. Renu Tewari et al [ 23 ] applied laser power and traverse speed as input parameters to evaluate the HAZ response of kenaf reinforced high-density polyethylene (HDPE) composite that was drilled with a low-power CO 2 laser. The study covered three different material thicknesses (3, 6.7, and 10 mm).…”

Challenges on machining characteristics of natural fiber-reinforced composites – A review

“…It causes undesirable alterations to the local microstructure and properties of the material adjacent to the cut and burning of the edges of holes in laser drilling. 187,188 The results suggest that the type of assist gas used can have an overall effect upon the quality of the holes. The FRP that had been processed with the CO 2 assist gas showed an improved surface quality.…”

“…Tewari et al. 187 focused on the investigation of the effects of laser power and cutting speed on hole quality characteristics in laser-drilled kenaf/high-density polyethylene composites. The results show that CO 2 laser is capable of drilling natural composite and optimum laser drilling parameters can yield improved quality of the drilled holes.…”