OPTIMIZATION OF WOOD SURFACE ROUGHNESS THROUGH ANALYSIS OF CNC ROUTER MACHINE PARAMETERS IN THE ENGRAVING PROCESS

Abstract

This study investigates the influence of CNC router machine parameters on wood surface roughness during engraving operations. Surface roughness directly affects paint adhesion, appearance, and quality of finished wood products. The main problem is that current machining practices use the same parameters for all wood types, leading to inconsistent surface quality. The objective is to find optimal cutting parameters for different wood species using the Taguchi method. Three wood types were tested: Merbau (hardwood), Pine (softwood), and Plywood (manufactured wood). The experiment used a CNC Router Z2-1325 with three parameters at three levels each: spindle speed (5,000-10,000 rpm), feed rate (100-300 mm/min), and depth of cut (3-9 mm). The Taguchi L9 orthogonal array design was used, requiring only nine experimental runs. Surface roughness was measured using a Mitutoyo Surftest SJ-210 portable tester. Results showed that different wood types require different optimal parameters. Merbau achieved the best surface finish (Ra = 2.093 μm) with 8,000 RPM spindle speed, 200 mm/min feed rate, and 9 mm depth of cut. Pine performed best (Ra = 4.318 μm) at 8,000 rpm, 100 mm/min, and 3 mm depth. Plywood achieved Ra = 2.093 μm at 8,000 rpm, 200 mm/min, and 6 mm depth. Statistical analysis showed that depth of cut was most important for Pine (p = 0.014), while 8,000 rpm was consistently optimal across all wood types. The optimization approach improved surface quality by 20-35% compared to standard practices. This study provides the systematic comparison of CNC machining parameters across hardwood, softwood, and manufactured wood categories. The findings give manufacturers practical guidelines for achieving better surface quality while reducing costs in wood processing industries. The Taguchi method proved effective for optimizing multiple parameters simultaneously with minimal experimental effort.