The Effect of CNC Machining Parameters on the Surface Roughness of Lake Paint Applied to MDF Surfaces

Aim of study: The objective is to determine the effect of CNC surface machining parameters on the surface roughness (Ra and Rz) of lake paint applied to MDF surfaces. Material and method: The test specimens were machined on a CNC machine using three different spindle speeds (10.000, 15.000, and 20.000 rpm), four different feed rates (1.500, 2.000, 3.000, and 5.000 mm/min), three different depth of cut (3, 5, and 8 mm), and two different tool diameters (5 and 8 mm) were machined on a CNC machine. A polyurethane primer and two cross-coats of lake paint topcoat were applied to the machined surfaces. After painting, surface roughness was measured using a stylus-based surface roughness meter, with Ra and Rz parameters. Main results: The results showed that spindle speed, feed rate, depth of cut, and tool diameter significantly affected the Ra value, while spindle speed and feed rate were the determining factors for the Rz value. While the lowest surface roughness values were obtained at a spindle speed of 20.000 rpm, the combination of a feed rate of 5.000 mm/min, a depth of cut of 8 mm, and a tool diameter of 5 mm yielded lower Ra and Rz values on MDF surfaces coated with lake paint. Furthermore, it was determined that a significant portion of the interactions among the machining parameters were statistically significant and that the combinations of these parameters influenced the final surface quality. Research highlights: This study contributes to the literature by evaluating the effect of CNC machining parameters on the final surface coated with lake paint, rather than on the machined MDF surface. The findings provide important scientific and practical data to optimize CNC machining parameters prior to painting in the furniture industry, improve surface quality, and develop more efficient production processes.