Adjustment of Mill CNC Parameters to Optimize Cutting Operation and Surface Quality on Acrylic Sheet Machining

Abstract

Acrylic is easy to machine. In addition to the advantages derived from the use of mill Computer Numerical Control (CNC) machine on acrylic sheet, there are at least two serious problems that need attention especially in cutting a small part with many vertices. These problems are the presence of excessive heat due to friction between the cutting tool with acrylic sheet on high RPM of spindle rotation, and soft acrylic flakes trapped in crevices of the cutting tools’flute.Generally, the cutting process using a mill CNC machine often is a practice of trial and error. At least nine basic technical parameters need to be optimized. The effectiveness of the parameter values are determined by observing and measuring the actual cutting time using mill CNC machine at given parameter settings, surface texture quality, the level of clarity of the cuts, characteristics of chip formation, and edge roughness.The experimental results showed that the adhesion of acrylic sheet and cutting tools is relatively low. However, the heat of cutting tool due to high spindle rotation, low feed rate, and relatively low melting point of acrylic, tend to form very small, soft, and hot flakes. The acrylic chips have great potential entering the crevices of cutting tools’ flutes, and reducing the cutting power significantly. In other condition, the cutting tool could even be broken if feed rate is too high. Some technical values of these parameters are recommended to obtain optimal CNC based cutting operation and surface quality on acrylic sheet.