Application of circular interpolation in processing the contours of agricultural products of hard shell seeds (Macadamia Nuts type)

Abstract

When processing hard-shelled agricultural products in the form of nuts with high nutritional value similar to macadamia nuts, breaking the hard shell without affecting the quality of the kernel is a difficult problem to solve. Some processing methods with high rates of productivity such as hammering or crushing have been used to break the hard shell. These are popular processing methods today. However, these methods cause high rates of nut fragmentation, which results in reduced product value and increased screening costs. This study proposes the use of disk-type sawing machining principles to cut the hard shell. Macadamia nuts have the highest shell hardness in the group. Based on the form of the hard shell, this study also proposes a digitalization for the cutting process through the application of a standard industrial numerical controller (Computer Numerical Control - CNC) with the circular interpolator G02/G03. In the proposed case, the parameters of the circular interpolator will have different meanings than those of traditional CNC machines. The relationships between the parameters of the circular interpolator with important geometric parameters of the hard shell and cutting tool diameter are also analyzed in detail. The result shows that these relationships are depending on the cutting tool diameter, hard shell diameter, arc to be cut on the shell body, and depth of cut (hard shell thickness). Additionally, the digitization of the cutting process is possible for automation and monitoring in the future.