Automatic macadamia nut cracker machine

摘要

This research is to design and build an automatic macadamia nut cracker. The study has two parts: Part 1 involved examining the physical properties of 250 macadamia nuts found that wet standard humidity 12.61%. The mean values ​​and standard deviations for width, length, thickness, and weight were 24.16 ± 1.76 mm, 25.00 ± 1.91 mm, 23.95 ± 1.89 mm, and 7.72 ± 1.66 g, respectively; for the kernels, the corresponding values ​​were 18.99 ± 4.04 mm, 19.86 ± 1.72 mm, 16.05 ± 1.57 mm, and 2.84 ± 0.71 g. The shell hardness was 2,092 N. Part 2 involved the design, assemble, performance testing of the prototype, which consists of three sections. (1) A raw material intake section with a 3 kg capacity that continuously feeds material into the cracking mechanism. (2) A cracking section comprising a cracking head and an impact point. (3) An exit section. The operation begins as macadamia nuts flow from the intake section into the impact receiver's socket. A cracking head strikes the nuts at the uppermost position, driven by a Geneva mechanism synchronized with the movement cycle, causing the shells to fracture before the nuts flow toward the exit section. Statistical analysis at a significance level of 0.05 revealed no significant difference in the percentage of whole kernels obtained across the three cracking speeds or between small and large macadamia nuts (66.07% and 66.83%, respectively); however, a difference was observed for medium-sized macadamia nuts, which yielded a whole-kernel percentage of 53.76%. Cracking capacity was directly proportional to macadamia size and cracking speed; large macadamias achieved maximum capacities of 7.86 ± 0.10, 11.50 ± 0.06, and 15.33 ± 0.35 kg/h at speeds of 2, 3, and 4 rpm, respectively. Economic analysis revealed a break-even sales volume of 13.59 kg for whole kernels, corresponding to a payback period of 16 days.