The purpose of this paper is to investigate the physical and mechanical characteristics of the roasted cashew nut during fracture, by subjecting the nut to varying impact load tests at different orientations to ascertain the critical impact load that fractures the shell without damaging the kernel within. This load value was correlated with other parameters; shell/kernel moisture content level, average nut mass, to determine the required projection velocity to achieve this force. This projection velocity is the critical factor in sizing and design of the optimum configurations of the shelling impeller.
Mechanical properties of roasted cashew nut were first determined to know their fracture points. Each component of the shelling machine was designed. The components were assembled and the machine was tested for performance.
Machine throughput capacity was determined as 15.57 kg/h; shelling efficiency was 95 per cent; and whole kernel recovery was 70 per cent.
The efficiency in terms of whole kernel recovery could be improved by improving the pretreatment measures on the nuts.
The paper presents a machine which is affordable to peasant farmers and requires little or no training for operation and maintenance. The advantage of reduced unit cost can be derived from large‐scale commercial production of this sheller.
