Design, Construction and Performance Evaluation of the Walnut Cracking Machine

The traditional method in Iran of cracking walnut manually, using harmer or knife cutter is labor-intensive, slow and tedious; besides, most mechanical crackers do not give satisfactory results in terms of kernel extraction quality. A prototype machine was developed to crack walnut. A walnut cracker was designed, constructed and tested to evaluate its performance. The cracker, which consists of a hopper fitted with a flow rate control device, a cracking unit, a sorter and power system, operates on the principle of attrition using crushing force from a cylinder and helix. The percentage of whole kernels produced was 66.66 %. The capacity of the machine was estimated to be about 25.2 kg/hr. A device of this nature can be manufactured for small entrepreneurs and industrial-level applications in the developing countries where bulk of the world walnut is produced. This paper describes the design and performance evaluation of the cracker as well as the implication of the results obtained.