Bandknife shearing of wool fibres
Thesis DisciplineMechanical Engineering
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
The separation of the wool and the skin is an important step in the processing of lamb and sheepskins in New Zealand Freezing Works. The chemical depilatory process used at present has a number of disadvantages. It has been calculated that substantial benefits to the freezing industry would accrue if this process was replaced by a mechanical wool removal system, which left a short stubble of wool on the skin. Initial investigations indicated the suitability of a continuous bandknife machine for cutting the wool. This thesis describes the investigation of both the cutting and skin handling processes, the building of experimental machines, and the testing and development proceeding from this. Model and small scale machines were built to investigate proposed systems, and two full size experimental machines were constructed. These machines were developed to the stage where reliable cutting was achieved. Although the length of stubble remained uneconomically long, it was considered that further development could overcome this. The cutting process was investigated by means of miniature, single fibre cutting machines. The technique of using high speed photography to record the brief cutting event while observing the fibre through a microscope was developed.