Objective assessment of knife sharpness over a working day cutting meat.

Knife sharpness is one of multiple factors involved in musculoskeletal disorders in industrial meat cutting. The aim of this study was to objectively evaluate, in real working situations, how knife sharpness changed over a working day cutting meat, and to analyse the impact of sharpening, steeling and meat-cutting activities on these variations. Twenty-two meat-cutting workers from three different companies participated in the study. The methods included measurements of knife sharpness in relation to real work situations and consideration of the way meat-cutting and sharpening operations were organised. Results showed that the type of meat-cutting activities, the steeling strategy adopted by the worker, including the types of tool used, and the overall organisation of the sharpening task all had a significant influence on how knife sharpness evolved over a 2-h period and over an entire working day. To improve MSD prevention, sharpening and steeling operations should not be considered as independent activities, but taken into account as a continuity of working actions. Appropriate assessment of knife sharpness by meat cutters affects how they organise meat-cutting and sharpening tasks.

Assessment of knife sharpness by means of a cutting force measuring system.

Following a brief description of the problem of musculoskeletal disorders (MSDs) in the meat industry and use of knives, this paper presents a study of the influence of the main intrinsic technical characteristics of a knife on its cutting performance. This study prompted design of a specific system for measuring initial cutting capacity and cutting edge retention. This design process preceded research into test conditions (cutting speed, sample nature and thickness, knife inclination angle, etc.) offering optimum test bench operation. This equipment was then used to study the influence of blade inclination angle, steel grade and sharpening angle on cutting performance. It has been shown that cutting force varies with blade inclination. Use of knives with curved blades and/or a blade inclined with respect to the knife handle is therefore preferred in relation to our cutting force reduction objective. It has also been shown that choices are in fact governed by compromises in relation to other parameters (steel grade and edge angle). These observations confirm the need to set up suitable training of knife users to achieve best possible cutting performance.