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The purpose of the study was to investigate factors related to force and postural exposure during a simulated meat cutting task. The hypothesis was that workstation, tool and task variables would affect the dependent kinetic variables of gripping force, cutting moment and the dependent kinematic variables of elbow elevation and wrist angular displacement in the flexion/extension and radial/ulnar deviation planes. To evaluate this hypothesis a 3 x 3 x 2 x 2 x 2 (surface orientation by surface height by blade angle by cut complexity by work pace) within-subject factorial design was conducted with 12 participants. The results indicated that the variables can act and interact to modify the kinematics and kinetics of a cutting task. Participants used greater grip force and cutting moment when working at a pace based on productivity. The interactions of the work surface height and orientation indicated that the use of an adjustable workstation could minimize wrist deviation from neutral and improve shoulder posture during cutting operations. Angling the knife blade also interacted with workstation variables to improve wrist and upper extremity posture, but this benefit must be weighed against the potential for small increases in force exposure.

Knives are used in industry, and particularly on meat packaging assembly lines, where a premium is placed on the speed of cutting. One consequence of this is that knife design and selection has been based on the speed of cutting as the most significant measure of a knife. In industry the cuts that knives make vary in difficulty with many factors such as thickness, contour, and temperature of the material being cut. These factors may change the speed with which these cuts are made. According to Taguchi's methods, a robust design is one that maintains high performance while remaining insensitive to changes in its environment. This means that a robust knife design would enable an employee to cut not only with as much speed as possible in one particular cutting scenario, but also with a consistently high speed in as many cutting scenarios as possible. An experiment with various knife designs was evaluated with Taguchi's method. Ten subjects cut outlined clay patterns in 15 min with each one of nine different knives. The nine different designs were generated from the following combinations; three grip sizes (44.4, 50.8 and 63.5 mm), three coupling angles between the grip and the blade (0, 45 and 90 degrees), three blade heights measured from the middle of the blade (10, 13 and 15 mm), and three blade lengths (85, 125 and 155 mm). Eight conditions of cutting material were used to generate 'noise'. They are combinations of temperature of the clay to be cut (from temperature (R) approximately 25 degrees C, frozen for 1 h (F) approximately 5 degrees C), thickness of the clay to be cut (15 and 25 mm), and orientation of the work surface (0 and 30 degrees). The result shows that the knife design of 63.5 mm grip size, 0 degree coupling angle, 13 mm blade height, and 85 mm blade length provides the highest number of cuts, the knife design of 50.8 mm grip size, 45 degrees coupling angle, 15 mm blade height, and 85 mm blade length gives the highest signal to noise ratio. The shorter blade (85 mm) is suggested by both designs, but the two designs are different in the other three variables. Further analysis of the noise variables shows that lowering clay temperature significantly reduces cutting speed. Although there is more than one design that can resolve changes in clay thickness and clay orientation, a 15 mm blade height is the only design insensitive to the clay temperature change.