Researchers Use Ergonomic Risk Assessment Tool to Study the Effects of Line Speed on Deboning Techniques and Yield

 

Research Intern Alex Baudin shows the Ergonomic Work Assessment System (EWAS), which consists of a “backpack” that captures the ergonomic factors of muscle exertion, posture, and repetition while a worker performs cuts on a poultry deboning line. EWAS is being used in studies to determine the effects of line speed on deboning techniques and yield.

Deboning lines are one of the more labor-intensive operations in poultry processing. Workers must perform constant repetitive movements at line speeds averaging 35-40 birds per minute. As consumer demand for deboned poultry products continues to increase, many believe processing plants will have to increase line speeds to meet that demand. The question, however, is will such increases affect deboning accuracy amounting to a decrease in yield?

“In the 1970s, the average line speed of a poultry deboning line was 28 birds per minute. Today, these lines run at speeds of up to 40 birds per minute, and deboners have to meet these demands. It is assumed that as the line speed increases, the accuracy of the deboner decreases, which could lead to a decrease in yield,” explains Sim Harbert, a research engineer at the Georgia Tech Research Institute (GTRI).

To help the industry assess that assumption, Harbert and a group of fellow GTRI engineers have built an Ergonomic Work Assessment System (EWAS) using commercially available technologies (Measurand ShapeTape, goniometer, and EMGs) to investigate various deboning techniques and the impact that line speed has on both yield and ergonomics.

EWAS consists of a “backpack” that captures upper back motion and contains a data acquisition and wireless relay mechanism. It also captures arm kinematics, wrist motion with an integrated dual-axis goniometer, muscle activation of three muscle groups using electromyography (EMG) sensors, and a specially instrumented knife (developed by the Liberty Mutual Research Institute for Safety) for measuring  grip strength.

Tests using the EWAS were recently conducted with four volunteer participants who are actual deboners at local poultry processing plants. A laboratory-scale cone line was set up in a temperature-controlled cold room (40°F) at GTRI’s Food Processing Technology Building. The deboners performed left shoulder cuts at randomly set line speeds of 25, 30, 35, and 40 birds per minute spaced 2 feet apart. A total of 50 cuts per line speed per deboner were made, after which the breast meat was removed and yield was measured using standard industry practices.

Initial results suggest that there were no significant differences between line speed and yield. In addition, the results suggest that yield loss is independent of the size of the birds. Researchers are still analyzing whether there is a change in deboning technique (based on collected biomechanics data) as the line speed increases.

“These tests integrate one variable that is particularly interesting to industry, namely, yield. Analysis of the preliminary data indicates that yield is not closely tied to line speed. While this result is interesting, more data needs to be collected to be able to draw more meaningful conclusions,” says Harbert.

Researchers are currently seeking an industry partner to conduct in-plant tests.