Improvement of the mold supporting tray in food skewer processing using finite element analysis

Abstract

Food skewers are an important export product from Thailand. A supplier can receive orders as high as three hundred thousand sticks per month. Skewer machines play a crucial role in fulfilling these orders. Data from the past three months shows that the most frequent production interruption is due to the mold part being pulled away from the mold supporting tray. As a result, the production line must be stopped to reposition the mold. The root cause of the problem was identified as the excessive deflection of the mold supporting tray under compressive force. In this work, Finite Element Analysis (FEA) was used to study the deflection of the mold supporting tray. The objective was to improve the tray to reduce its deflection. Three new designs were created by modifying the current tray. A compressive force of 630 Newton was applied to the mold to produce a compression load on the mold supporting tray. The deflection was then predicted using FEA. The deflection predicted is 16.48% less than experimental results. The deflection of the current tray was predicted to be 0.2777 mm, while the best alternative design had a deflection of 0.2450 mm. As the new design can decrease the deflection by 11.78%, it was then fabricated for experimental validation.For tray stiffness, the FEA result is 20.51% higher than experimental results. Despite these differences, the experiment agrees well with the FEA that the new tray design can reduce deflection and, consequently, reduce the mold’s pull-away problem.