Mechatronic design of high-speed packaging machinery

Packaging products in corrugated containers revolutionised the food and retail industry. Corrugated case manufacture is high volume, high speed, high product variation, and has low unit cost. This places huge demands on the design of the casemaking machinery.

This research has tackled manufacturing problems in case manufacture to improve quality with poorer quality (recycled) board, and to increase production speeds.

A consumer survey of end users found deficiency in case squareness. Unsquare cases jam automatic case erectors halting production lines. The cause is case panels being skewed during folding. This problem is commonly known as "fish-tailing".

Experimentation and high speed video studies proved this but also pointed at poor squaring after folding. Research to date on folding has failed to prevent fish-tailing so a new squarer was invented to address this problem.

Mechatronics was used to design an in-line squarer and a half-size rig was built. All electronic, mechanical and software design aspects were integrated from the beginning.

The squarer squares each case individually after folding whilst they travel through the machine. The flattened case is held square by four lugs, one at each corner, each mounted on a belt. The lugs squeeze the case square and a glue joint is formed. This is achieved using quick and accurate servomotors, and sensory integration and feedback control for lug positioning and tactile sensing on lugs as they squeeze cases. All this is controlled by a single programmable controller. This fast, flexible squarer can produce perfectly square cases despite variations in board size and quality. The operation of the machine was studied using high speed video.