Keeping motion control under control is a machine design consideration but one that has direct implications for packagers. A case in point is a Schneider Packaging Equipment (Brewerton NY) wraparound case packer installed in early 2000 at Jersey Juice Ewing NJ. The machine’s design reflects Schneider’s use of servo-motor-powered timing belts to automatically load products with advanced pick-and-place capability.
Schneider’s 5WR (five-panel wraparound) case packer loads 4-oz portion cups of shelf-stable juice one 16-cup layer at a time onto a corrugated blank. The cups are loaded simultaneously at three stations by a trio of 4x4 vacuum pick-and-place heads. Each vacuum cup grips a portion cup. The first head delivers the bottom row the case blank indexes and the second layer is placed then the case blank indexes again and the third layer is placed yielding a 3-layer 48-count pack.
At 330+ cups/min
As of early February ’01 Jersey Juice reported it was operating the case packer at a rate of 330 cups/min. However plant manager Ken Caldaro feels they could reach a speed of 700 cups/min as filling capacity is increased.
The accumulation of product and loading process is both custom and unique. Air cylinders provide the vertical motion to the three pick-and-place heads mounted on a single carriage. The reciprocating horizontal pick-and-place motion is closely synchronized with the intermittent vertical motions the latter of which is triggered when the carriage reaches its end position (see “Tech talk” sidebar). It was vitally important that the start and stop positioning of the pick-and-place carriage be precise accurate and repeatable.
Jersey Juice feels that it is. Caldaro tells Packaging World “The pick-and-place accuracy is dead-on.”
Key to such accuracy was the use of a Zero-Max (Plymouth MN) CD Double Flex Coupling. The coupling transfers the rotary motion of the servo motor into the linear motion required for the horizontal back-and-forth movement of the pick-and-place carriage. The 2 hp Allen-Bradley servo motor from Rockwell Automation (Milwaukee WI) operates at speeds to 4 rpm and has a maximum torque of 31’’/lb with linear speeds to 4’/sec. There are two other Allen-Bradley servo motors and drives on the machine.
If the coupling is too flexible the pick-and-place mechanism accuracy is lost. Too rigid and the system is damaged. The Double Flex coupling hits the center of the target.
“The coupling is very durable requires no maintenance and is washdown-resistant” notes Stan Johnson Schneider vice president of engineering.
Caldaro says the new case packer equipped with hot melt glue system touchscreen visual display and PLC controls provides improved overall efficiency reliability and output compared to Jersey Juice’s previous wraparound packer.
“It’s a very smart machine” Caldaro sums. (RL)