A bearing exists for every linear motion application. The trick is to pick the right bearing. For one brewery, the previous choice of linear rollers and ball bushings in a cantilevered arm palletizing system led to too much downtime. The right choice, of cam rollers and pillow block housings, helped keep beer flowing. 
Once beer is brewed and poured into cans, an automated cantilevered arm palletizing system stacks the full cans onto pallets and positions pallets of empty cans to the filling station. The forward movement of the cantilevered arm is propelled by a cam roller and linear bearing system that allows the arm to cycle through the pallet stack, feed the cans through the filling station, and remove any plastic interleave material from the stock. This linear motion application required a tolerance for high shock load and vibration under constant reciprocating stroke in order for the palletizer to operate efficiently.
The original linear motion components– linear rollers and ball bushings—could not handle the high shock loads and vibration. The components underwent severe fretting corrosion, and the cantilevered weight would wear the ball bushings and spall the shafting—creating accumulated particulate. These fine metal shavings would build-up within the ball bushing housing, causing the arm to stall and bringing the whole palletizing process to a grinding halt. Replacing the parts and stopping the production process increased production costs and time, and decreased profits.
PBC Linear recommended Redi-Rail® cam rollers and Simplicity® pillow block housings. The smooth, sturdy anodized rails of Redi-Rail® provided rigid linear guidance of the palletizer. Steel inserts along the rail ensured tolerance of vibration and load—allowing the rollers to glide smoothly, quickly and accurately.
Plane bearing pillow blocks replaced the ball bushings. Composed of no rolling materials, Simplicity® products delivered even disbursement of load. This wide point of contact eliminated damage to the shafting and ensured smooth, wear-free operation. These products also absorb vibration, and can handle 20 times the load capacity of conventional ball bushings and push potential contaminants off the shafting.
Coincidentally, Redi-Rail’s mounting holes were perfectly lined up with the previous ones, making the replacement easy. Unscheduled shut downs and stalling were eliminated; allowing more cans to be filled.
PBC Linear
RST.pbclinear.com
::Design World::
Filed Under: Factory automation, Bearings, LINEAR MOTION, Motion control • motor controls