Dairy processing creates a difficult working environment for linear motion. Being a perishable item, milk must be controlled and quickly filled into its container, packaged and shipped out for consumption. Also, since milk spoils in an open environment, periodic washdown and cleaning of the packaging area is required to ensure no contamination enters the finished product. The daily periodic washdown process caused a packaging manufacturer to seek out a new linear motion system after experiencing repeating downtime and machine failure on their milk carton caser equipment.
Background: The milk carton caser machine initially was operating using linear ball bearing and 440 grade stainless steel shafting to assembly the milk cartons into a case. Over time, the shafting would oxidize as a result of the cleaning solvents frequently used to rinse the machine during the washdown process. This caused the linear bearings to fail, and was accelerated by the overhung load of the casing equipment.
Problem: The cleaning solvents in the washdown process oxidized the 440 grade stainless steel shafting – causing rust. While the 440 grade series does provide some protection against corrosion, it is partly composed of carbon to make the shafting harder and more durable. Therefore, over time and repeated exposure to chlorides in the cleaning solution, it will oxidize. As rusting progresses, the linear ball bearings performance is further reduced, eventually leading to total machine failure for the carton caser.
Solution: To reduce machine downtime and preventative maintenance, PBC Linear recommended retrofitting 316 grade stainless steel Simplicity® linear plain bearings as well as 316 grade stainless steel shafting. Simplicity plain bearings technology is self-lubricating, requiring little to no lubrication or maintenance upkeep. Equipped with a Frelon® J liner, Simplicity bearings are designed for chemical and corrosion resistance. The outer bearing shell and shafting’s 316 stainless steel composition does not contain carbon, meaning it will not corrode in a washdown environment, providing extended life for the milk carton caser.
Results: After the Simplicity bearings and shafting were installed, unplanned machine downtime was eliminated and the manufacturer reported no problems in further performance or operation.