You probably use them every day, but haven’t given them much thought. They package your food, contain your garbage, and protect your purchases from the rain. Plastic bags are ubiquitous in our society, yet few ever wonder how they are made, and what is important to keeping up production of a steady supply of these crinkly wonders. Plastic bags are manufactured by machines, and the plastic bag machine spare part industry is critical to keeping the plastic bag supply chain flowing.
The common shopping bag is made of polyethylene. High density polyethylene (HDPE) is used for the thinner translucent plastic shopping bags you get at grocery stores, and low density polyethylene (LDPE) is used for the opaque plastic bags you get at clothing and department stores. HDPE or LDPE, the process for making the bags is essentially the same. To start, solid pellets of the appropriate polymer are melted, mixed, and then extruded into a long tube of plastic. The tube is cooled and then flattened by rollers in the plastic bag machine, and the flattened tube is spun into a large roll. One roll can produce up to 25,000 plastic bags. This master roll can then be transferred to different machines to be printed with text and images and cut to different widths and lengths, sometimes with a cut-out handle included, creating different bag sizes and styles for different customers. The bags are bound together and packaged for shipping, and from there they are ready for distribution.
All this polyethylene manipulation is done by machines with many moving parts. As is best practice with any complicated equipment, bag manufacturers keep a plastic bag macine spare part collection on hand at all times to minimize manufacturing down time and profit loss. Original equipment manufacturer (OEM) parts can be expensive, however, so high quality aftermarket replacement parts are in high demand. Aftermarket replacement parts manufacturers work from the OEM part specifications when designing their parts, many including a warrantee and a guarantee of quality with the purchase of their parts. Rollers, gears, washers, seals, and lubricants can all be purchased as aftermarket products styled after specific brand name parts, for a significant savings over OEM.
So the next time you reach for a plastic bag in the check-out line but there aren’t any available because of a supply issue with the manufacturer, think to yourself “someone must not have had the right plastic bag machine spare part handy to handle the machine breakdown!” Be sure to have a list of plastic bag spare part vendors on hand for bag machine breakdowns.