Three production lines converge onto a roller conveyor system that feeds the packaging line. Each product is large enough to be packaged in its own large cardboard shipping box, which serves double duty via the box label as the product box (appliances, televisions, and other large products are often packaged this way). The packaging line includes a hot glue boxing machine, a box labeler, and a palletizer (affixes the box to a standard wooden pallet). Several times a week, something goes wrong, and the packaging line shuts down; after several minutes, the production lines that feed it also shut down to avoid a pileup.
To reduce the downtime, where should you look first?
You could begin by looking at the machine that breaks down most often, but because glue machine problems can also cause downstream problems with the labeler and palletizer, start with the glue machine. For example, is glue getting onto the rollers and other parts of machinery? If so, investigate how to adjust the glue temperature, spray pattern, or other attributes (a simple adjustment in the PLC may be the fix). But make sure the glue is applied adequately to hold the boxes together.
Sometimes in an effort to increase production, roller feed rates are sped up. If the conveyor is moving too fast for the packaging equipment to perform properly, the solution is also probably going to be a PLC adjustment.
Make sure you also look at the maintenance procedures. Are they adequate? Are they even being performed?