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Troubleshooting - Inconsistency on Automatic Bottle Cappers

Automatic capping machines are a part of almost every packaging system, given that almost all products, and especially liquids, need to be sealed to protect and contain the product. While a number of different automatic capping machines exist, there are some common issues that could result in inconsistent tightening or sealing.

Cap Delivery Systems

Most automatic capping machines will use a cap delivery system that consists of a vibratory bowl, elevator, chute or some combination of all of these. Inconsistent performance by an automatic capper can stem from the delivery of the caps rather than the capping machine itself. Closures must present to the bottle in a fashion that allows them to be not only easily stripped at one per container, but also in a manner that will not cause cross-threading, tilted or loose caps or even completely missed caps. While not a lot of adjustment should be necessary for cap delivery systems once installed, operators can check the positioning of the delivery on the conveyor as well as the position of the caps as they are presented. However, depending on the type of capping machine, even slight adjustments to cap delivery systems can significantly affect performance, so it is often better to check other areas first as well as consult with the machine manufacturer before making adjustments if this cause is suspected.

Bottle Stability

Once caps are presented to the container, the container must be stabilized throughout the capping process to ensure consistent, reliable seals. For instance, the tightening disks on a spindle capper must make contact with the cap at a precise spot to ensure that caps are repeatedly tightened in the same manner. Spindle cappers employ gripper belts for bottles as well as stabilizer bars for caps to keep the bottle and cap combination secure throughout the process. Different capping machines may utilize different manners of stabilizing bottles and caps, but when inconsistent capping occurs, an operator should also check the stabilizing components of the machine to ensure they are positioned correctly. Again, adjustments will depend on the type of capper being used, but such adjustments will typically require no more than turning a knob or hand crank to tighten or loosen belts, rails or other components.

Wear Parts

Some component of a capping machine will usually touch the cap or other closure to secure it to the container. In many cases, such parts are what are called wear parts. The belts and disks of the spindle capping machine mentioned above contact the bottle and cap, respectively. Over time, both of these items will wear away from repeated use, necessitating replacement. The cause of inconsistent capping can be as simple as excessive wear from the long term use of the wear parts. An operator experiencing inconsistent capping should also check any wear parts on the machine and replace those that show significant wear. Keeping additional wear parts on hand not only allows for quick replacement but also gives the operator a point of comparison when evaluating the amount of wear on the parts being used.


While by no means an exhaustive list of possible issues, the areas listed above will be the source for most instances of inconsistent capping. As with all LPS packaging machinery, technicians are available to help identify and resolve capping issues should they occur. To speak with an LPS Packaging Specialist, simply call Toll Free at 1-888-393-3693 and ask for the Technical Service Department.