Today’s consumer packaged goods (CPG) market is driving the need for greater agility and flexibility in packaging machinery. Shorter, more customized runs create more frequent machine changeover. Consequently, reducing planned and unplanned downtime at changeover is one of the key challenges CPG companies are working to improve.
Many packaging machine builders are now providing fully automated changeover, where motors move pieces into the correct position upon recipe change. This has proven to be a winning solution, however, not every application can accommodate motors, especially those on older machines.
Guided changeover represents an opportunity to modify or retrofit existing equipment to improve agility and flexibility on older machines that are not yet ready to be replaced.
An affordable intermediate step between fully manual and fully automated changeover:
A measurement sensor can be added to provide position feedback on parts that require repositioning for changeover. By using indicator lights, counters or displays at the point of use, the operator is provided with visual guidance to reposition the moving part. Only once all parts are in the correct position can the machine start up and run.
By utilizing this concept, CPG companies can realize several key benefits:
- Reduced planned downtime: Adding guidance reduces the amount of time it takes to move parts into the correct position.
- Reduced unplanned downtime: Providing operator guidance minimizes mistakes, avoiding jams and other problems caused by misalignment.
- Reduced waste: Operators can “dial in” moving parts quickly and precisely. This allows the machine to be fully operational sooner, minimizing runoff and scrap.
- Improved operator training: Providing operator guidance helps CPG companies deal with inevitable workforce attrition. New operators can be quickly trained on changeover procedures.
Selecting the correct sensor
A variety of sensor technologies can be used to create guide changeover; it’s really a matter of fit, form and function. Common technologies used in changeover position applications include linear positioning transducers and encoders. Other devices like inductive and photoelectric distance sensors can be used with some creativity to solve challenging applications.
Available mounting space and environmental conditions should be taken into consideration when selecting the correct device. Sensors with enhanced IP ratings are available for harsh environmental conditions and washdown.
Analog devices are commonly used to retrofit machines with older PLCs, while IO-Link can be used in place of analog for a fully digital solution, enabling bi-directional communication between the sensor and controller for condition monitoring, automatic device replacement and parameter changes.