Integrated Motion Control
Applications
Cartoner with ControlLogix and Ultra3000
Cartoners provide the packaging for a wide variety of consumer products ranging from pet foods to breakfast cereal. Because cartoners provide the packaging for products that are directly received by the consumer, they are usually equipped with additional features such as a code-date printer, leaflet, or coupon inserter. These machines can be grouped into two main categories: vertical cartoners and horizontal cartoners.
As incoming product enters the cartoner machine, it is collated into the appropriate pack pattern. A flat case is then selected from the case magazine, opened and positioned for insertion. Individual cartons are pulled into the machine based on their position as tracked by sensors that detect the movement of product passing by on the conveyor. With precise timing and positioning, the entire load is then placed into the case (from the top in vertical cartoners, and from the side in horizontal cartoners). Carton flaps are then folded as the case moves into a sealing station where a tape or glue dispenser is used to seal the major flap on the carton.
Design Challenges
Basic machine requirements are not unlike others in the packaging process: cartoners need to be fast, reliable and flexible enough to handle different types of boxes and configurations. From a control standpoint, however, the cartoner presents some exclusive challenges. Unlike upstream packaging machines, speed is less of an issue with the case packer and the priority shifts to the need to synchronize all the mechanical motion elements that drive the process.
For example, precise positioning of the pressure-sensitive tape or glue dispenser is critical for achieving an effective seal. Data from machine sensors, which are detecting carton positions, needs to be quickly routed through the network to the machine controller without delay to ensure an accurate seal.
Another key factor to successful cartoner design is adapting machine performance to the changing product mix — whether it's smaller products in smaller bags, different material in different shapes or running at faster speeds - without consuming valuable engineering time. In addition, to prevent costly product damage, cartoner machines must incorporate highly responsive controls, capable of detecting equipment jams and quickly stopping the machine in mid-process, if necessary. Other cartoner-related requirements include:
- Tracking various product attributes using shift registers.
- Manipulating and shifting large volumes of data.
- Positioning driven outputs (e.g., glue control, reject control, etc.).
- Providing control across multiple mechanical assemblies that each add work to the product. The trend in the industry is to replace mechanically linked assemblies with an "electronic line shaft."
- Scaling the machine's complexity without sacrificing performance.
- Using more axes than in the earlier mechanical devices due to increasing flexibility and speed requirements.
- Reducing machine down time due to product jams and continuing the process with minimal operator intervention.
Rockwell Automation Solution
The integrated packaging architecture address these design challenges.
- Ultra3000 drives help ensure position accuracy and reduce motion cycle time.
- Absolute feedback enables the cartoner to maintain position, even when power is interrupted. This eliminates expensive and time-consuming homing routines.
- Servo indexing moves the conveyor to a fine positioning point quickly and repeatedly, while electronic gearing ensures that date stamps are applied or coupons are inserted into the packages at an optimum, programmable ratio.
- Detailed drive and motor status information is easily accessible from the Logix controller and graphical trending capabilities in RSLogix 5000 software allow users to collect and view critical motion parameters.
- Output cams provide a simple programming interface to schedule position-based output triggering. These cams also can be enabled by other inputs or events.
- Built-in instructions provide a common scalable interface to hardware implementations called for by the specific speed and tolerance requirements.
- Built-in motion control provides synchronization of multiple axes through gearing and camming.
- Logix controllers can generate any number of virtual axes to use as references for synchronizing real axes.