Motion architecture case study: Software + Ethernet modules for coordinating packaging tasks

The combination of the PPC-2015 Panel PC running NI LabVIEW with the cFP-1808 sub-system allowed DSA to deliver a robust mechatronic solution to a production throughput problem presented by our customer. This system runs 24 hours a day, 7 days a week, with a throughput of 28 boxes per side in a 24-hour period. This is a yield of 12,554 parts packaged in a single day.

The Challenge: Injection molded parts for the pharmaceutical industry were created on two independent injection molding systems. Star Automation robots remove the parts from the mold machines and place them in bins for manual packaging. The customer needed an automated system to collect and package parts from these systems.

The Solution: Data Science Automation designed a single automated system that interacted with two independently running production lines. The system utilized a Compact FieldPoint Ethernet module from National Instruments to control a central receiving and packaging system, the core of which was a two-axis motion system.

In order to increase production line throughput, a manufacturer of injection molded pharmaceutical parts wanted to develop an automated packaging system that could service two independent production lines. Data Science Automation developed a robust automated packaging system that collected the finished parts from Star Automation robots four parts at a time. The parts were collected until thirty-two parts were waiting in a marshalling area, at that time the new automation system guided the parts to a pick-up area serviced by a two-axis picking system that grabbed the parts and placed them in a box.

Getting to the problem: To meet their production requirements, the customer had two injection molding machines that are situated side-by-side on the shop floor. These machines operated independent of each other and produced parts at an aggregate rate of 16 parts per minute. At the end of each injection molder’s 30-second production cycle, the Star Automation robots would remove from the injection molding machines the four new parts that had been formed and drop them into a collection bin. In the past, human operators would come by periodically and box the accumulated parts by hand. This manual process – besides being mind numbingly tedious –also formed a significant bottleneck in the production process.

Mechatronics solution: The main challenge in the mechatronics solution was the desire of the customer to have only one packaging machine servicing two separate asynchronous lines of production. DSA selected the PPC-2015 industrial panel PC (with touch screen) to hosts the application controlling the new packaging machine. The PPC-2015 communicates with the cFP-1808 through an Ethernet cross-over cable.

In terms of software architecture, the code broke the mechatronics solution to the packaging problem into nine main sub-systems:

• Pick and Place servo robot moving in the X and Z axes
• Two accumulator stations that interact and collect parts from the Star Automation robots
• E-Stop system that monitors for guard door openings or E-Stop button presses
• Two conveyor systems that move the boxes into place under the Pick and Place robot station and eject full boxes
• Alarm system that notifies operators of any system problems or I/O failures
• Foam level and Air Supply monitoring system that keeps track of air pressure for the sub-system pneumatics and packaging foam supply levels
• Manual Commands response system that reacts to system commands when it is in manual maintenance mode

The code for managing these sub-systems is encapsulated in subVIs that independently and in parallel with one another (Figure 1). The internal structure of the subVIs is based on the State Machine architecture, and communications between the various state machines is handled using Queues and Functional Globals.

Figure 1 – Main Block Diagram shows the nine separate subsystem state machines that all run in parallel to make the packaging machine work.

Physically, the packaging system is split into mirror sides consisting of an Accumulator and Conveyor that service one Star Robot drop-off. The Accumulator stations collect parts until two rows of sixteen parts are in place. It then pushes these parts into the Pick and Place staging area. The packaging system is shown in Figure 2.