Robotic Unloading Gantry

This device is part of the same laminated panel line as the cold wire system mentioned in the previous post.

It is essentially a servo controlled automatic robotic gantry system.
This machine removes the finish product from an in feed conveyor and stacks it into a stack of a predetermined height, at which point a side transfer system removes the stack of product from the stacking position and sends it to a stretch wrapper.

The control system is based around the multitasking motion control system by Baldor called the NEXT MOVE ESB. The Next Move can control up to 3 servo axiom and 4 stepper motors.
Although this system only had a need for two controlled axiom, the Next Move was chosen due to its flexibility and Mint MT multitasking environment, which has to be given some credit for the outcome of the system, as its ease of configurability helped reduce lead time on the commissioning of this system.
This controller was paired with two Baldor FlexDriveII Servo drives, which were selected for there size (>7kW) and easy connection to the Next Move

Product is positioned for collection by the gantry via ABB drives and an Omron PLC system. The PLC is connected to the Next Move via and industrial PC running a custom written (by C&L Controls) HMI package implementing the Next move USB drivers and OMRON CX-Server. All critical information is hardwired, yet the PC was used to allow future changes or remote debugging if required.

The lowest required cycle time of the system was around 19 seconds, however this speed is required less than 5% of the time, with most required cycle times around 35-50 seconds. Hence, speed and acceleration can be altered via a trim pot control mounted in the cabinet. This reduces R&M cost and power consumption.

As the product stacks can vary in configuration, either to optimize stack size, or to allow for simpler onsite product handling, the means was provided to change configurations at the flick of a switch while the line is producing. Also part of the stack optimization, the system has the ability to flip the product automatically.

The system was required to handle a large variety of products of different dimensions and profiles, and as unlikely as it was, there was no guarantee that the all products of any given product run would be the same.
It was for this reason that the gantry dynamically adjusts position to accommodate for any change in product type or thickness.

The movie demonstrates a flipped product of a new thickness being picked up. The gantry measures the panel thickness using temperature compensating ultrasonics mounted on its main structure, it then adjust its position to pickup the product in the correct location, and allow stacking with tolerances <2mm.