Coining control at the Royal Australian Mint

When the Royal Australian Mint invited tender submissions to carry out the complete redevelopment of its coin production and warehousing facility in Canberra, innovation was high on its list of selection criteria. A heavy reliance on manual labour, ageing equipment and outdated processes had seen the development of inefficiencies in some areas, and had the Mint looking for a contemporary materials handling solution.

In seeking out such a solution - one that would optimise workplace safety, improve security and enhance production efficiency - the Mint followed a competitive tendering process involving some of Australia’s most innovative industrial solutions providers, and eventually awarded the project to materials handling systems specialist Australis Engineering.

Australis Engineering redesigned the entire materials handling and warehousing operation, rather than simply automating the Mint’s existing processes. A key element of the design was an information-enabled automation and control solution from Rockwell Automation.

Manual money making

The Mint’s coin production process is carried out across three levels of the facility. Prior to the upgrade, coin blanks would arrive in 200-gallon drums (two per pallet) from the basement level and then be transferred to the mezzanine level via a goods lift where they were unloaded into wheeled tote bins. These bins were positioned over hoppers which fed multiple individual coin presses on the production floor below. Once pressed, the coins were counted, dispensed into tote bins, then tipped into drums and readied for packaging and delivery.

For the majority of the production process, the drums of blanks, tote bins and finished coins were manoeuvred about the facility and emptied using manually operated forklifts. The high level of manual handling, combined with the forklift and worker interaction, had become a safety concern. Removing this reliance on manual handling, maximising the physical separation of workers and forklifts, and improving overall system safety were key drivers that prompted the upgrade.

“While improving safety was one of the primary goals of the facility upgrade, we also set out to address issues of security and accountability,” says Royal Australian Mint’s Chair of the MHWS Steering Committee, Marlene McClelland. “We’ve implemented a highly integrated and automated process to ensure that blanks and finished coins are properly accounted for - from receipt of raw material, through the production process, to quality control, warehousing and dispatch.”

Automated efficiency

Australis Engineering ensured that automation lies at the heart of the Mint’s upgraded production facility. Automatic guided vehicles (AGVs), a robotic decanter, numerous belt-, roller- and bucket-conveyors and an innovative multiaxis bucket conveyor have replaced the human-operated forklifts and much of the manual labour. Equipment such as stretch wrappers, coin inspection and robotic packaging technologies, and an automated Vision Counting System (VCS), have also been incorporated into the production process. The automation and control solution, paired with production intelligence software from Rockwell Automation, oversees the control and operation of the upgraded process. Implemented by system integrator Start Services, the new control system permits a more efficient movement of materials through the Mint’s facility. Upon receipt, each drum of blanks is assigned and labelled with a unique identification barcode, which it retains for the duration of the manufacturing process. On the direction of the control system, AGVs take the barcoded drums to a holding area and, when required, on to the robotic decanting station. Once decanted, the blanks are fed by the VCS into the multiaxis bucket conveyor which transfers them to any one of the coin presses.

Figure 1: The Mint’s multi-axis bucket conveyor transfers the blanks to any one of the coin presses.

Once pressed, the newly minted coins are re-counted and transferred to the packaging area, where they are loaded into drums, small bags or bulk cartons. Damaged blanks and coins are accounted for and redirected to a holding area.

“By incorporating centrally controlled AGVs, robotic systems, the VCS and the multiaxis bucket conveyor into the process, we’ve managed to eliminate the potentially dangerous and time-consuming manual handling tasks while also significantly improving auditing functions,” says Anthony Gustafson, Engineering Director at Australis Engineering. “As a result, the Mint’s production floor is a safer, more secure working environment, with a substantially improved audit trail for circulating coins.” The upgraded facility has been designed to process 2.2 million coins per day, and in practice can achieve in excess of 2.4 million coins per day.

Comprehensive control

The Mint’s upgraded control system features an integrated control architecture, comprising a network of controllers, drives, EtherNet/IP communications and distributed I/O - all linked to a site-wide manufacturing execution system (MES) founded on FactoryTalk production and performance software.

Standard sequential control functionality is managed via a ControlLogix controller, while safety applications are controlled using a GuardLogix controller. Two separate EtherNet/IP networks - one for standard and safety communications, and one linking the controllers to the Mint’s MES - are also employed. A distributed array of both Point I/O and Guard I/O with EtherNet/IP connectivity supports the facility’s distributed I/O requirements.

A real-time EtherNet/IP socket interface was developed by Start Services to link the proprietary AGV host PC with the MES system. “The MES acts like a soft-controller, interfacing and responding to the AGV host computer,” says Richard Bailey, Start Services Director. “This allows the Mint to track the site’s inventory and obtain the status on any one of the 1000-plus pallets live in the system.” Similarly, other third-party systems, such as the coin counting machines, barcode scanners and printers, and robotic systems are interfaced with the control system.

Control sequences, such as blank-decanting and coin-pressing are all self-contained. However, some control sequences interact with each other, or rely on instruction from the MES. For example, when a new empty pallet is delivered to a coin press for filling, the MES will identify the pallet and inform the controller that the pallet is in position. The controller then takes over, executing the control sequence. Once complete, the controller informs the MES.

Each of the coin presses and the packaging area is equipped with a mobile control station trolley equipped with a VersaView industrial HMI computer. With connectivity to the MES, the HMIs provide an information display of machine status, operator command display, and alarm annunciation and acceptance.

“The HMIs provide an instant visual overview of the process elements and activities within the complex materials handling process,” says McClelland. “This assists us with identifying and remedying potential process hold-ups quickly, resulting in optimised productivity.”

SIL 3 safety

In addition to minimising the extent of manual handling processes, the separation of machinery, AGVs and staff on the production floor was paramount. Here, safety light curtains protect the robotic decanting, packaging and conveyor areas, while each of the coin presses incorporates emergency stop buttons.

The GuardLogix-based safety control system ensures that all energy sources are isolated and the equipment has come to rest before any of the access gates can be opened. Gates are fitted with Guardmaster interlocking systems, which provide SIL 3-compliant latching functionality in the safety zones. Similarly, if light curtains are breached, the safeguarded machinery is automatically shut down.

The facility’s variable speed drive applications (used to regulate the speed of the plant’s conveyors) are founded on the PowerFlex 70 AC drive with ‘DriveGuard’ option. ‘DriveGuard’ consists of an electronics card internally mounted within the drive that equips each drive with ‘safe off’ functionality compliant with Category 3. Importantly, it achieves this functionality without requiring the dual drive output safety contactors typically used in legacy Category 3 drive applications.

Figure 2: Australis Engineering redesigned the Mint’s entire materials-handling and warehousing operation.

Information to act on

The facility’s highly functional MES allows the Mint to capture, consolidate and distribute data throughout the enterprise in a purposeful and service-oriented way. Here, the FactoryTalk Production Centre and FactoryTalk View SE platforms play a vital role.

“This information management architecture allows the RAM to fully leverage production data,” says Johan Lourens, Rockwell Automation Quality & Project Manager. “It presents a powerful tool for process optimisation and improvement, product tracking and scheduling, as well as reporting, reconciliation and communications to other management systems, such as the ERP system.”

Coin and blank inventories can be tracked while maintaining a production history. High-level production coordination, including assignment of coin presses, management of process and control tasks, and control of third-party equipment can be achieved, ensuring production goals are met. Furthermore, customised reports can be configured and generated, and long-term records of production outcomes can be kept.

“Previously, inventory management was a manual process, so the ability to track product movement and obtain instant inventory reports streamlines this process,” says McClelland. “With high levels of control and information gathering, we are now able to gain a better understanding of the consumption patterns and productivity of our coin pressing process. This level of insight has enhanced our understanding of production capabilities and will assist in future strategic planning.”

Swift, secure and scalable

According to the Mint, the production facility’s performance has been steadily improving since final commissioning, with a quantifiable increase in productivity.

Workplace safety and security has also improved at the Mint. “The automation of forklift operations has been key to this improvement in safety,” says McClelland. “Also, with the ability to trace product from the supply of blanks, through our processes to our customers, we have realised significant improvements in the secure handling of materials.”

Looking ahead, the Mint plans to further integrate the coin presses themselves into the facility-wide control system. Here, the Mint is aiming to improve press management, maintenance and tooling, and will include the barcoding of coin-press tools in an attempt to gain a better understanding of tool management and wear.

“We’re very pleased with the control solution, as it’s not a static system,” says McClelland. “It will support future continuous improvement efforts, as it allows us to expand and build on the existing control architecture and programming. As a result of this project, the Mint is now equipped with world-class automated materials handling infrastructure.”