Easy Safety Implementation in Today’s Complex Application Environment
Lessons are being learned with safety applications that are being successfully implemented across a multitude of industries, like automotive, aerospace, material handling, food and beverage, solar and more. These case studies show the gains achievable through the implementation of safety systems that increase safety, reduce downtime, speed deployment and improve productivity across multiple sectors— automotive, aerospace, and even non-industrial.
USE CASE ONE – AUTOMOTIVE
A major Detroit-based U.S. automotive manufacturer needed a manufacturing system capable of producing two types of transaxle assemblies: one was a traditional clutch for a front drive unit; the other was for hybrid vehicles. The challenge— the manufacturing system had to be capable of producing a batch size of one with any product mix, and it needed the flexibility to accommodate future requirements. The automaker turned to KUKA Assembly and Test, an OEM integration company providing manufacturing solutions to automotive manufacturers worldwide to design and implement the solution.
Key Design Points
Two principal manufacturing systems were involved: a dry line and a wet line. Transaxles were assembled on the dry line; on the wet line, they were filled with appropriate fluids and tested. The heart of the main line was a unique vertical conveyor system that uses a special carrier platform design. This was constructed specifically for the project and designed to accommodate each transaxle put out.
The pallets mechanically latch into the vertical conveyor; rotors built into the conveyor move the pallets. The wet line is a traditional horizontal conveyor with pallets designed to accommodate each type of transaxle.
The wet line conveyor was designed and built into 10’ sections to standardize KUKA’s modular design, and to facilitate disassembly and reassembly at the customer’s site. The entire line was constructed and tested in Kuka’s shop prior to shipment to the customer.
Because the conveyor for this modular manufacturing system was so large, there were several segments assigned to it according to various manufacturing tasks. (These segments were self-contained portions of the line.) For this, the Siemens safety solution provided an efficient distributed architecture, communicating with PROFISAFE over PROFINET, ultimately connecting to the Factory Ethernet network.
The automation and control components used for the project are based on Siemens’ Totally Integrated Automation; and these are designed to work together within a distributed architecture. The architecture supports physically distributing components when needed, but also allows multiple control functions to be integrated within the same system.
In this system, safety is integrated as well as distributed. All the technology necessary for hardwiring safety I/O is backed by a safety control system, but now all components can be integrated into the main controller. Further, the safety I/O can communicate to the main controller via the same PROFINET cable that is used by the standard I/O. Both the standard and safety I/O do not need to be confined to a cabinet, as most components can be machine mounted.
Any changes that needed to accommodate workflow — or, as in this case, needed to increase the capacity – were very easily achievable. The automation components could be easily moved, added as needed, etc., as everything moves very easily, connects and disconnects, be it power, control, communications and also the safety components.
Because of the manufacturing systems modularity, and also the control systems distributed architecture, the installation at the customer’s site was greatly simplified. Once the conveyor was reassembled, the distributed controls and power connectors were reconnected by simply plugging them in.
Using this modular design approach, KUKA saved a significant amount of installation time. With all the technology, manufacturing systems were assembled and tested in the shop. The systems were taken apart in the shop for shipping and reassembled on site. All sections had to be rewired on site at every I/O point, and this had to be verified.
Typically a process like this, with all the technology, would take three or four months. But with the new automation system, KUKA didn’t have to pull wires, didn’t have to re-terminate, when they reassembled on site. The approach saved about 60% of the installation time. This is a significant benefit for any OEM.
Additional time saving was realized during commissioning. When the system sections were put back together at the customer site, the automation components communicated instantly via PROFINET. Virtually everything worked right away. If a load didn’t respond correctly, the PROFINET network indicated exactly where the issue was and what was wrong.
Further, factory floor workers easily understood the automation system’s diagnostics and messages— so maintenance technicians could diagnose the system without needing to plug in a laptop. This was a huge benefit. The techs were able to successfully maintain the controls and network by viewing the HMI screens and marking the fault lights on controllers and switches used in the solution.
Exceptional Cost Savings
Using the Siemens TIA control architecture was very attractive to KUKA from a cost perspective; it saved them approximately 15% on the project in terms of automation hardware.
Other than the individual costs of distributed architecture components (i.e., with IP65 and IP67 ratings), it might cost a little more than the cabinet-bound counterparts; but the total assembly and installation costs were much, much lower. In addition, fewer cabinets were needed, and all those that were necessary were significantly smaller. Other savings included less wiring, lower labor costs and shortened testing time.
This particular system was the third in a series of transmission manufacturing systems. As a result of this project, the modular manufacturing systems plan enabled production volume to increase by a factor of 3.5. All plant personnel were able to come up to speed quickly, and diagnostics and maintenance have been greatly simplified.
Summary of Benefits
- Safety integrated with standard technology
- Easy to understand diagnostics and messaging
- 15% savings on automation hardware
- Less wiring, lower labor costs and shortened testing time
- 60% savings in installation time
USE CASE TWO- COMMERCIAL AEROSPACE
Plano, TX-based Advanced Integration Technology (AIT) is a supplier of turnkey industrial automation systems, typically for leading aerospace suppliers. They have made major strides in machine safety.
As the primary contractor on the Boeing Dreamliner, AIT had responsibility for the final assembly and body join functions. They were charged with delivering a fully automated positioning and joining system.
Outside of Boeing, the system components were moved to their respective locations. Once the system was visibly joined, a measurement system onboard located the airplane sections. This information was fed to AIT system software applications. From those data points, the system calculated how much was involved in each section (e.g., nose, tail, wings, etc.) and how much they needed to move to ensure an exact fit to the adjoining section. This is very precise alignment that ensured a smooth rapid build of each fuselage.
AIT designed the overall layout of the control architecture with a programmed SIMOTION system with a SIMATIC 7 PLC with distributed I/O and integrated safety. It also provided support for Boeing’s internal structure— and the critical part was support for lifecycle requirements.
This basic architecture was then multiplied by the number of control nodes needed for each specific operational system. With the addition of a few PROFINET cables, the final body join assembly tool ran as a single entity.
Running together in this configuration, the safety devices worked coherently, providing the proper response level to all E-Stop situations. Each unit’s motion controller receives commands to perform uniform group movements with the tool as a whole via the network connected through the HMI.
A comprehensive safety scheme with SIMATIC Safety PLCs was the central element of the system. This communicates over PROFINET.
There were three main sections to the fuselage joined using 14 positioners to transport structures that either moved independently or were indexed to the factory floor for stability. Real time positioning measurement data was logged with an integrated GPS.
In operation, the safety principles manifested themselves in the form of physical barriers that isolated personnel from danger.
The control systems, including the safety PLCs, monitor the operating conditions within established parameters. With the integrated safety and control, the project had a single system for both standard and safety automation. Having one bus and one engineering tool for both standard and safety technology reduced the cost significantly.
As a collateral benefit, the software solutions allowed easy replication of series machines. Likewise, onboard diagnostics simplified troubleshooting and reduced downtime tremendously, while speeding restart after any issue was resolved.
The safety integration in the control system allowed uniform user interfaces, reuse of data libraries, and reduction in the variety of control cabinets required.
With advanced PLCs and industrial Ethernet technologies, the safety system proved a huge production asset for Boeing, protecting workers from harm while ensuring maximum availability and uptime, key requirements for the aerospace concern. There were also reductions in both initial capital expense and field operating expense.
USE CASE THREE- DEFENSE AEROSPACE
The Lockheed Martin F-35 Lightning II is the next generation fighter plane.
The F-35 is a single seat, single pilot, fifth generation multirole fighter designed to perform ground attack, reconnaissance, and air defense missions with stealth capability.
In order to meet the unique requirements of manufacturing this fighter, Lockheed Martin went to Shelby Township, MI-based Fori Automation, a leading equipment designer and system integrator that supplies specialized automated guided vehicles (AGVs) to increase manufacturing performance and efficiency.
At the heart of its AGV design, Fori selected Siemens SIMATIC Safety controllers, SCALANCE wireless switches, and portable HMI solutions as the integrated automation solution to meet all the manufacturing objectives of Lockheed Martin.
There were five essential requirements for the solution:
1. Interlocks were needed to ensure a safety environment for workers and to prevent collisions.
2. The Marietta, GA and Fort Worth, TX lines needed to use the same or similar equipment in order to provide commonality across the two production sites.
3. The transport system needed to be highly flexible to accommodate a combination of move scenarios.
4. The system had to be similar to other systems so that maintenance and training were similar to other existing systems.
5. The system had to be robust and reliable.
Fori developed a 12” wide position magnetic measuring device that gauged the intensity of the magnetic field to enable the AGV to position itself at an assembly station. The key aspect here— the accuracy had to be +/- 4 mm.
Each AGV measured 67” wide, 181” long, and 28” high. It supported tooling weighing about 12,000 lbs.
The tooling is transported to 14 process stations. Each AGV must hold that tolerance every time it is moved. At each station, the tool clamps onto pillars built to hold it rigidly in order to maintain accuracy when drilling occurs. Three automated drills make between 2,000 and 3,000 holes every time they are at a station.
The AGV positions itself beneath the tool and picks it up. It goes through safety protocols before moving the tool out of one station and into another. Each time an AGV slides under the tooling, the stations release arrangement clamps to ensure secure engagement. This required intense navigation, guidance, and propulsion systems to sync, utilizing the servomotors in the lifting mechanism.
Fori turned to Siemens to help solve a number of challenges.
These included the need for control system space reduction, improvement in control system communication, and simplification of operations.
To reduce space requirements, Fori specified SIMATIC ET 200S Fail-Safe CPU. This eliminated the need for safety relays, and allowed for a centralized, flexible and expandable AGV safety system. Its compact and low profile design opened up flexible mounting solutions. Also, Siemens rapid roaming technology allowed for uninterrupted communication as AGVs switched between access points.
Finally, use of the Siemens portable HMI simplified operations for Lockheed Martin personnel and promoted consolidation of all user interface devices, all while providing integrated safety. This drove down costs while meeting all required safety standards.
Bottom line, control, safety, configuration and diagnostics were at hand in a single, compact ergonomic unit.
USE CASE FOUR – NON INDUSTRIAL
Controlling a myriad of gates at The Elephant Community Center of the Smithsonian National Zoological Park was the challenge for Belmont, NC-based Solvere, a Siemens Solution Partner.
When Solvere was drawing up his list of initial project challenges, elephants getting scared wasn’t one of the challenges on the list, but when the team was designing a control system for the hydraulic gates, avoiding unexpected movement from the gates that would spook the elephants proved to be a challenge that needed to be considered.
There are 56 doors that guide the elephants from one section to another. There are also times they need to be isolated (e.g., for quarantine, for segregating the bull from the herd).
One set of doors in the Elephant Community Center holds the pachyderms in a small pen used for medical care. You can’t spook the elephants, because if they are startled, they or the zookeeper could be put in danger; and if the gate frightens an elephant once, it remembers the setting – and it won’t go through again.
While the setting was unusual, many elements were familiar: actuating hydraulic controls; using a wireless link; and so on.
The doors are huge and hydraulically driven, and they need to be controlled wirelessly— wherever the staff are, they have to have the ability to control the gates.
There is one hydraulic system for all the doors, and they are controlled by solenoids for the individual doors. Solvere used a Siemens PLC to manage all the inputs and outputs that controlled the doors for their two main functions—controlling the door movement (i.e., open or close) and controlling the speed.
There were, of course, aspects not close to common industrial issue; for example, the technology experts working on the project actually walked among the elephants (accompanied, of course, by the zoo keepers).
There was only one bull in the facility. When one of the project leaders came into the facility, the bull picked up a drain cover and was ready to throw it as he wasn’t familiar with him and was looking to establish his dominance. Needless to say, the zookeeper got him out of there quickly.
Another engineer was isolated from the herd by one of the gates – left alone to do some programming. The programmer didn’t notice that one of the herd had come close to the gate, near which he was sitting. The elephant did a full on trumpet, amplified by being in a concrete building.
Solvere selected the Siemens Safety PLC for the project; its reliability up to SIL 3 ensured no single point of failure. The zookeepers’ major focus was reliability— as in the event of a failure, death was a real possibility.
The on reliability extended as well to the wireless network connections. The bandwidth requirements were very low, so the designers could focus on highly reliable coverage. With zookeepers moving amidst the elephants, dead zones were not an option.
Ensuring that the wireless routers were supplying full coverage was a challenge, as the concrete walls that housed the elephants were very thick. There were metal bars on the doors, and the access points had to mounted very high into the ceilings, which were 20’ high and protected by metal grates (to keep the elephants from getting into the wiring).
Solvere also worked with Siemens to do the project modeling. They ran Siemens modeling software that took everything into account (size of the structure, materials, etc.). In addition to the wireless controls, there was one central controller that was wired, as well as the emergency buttons throughout the enclosure.
The zookeepers at the Smithsonian National Zoological Park have been delighted with how the Siemens safety integrated system has worked, meeting all requirements and keeping both staff and the elephants happy and healthy. In this case, lack of reliable performance would indeed be the elephant in the room.Have an Inquiry for Siemens about this article? Click Here >>