How to increase the productivity and safety of machines
Chinese companies are increasingly successful at holding their own on the world market with high-quality, reliable machines. Those that, like Heng Chang Machinery Co. Ltd (HCH), must comply with European standards and regulations. For more than a year, the company has been counting on Pilz’s flexible, easy-to-use automation system – offering clients added value in handling, diagnostics, and performance.
When a well-known American manufacturer of grooming and hygiene products orders ten plants at once from a Chinese company, one can assume that that company possesses well-grounded know-how and delivers products of the highest quality. The plants for producing diapers consist of a series of process stations with multiple material feed and processing units. The basic material is pulp, which is prepared by so-called fiberizers and made ready for processing. Over a length of about 30 meters, several manufacturing steps are required before the diapers speed off the conveyor at a breathtaking pace. They are then folded, packed into units with the same number of items, and boxed for shipment.
The 400 or so employees at Heng Chang Machinery Co. Ltd, a Chinese company founded in 1988, produce machines and plants for disposable hygiene products. They do so with increasing success: the Anging-based company’s high quality, productivity, and safety standards have allowed it to hold its own internationally. The fact that productivity and safety go hand-in-hand has been clear at HCH at least since the beginning of its cooperation with Pilz, an automation company, which has been represented with its own subsidiary in Shanghai since 2006.
Complexity made simple
To meet the customer’s requirements, HCH initially wanted to implement a safety solution using the programmable control system PSS 3000 in conjunction with SafetyBUS p, but refrained from doing so on the advice of Pilz’s automation experts. The programmable control system PSS 3000 would not have been strictly wrong, but it would not have been state-of-the-art, either. Complex, modularly constructed, and widely branching systems with several different safety functions require a clearly structured safety control system that is easy to program and operate. Pilz’s automation system PSS 4000, practically the successor of the PSS 3000, is an all-in-one solution that encompasses control, sensors, operation, and monitoring. It is remarkable for its systematic distribution of control functions to the periphery using the mechatronic approach. Even tough requirements can be met simply and flexibly with this system. And safety and productivity are never at odds.
Exchanging data in real time
In the highly automated diaper production plant, there are a great many safety-relevant signals to monitor: safety gates and coverings alone account for around 50 of them, and the driven unwinding axes present a potential risk. In addition to further protective mechanisms, emergency stop buttons are distributed along the system. The actual safety task is performed by two central control systems PSSuniversal PLC in the control cabinet in cooperation with a total of 18 modules in the decentralized I/O system PSSuniversal in the periphery. The PSS 4000 is connected to the machine control system through Ethernet/IP protocol. Unlike the programmable control system PSS 3000, the automation system PSS 4000 uses real-time Ethernet SafetyNET p for communication. It is based on standard Ethernet and has been the performance standard in office communications for many years. The communications standard, however, can do much more and fulfils all requirements for use in routine industrial operations. In addition, the automation system PSS 4000 is more flexible and easier to operate – from the project planning phase to the operational phase.
Configuration and programming are performed quickly and intuitively using the software platform PAS4000.The tools for configuration, programming, commissioning, and operation are closely harmonized. In addition, there are no software licensing costs – only the functions that are actually used are charged. The software platform PAS4000 gives the operator a central overview of a distributed user program at all times.In PAS4000, all control systems can be configured, programmed, and diagnosed in the network.Simple, uniform handling of the entire project allows the cost of engineering, commissioning, and maintenance to be significantly reduced. Process or control data, fail-safe data, and diagnostic information are exchanged and synchronized among the various automation components via Ethernet.
An advantage for hygiene
But it is not only the performance of the hardware and software components used that wins over HCH’s customers. Pilz supported the customer from the basic conception to the plant test run with consulting and technical assistance. This included risk analysis, selection of modules, and software programming. The PAScal Safety Calculator proved to be an indispensable, easily understandable aid. The tool calculates the PL (Performance Level) and SIL (Safety Integrity Level) achievable for safety functions on plant and machinery depending on the components used.
“HCH has confirmed many times that we have gained their trust and won them over completely with our comprehensive consultation concept, the application of the automation system PSS 4000, and the resulting advantages for the customer,” says Cloud Yin, Senior Application Engineer for Pilz Shanghai. The fact that Pilz’s services entail lifelong support, stretching far beyond the date of delivery, is something that HCH values greatly.
The diaper-manufacturing plants, equipped with the latest technology, get high marks for increased quality and productivity. The Chinese company knows that the user enjoys significant advantages in safety and convenience with the integration of the automation system PSS 4000. Taken together, all this increases competitiveness, especially in the North American and European markets. That is why Pilz and its automation solutions and services will continue to be a valued partner of HCH in the future.