Polyurethane foam plays an essential role in automotive applications, particularly in the area of soundproofing. The exact recipes are frequently fine-tuned with additives to deliver customized materials properties. To increase its production capacity, polyurethane foam specialist Otto Bock Kunststoff (since renamed FoamPartner), added a new facility next to its Rochester, NY North American headquarters. Built in 2018, the new plant features multiple workstations for blending liquid polymers to produce soft, nonflammable, sound-absorbing plastic parts. Otto Bock Kunststoff tapped system integrator Process Automation Solutions (PAS) to design and implement the automation. The result is state-of-the-art controls system that leverages 18 smart drives from Siemens networked on a PROFINET industrial Ethernet fieldbus (see figure 1).
The polymers used to make the foam are kept in a set of four storage tanks. The operators start a batch process based on one of the company’s 20 recipes, adding polymers in varying proportions to one of three mixing tanks. The tanks circulate and mix the base materials before the operators manually add quantities of special additives. When a batch is approved by the quality assurance/control department (QA/QC), the final liquid polymer product is automatically pumped into 1,000-kg totes, smaller storage bins, or into other trucks for delivery to customers.
Tight batch process control is critical for ensuring final product quality, and requires controlling setpoints, current flow, and motor speeds, as well as monitoring equipment status to detect potential faults. Using networked smart drives helps ensure proper operation and maximize uptime with online diagnostics and remote accessibility.
Tight batch control is key to manufacturing a successful product. This goes beyond using exact volumes of polymer. “In this case, tight batch control means speed for agitation while mixing product, so exact quantities are pumped,” says Ingo Magura, senior project manager at PAS. “Upgrading to automated systems from the company’s former manual procedures has labor efficiencies and increases accuracy.”
The smart approach
Although Otto Bock Kunststoff originally intended to use a traditional, motor-mounted drive system, PAS calculated that using networked smart drives would significantly reduce engineering, hardware, and commissioning time and costs, as well as contribute additional information needed for measuring system performance.
“In the old facility, there was a control system by a little-known brand with limited capabilities and pretty much no support,” adds Magura. “The new system is energy-efficient, automated (reducing manual intervention), allows automatic reports, and is remote-accessible through a secure connection.”
Control components in the polymer blending solution by PAS include Siemens TIA Portal v15 software, WinCC SCADA system, S7-1515 CPU and remote I/O rack, as well as 18 Siemens Sinamics G120 drives and two Siemens Comfort panel field HMIs—all networked with PROFINET. The drives work with 460-V, 3-phase NEMA motors, ranging from 1.25 kw to 11 kW, which serve the blending application’s pumps and agitators (see figure 2).
“Having the smart drives, PROFINET, and the control system allows for seamless integration,” says Magura. “Since PROFINET already connects all the components, commissioning time is drastically reduced compared to using traditional drives, which require that a dedicated cable be hooked up to each drive from an engineering laptop PC for commissioning. In contrast, with smart drives connected by PROFINET to the PLC, there’s just one Ethernet cable, compared to eight that would have been needed if Ethernet wasn’t used.”
The functions of these cables include:
- Speed setpoint (4-20 mA);
- Actual speed (4-20 mA);
- Actual current (4-20 mA);
- Drive Ready (discrete input);
- Drive Enable (discrete output);
- Drive Fault (discrete input);
- Drive START (discrete output); and
- Drive STOP (discrete output).
“Since no additional hardware such as I/O cards is required to read the actual speed of the drive/motor, this technology enhances accuracy,” he adds. “Plus, when you multiply these cabling and I/O costs by 18 drives, it becomes evident that a smart bus system reduces both hardware and cable installation costs. The cabling and I/O would have cost at least $31,000 more if hadn’t wired the drives to the PLC using PROFINET.”
PAS also took advantage of the Siemens Sinema Remote Connect system, which is secure and enables them to modify software or troubleshoot problems remotely. Production adjustments can be from a password-protected screen on the WinCC SCADA system.
Multiple ongoing gains
Beyond initial equipment and commissioning savings, deploying smart drives and PROFINET is paying ongoing dividends for both Otto Bock Kunststoff and PAS. “PROFINET is deterministic, so we can fine tune the control loops immediately and efficiently,” he says. “In addition, we have all the measured values from the devices at our disposal, such as hours run, which can be sent from a drive to the PLC in a few mouse clicks. That’s efficient engineering.”
“By using this fully integrated control system platform, including the drives, HMIs and PROFINET, we were able to estimate our engineering costs more tightly, reduce the price to the customer, and demonstrate that PAS is a more efficient solution partner.”
Finally, key performance indicators (KPI) can be easily calculated using the vast amount of data now available from the company’s polymer blending application. Networking over PROFINET also makes it easy for users to add new KPIs by analyzing data from the smart drives. These KPIs also bring further insights into Otto Bock Kunststoff’s network and manufacturing process, and open the way for predictive maintenance and future hardware upgrades.
“As for the future, Otto Bock Kunststoff has similar blending systems in Germany and Asia,” concludes Magura. “So, the goals of its U.S. team are to apply these best practices in the other facilities.”
Original article appeared in Controlglobal.com as written by Jeanne Schweder.Have an Inquiry for Siemens about this article? Click Here >>