PC Control and EtherCAT improve automotive machine redesign with enhanced functionality, simplified wiring and a 9% reduction in component costs
As automation technologies advance and consumer trends change, machine builders can either stick to traditional methods until no longer feasible or work to adopt leading-edge solutions. For Pensar Otra Vez, Inc. in Tucson, Arizona, the second option makes the most sense. The idea of regularly reevaluating components, processes and strategies is even in the company’s name: It literally means “think again” in Spanish. So when one long-term customer, a tier-one automotive supplier, needed to build a new elevated-temperature PCB test handler in 2019, Pensar Otra Vez Project Manager Mike Edwards automatically went back to the drawing board rather than copying the existing design.
A mechanical engineer by training, Edwards founded his company as Pensar Tucson in 1994 after two decades working in the industry for Texas Instruments and Adept Robotics. “Then Adept purchased Pensar Tucson in 2000 to build fiber optic machinery, but when that industry dropped off as quickly as it ramped up, we bought the company back in 2002,” he says. At the time, an employee who was a native Spanish speaker joked about calling it Pensar Otra Vez. The name stuck. Over the years, the company has built machines for many industries, concentrating on medical, battery and automotive manufacturing. Prior to redesigning the elevated-temperature PCB test handlers, the company had produced a similar machine that operated at a slightly lower temperature that was installed in Bangalore, India, so it was prepared for the new challenge.
More than 20 Pensar-built handler machines were already in operation at the customer’s plant in Texas, so there was a clear baseline to measure improvements. The handlers receive an incoming PCB at room temperature, elevate the PCB temperature to approximately 110 degrees Celsius and hold that temperature within ±3 degrees during a functional test of the PCB to simulate operating conditions in a vehicle. Since the test time is under 120 seconds, the test handler must quickly add heat to the product. Throughput is important, so the handler needs to maximize testing time versus handling time.
Turning up the heat on machine performance
The new elevated-temperature PCB test handler needed to increase performance, adhere to testing processes and reduce component costs. Pensar Otra Vez wanted to meet these goals while reducing cabling requirements, minimizing footprint and increasing user-friendliness. Inside the handler, the PCB products progress through four preheat stops on the conveyor to reach the test stop. At each preheat stop, infrared temperature sensors monitor temperature rise. Previously, this created a wiring challenge with significant costs for labor and cables. In addition, the company wanted to update the system’s HMI for easier operation and maintenance. The end user customer also wanted the machines to improve data acquisition and analytics capabilities as a path toward IIoT and Industrie 4.0 concepts. This automotive vendor has plants around the world with key initiatives aimed at measuring processes and enhancing efficiencies.
“Energy management in this customer’s factories is growing more and more important. This includes everything from automatic power down of conveyors when not in use to accurate motor rpm monitoring,” Edwards says. “The end user already utilized sophisticated data acquisition at the host level to monitor and predict machine performance. But the older design used components from multiple vendors to perform the process such as an independent temperature zone controller to operate the temperature loops. Collecting more data – if available and possible using the previous design – was a programming challenge, since a clean path was not always available for communication among devices.”
While the customer previously completed the machine programming in-house, Pensar Otra Vez took up the task this time. The original machine control logic was created in Visual Basic (VB) to run on a PC-based controller, but the automotive manufacturer wanted greater flexibility and access to performance data across the system. The engineering team at Pensar Otra Vez collaborated with Dan Distefano, Owner and Senior Software Engineer at D2 Engineering LLC, on design and programming of the updated system. “One of the main goals was to provide access to all systems and devices through a single development environment,” Distefano says. “Having more than 20 years of experience with Beckhoff solutions, it was clear TwinCAT 3 automation software and the EtherCAT industrial Ethernet system were the best fit, as they would also enable simple integration of third-party components.”
PC-based automation passes the test
The team worked closely with Casey Taylor, Regional Sales Engineer at Beckhoff, to specify the best components and systems for the application. “Pensar Otra Vez has been working with Beckhoff for about 10 years and knows our automation portfolio well. In this application, the Beckhoff platform offered great opportunities to streamline system communication and access more performance data across the EtherCAT network,” Taylor says. Implementing TwinCAT 3 as the universal engineering and runtime software simplified design and commissioning of the new handler controls.
Integrated into Microsoft Visual Studio, TwinCAT 3 allows programming in computer science standards and all IEC 61131-3 languages with object-oriented extensions. Distefano leveraged several important packages within the software suite: “We implemented TwinCAT HMI for the operator GUI, TwinCAT PLC and Motion for the machine control and TwinSAFE for the integrated functional safety system. Having the same Visual Studio front end helped us accomplish the main goal of easy access through a single development system.” These capabilities improved the ease of support both in the field and remotely.
The TwinCAT runtime is loaded on a C6030 ultra-compact Industrial PC (IPC) from Beckhoff that boasts a seventh-generation Intel® Core™ i3 processor with two cores and a 3.9 GHz clock speed. For a more robust operator interface, the handler features a CP3921 multi-touch Control Panel. The custom push-button extensions and a 21.5-inch (1920 x 1080) display were very impressive, according to Edwards: “Not only are the new Beckhoff touchscreen displays enclosed in very sleek aluminum enclosures, but they also have the option to add the e-stop and other switches in the bezel below the touchscreen. This product simplified wiring, and it grouped together essential operator inputs in a way that just makes sense.”
EtherCAT enhances communication and motion control
Through its openness, robust built-in diagnostics and real-time communication performance, EtherCAT improves machine design and operation by connecting all key machine components into one ecosystem. EtherCAT does not use IP addresses for network devices; instead, it automatically identifies and configures each device on the network using Automation Device Specification (ADS), the device- and fieldbus-independent interface built into TwinCAT. “As a result, each device can be accessed, commissioned and debugged without the need for additional software,” Distefano adds.
The free choice of network topology, use of one-cable automation (OCA) via the EtherCAT P standard and elimination of switches also helped in reducing machine footprint and wiring complexity. The handler uses a mix of IP20-rated EtherCAT I/O terminals, IP67-rated EtherCAT Box modules and OCA solutions that provide communication and power for field devices in a single cable. “EtherCAT P and machine-mounted I/O components allowed us to run just a single cable back to the main control cabinet. In addition, use of Beckhoff components inside the control panel eliminated even more wiring and basic terminal blocks with significant reductions in panel space and wiring time to sensors and motion control components in the field,” Edwards says.
To load the PCBs through the elevated-temperature test stations, the handler machine operates a conveyor powered by Beckhoff AS2022 stepper motors paired with AG2250 7-to-1 gearboxes. DIN rail-mounted EL7047 Stepper Motor Terminals power the two-phase stepper motors, delivering 8–48 V DC at 5 A via a one-cable connection. The IP54-rated AS2022 Stepper Motors feature a torsion-proof, integrated encoder. “The previous design used a motor plus gearbox for each side of the edge belt conveyor. The motor speed output value was a numerical analog number that didn’t read as motor rpm or belt fpm,” Taylor says. “The Beckhoff drive technology could easily display true motor rpm, so the two conveyor sides could be accurately monitored and adjusted.” As with the other components, this provided greater control and data acquisition compared to the previous machine design through PC-based automation from Beckhoff.
Machine redesign elevates PCB testing
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“In the automation world, it is relatively rare to have the opportunity to directly compare newer technology with the previous way of performing the task,” Edwards says. “Redesigning the elevated-temperature PCB test handler for our automotive-industry client offered the perfect chance for an apples-to-apples comparison.”
Use of EtherCAT I/O modules led to a savings of 9% in cost, 11% in field wiring labor through improved wiring efficiency and 12.8% in electrical cabinet size, mainly by reducing the number of terminal blocks. Also important to the Pensar Otra Vez team was the significant reduction in debug time. All of this was possible along with easy integration of third-party devices, such as the infrared sensors, on the all-encompassing EtherCAT network.
After the design and build were complete, the Beckhoff benefits included a reduction in controls design time of about 36 hours for the project, according to Edwards. “Programming was consolidated into a single point, and additional features – such as temperature control and measurement, energy usage and speed monitoring – that were not available with prior components offered greater flexibility,” he says. The inherent connectivity of Beckhoff PC-based controllers enabled greater support and maintenance savings for the end user, and it simplified future upgrades and planned remote monitoring of the system for energy efficiency and other corporate goals based on big data. This is part of the strength of the Beckhoff platform, according to Distefano: “Networking all devices over EtherCAT allowed us to gather more information for machine processes and diagnostic support with minimal software development and no additional hardware.”
While providing support for the customer was crucial, Pensar Otra Vez also relied on support from Beckhoff to ensure success with the redesign. “As an integrator, we are always looking for the best off-the-shelf components to go with our customized tooling, but the size of most vendors’ product catalogs can be daunting. Casey Taylor and the application support team at Beckhoff were a great help in this area, and with consultation on new design approaches,” Edwards says. The redesigned handler has been operating in the field without issue, and the Pensar Otra Vez team would like to retrofit the others with the new Beckhoff architecture eventually. It’s easy to think the machine has reached its most optimized state, but with flexibility and modularity to support future adjustments, there’s always the opportunity to think again.
Are you ready to boost machine capabilities with a fully integrated automation platform? Contact your local Beckhoff sales engineer today.
James Figy is the Senior Content Specialist at Beckhoff Automation LLC.
A version of this article previously appeared in Machine Design.
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