Given the scale of its production and the precision required for its parts, Zhongli North America Inc. had no alternative to automating its manufacturing plant’s welding cells. The Tier 1 auto chassis component manufacturer, located in Shelby Township, Mich., has been fine-tuning its Kuka-driven automated welding process for the better part of 2024 since beginning North American operations in 2023.
With its parent company and all previous manufacturing established in Shanghai, China, Zhongli elected in 2023 to bring production of chassis components, primarily those related to noise, vibration and harshness (NVH) performance, to North America for OEM manufacturers.
“Our volume, throughput and customer requirements drove the move to automate,” says Anthony Valitutti, Zhongli North America’s plant director of operations. “Our welding process requires repeatability and reliability, but we had no experience with robotic companies. Though we’ve done a significant amount of robotic welding in China, it was all new to us here.”
Robotic welding
To ensure the right choices were made, Zhongli sought out an experienced partner and began working with Detroit-based integrator IMG, a custom automation solutions provider that, in turn, pointed the company to Kuka.
“They were open and honest with us and told us Kuka was our best bet for what we were trying to do,” Valitutti says.
Zhongli needed to automate its MIG welding and material handling system to produce control arms for automotive suspension systems. Each control arm is built by welding three components with four welds. Four robotic welders operate between two fixtures and perform 16 welds simultaneously to form four control arms.
When the 16-weld cycle is complete, material handling robots move the control arms to a cooling station for approximately 10 min. Once cooled, the parts proceed to a post-pierce station where two clevis holes are punched. The robotic material handlers then move the parts onto the final conveyor line.
Kuka’s KR Cybertech nano Arc HW robots are tasked with the precision welding, providing extremely fast and precise continuous-path motion. The 6-axis robot uses a hollow-wrist construction for reduced main axis motion with repeatability of 0.04 mm. The KR Quantec-2 tackles the material handling duties within the cell, moving the components and fixtures with an accuracy of 0.06 mm.
“Hand welding simply isn’t feasible for this application or for automotive in general,” Valitutti says. “With Kuka robotic automation, we get the consistency and overall quality that we need.”
Realizing results
The automated cell provided economic, logistical and safety solutions in addition to producing the desired manufacturing results. The KR Quantec robots eliminated the need for human material handlers to move parts and fixtures between stations. Having operators within the cell would slow the process dramatically, require a larger cell footprint and pose inevitable safety issues caused by people moving in and about live robotic welders.
Zhongli uses Kuka.ArcTech, an intuitive modular welding software package that controls all essential welding tasks. The software allows operators to program and optimize weld parameters regardless of whether the power source is a MIG/MAG, TIG or plasma device. Overall cell development and material flow was developed using Kuka.Sim, allowing Zhongli engineers to optimize processes virtually outside the production environment. Digital cell development and simulation allowed Zhongli to refine its processes with minimal cost and effort, which is essential when bringing a complex application online.
“Kuka has performed very well,” says Kyle Fleeger, Zhongli North America’s manufacturing and maintenance engineer, who has been actively testing and tweaking the cell since it went into operation. “We’ve done many trials on gas types, wire types, and different diameters and thicknesses, and we’ve been able to make changes the same day. Kuka has been very incorporative of the different styles and trials that we attempt in our efforts to achieve a better product.”
That sort of cooperative support and responsiveness has also been instrumental in commissioning the cell quickly and getting parts to Zhongli’s customers.
“One of the issues we originally had was customer timing, and that was a huge benefit that Kuka gave us,” Valitutti says. “Kuka had a much shorter lead time for the robots than anyone else we could have potentially looked at.
“Additionally, we had a lot of the typical issues you encounter when bringing a system like this online, but we were able to get through them quicker than we probably would have with any other company.”
Future growth
From a shop floor view, Fleeger says Kuka’s precision, reliability and overall high quality provide a solid manufacturing base to produce a first-class product.
“This automation allows us to achieve the critical characteristics in our products that our customers require,” Fleeger says. “Even with its complexity, Kuka automation brings a certain simplicity. It allows you to understand how it’s controlled and how to modify it to incorporate what you need and want to do to make a better product.”
As far as Valitutti is concerned, the Shelby Township manufacturing plant’s welding cells are just the beginning of the company’s future automation strategies.
“We’ve started discussions about automating some of our very manual processes, and we’ve high hopes of automating a lot of what we do here,” Valitutti says. “Kuka has been a great partner through this process, and we’re looking forward to continuing that relationship.”
