Bemis, BASF Develop Lightweight Hydraulic Tank for Compact Excavators

September 11, 2024

Ryan Gehm

Bemis Manufacturing and BASF collaborated to develop a lighter-weight and lower-cost hydraulic tank for compact excavators that was recognized with a lightweighting award traditionally reserved for automotive innovations.

Receiving an honorable mention in the Enabling Technology category of this year’s Altair Enlighten Awards, the development team leveraged a combination of injection molding and vibration welding techniques to lower costs by approximately 20% and reduce mass by about 5% compared to the traditional roto-molding process. The solution also is more eco-efficient, delivering both environmental savings (reductions in lifecycle CO₂ emissions) and reducing lifecycle costs.

The awards were presented in August at the Center for Automotive Research’s Management Briefing Seminars in Traverse City, Michigan.

“We needed a way to produce large, complex parts with shorter cycle times, while reducing secondary processing waste,” Jeff Lallensack, senior project engineer at Bemis Manufacturing, said in a statement. “The BASF team understands our business and their engineering expertise in vibration welding improved the functional performance of the hydraulic tank by successfully containing vibration weld flash during processing.”

The hydraulic tank uses a BASF polyamide 6 (PA6) grade, Ultramid B3WG6 GPX BK23238, reinforced with 30% short glass-fiber. BASF says this specific grade of Ultramid is optimized for exceptional vibration-weld joint strength and high-temperature fatigue strength. The material delivered performance improvements on both static and fatigue performance requirements. The tank met the OEM’s requirement of 100 fatigue cycles of vacuum load at 200°F (93°C).

The development team also leveraged BASF’s CAE expertise, specifically its Ultrasim and Burst Failure Index (BFI)-for-weld methodology, to optimize part geometry and meet performance requirements. The hydraulic tank measures approximately 790 x 350 x 465 mm (31.1 x 13.8 x 18.3 inches).

“We had the challenge of developing one of the largest hydraulic tanks ever injection molded. We used a [2200 US Ton] two-barrel injection machine to mold both halves of this tank and subsequently join them via vibration welding technology,” Andy Raml, president of Contract Molding Services at Bemis Manufacturing, said at the awards ceremony. “BASF is a phenomenal partner, not only providing enhanced materials but also [delivering] accurate simulation predictions used in the design FMEA (failure mode and effects analysis) process to ensure we could achieve the integrity and the pressure requirements of the tank.”

Equipped with two barrels, the injection molding machine enables both components to be molded simultaneously. This process assisted in significantly reducing cycle time compared to roto-molding, which requires secondary operations such as drilling holes for oil inlets that can lead to fluid contamination. The new process also supports the potential for increased production volumes.

“At BASF, collaborative innovation with our customers … and customer-led engineering is crucial to their success as well as ours,” Ankur Bhosale, senior principal engineer of performance materials at BASF, said in a statement. “As a team, we made the impossible possible by delivering approximately 20% cost savings to our customer partners while delivering an eco-efficient solution. It’s a true demonstrator of the power of co-creation.”

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