How MES Helped Donaldson Hy-Pro Overcome Casting Challenges for a Hydraulic Filtration Housing

As a manufacturer of the highest quality hydraulic filtration systems designed to reduce the environmental impact from the use and disposal of industrial fluids, Donaldson Hy-Pro is on a mission to eliminate equipment failures, end downtime, and increase the longevity of hydraulic equipment.

It takes extraordinary attention to detail, exacting specifications, and tight manufacturing tolerances for their filtration solutions to solve the hydraulic & lube oil and diesel fuel problems of their customers.

So, when Donaldson Hy-Pro needed a high-precision filtration head for a new product launch, they turned to MES for help in developing the prototype designs, engineering the solution, sourcing suppliers, and coordinating the efforts of multiple teams and suppliers.

This case study explores how MES delivered a high-quality, engineered casting solutionwith advanced machining despite having to navigate an extended design process, deliver multiple variants, and coordinate multiple suppliers and teams.

Application: In-Tank Filtration Assembly for Particulate Contamination Removal

According to Donaldson Hy-Pro, TFR2 In-Tank Filter Assemblies are ideal for particulate contamination removal in hydraulic power unit return line and mobile hydraulic OEM installations. Available in a compact design and three head size options, the TFR2 uses an inside-to-outside flow to remove dirt and contaminated fluid with the element.

Specifically, thehead of the filtration assembly is comprised of the filter, gauges, a lid, and input/output path, all of which are designed to deliver clean fluids back to the tank smoothly.

The Need for Consistency in Industrial Hydraulics

Because the head is integral to the fluid contamination solution, it does the heavy lifting. That means the product head (housing) had to be manufactured with the utmost consistency.

While consistency in diecast manufacturing is always important, this time it was even more crucial. To perform at its best, the assembly needed to be able to withstand the high pressures and dynamic conditions of hydraulic systems. It also required a pre-seal feature and zero-leak bypass valve.

The MES team knew that precise, repeatable tolerances would be essential to creating reliable sealing surfaces to help prevent costly (and potentially hazardous) fluid leaks.

Precision

• Hydraulic systems operate under high pressure.
• Dimensional variations (even small ones) can result in leaks, pressure drops, or complete system failure.
• Tolerances are typically measured in thousandths of an inch/fractions of millimeters.

Reliability & Safety

• Hydraulic components must align precisely with other parts of the assembly.
• Inconsistent parts could cause misalignment, resulting in improper sealing.
• Failure can lead to costly downtime or, worse, catastrophic and dangerous events.

Performance

• Flow rates [100 GPM]and pressure handling depend on exact dimensions and material properties
• Inconsistent wall thickness affects thermal behavior and pressure capabilities
• Surface finish [125 microns] irregularities can increase wear and friction

The diecasting process is ideal for hydraulic components because it can deliver this needed consistency through controlled metal flow, rapid solidification, and highly repeatable production parameters.

The Challenge: A Complex Filtration Head

When Donaldson Hy-Pro needed a reliable partner to provide design support, manufacturing expertise, and global supply chain sourcing and management, they turned to MES.

Our challenge was to help finalize the development and manufacture of a new product: an innovative filtration head for in-tank filter assemblies, comprised of two parts provided by MES.

The filtration head, cast from ADC12 aluminum alloy, required a highly complex buttress thread—not only for strength, but for precise engagement. The thread had to start and stop at the exact position—without fail—to ensure proper alignment with the lid. Machining consistency was critical, as each rotation of the 356-T6 aluminum lid applied axial force to the internal filter, pushing it into its seated position. Too much or too little pressure would misalign the filter, compromise sealing integrity, and potentially interfere with proper installation.

This complexity was especially apparent in the design and production of the lid. Unlike more common NPT thread designs, which rely on a tapered profile to create sealing pressure, the TFR2 application demanded a buttress thread capable of withstanding high axial loads while maintaining a secure, repeatable engagement. This thread type was chosen to eliminate the risk of the lid disengaging under dynamic hydraulic pressure—a failure mode that could lead to system leakage or, in the worst case, explosive separation of the lid.

The stakes were high. The head component is rated for a maximum operating pressure of 150 psi (10 bar), and in real-world conditions, pressure surges can drive transient loads far beyond that. If the buttress threads are even slightly out of specification—due to pitch error, poor surface finish, or misalignment—the resulting forces could cause the lid to dislodge violently, posing a serious risk to equipment and operator safety.

Precision at the Thread Interface: Tolerances That Leave No Room for Error

To meet Donaldson Hy-Pro’s safety and performance specifications, MES engineered the lid’s thread form in strict accordance with ANSI B1.9-1973. This involved manufacturing a single-start buttress thread with a 5.48 mm pitch and a 6-degree pressure flank angle—geometry specifically selected for its load-bearing strength and shear resistance. But strength alone wasn’t enough. Dimensional tolerances had to be controlled down to ±0.025 mm on the pitch diameter and ±0.01 mm on thread start position, ensuring perfect thread timing and leak-free engagement with the head.

These tolerances presented a significant challenge within a gravity die casting process. MES overcame this by:

• Designing precision steel tooling with optimized thermal expansion profiles
• Applying thread-forming simulations to preemptively correct for post-casting shrinkage (approx. 0.6%)
• Utilizing CNC-controlled thread milling with custom cutters to ensure uniformity
• Verifying every production lot with non-contact optical metrology systems capable of detecting deviations as small as ±0.005 mm
• This level of precision at the thread interface not only ensured dimensional consistency but also guaranteed that every lid would seat and seal correctly—every time.

The MES Solution: Global Sourcing, Expert Engineering Support, and Precision Diecasting

Engineering Collaboration

Armed with marching orders to “deliver a part to print,” the MES team got to work. First up? Ensuring flawless thread alignment.

• Leveraged advanced CNC machining expertise to ensure consistent thread placement.
• Made pre-seal design adjustments to guarantee proper filter seating.
• Delivered three variants.

Design Agility

Throughout the months-long development process, MES worked closely with Donaldson Hy-Pro to accommodate ongoing design adjustments and changing requirements.

• Employed an iterative design process to align with the customer’s evolving port configurations.
• Ensured that design was optimized for efficient manufacturability at scale.
• Quickly adapted to design changes and variations.

Global Sourcing

To ensure component integrity, MES leveraged its global network, selecting high-quality suppliers to manufacture the filtration head and lid at a lower cost without sacrificing quality.

• Developed a casting solution that leveraged the expertise of two different suppliers.
• Implemented stringent quality control measures to verify dimensional accuracy.
• Managed multiple supplier relationships, ensuring compliance with the project’s exacting standards.

Precision Diecasting

Because precision and consistency were non-negotiable, the MES team closely collaborated with suppliers to ensure component integrity.

• Ensured structural strength and reliability by using high-pressure die casting (HPDC) to manufacture the filtration head.
• Used gravity die casting to the lid, allowing for superior dimensional accuracy and thread precision.
• Relied our in-house Supplier Quality Engineer (SQE) to ensure consistency and compliance at every step.

The Results: A Precision-Engineered Filtration Head

From global reach to technical expertise to a relationship-driven approach, this project is another example of how MES delivers consistent performance, supply chain resilience, and value-added solutions to our customers—and to you.

“We successfully closed the project through PPAP (Production Part Approval Process),” explains MES Sales Account Manager Austin Downs. “Since then, we’ve been promoted to their parent company for RFQ. It’s a huge compliment and a testament to our capabilities and reputation, and we look forward to partnering with them,” says Austin Downs, MES Sales Account Manager.”

To learn more about the MES way or to explore how MES can help with your next project, contact us today.

Specifications At-a-Glance

Filtration Head for TFR2 In-Tank Filter Assemblies

• Application: Particulate contamination removal in hydraulic power unit return line and mobile hydraulic OEM installations
• Type of material/metal: Aluminum
• Processes: HPDC (high-pressure diecasting), GDCgravity diecasting
• Component dimensions: 4.85” x 7.50”
• Weight: 1.5 [lid] -2.5 kg [head housing]
• Max operating flow: 225 gpm (852 lpm)
• Max operating pressure: 150 psi (10 bar)