Cast Parts for Pump Repair: A Case Study of Short-Lead-Time Casting

By Rakesh “Rocky” Nalla, Engineering & Quality Manager, BIMAC Precision Castings

BIMAC Precision Castings, an Ohio-based investment casting foundry, is well-versed in handling urgent, time-sensitive orders. Major pump manufacturers rely on BIMAC when their customers need to restore pumping systems in pipelines and processing facilities. These situations often involve small order quantities, unknown component requirements prior to disassembly, and an immediate need to resume operations.

To meet these demands, BIMAC has developed a proven, streamlined process for expediting casting production—without compromising quality. The components most commonly required are large impellers, diffusers, and housings. These are critical, high-stress parts found in pumping systems used across the water, oil and gas, chemical, and power generation industries. For operators of these systems, downtime is costly, and lead times on replacement parts are absolutely critical.

In many cases, orders are awarded to the foundry that can quote and deliver the fastest turnaround from initial inquiry to shipping the finished casting. To remain a top choice in this competitive space, BIMAC has refined its internal workflows to reliably produce high-quality pump repair castings within accelerated timelines. We not only quote some of the shortest lead times in the industry – we consistently deliver on them.

In addition to speed and reliability, customers frequently tell us we offer some of the most competitive prices in the market. By maintaining efficiency throughout our operations and leveraging deep industry experience, we’re able to provide exceptional value, earning us the trust and repeat business of customers across the United States and beyond.

What follows is an overview of BIMAC’s specialized process for expediting pump-repair castings. An approach that continues to distinguish us in the field.

Rapid Prototyping: The Key to Casting with Short Lead Times

At BIMAC Precision Castings, two metalcasting processes are utilized to meet a broad range of part specifications: investment casting (lost-wax process) and ceramic mold casting (Shaw Process). For standard production, both processes rely on permanent tooling—typically fabricated from aluminum, stainless steel, or legacy wood-and-resin pattern materials. However, for time-sensitive pump repair components, the lead time required to fabricate permanent tooling is prohibitive.

To address this, BIMAC leverages additive manufacturing to produce polymer patterns without the delay of traditional tooling. Upon receipt of a digitized part file (typically in STEP format), BIMAC’s engineering team initiates a simulation workflow using Solid Cast software. This simulation models solidification behavior, gate and riser placement, and alloy flow to ensure dimensional accuracy and defect-free castings.

Once gating and shrinkage allowances are optimized, a full-scale pattern is produced using a Voxeljet binder jetting system, employing printer polymethyl methacrylate (PMMA). This polymer exhibits favorable burnout characteristics for producing quality castings. The PMMA pattern dimensionally compensates for expected shrinkage of the cast alloy and is typically ready within three business days of customer file submission.

Following pattern production, the component enters the ceramic shelling phase. The pattern is successively coated with refractory slurry and stucco to build a high-integrity ceramic mold. Shell build-up and curing are completed within the first week after receipt of the customer’s order. After dewaxing and burnout of the PMMA pattern, casting proceeds using standard investment casting practices.

This rapid response workflow enables BIMAC to deliver high-quality, mission-critical pump repair castings with minimal turnaround time, without sacrificing the metallurgical or dimensional integrity required in high-performance applications.

BIMAC uses Solid Cast casting simulation software to ensure optimal casting outcomes, casting the part right the first time, every time.

Figure 1: Steps for short-lead-time casting of pump repair parts (left to right): CAD file of part, Solid Cast casting simulation, PMMA pattern, ceramic shell ready for pouring, final cast part ready for machining

Infinite Alloy Combinations in Stock

Another critical factor enabling BIMAC to accelerate turnaround for expedited orders is our extensive in-house inventory of master alloys and alloying agents. This allows us to formulate virtually any alloy composition required by the customer without delay. By maintaining stock of a broad range of base metals and alloying elements, we eliminate lead times typically associated with sourcing raw materials.

Within the second week of receiving the customer’s order, BIMAC is typically able to melt the specified alloy and pour the casting. We accommodate a wide range of specifications, including standard and specialty grades such as bronze alloys, stainless steels, and high-performance superalloys to meet the demands of various industrial applications.

BIMAC operates as a high-mix, low-to-medium volume foundry, capable of producing complex castings across a broad material spectrum. Commonly cast alloys for pump components include:

CA6NM: A low-carbon martensitic stainless steel with excellent mechanical properties, fracture toughness, cavitation resistance, and weldability. ideal for high-stress, corrosive environments.

WCB: A medium-carbon cast steel frequently used in pressure containing applications such as valves, vessels, and pipework due to its strength, toughness, and weldability.

316 Stainless Steel: An austenitic stainless steel alloy containing chromium, nickel, and molybdenum, offering superior corrosion resistance particularly in chloride rich or chemically aggressive environments.

CD4MCuN: A cast super duplex stainless steel that combines the corrosion resistance of austenitic grades with the strength of ferritic steels, optimized for use in highly corrosive or abrasive conditions.

Additionally, BIMAC routinely casts nickel-based superalloys such as Inconel (e.g., IN625, IN713) and tin bronze alloys such as C90500, supporting diverse applications across the pump, power, chemical, and marine industries.

To ensure metallurgical precision, BIMAC utilizes an in-house optical emission spectrometer (OES) to analyze and verify the chemical composition of every heat prior to pouring. This quality control step guarantees full compliance with customer specifications and industry standards.

With complete control over alloy formulation, melt chemistry, and casting operations, BIMAC delivers expedited castings with no delays due to material availability or third-party dependencies.

Finishing Castings for Pump-Repair

By the end of the third week following order receipt, BIMAC typically completes the casting process. Our facility is fully equipped to perform all essential post-casting operations, including gate and riser removal, precision grinding of runners, and comprehensive ceramic shell extraction. Special attention is given to internal cavities and impeller flow passages, where precise cleaning is critical to ensure functional performance. In addition to casting and cleaning, we also ensure proper heat treatment or annealing operations as required by the material specifications. BIMAC works closely with several heat treatment partners located within a five-mile radius of our facility, offering a full range of thermal processing services including normalizing, annealing, solution treating, aging, and quenching to meet customer specifications and material property requirements.

BIMAC’s workforce is highly trained in the specialized cleaning protocols required for rapid prototype castings, particularly for components with complex geometries such as impeller vanes, narrow passageways, and discharge ports. Our expertise ensures that all internal features are meticulously cleaned, free from residual ceramic material or inclusions preserving both hydraulic efficiency and dimensional integrity for downstream machining.

By the fourth week, castings are prepared and shipped to the customer, allowing for immediate transition to final machining and pump reassembly. This streamlined workflow minimizes system downtime and supports rapid restoration of critical operations.

Ensuring Quality

In this industry, speed of delivery often determines the winner, but rapid turnaround is meaningless without uncompromising quality. At BIMAC, we prioritize getting the casting process right from the start to minimize defects and reduce returns. Our experienced process engineers leverage Solid Cast casting simulation software to optimize the design and placement of gates and risers. This virtual simulation is essential for accurately predicting mold filling, solidification patterns, and potential porosity, enabling proactive defect prevention. By ensuring sound castings upfront, we achieve consistently fast turnaround times even for low-volume, urgent orders.

We comply with all customer-required testing protocols to ensure our parts fully meet specifications. While we do not perform non-destructive testing (NDT) in-house, we partner with a NADCAP-approved NDT provider located right next to our facility, offering a broad range of inspection services with next-day turnaround to support rapid delivery.

Figure 2: Solid Cast casting simulation of BIMAC part

BIMAC: A Trusted Supply-Chain Partner for a High-Value Industry

Since BIMAC began producing small quantity pump component castings with expedited lead times, our order volumes have doubled – an indicator of the critical value our parts provide in maintaining essential systems. Whether it’s keeping water flowing, delivering power to homes and businesses, or supporting transportation infrastructure, we play a vital role in sustaining operations across multiple industries.

While the cost of a cast pump impeller or housing is modest compared to the economic impact of restoring a processing facility or pipeline, we take great pride in serving as a trusted supply chain partner to the pump and pipeline sectors. To consistently win short lead-time pump repair jobs and meet delivery commitments, BIMAC has purposefully structured our facility, rigorously trained our workforce, and cultivated strategic partnerships.

Our ability to offer rapid delivery on small orders, particularly for pump repairs, also stems from the practical application of Lean Manufacturing principles. Key practices include reorder point raw material replenishment, organized and efficient shop floor layouts, and operator cross-training all designed to eliminate bottlenecks and minimize processing delays.

We have built a responsive, agile system that matches the urgency of the industries we support because we understand that casting parts is not just a manufacturing task it’s about keeping critical infrastructure operational. BIMAC’s success demonstrates that speed, precision, and reliability are more than objectives; they are the foundation of the real value we deliver to our customers.