Fan-tastic Castings: Putting a Spin on Supply Chain Management

Commercial fan manufacturer Big Ass Fans is handling its rapid growth through open relationships with its suppliers.

Shannon Wetzel, Managing Editor

(Click here to see the story as it appears in the January/February issue of Metal Casting Design & Purchasing.)

Large industrial fans spin silently above the open-air office environment at Big Ass Fans (BAF) in Lexington, Kentucky. They are the ever-present symbol of the company’s mission and foundation. Started in 1999 as the HVLS Fan Co. by Carey Smith, the company looked to reinvent the market with massive ceiling fans that moved a high volume of air at a low speed. When customers kept referring to these fans as “big ass fans,” a new company name and image was born.

The company model that relies heavily on engineering, research and development, and cutting edge marketing has created tremendous growth. From 2009 to 2015, BAF grew from  about 150 employees to more than 800, working in facilities worldwide to provide huge ceiling fans to manufacturing facilities, gyms, stadiums, restaurants and now even homes.

BAF has used cast metal components in a variety of its products from its inception, and use has grown and evolved as the company has grown and evolved. All the while, the fan maker has stuck to its original principles of pushing R&D and sourcing components locally.

“There are a lot of benefits [to relying on locally-made components]—supporting local economies, less waste and all that,” Smith said. “But quality control is our biggest reason. We assign a quality control engineer to each one of our suppliers to make sure the components they make match our strict design requirements. We work closely with suppliers as we develop new products and, in the rare case that an issue arises, it’s simply easier and quicker to work with a local supplier than an overseas supplier. The closer they are, the more agile they are.”

Sean O’Brien is a purchaser at BAF who has been with the company for eight years—through the major growth spurt. He works with upwards of 250 machine shops, metal fab shops, robotic welders, plastic injection molders, metalcasters, screw shops and metal spinners.

“We have a very good relationship with our current suppliers,” O’Brien said. “We lean on them pretty hard for new product introduction, but we get them involved early for their advice on designing the part.”

BAF basically created a market for itself in large industrial fans, so it is creating new technology, applications and standards for the air movement industry. It has dedicated R&D facilities creating and performing standardized tests regarding aspects like airflow and sound. Business development staff identify customer needs, and engineering finds solutions to meet those needs—and quickly. BAF assembles its fans, but all other manufacturing processes are through outside suppliers, and they need to be onboard with the speed, flexibility and quality that has given BAF an edge over its competitors.

 “We move fast, so complexity and confidence in the process are important to us,” said Richard Oleson, senior design engineer. “I personally have a fondness for casting. You can create a lot of details and I know what the part is going to be at the finish. Other processes, you have to put a lot of bolts and pieces together.”

When it comes to deciding what manufacturing method will be used to create a component, the product development team looks at the material and process that would best fit the task it has to perform from cosmetic and functional standpoints.

“We don’t do primary processing here. It sounds like a weakness but it leaves us completely free to choose the process that fits the applications, rather than sticking with the process that is on the shop floor,” Oleson said.  

Diecasting, which is the casting method most often used in BAF products, holds advantages of quality, detail and cost benefits for high volume production over other metal forming processes, and its surface finish is ideal for cosmetic applications. As Oleson explains, when fabricating with sheet metal, the material is pressed into a shape that is harder to keep within tight dimensional tolerances.

“You design a part, but the fabricator will take a flat sheet of metal and press it into what they hope is your shape. The material wants to spring back. The sheet of metal has to be formed in stages and a lot depends on how the metal reacts. With casting, you can make more complex parts but it is a simpler process.”

As BAF has developed new products, the use of diecasting also has grown, particularly with the launch of a line of fans for which BAF designed and assembled the motor two years ago. Coinciding with the design of the motor was a push to redevelop several components as die castings at the same time.

“It was the first time we assembled our own motor,” Oleson said. “We designed the detail, structural requirement, precise location of the holes, and how the blades would rotate about the center of the motor. Casting allowed us to design all the shapes we wanted to shed weight and allow a path for the internal electronics to get to the motor.”

This motor—for the Essence line—is not the company’s first foray into diecasting, but it was the first time it made a concerted effort to utilize the process upfront when it could be most advantageous. Because the company moves so fast in product development, a few past components that might have been perfect for diecasting ended up as extrusions or fabrications because of the long tooling time associated with diecasting. Some of these have been converted to diecasting, but the Essence was the opportunity to get the parts as die castings from the start.

One of BAF’s directives to product development is to make fans that are as efficient, unobtrusive and quiet as they can. To achieve this, the various components of the fans must work seamlessly together in balance. Design details like concentricity of holes, dimensional tolerances and feature locations all are critical.

“Diecasting has better process control [than other metalforming methods] and gives us the number of parts we need,” Oleson said.

During the design phase of the electronics enclosure for the Essence motor, BAF worked closely with its die casting supplier, Production Castings, Fenton, Missouri, to optimize designs and meet production deadlines.

“[Production Castings] has a relationship with other casting suppliers who do diecasting with a different spin—low volume rapid prototyping and investment casting,” Oleson said. “So we prototyped with investment casting and when we were happy there, we tooled up as a short run die casting—all before making a hard production tool. By the time we did the hard tooling, we knew a lot about the product. I don’t know if we would have done it that way if the opportunity was not there.”

Production Castings and BAF first connected at a trade show where O’Brien and Production Castings sales engineer Mark Preuss talked in great length about how the two companies might be a good fit for each other. About a year later, the fan manufacturer presented an opportunity to the casting supplier to produce a component on a tight deadline.

“Sean needed us to produce a die cast mold and provide first article samples that included secondary machining and powder coating in eight weeks or less,” Preuss said. “We accepted the challenge and they sent a supplier quality manager to visit us. Working closely with him and Sean, we were able to meet the challenge and the rest is history.”

At BAF, every supplier is assigned a quality engineer who examines each source for cost, quality and delivery. Before becoming a supplier, a company is visited by a quality engineer who will look at the infrastructure, evaluate quotes and review on-time delivery statistics.

“We have an ongoing process of finding new suppliers,” O’Brien said. “It starts upfront with the visit and going back and forth with quoting. We expect them to be upfront with us, and we are upfront with them in regard to volumes and forecast.”

O’Brien said he wants to know from the supplier what happens to the purchase order when it shows up in their inbox. He wants to know what the process is with the order after the account manager receives it, and what the checks and balances are for how it will be produced. 

“We ask for accurate lead times on our quotes so we can plan our lead time around that,” he said. “And anytime we get an updated forecast, we communicate that to the suppliers. When we partner with someone, we are very open as far as numbers we are going to need.”

This openness continues through the engineering and design stages of product launch. Through the prototyping phases of the diecast motor enclosure mount, engineers at BAF worked closely with the casting supplier to make adjustments through the initial prototype, soft tool and hard tooling phases.

“On new projects, engineering works with us in advance to make sure the designs are feasible. Once the product line is in production, the engineering team is always ready to assist us with any quality and productivity improvements that we may want to implement,” Preuss said. “They understand our processes and are always open to new ideas to help us make a better casting.”

The result for the enclosure was a more sophisticated part, Oleson said.

“We adjusted the shape of the curve, the details on the inside of the cap, and the cross-hatchings on the lid,” he said. “Our suppliers know their process better than us, so it is not uncommon for them to make recommendations to improve the function or manufacturability. The earlier diecast part we made was not as complex.”

The volumes and speed to production required by BAF steered the company to diecasting, but it had used sand cast and permanent mold cast components for a time in earlier years. You’ll still find some sand castings in the gearboxes the fan maker buys from a local manufacturer. But for the most part, BAF uses aluminum and sometimes zinc die castings and this use will likely grow, O’Brien said, as the company continues to rapidly expand further into the commercial and residential markets, as well as lighting.

“I think we’ll continue with a strong need for castings in the future, because of the finishing capabilities, as we are getting into custom-type product lines,” O’Brien said. “It’s going to just continue to grow.”

ighter, stronger aluminum components is the ultimate goal in a recently started research project that joins industry, research and academic institutions to develop innovative manufacturing solutions and transfer them into real-world production.  
In August, Lightweight Innovations for Tomorrow (LIFT) announced a new project intended to advance technologies for diecasting and heat treating aluminum parts, primarily for aerospace, defense and automotive applications.
“If we can reduce just a few ounces of metal from automobile engine mounting cradles or the housings that hold transmissions, we can deliver an impact that is multiplied by the millions,” said Larry Brown, executive director, LIFT. “In aerospace, an added benefit might lower manufacturing costs as well as increase fuel savings from the lighter weight designs.”
LIFT is operated by the American Lightweight Materials Manufacturing Innovation Institute and is one of the founding institutes in the National Network for Manufacturing Innovation, which is a federal initiative to create regional hubs to accelerate the development and adoption of cutting edge manufacturing technologies. It was formed in 2014, and the vacuum diecasting project is one of the first two started. The other project focuses on thin-walled gray iron parts.
Lead partners for the project are Boeing and The Ohio State University. The focus is to develop key process technologies (super vacuum diecasting and a shortened heat treatment) and computer engineering tools for 300 series aluminum diecasting alloys to improve mechanical properties and reduce the minimum wall thickness (up to 40%) and weight (up to 20%). According to Alan Luo, professor of materials science and engineering and integrated systems engineering, The Ohio State University, the project will reduce the variability in quality and improve the mechanical properties of high pressure die castings. The project also will explore new design methods of lightweight castings using local mechanical properties predicted by the new computer engineering tools, as opposed to the current casting design using minimum properties of cast alloys.
“If you can take a common part, such as an access panel you see on the wing of an airplane and use high integrity die castings, it could reduce weight and manufacturing costs,” said Russ Cochran, associate technical fellow, Boeing. “We hope to demonstrate that advances in high vacuum diecasting will produce parts that meet all the rigorous performance specifications we require, while realizing weight and efficiency goals.”
In current high-speed aluminum diecasting, microscopic air bubbles can form inside the part as the molten metal races through the mold. These tiny bubbles are not an issue for most diecast parts in typical applications, and engineers allow for them by using more metal and making parts thicker to meet strength and other performance requirements. These aluminum parts can achieve tensile strengths up to 47 ksi and minimum wall thicknesses of 0.04 in.
For this project, however, researchers are looking at methods to cast thinner walls with increased strength for structural applications, and for that, the bubbles can be detrimental. By applying a vacuum to the mold, diecasters remove air from the environment. Air is the culprit for porosity.
“We know in the laboratory that if we pull all the air out of the mold just before the molten metal flows in, we can eliminate the bubbles,” Luo said. “Without bubbles, we can design thinner parts that are just as strong and durable, but with less metal and lighter weight. There are other benefits, as well, because the new process allows us to heat treat parts after they are cast, which will improve their performance in service.”
The group also will be working on a shortened solution heat treatment to improve mechanical properties cost efficiently. A simple T5 heat treatment (where castings are cooled from an elevated temperature and artificially aged) has shown in preliminary work to increase yield strength by 40% for E380-type alloys. Now researchers want to see if a shortened T6 heat treatment (where castings are solution heat treated and artificially aged) can be developed to achieve even better properties in 300 series aluminum.
An important part of the two-year project will be enhancing the ability of computer models to predict the performance of aluminum diecast parts by combining information about the microstructure of the metal with a host of design and production parameters. The process, called integrated computational materials engineering (ICME), has great potential for reducing the time it takes to design and qualify new components for vehicles and will address some of the key challenges in implementing thin-wall diecasting technologies: die design, process control, casting design and process simulation.
Currently, castings are designed using the minimum properties of alloys as a baseline for the entire part. The ICME approach will allow designers to pinpoint higher or lower minimum properties to localized regions.
The aim is to connect the thermodynamic prediction of alloy composition and heat treatments to process modeling, which will enable designers to locate specific properties in specific areas of a part to meet service loading conditions. When load paths are clearly defined, the research group also plans on establishing topology optimization techniques to enhance design optimization.  
In the first three months of the project, the group has selected the baseline alloy (A380) and identified an experimental high strength aluminum alloy for structural casting development for aerospace and automotive applications. A concept design on a thin-wall casting die also has been started. The die is based on a thin-walled zinc die casting, which is being redesigned for aluminum. Researchers have begun mechanical property evaluation and ICME model validation in thin-wall casting development. Key real-world applications, such as an aerospace wing fuel door, to demonstrate the benefits of vacuum diecasting and ICME have been identified.  
“What we are doing here is bridging the gap between great research in laboratories and great manufacturing skills in private industry,” Brown said. “Once you bring these innovations into production, the results just multiply.”
Lightweight aluminum diecast components have a significant market to fill, particularly in the transportation industries, including aerospace, automotive, military and marine. Industry partners from these markets include Eaton Corp., Comau and Nemak. On the research side, Worcester Polytechnic Institute, Southwest Research Institute, the University of Michigan and Massachusetts Institute for Technology have joined the effort, while the American Foundry Society and North American Die Casting Association are assisting with modeling, technology oversight and dissemination of knowledge on how to manage the new thin-wall aluminum diecasting process in a production environment.
LIFT is operated by the American Lightweight Materials Manufacturing Institute and was selected through a competitive process led by the U.S. Department of Defense. It is one of the founding institutes in the National Network for Manufacturing Innovation, a federal initiative to create regional hubs to accelerate the development and adoption of cutting-edge manufacturing technologies.
After the two-year project is concluded, the group plans to deliver design guidelines and property specifications for thin-walled aluminum diecasting and ICME models for thin-wall casting design with location-specific properties. As these technologies and guidelines are incorporated into production diecasting operations, the options for aluminum components in structural applications will expand.   ■