Hydroforming

Dana’s approach to employing high-pressure hydroforming technology has enabled its customers to reduce weight, improve quality, and enhance overall product performance in a cost-effective manner.

The tubular hydroforming process involves the application of fluid pressure to the inside of a tubular blank, which is captured within a mold cavity that defines the shape of the finished part.  The internal fluid pressure is then increased to force the tubular blank to expand into conformance with the mold cavity, thus taking the shape of the finished part.

At one time, machine limitations prohibited Dana from cost effectively applying the high-pressure hydroforming process to larger structures.  So the company designed its own hydroform machine, called the Robo Clamp™ press.  Using a “purpose specific/part optimized” design philosophy, the Robo Clamp press has lowered the threshold for economic feasibility of applied hydroforming.  The company currently has five Robo Clamp presses that have 10,000 to 14,000 metric tons clamping force and bed lengths up to 5 meters.

Dana recently began supplying structural systems to the Ford Motor Company for its Ford Expedition and Lincoln Navigator sport-utility vehicles.  The structural systems are produced using Dana’s Robo Clamp technology.  The hydroformed side rail consists of a single piece "tubular" design, which eliminates multiple stampings and results in significant weight reduction over comparable stampings while conforming to the packaging constraints of the vehicles.

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Hydroformed Driveshafts

The development of hydroformed driveshafts is a joint effort between Dana’s driveshaft and structural systems engineers.  Their integrated knowledge of hydroforming, crash protection, and energy absorption is providing value-added technology to the driveshaft environment.

Hydroformed shaft systems can have integral crush initiators formed in the tube structure.  The process will allow a driveshaft to be formed from tubing and assembled without traditional machined tube yokes.  Hydroformed driveshafts will be lighter and stronger and require fewer component welds.

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Magnetic Pulse Welding and Forming

Magnetic-pulse welding gives Dana customers more flexibility in tailoring driveshafts to specific needs and applications.  Driveshafts have been prototyped and developed initially for 89 - 102 mm tube diameters with 2.1-mm wall thickness.

The current equipment can be tooled for up to 150 mm diameter thin walled tubes for light-duty and medium-duty applications.

“Our magnetic-pulse welding process allows us to join steel and aluminum components to create a wide variety of innovative driveshaft designs,” says Jim Duggan, a chief engineer at Dana.  “The result is a bond that outperforms conventional MIG welding and other metallurgical joining processes.”

How It Works

The process creates an intense magnetic field by rapidly downloading large amounts of electrical energy into a specifically designed coil.  When an aluminum tube is subjected to the magnetic field, it collapses inward with sufficient force to weld itself onto a stationary component, such as a steel or aluminum end fitting.  The process produces a solid-state weld that uses no heat, and the machine tooling controls the component orientation.

Steel components can withstand the high stresses associated with small diameters while aluminum provides the advantages of corrosion resistance and light weight.  Marrying these materials with the improved magnetic-pulse process allows Dana to design lightweight, compact components using the benefits of the materials and the process. 

Flexibility in Frame Design

Dana engineers have begun to explore more-advanced uses of this technology.  For example, engineers in Dana’s Structural Solutions Group have recognized the potential for welding aluminum and steel to fabricate lighter frames and other structural components.  The process is presently being used to develop new structural products, including a new line of full-size, light-truck frames.

Joining Metals and Composites

Dana engineers are using magnetic-pulse welding to join different metals on a molecular level, resulting in extremely strong, structural bonds.  With a combination of pulse forming and pulse welding, they have also developed a way to assemble structural composites and metallic components together.  This process allows the seamless integration of resin composite members into traditional metallic structures.

These advancements collectively allow Dana to design unique, lightweight, compact components that take advantage of the benefits of each material involved. 

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Advanced Line Sequencing

Owensboro, Kentucky, U.S.A. Facility

A light blinks on at Dana’s frame manufacturing facility in Owensboro, Kentucky, U.S.A., signaling completed assembly of a Tundra pickup truck or Sequoia sport utility vehicle 73 miles away at the Toyota plant in Princeton, Indiana.  Time to build another frame.

That’s lean manufacturing the Dana way.  Dana is the only light truck frame manufacturer in North America to build and ship light truck frames in sequence to match the customer’s order.

Dana uses an advanced line-sequencing process with Toyota to build in lot sizes of one.  The process reduces inventory and increases efficiency.  Fourteen frame models are built on one assembly line in random order, which means fast changeovers (less than one second). 

This precise process is possible due to on-line communication between Dana and Toyota.  Dana’s Production Instruction System automatically sequences orders on the assembly line. After final inspection of the frame, it is stamped with a serial number and sent to the paint department.  After painting, bar-code and identification labels are applied and the frame is ready for transport.

The light signaling a completed truck at Toyota is one of 25 on a large display panel at Dana’s facility.  When all the lights are on, 25 frames are stacked on a truck and shipped to Princeton.  On the return trip, the same truck delivers parts to Dana to keep its production lines running at peak efficiency.

The result?  The entire process, from order to delivery, takes only 8.7 hours, helping Toyota get its trucks and SUVs to market faster.