Supplier marries patented welding process with robot for a cost-saving cell
Supplier marries patented welding process with robot for a cost-saving cell
April 2012 - When a buyout prompted a Milwaukee-based automotive manufacturer to close its engineering department in 2001, the news spurred a new beginning for Chris Smith. “It forced us to be creative in a search for new employment opportunities,” he says. “At the time, I had been researching friction stir welding, and we saw a real business opportunity there. The emerging technology had the potential to make dramatic changes in joining materials at a substantial cost savings when compared to traditional welding methods.”
In April 2001, Smith co-founded Friction Stir Link Inc. with John Hinrichs in Brookfield, Wis. Today, the company houses more than 100 personnel and is using an IRB 7600 industrial robot from Auburn Hills, Mich.-based ABB Robotics, North America to provide a high-performance, low-cost friction stir welding work cell for economically sensitive industries.
The friction stir welding technology and production supplier is one of only a few licensed fabrication facilities in the United States with the expertise and equipment to provide customers with the patented welding process. The company offers development and design work, prototyping, fabrication and production services.
A new approach
According to Smith, friction stir welding was invented in 1991 by Wayne Thomas of The Welding Institute, Cambridge, England, and introduced in Europe in 1995. The process was first used to weld extrusions for marine applications before it was commercialized for use in other markets such as rail, heavy truck, automotive, aerospace and medical.
“Our initial job was to educate people here in the U.S. about the technology, demonstrate that the process could be successfully used and that the cost savings were significant enough to persuade companies to set aside the risk commonly associated with new technologies,” says Smith.
Friction stir welding is a solid phase (no-melting) process that uses the rotation action of a friction stir tool with specially shaped geometry to create friction that, in turn, generates the heat needed to mix and move material from one side of a seam or joint line to the other. Compared to traditional welding processes, friction stir welding improves static strength and fatigue properties and is less sensitive to contamination. Though not suited for the traditional T-fillet joints used in fusion welding applications, the process can be used for a variety of other joint configurations such as butt and dissimilar butt welds, lap penetration and lap fillet welds. Materials include aluminum, bronze, copper and titanium as well as magnesium, steel and plastic.
The first step involves designing parts specifically for the process. “In the automotive market, for example, where the design cycle can take up to three years to complete before a new vehicle hits production, someone has to determine up front that they are going to commit to this process,” says Smith. “That’s a big decision.”
Friction Stir Link landed its first major production job in 2004 for the marine industry. The company now fabricates panels for marine decking 10 ft. to 50 ft. wide and 10 ft. to 50 ft. long from aluminum 2 mm to 8 mm thick.
“We knew we wanted to incorporate robots to maximize our productivity and provide multidimensional welding,” says Smith. “Prior to 2001, robots didn’t exist that were robust enough to support friction stir welding. I was already familiar with ABB robots through my previous experience with the automotive manufacturer.
When ABB introduced the IRB 7600 in 2001, it was the industry’s first robot with a high enough payload to handle our welding process. The adaptability and flexibility of the robot provided us with a more efficient solution by helping to lower our labor and operating costs. We were also attracted to the equipment’s open control architecture. It allowed us to develop our own application software to make a friction stir welding robotic cell viable.”
Reduced operations
ABB is a global supplier of industrial robots, modular manufacturing systems and service. With more than 190,000 robots installed worldwide, ABB designs and produces systems that help manufacturers improve productivity, product quality and worker safety.
Friction Stir Link installed its first ABB robotic cell in 2004. The company currently has four robotic friction stir welding stations. Some stations are powered by custom machines because robots aren’t yet powerful enough to perform friction stir welding for applications that include, for instance, some aluminum alloys above a certain thickness level that require higher forces, says Smith.
“We still weld a lot of very large parts for the marine market,” he says. “The ability of the friction stir welding robotic cell to reduce non-value-added operations makes the cost reduction for these larger parts substantial. Once we were able to demonstrate with the marine job that the process worked, the door quickly opened to us for jobs from rail and heavy truck customers.” Smith also is seeing a transition from low-volume requirements to medium- and high-volume applications as acceptance for friction stir welding continues to grow.
This trend can be attributed, in part, to increased demand for lighter, stronger materials that can support greater fuel efficiency. “Manufacturers’ choice of these materials is pushing processes like friction stir welding to the forefront because of its suitability for these alloys,” says Mark Oxlade, welding manager for ABB Robotics North America.
“When you MIG weld, for example, all alloys have a heat-affected zone and react in different ways,” he says. “Generally, there is also some amount of clean-up that has to be done. Friction stir welding is able to join these alloys more easily and provide a superior joint because there is less heat input, yielding and smaller and less negatively affected HAZ. You don’t have to post heat treat the material, and typically, there is little to no clean up.”
The friction stir welding robotic cell also supports fabricators’ requirements for 3-D joining of dissimilar materials. Manufacturers of high-end vehicles in particular want the ability to join three or four different metals to achieve the right look, feel and sound for customers. “A seamless transition from metal to metal is essential for these applications,” says Oxlade. “The ability to friction stir weld different materials provides a high-quality consistency and a superior post-process result. Requirements for 3-D have been around but there wasn’t a robot that could perform 3-D in friction stir weld until now. The ability to combine a robot with friction stir welding for 3-D applications opens up new possibilities for users like Chris.”
Cost savings
Friction Stir Link designs its own tooling for parts produced with the robotic cell. “The robot has the flexibility to accept a wide range of parts as well as the tools we design to friction stir weld those parts,” Smith says. “Because the robot is programmable, we can easily change from tool to tool, and the robot is able to recognize which tool is positioned on the arm.”
The company produces 200 miles of friction stir welds per year to make panels for truck trailer beds. Panels are 8 ft. wide and 40 ft. to 50 ft. long. The cell’s ability to reap cost savings for customers is attracting smaller part work such as heat exchangers, automotive structural components and medical devices. The process also is being transitioned into fabrication of complex assemblies.
“We’ve been able to demonstrate significant quality and cost improvements so designers are beginning to take advantage of the process by designing products specifically for the process,” says Smith.
The primary objective for Friction Stir Link is to continue developing low-cost solutions able to manage the very high forces of its friction stir welding process. “Without robots, you have to use custom-built machines, which are more expensive and must be operated by a person,” says Smith. “The ability to partner with a group like ABB supports an exchange of expertise and knowledge that is mutually beneficial to our business goals.” FFJ
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