Application Stories

CORSA Improves Productivity and Weld Quality Using STT And Robotics

Problem
Reducing spatter and increasing production speed while maintaining high weld quality on thin gauge, stainless steel parts used in specialty exhaust systems for high-performance vehicles.

Solution
Lincoln Electric's pre-engineered System 10 robot welding cell with an Invertec® STT power source featuring the Surface Tension Transfer® process.

Results
Dramatic reduction in per-part welding time, the virtual reduction of spatter, and excellent weld quality. 
 
CORSA Performance Inc.A manufacturer of high performance stainless steel marine and automotive systems uses Lincoln Electric's system 10 robotic welding system to dramatically improve production and weld quality.

Performance vehicle owners love the roar of their engines while accelerating. But that same sound translates to a head-pounding drone and resonance during cruising speeds, making it hard to hear the radio or carry on a conversation.

CORSA Performance, Inc. of Berea, Ohio, developed its patented (Reflective Sound Cancellation) technology to deal with the issue. This unique muffler technology offers noise-suppression during cruising, and enhances the engine sounds during full-throttle acceleration.

 

About CORSA Performance
CORSA Performance is an engineering and manufacturing company that specializes in high performance stainless steel marine and automotive exhaust systems. CORSA is the only marine/auto aftermarket manufacturer in-house hydro forming capabilities. The company also has titanium welding and forming capabilities.

The first automotive muffler system developed by CORSA was intended for the fifth generation Corvette (C5). Before the system even went into production, it was selected for installation on the 1998 Indianapolis 500 Pace Car. Since that time, business has exploded, thanks to a growing enthusiasm for the Power-Pulse RSC Reflective Sound Cancellation exhaust system among car buffs.

The Challenge
Reducing spatter and increasing production speed while maintaining high weld quality on thin gauge, stainless steel parts used in specialty exhaust systems for high-performance vehicles.

CORSA Performance, Inc. of Berea, Ohio needed to find a way to increase production volumes and eliminate bottlenecks caused by the company's manual TIG welding methods. According to Jim Browning, CORSA's owner and president, weld quality was just as important as high volume. "When a CORSA system is pulled from the box, the first thing the customer notices is the welds," said Browning. "So while production speed was important to us, we also needed a system that would create consistently high-quality, spatter-free welds."

 
Solution
Lincoln Electric's pre-engineered System 10 robot welding cell with an Invertec™ STT power source featuring the Surface Tension Transfer® process.

System 10 Robotics

The system 10 is a pre-engineered, two-fixed table welding workstation, which is assembled and shipped ready to install. It utilizes a six-axis Fanuc ARCMate 50iL robotic arm with 3 kg payload, and Fanuc R-J3 controller. Lincoln recommended this system to CORSA because it is well-suited for applications with small parts. An operator is able to load and unload one side of the cell while the robot welds simultaneously on the other side - facilitating excellent production rates.

Because of the thinness of the stainless steel used in the parts, Lincoln recommended the STT II power source to CORSA. Unlike standard CV MIG machines, the STT has no voltage control knob. The STT uses current controls to adjust the amperage independent of the wire feed speed. This makes it much easier to make welds that require low heat input without melting through the base material. Also distortion, spatter and smoke is minimized.

"We took our parts to Lincoln and watched as they welded them on-site with the robot," said Paul Goth, Robot Programmer/Process Engineer at CORSA. "The quality of the parts Lincoln produced was what finalized our decision to buy the System 10."


The Result
Dramatic reduction in per-part welding time, the virtual reduction of spatter, and excellent weld quality.

After CORSA's new System 10 robotic arc welding system was installed in September 2001, welding production improved from 44 to 180 mufflers per day. CORSA quickly realized that the arc welding robot could be utilized to grow business in other areas, and has since converted 12 of its manual welding stations to robotic stations.

 
C5 Corvette and Camaro Muffler
Automated Welding on End CapThe C5 and Camaro muffler is a long, 22-gauge, 304 stainless steel oval cylinder-shaped case with an 18-gauge end cap. The end cap is a stamping that comes into the CORSA Performance plant from an outside vendor while the case is rolled and formed in-house. At the welding stage, the System 10 robot completes the welding by making two 28" fillet welds around the circumference of the part on each end cap. The C5's thin case is prone to melt through, yet needs to have a weld with good penetration. For the C5 application, CORSA uses a tri-mix gas (90% Helium, 7.5% Argon and 2/5% CO2) with .035" 316Lwire. Before automation, it took one TIG welder 20 minutes to weld one C5 muffler. Today, the system 10 is able to produce the muffler in under two minutes. And since a single production worker can operate the robot, the company's skilled welders have been reassigned to other welding duties.

 

A MIG weld that looks like TIG
After welding, all parts are polished to either a satin or a mirror-like finish. "The advantage of STT technology is that we don't have to deal with spatter, so we can go straight to polishing, saving us labor time," remarked Goth. "The robot gives us high quality MIG welds that look like TIG welds."

According to Goth, STT and the System 10 provide smooth, strong welds that have excellent fusion. "We fee that the weld quality we are getting now is even better what we were getting with manual TIG methods. The welds are more uniform, much straighter and you don't see the starting and stopping points as you do with TIG welds," he said.

"Since switching to the robot, we are still getting compliments on our welds from customers." CORSA Performance is also pleased with how easy it is to changes welding parameters when setting up welding procedures. I can change one setting, such as amperage, and not have to worry about affecting other parameters like wire feed speed," noted Goth. "The machines can even be programmed to do such unique things as a weave pattern. And, we have reduced scratches and other blemishes that resulted from too much part handling with manual welding methods."

CORSA Performance Inc.

By switching to robotics, we not only benefit from increased throughput in our system, but the cost of each part has gone down," Said Browning. "Since installing the robot in our shop, we have reduced the backlog in our sales and been able to meet customer demands. We couldn't be meeting our current production volume without it. It will pay for itself many times over."

Bottom line, the System 10 has increased per-day production volumes by 500%

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Originally Written 2/18/03

 

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