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New Robotic System Provides Quality Welds and High
Productivity to Exhaust System Manufacturer
 High performance vehicle owners love the roar of their engines while accelerating, but with most exhaust systems, this sound translates into a
head-pounding drone and resonance during cruising speeds. This makes it hard to hear the radio or carry on a conversation with a passenger. To correct this problem, CORSA
Performance, Inc. of Berea, Ohio, has developed a patented Power-Pulse RSC® (Reflective Sound Cancellation) technology. This muffler technology allows CORSA to provide the
necessary noise-suppression during cruising, yet enhance the engine sounds during full throttle acceleration.
Because of these attributes, the CORSA Performance Power-Pulse mufflers
have been utilized on a host of vehicles, including Corvettes®, Camaros®, Firebirds®, Dodge® VipersTM, Cadillacs®, Chevrolet® and GMC® Trucks and
S.U.V.'s, among others. Recently, the company's catalytic converter-back exhaust systems have even become a General Motors® Service Parts Operations Licensed Product.
 High demand for these exhaust systems prompted CORSA Performance personnel to look for ways to increase production volumes and eliminate the bottlenecks
caused by the company's manual TIG welding methods. To do this, CORSA Performance teamed up with Lincoln Electric and introduced an arc welding robotic system into its operation in
September 2001. The robot did exactly as it was intended to do... " increase welding production volumes of the company's popular Power-Pulse muffler for the C5
Corvette from 44 mufflers to 180 mufflers per day.
In addition to the mufflers, CORSA Performance soon discovered that the arc
welding robot could be utilized to grow business in other areas. The company, which is also the largest manufacturer of exhaust systems for the marine industry,
has since routed 12 automotive and marine parts from manual welding stations to the robot. And, because the robot only requires one operator, skilled welders are
free to take on other work at the 58,000-square-foot, 89-person facility.
Although increasing production volumes was a major impetus for purchasing a
robot, according to CORSA Performance Owner and President Jim Browning, the consistent quality a robot could provide was a critical factor in the decision.
"Since we provide exhaust parts for high performance vehicles, as soon as our systems are pulled from the box, the first thing the customer notices is the welds,"
said Browning. "For this reason, it was of the utmost importance to have a robot that would not only aid in our production goals, but also create a high-quality, spatter-free weld."
To accomplish these welds, CORSA Performance turned to The Lincoln Electric
Company's pre-engineered System 10 robot welding cell with a Surface Tension Transfer® (Invertec® STT II®) power source. This power source is able to
produce a weld with reduced spatter and offer controlled heat input, which is necessary on the thin gauge, stainless steel parts that are used in CORSA Performance's exhaust systems.
Exhaust System Creation
CORSA Performance, which opened its doors in 1989, is an engineering and
manufacturing company that specializes in high performance stainless steel exhaust systems for the marine and automotive aftermarket. Founded by Jim
Browning, CORSA is the only manufacturer in the marine industry and automotive aftermarket to have in-house hydro forming capabilities. CORSA also has titanium welding and forming capabilities.
Formed to supply the marine industry, CORSA Performance currently enjoys an
85% share in this market, supplying well-known boat manufacturers such as Baja Marine®, Donzi®, Formula®, Cobalt® and Crownline®. In 1998, the company
expanded to the automotive industry. The first muffler system developed by CORSA for an automotive application was intended for the fifth generation
Corvette (C5). Before these even went into production, the muffler was selected for installation on the 1998 Indianapolis 500 Pace Car. Since that time, business
has grown tremendously as more and more car enthusiasts discover the attributes of Power-Pulse RSC Reflective Sound Cancellation exhaust systems. The result
is a "tuned" muffler that "cleans up" the noise without eliminating the pure sound of power associated with a high performance vehicle. CORSA's stainless steel
Power-Pulse™ line of mufflers are tuned to each vehicle to eliminate passenger cabin resonance and to produce just the "right" sound.
Finding a Solution
With approximately 85% of CORSA's parts requiring welding, finding a solution
outside of the traditional manual welding methods was critical. Although the company investigated a number of different robotic welding systems when it
decided to automate the welding process, CORSA ultimately chose the Lincoln System 10 because of its capabilities and local service availability.
 "We took our muffler parts to Lincoln and watched as they welded them on-site with the robot," said Paul Goth, Robot Programmer/Process Engineer at
CORSA Performance. "Seeing the quality of the parts produced made us decide on the System 10."
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 ARC Mate 50iL robotic arm with 3kg payload, and Fanuc R-J3 controller. Lincoln Electric recommended this
system to CORSA Performance because it is well-suited for applications with small parts.
The unit features a complete metal surround flash and safety barrier and bi-fold
safety doors with interlocks. With this unit, a CORSA Performance operator is able to load and unload one side of the cell while the robot welds simultaneously
on the other side â€" further helping to increase productivity rates.
Because of the thinness of the stainless steel, Lincoln recommended the STT-II
for use at CORSA Performance. 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 which require low heat input without melting through the base material. Also, distortion, spatter and smoke are minimized.
Welding Operation
 Parts that are welded robotically at CORSA Performance are chosen based on their volume and throughput in the shop. Each part design has
its own set of fixturing and tooling which is built in-house in their tool room. "Your imagination is your limitation," noted Goth. "If a part is currently
being MIG or TIG welded, I imagine the System 10 robot welding the part and then determine if the robot can do the job with the proper fixtures."
There are currently 12 parts welded by the
System 10 at CORSA with many more planned for the near future. To provide an example for this article, we will focus on the two most popular components in each of the company's market segments.
C5 Corvette and Camaro Muffler
The 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" 316L wire.
Previously, it took one TIG welder 20 minutes to weld one C5 muffler. Now, the
System 10 robot is able to produce the muffler in under two minutes. Since one production worker is able to operate the robot, the skilled welders have been
reassigned to other welding duties. Using the robot, production volumes per day have jumped by 500%.Â
Marine Silencer Tips
This part consists of a 16-gauge, 316L stainless steel formed case with a ring
welded onto it. The tubing for this part is cut to length and formed by CORSA, while the ring is purchased from an outside vendor. The welding for this part
requires the robot to make four small stitch welds to hold the ring inside the tube and then one continuous 12" circular weave weld around the outer circumference
of the part. For all the marine parts, CORSA uses a tri-mix gas (90% Helium, 7.5% Argon and 2.5% CO2) with .035" 316L wire.
In the past, the silencer tip was welded manually using TIG, which could take from
three to five minutes per part. With the arc welding robot, welding time has been reduced to 35 seconds per part.
After welding, all parts are polished to either a satin or a mirror-like finish. "The
advantage of the STT technology is that, without the problems associated with spatter, we are able to go straight to polishing, saving us labor time," remarked
Goth. "The robot gives us high quality MIG welds that look like TIG."
According to Goth, the STT and System 10 provides smooth, strong welds that
have excellent fusion. "We feel that the weld quality we are getting now is even better than 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," said Goth. "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 change 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 machine 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."
"By switching over to robotics, we not only benefit from increased throughput in
our system, but the cost of each part has gone down," claimed 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."
Programming and Service
One of the most important aspects of purchasing a welding robot, especially for a
company that has never ventured into robotics before, is being able to program and troubleshoot the machine.
Goth, is now responsible for developing welding programs for all the company's
parts. "Lincoln did the initial programming for the C5 muffler, but since we've added more parts, I've been able to do all the programming in-house," said Goth.
"I went to a three-day training seminar at Lincoln Electric where I learned the basics and learned the rest by working with the robot and testing its capabilities
. It really is easy to program but can be difficult to get the picture perfect weld. It has definitely been a real learning process for me. I consult with several of our
expert welders to help me obtain a weld that is strong and looks nice."
Once Goth installs a program, the operator has to simply push a few buttons on
the robot's teach pendant to call up a specific program. This makes it easy to switch from one part to another.
Goth has also been pleased with the service Lincoln has provided. "When we run
into a problem, I've just had to call the company's hotline and the technicians have walked me through the solution. They won't hang up until the problem is corrected," said Goth.
Future
In the future, CORSA Performance plans to move more business from manual
welding to the robot. "The robot has enabled us to stay ahead of demand, and will help us continue to expand our business," said Browning. "We are continually
looking for ways to increase quality and reduce costs. |
