Briggs & Stratton Introduces Automated Welding with ABB Robotic Docking System

In 1996, the Specialty Products Division of Briggs & Stratton, located in Milwaukee, Wisconsin, expanded its services after 15 years of exclusively manufacturing commercial engines.  Specialty Products became responsible for the manufacturing, design and engineering of engine components for its parent company.  Eventually, it expanded to serve other OEMs as well.  

Although Specialty Products offered a full range of component manufacturing and finishing services, the company outsourced all its welding, until recently.

To round out its list of services and reduce outsourcing costs, Specialty Products decided to bring the welding of a 6 hp InTek engine muffler in-house.  The complicated nature of the welds posed a problem, however, since the muffler was made of two metal types and three metal thicknesses.  Specialty Products found the solution in an ABB Flexible Automation robotic welding system.

"When we looked at the difficulty of the welds- involving variations in welding heat and travel speeds-we knew it was more efficient to get a robot and operators than to hire welders," says Rob Poehlein, manufacturing engineer, Specialty Products Division.  "With skilled welders being so rare and unemployment at an all-time low, we felt automation was the best option."

Confirming the decision to automate, Specialty Products' calculated a return-on-investment of less than two years and the creation of six new operator jobs for the company.

After months of considering automation systems, Specialty Products chose the ABB RDS -1400P robotic docking system with a Miller Electric Auto Invision welding power source.  To make automation integration simple for the customer, ABB Flexible Automation referred Specialty Products to a local automation systems integrator (ASI), Machinery & Welder Corporation, Milwaukee, Wisconsin.   Using Specialty Products' specifications, Machinery & Welder worked with ABB and Miller to put the entire system together.  This included coordinating the components, including the robot, power source, wire feeder, water cooler, fixturing and indexing table.  Since ABB and Miller have teamed up with other automation leaders to form the ITW Welding Automation Alliance, ASIs can gather resources from all the Alliance members to provide fast and efficient set-up and operation, along with optimal compatibility.

The RDS-1400P robotic docking system incorporates indexing or stationary tables.  It is pre-wired and interconnected for easy setup.  The system includes a six-axis IRB-1400 robotic arm, an Auto Invision with internal control and pulsing capabilities and a Miller CoolMate"! 4 water cooler.

The biggest selling point for Specialty Products was the optional BullsEye® system, a feature not offered by any other robot line it considered. The BullsEye system monitors the tool center point and automatically makes any necessary adjustments.  The system also adjusts for contact tip wear and changes in wire, verifies that the robot arm is accurately calibrated and automatically updates torch angle.

The Process
The welding process for the mufflers on Briggs & Stratton's InTek line of small engines begins when the operator fixes two sets of parts comprised of a muffler assembly, a bracket and a tube onto the indexing table.  When the operator pushes a button, the table rotates and stops in front of the welding arm where it makes one 3/4 in. lateral and two- 2.5 in. orbital welds to join the tube to the bracket and the muffler assembly (using 035 solid wire and 90/10 Argon/CO2 gas).  While the arm is welding on one side, the operator is unloading the welded mufflers and re-loading new parts onto the other side.  The whole cycle takes 90 seconds (or 45 seconds per muffler).

"We supply components to other OEMs in addition to Briggs & Stratton, so we never know what projects we will work on in the future," Poehlein says.  "Right now we are quoting muffler welding for other companies, and perhaps later we will do some totally unrelated welding.  That's why it was so important that we get a flexible system that allows for many options."

Power Sources
Flexibility is the reason Specialty Products chose the Auto Invision inverter-based power source over a traditional transformer-type welder.  Although the Auto Invision's pulsing capabilities are not currently utilized, the option is available if a future project calls for it.

"I recommended the Auto Invision to Specialty Products because its power and control make the system more flexible," says Joe E. Campbell, vice president and qualification and certification manager, Machinery & Welder.  "The Auto Invision gives the operator control over all the different parameters, much more so than a non-inverter power source.  This option is important because Specialty Products doesn't know what projects will come up in the future, and what parameters will be required for those projects."

Once the muffler welding was in-house, Specialty Products decided to bring the muffler component manufacturing in as well, thus creating two new stamping jobs.  Making the parts internally helps Specialty Products hold tighter tolerances, control the consistency from batch to batch and modify the design of the parts for tighter fit-up.  The result is a higher quality product.

When Specialty Products installs additional systems and begins welding other parts, quick die change plates on the RDS-1400P will make switching from one project to another simple and fast.  This will improve lead times because Specialty Products will be able to react to and fulfill a variety of product orders quicker.

Training
As an ASI, Machinery & Welder also provided initial programming and operator training to be sure Specialty Products was prepared to use their new automated welding system.

"I spent two weeks of initial programming and then hours of sample production to make sure the welding was just right,"' Campbell says.  "We continue to provide technical assistance and service whenever they need it, but now they know how to handle all programming internally."

The systems were easy to program for Poehlein.  Although he had no previous robotics experience, he had no problems learning ABB's Easy Arc program.  Poehlein has also found the RDS-1400P system to be very reliable.  While a loose fixture or an operator error may slow down production temporarily, the robot itself is seldom the cause. 

"The system and the program are very consistent," Poehlein says.  "We work with a very tight time table, so that kind of dependability is important."

Now that the RDS-1400P is working well for Specialty Products, Poehlein sees a potential for the growth of robotics in other areas.

"The system has opened the door for robotics, not just welding.  There is a possibility for material handling, assembly and more.  We've had a good response from employees wanting to run the robots because they sense that it's something that is here to stay in our industry."