Lincoln Electric Developed Custom Automated Robotic Welding Solution for Bit Block Assembly
at Joy Mining’s Franklin, PA, Plant
All Joy Mining products are distributed and supported by the company’s 46 facilities, located in eight countries around the world – Australia, India, China, Poland, Russia, South Africa, the United Kingdom and the United States.
Welding is an essential step in the Franklin facility’s production of longwall and continuous miner systems used for the underground extraction of coal and other bedded materials, such as salt, potash, gypsum and oil shale. Longwall mining accounts for about 50 percent of global underground mining production, while continuous mining covers about 45 percent.
The company recently moved a portion of their semi-automatic welding systems to automated GMAW (MIG) welding for the bit block and pedestal assemblies produced at the Franklin plant for these mining systems. These assemblies hold the massive, custom bits that drill into the rock surfaces in underground mines.
The welding process
According to Craig Cerminara, A & R welding engineer at Joy Franklin, the company sought to move 98 percent of the bit block-to-pedestal welding activities to an automated system from semi-automatic MIG welding.
At this station, workers attach bit blocks made from treated, air-hardened steel to a carbon-steel pedestal via semi-automatic MIG welding. One welder can fabricate between eight and 10 bit blocks in an eight-hour shift. Each of the plant’s three shifts have six to eight welders at the bit block station, welding the assemblies and adjusting the angle radius of the block, depending on the customer’s specifications. Joy Mining management knew it was time to streamline the process while increasing the production rate.
“All companies face challenges in today’s economy, especially those in heavy manufacturing. Obviously we were looking at as many different solutions as possible to make necessary process improvements. First and foremost, we were seeking to increase our productivity and reduce costs, while maintaining quality manufacturing,” Cerminara notes. “Automation was one option that really stood out to allow us to introduce a more modern solution to our bit block-to-pedestal welding process. We weld a great number of these parts, and they lend themselves well to automation, so we decided to seek a custom solution to help us achieve this.”
Detailed metrics and evaluation
To ensure that the company would find the right integrator to match its automated welding needs, Cerminara and his team put together a detailed evaluation system to compare manufacturers, their products, and their services, evaluating each supplier’s offerings and abilities on 32 different metrics.
“The metrics were designed to measure and compare each of the integrators against one another for all of the services and specialties we thought would be important to support Joy as a company,” Cerminara explains, noting that some of the key metrics included the following:
• Demonstrated ability to provide “complete support” for the automated system
• 24/7 technical support
• Overall integration of the cell
• Cost of the system
• Weld quality
“Many of integrators we were considering scored very well on all of the metrics, but in the end, Lincoln Electric’s Automation Division scored the highest and was the best fit for what we wanted to do here at Joy Mining,” Cerminara notes.
Cerminara says Lincoln Electric fared well in a number of the metrics. He cites such factors as accurate cycle time estimates, overall system cost and the willingness to provide ongoing support for the custom system after installation as three leading reasons why Lincoln Electric won the contract. But, other influences also figured prominently into the decision.
Beyond internal process improvements and savings, Joy Mining also wanted to remain dedicated to providing the global mining industry with products that would hold up to harsh underground environments and heavy use – anywhere on the map.
“When we were making our decision on which automated system to use, we also took into account the global reach of the supplier we selected,” Cerminara says. “Lincoln Electric’s ability to provide support around the world was another contributing factor.”
The shop also uses a pre-engineered automated system from Lincoln Electric to perform etching of serial numbers and other alpha-numeric information on various parts manufactured at the plant. Prior experience with this system helped Cerminara become familiar with the capabilities Lincoln Electric could provide when offering a custom automation solution.
“We wanted an integrator that would take responsibility for all aspects of the system, not just the robot,” Cerminara explained. “We already had a history with Lincoln Electric welding systems and knew the company would step up in any situation and take care of any challenges and necessary troubleshooting.”
After reviewing the results of their metric evaluation, Cerminara and his team decided to replace nine semi-automatic Lincoln Electric Idealarc® DC-655/LN-10 stations used for bit block-to-pedestal assemblies and install two automated welding stations in their place. The custom-designed solutions feature Power Wave® 455M high performance, inverted-based welding power sources, FANUC ARC Mate® 100iC robotic arms, and Harris® Preheat Torch systems and temperature-sensing devices. The systems use Lincoln Electric SuperArc® L-56 premium mild steel MIG wire in .045 (1.1 mm) inch diameter.
Once the automation system started making production welds, Cerminara and his team were able to track notable changes in productivity. To date, the conversion to automated welding has resulted in an 8 percent increase in bit block-to-pedestal assembly productivity. Additionally, it has saved more than 12,000 hours of work annually.
“We can weld the same number of assemblies with one operator running both stations per shift. In the past we needed between 6 and 8 welders to manually produce the same number of parts. With automation, we need only 3 operators per day vs. the 18 to 24 required in the past,” Cerminara says. “Automation has made the difference we thought it would. When you look at the productivity increase, the return on investment and other numbers, all of those metrics have been met or exceeded with the installation of the automation equipment. Overall, the results have been spectacular.”