Data Collection Leads to Reduced Scrap, Increased Quality
Having been in business for more than 150 years, Intermet is considered an expert in designing, engineering, and manufacturing castings from ductile iron, aluminum, magnesium, and zinc. The operation has a capacity of more than 700,000 tons annually. With headquarters in Ft. Worth, TX, the corporation consists of three multi-plant manufacturing divisions: ferrous, die cast, and PCPC (pressure-c...
Having been in business for more than 150 years, Intermet is considered an expert in designing, engineering, and manufacturing castings from ductile iron, aluminum, magnesium, and zinc. The operation has a capacity of more than 700,000 tons annually. With headquarters in Ft. Worth, TX, the corporation consists of three multi-plant manufacturing divisions: ferrous, die cast, and PCPC (pressure-counter-pressure casting, an advanced aluminum casting technology). Intermet’s products include chassis, brakes, powertrains, and interior auto body components, and can be found on vehicles produced by most major auto manufacturers.
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In the early 1990s, Intermet began working with GE Fanuc Intelligent Platforms, implementing Proficy HMI/SCADA iFIX monitoring and control at its Columbus, GA, foundry, one of four facilities in the ferrous group. The goal was to speed production data-collection and -sharing throughout the plant. Applications expanded quickly, and the company has now upgraded to version 4.0 and added Proficy Historian 3.0 and Real Time Information Portal 2.5 to the package.
In 1999, the company began integrating work by its division manufacturing systems programmer, Tom Ihrie, into the Proficy system. Assisted by GE Fanuc system integration partner Advantage Industrial Automation, Duluth, GA, the company developed a way to improve its ability to collect critical process spectrometer data and generate reports on casting metal quality. What began as a data collection system was soon helping boost efficiency and make decisions about plant operations.
"When we started looking at data monitoring, we found many of our issues were driven by scrap," says Mike Smith, the facility’s process improvement manager. "We’d look at product trends one day and everything looked good. The next day they’d be bad. When you see those kinds of ups and downs, you know something in your own process is making it occur. With a process as large as ours, with several interconnected functions and so many variables, a lot can go wrong. We launched this project because we had to learn more about our process so we could stop saying ‘I don’t know.’"
Data into action
Among the most significant benefits of Intermet’s data collection system has been the reduction of scrap due to improved process accuracy, in particular when measuring pouring temperatures. "If you are off by a couple of degrees, you have more scrap," explains Ihrie.
The improvements have helped make the cast more precise, adds Smith. "Sand or slag inclusions are our number one scrap problem. Reducing these is where we see the biggest benefits. But there have been other benefits as well. The system allows us to customize and personalize screens, so technicians can create their own process displays and determine how and what they want to see. The temperatures they take go directly into the data capture system, eliminating manual operations and paperwork."
Before the spectrometer data project, operators would manually burn a sample and record data from the analysis instrument. Now tighter control using Proficy means more tests can be made. In fact, the number of burns has risen from 40 to 300 per shift, giving operators more time for engineering and production instead bookkeeping. "These are highly-trained technicians who were wasting time doing paperwork," says Smith. "Now they have more time and can take more samples. This helps us learn more about our process."
Smith provides an example of how the system helps Intermet maintain quality and pinpoint problems: "Molding is a key area where three process interactions are critical: green sand properties, the ramming and delivery of the molds, and the iron pouring of the molds. At any one instant, any of these variables can cause issues. Historian lets me put the variables together and see how one affects the other. I don’t have to call IT and ask them to compare this to that. I just pull the data up on the screen. I can do this with any parameters the system captures."
Adds Buxkemper, "If we are concerned about a property of a metal or of the manufacturing process, the system allows us to determine which parts were affected—or more importantly which parts were not affected. We can isolate the problem and not have to scrap more parts than were affected because we can go back and show definitively when and where a problem occurred and which parts we need to be concerned about."
Intermet’s data collection system also impacts energy management, an important area in an industry with melting operations that consume large amounts of electric power. "We cycle our equipment based on demand to save energy, and anticipate the demand based on startup time," says Smith. The company also reduces electricity use by monitoring air pressure in some compressors. Turning units off and on as needed saves about $10 to $15 an hour.
To meet environmental compliance requirements, Intermet must keep records for the Environmental Protection Agency (EPA), as baghouses and dust collection systems are inherent to this industry. "We’ve hooked our baghouse monitoring system to the data collection system so that it gives us real-time performance information," says Smith. "Employees used to walk around the plant each shift taking readings by hand. Now the system captures the data and the EPA is happy with our digital records because they are more accurate."
The Columbus plant has reduced scrap by 1%, or approximately 4,400 tons of castings since 2004. "Alloys are expensive," notes Buxkemper, "so consistently tracking the chemistry the way we do now ensures we aren’t wasting money by adding too much of an alloy." The company consistently saves about half a pound of copper per ton of castings, a significant amount at a facility capable of producing 140,000 tons of castings a year.
The success of the Proficy system at the Columbus ferrous plant has led to its roll-out at the other three ferrous plants. The company completed the installations before the end of 2008 and is already accruing benefits at all four facilities.
Although Intermet did not set out to be green or to achieve sustainability, many of the results it has achieved turned out to be just that. It has reduced the number of production cycles and cut energy use. Products are more consistent, made more efficiently, and higher in quality. "We were focused on efficiency and conservation before it was the thing to do simply because it helped us save money and be more competitive," says Buxkemper.
And this is only the beginning, insists Smith. "If you look at the economy and the automotive industry, this kind of system is more important than ever because it lets you focus on the process controls that impact your manufacturing costs. Industries across the globe are facing re-structuring and downsizing, which only amplifies how important it is to drive performance and eliminate that ‘I don’t know’ factor."
|Jeanine Katzel is a contributing editor to Control Engineering. Reach her at firstname.lastname@example.org
Delicate coordination required for ferrous castings
At the pouring deck, the two processes come together in an operation that requires impeccable coordination. If the ladles don’t move to the pouring deck fast enough, you run out of iron and some of the sand molds go to waste. If the ladles move to the holder deck too fast, the molten iron backs up. Once removed from the holding furnaces, ductile iron must be poured within about 15 minutes. Too long and it must go back to the furnaces for reprocessing, which is costly and inefficient.
Assisted by GE Fanuc system integration partner Advantage Industrial Automation, Intermet’s division manufacturing systems programmer Tom Ihrie developed a creative way to work with Proficy to capture data about how fast molds are produced and ladles are moving (or not), to make sure the two are aligned.
Complete process tracking
Molding: The system captures key operation parameters that make good castings. Operators can troubleshoot a temperature, machine, sand, or chemistry problem in minutes instead of hours.
Melting: The system monitors furnace efficiencies in real time, allowing operators to react to issues much faster.
Finishing: The system monitors and controls blast efficiency in real time, bringing costs to all-time lows. Mill amperage is also tied in; if a casting gets hung up, the system recognizes it, stops the mill, and backs it up, preventing damage and saving money.
Chemistry analysis: The system helped the plant achieve 100% chemistry analysis feedback on the floor and automatically capture data.
Maintenance: The system monitors performance instead of a person manually gathering results. It is also a tool to troubleshoot equipment issues.
Quality: The system organizes data about quality and makes reports available to those who need them.