Specializing in high and low volume work, close tolerance machining and leak testing of aluminum castings for the automotive industry, Metal Technologies has spent the past 14 years developing its niche as a second-tier supplier to leading car and truck manufacturers. The company attributes much of its successes to fully automated manufacturing cells that utilize advanced machine tools from top suppliers such as Mazak.
Located in the small, discreet community of Bloomfield, Indiana, Metal Technologies works on several high-profile projects inside its 134,000-square-foot, ISO 9001:2008-certified facility. The company, consisting of 105 employees, takes a lot of pride in its work, which includes diesel engine oil pans, front and rear crossmembers for a popular sports car, hybrid bus housings, automatic transmission bell housings and six-speed transmission housings. Furthermore, the company makes much of its own equipment, machining fixtures and leak test systems.
Metal Technologies, founded by former GM employees, started out in 1996 as a metal fabrication company that supported its tool shop, Bedford Machine and Tool. In 1998, however, Metal Technologies kicked its production work into high gear after securing its front and rear crossmember program, which involves producing approximately 70,000 parts annually.
“The crossmember program was the stepping stone that got us visibility,” said Randy Lovelace, product development/field sales engineer for Metal Technologies. “Any time you work on parts for a high-profile vehicle, it’s going to give your company some name recognition. Due to this work, other automotive companies started looking our way.”
Following the crossmember program, Metal Technologies won the bid for producing oil pans for a diesel truck engine. At which point, the company realized it needed to further incorporate automation into its operations as a way to lower part costs, increase production rates, improve safety and successfully move its business into the future.
“We started out manufacturing 50,000 of the oil pans annually, and when you make parts like this that weigh between 50 and 60 pounds, you don’t want your employees repeatedly lifting such heavy weight. That’s when we knew we needed to purchase a robot and build our own end-of-arm tooling,” said Lovelace.
This particular oil pan project recently transpired into more oil pan work with a totally different auto manufacturer, requiring Metal Technologies to invest in its largest, most advanced manufacturing cell to date. Dubbed the “Scorpion,” the cell uses extremely high levels of automation to meet the stringent demands required for producing 6.7-liter oil plans for a popular diesel truck model over a five-year program.
With high production rates of 800 oil pans per day, the Scorpion cell includes eight Mazak HORIZONTAL CENTER NEXUS 5000 machining centers with pallet changers and broken tool detection, 11 Ethernet-capable Fanuc R-2000 industrial robots that load and unload parts and help transport them to final assembly, four conveyor belts, visual inspection equipment, a coordinate measurement machine, leak test equipment and process tracking capabilities.
According to Nick Shelton of Shelton Machinery, Metal Technologies’ Mazak distributor located in Fishers, Indiana, the shop is able to stay competitive and secure prominent automotive work because it is not afraid of taking risks when it comes to implementing complex automation into its operations.
At the beginning of the manufacturing process for the 6.7-liter oil pan, each aluminum casting, which measures 27” x 16” x 7”, goes through a stamping process and receives a barcode with serial numbers for future tracking purposes. The Fanuc robots then load the castings into the Mazak HORIZONTAL CENTER NEXUS 5000 machines, which run complete finished parts.
The company uses continuous pressure hydraulics on its robots to make sure parts stay clamped during the loading and unloading process. If pressure is lost, the cell will shut down. The company also uses air sensing on its fixtures to make sure the part is positioned properly inside the machines. If not, the cell will stop, which keeps the machines from crashing and possibly damaging their spindles.
Inside each of the Mazak machines, a casting undergoes two different machining operations: one while the casting is sitting upright and the other while the casting is on its side. A robot unloads and reloads each casting between the two operations. The cycle time for each machine to complete a finished part is about nine minutes.
“The Scorpion cell is an arsenal of highly intelligent equipment that is capable of making minor adjustments during the manufacturing process,” said Lovelace. “The cell follows trending so it can react accordingly. In other words, if the system sees a minor spike in something, it won’t necessarily react to it as it might only involve a chip being in the way.”
The high-speed, high-power Mazak HORIZONTAL CENTER NEXUS 5000 machining centers inside the cell all feature an 18,000-rpm, 40 hp spindle with an advanced compact integral spindle/motor design, allowing Metal Technologies to achieve rapid feedrates of 2,362 ipm per axis at 0.8G acceleration for quick starts and contouring.
Metal Technologies uses 60 tools in each machining center’s magazine, which mainly consists of tooling made out of diamond and cubic boron nitride. The CAM-driven tool changing in each of the HORIZONTAL CENTER NEXUS 5000 machines further reduces the company’s non-cut times by ensuring fast and reliable 2.7-second chip-to-chip tool change cycles.
According to Lovelace, he researched several machine tool brands for this program and one of the reasons he chose Mazak was because the HORIZONTAL CENTER NEXUS 5000 offered 30 percent more spindle power than similar competitive designs, which is key because the oil pan has an intricate groove that requires higher rpm processing. Plus, the machine’s travels of 28.7” in X and Y and 29.1” in Z provided Lovelace with the type of working envelop he needed.
Lovelace also noted that Mazak was also the only company that said Metal Technologies could operate a machine in a one-up setup; whereas the competition said two parts were required for each fixture. While two parts per fixture can eliminate tool changes and reduce overall cycle time, Lovelace discovered it would be more advantageous for him to have one part per fixture, allowing the company to save on fixture costs and achieve easier operation for the loading and unloading of parts.
The Mazak machine’s chip conveyor height was another major selling point for Lovelace. “Our Mazaks can accommodate chip hoppers triple the size of what competitive brands can. I’ve got eight machines running constantly and chip removal is a big deal for us. I’ve been able to cut my material handling in half thanks to Mazak,” noted Lovelace.
Another advantage of Mazak’s tall chip conveyor is that the coolant’s travel distance to the scrap hopper is longer. This provides additional time for more coolant to run off the conveyor and return to the machine tanks, as opposed to being dumped into the scrap hopper along with the chips. “Our machines use about 400 gallons of coolant, and our high-pressure systems hold about 100 gallons. So the more coolant we can reclaim, the less we need to purchase and the more we cut costs,” said Lovelace.
Once the Mazaks are done machining the aluminum castings, robots unload them onto the conveyors where they head to a wash bay for efficient chip removal. Metal Technologies must follow a cleanliness specification for this program. Therefore, at least once a day, an employee must randomly select one of the machined castings to take back to a lab for washing, drying and weighing. The sediment that washes off the part is required to fall within 10 milligrams of the original specification.
As parts leave the wash bay, a robot picks up one in 10 parts to audit and aligns it with a coordinate measuring machine to inspect all of its surfaces to make sure everything is within tolerance. At which point, the company also runs leak tests. Because the part has several critical features on it, the company also performs offline audits at random using another coordinate measurement machine that sits behind the cell.
Also as part of the manufacturing cell, Metal Technologies built its own human machine interface, or HMI, panel that is viewable from across the plant to help with monitoring the entire oil pan machining process. The HMI panel is tied into the cell and anytime something goes wrong with a piece of equipment, the panel sets an alarm and flashes red. The HMI panel also allows management to view the cell’s alarm history and see how long it took an employee to acknowledge an issue.
In addition to machining the 6.7-liter oil pans, Metal Technologies also performs assembly work on the parts, which includes adding tubing, plugs and gaskets. Upon leaving the manufacturing cell, an assembly robot scans each part’s barcode, which then feeds the information into a database Metal Technologies built for keeping tabs on the part throughout the entire assembly process.
Right now there are four stations that make up the assembly process. Currently, the part is at each station for approximately 90 seconds. However, Metal Technologies is working on reducing that time to 60 seconds per station to create a buffer should the company ever need to play catch up.
Once the assembly process is complete, the part weighs approximately 30 pounds and must undergo a final leak test. If the part passes the leak test, Metal Technologies has a robot with a camera take pictures of the part to verify that all of the features are properly in place. The photos are then stored into the company’s tracking system, and the oil pan makes its way to the engine assembly plant. And from there, the assembled engine goes to the vehicle plant.
“We want to make sure every oil pan is perfect and accounted for before it goes out our doors,” said Lovelace. “You don’t want to be responsible for any bad part making it to the vehicle plant because the fallout is horrible.”
While Lovelace is enthusiastic in seeing a plan come together and takes pride in his company’s ability to successfully launch a fully automated manufacturing system under a time crunch, he knows the high pressures involved in machining parts for the automotive industry versus other sectors. With the urgent demands and just-in-time logistics automotive companies require, one little snag in a production machine shop’s processes can wreak havoc on a vehicle plant and result in some very upset customers and lost business. But Lovelace says he isn’t too worried. His company keeps a bank of parts and purchases the most reliable, high-performance equipment on the market.