Shop Solutions: Tooling Up for Machining Motors
Located in the heart of the South Texas petrochemical area, Bradleys' Electric Motors (Corpus Christi, TX) is a recognized leader in all motor-repair fields, handling motor sizes from fractional to 25,000 hp (18,650 kW). Bradleys offers large electric-motor repair, large electricmotor storage and maintenance, and new-motor sales from its 59,300 ft2 (5509 m2) facility.
In 2008, the company decided to expand its manual machining shop to a CNC shop to meet the schedule for delivery of a machined shaft for its largest customer. It invested in three CNC machines, including a Sun Firm CST 4160 lathe, an Atrump M-class VMC with Centroid controls, and a horizontal milling machine model HMC-100 from Machining Systems. The new HMC was modified to accommodate a 60 x 72 x 40"(1524 x 1829 x 1016 mm) in the X, Y, Z axes, as well as an integrated four-pallet changer and 48-piece toolchanger.
Prior to these machines being installed, Bryan Faircloth, who had served as Bradleys' quality and safety manager, and two other machinists attended CNC programming classes to learn how to program and run the equipment. After one machinist got sick and missed the training course, while the other headed to another opportunity, Bryan took on the shopfloor responsibilities, as well as the title of CNC programmer and manufacturing manager.
"Mind you," says Faircloth, "At this point, I didn't even know what an insert was. After I headed down the road of hard knocks, a friend of mine, Javier Martinez, who worked at Extreme Tool, told me he was a Seco distributor. Javier came in along with Seco Tools Technical Specialist Brian Joshlin, and suggested trying a Seco tool on the lathe, establishing our first successful joint project."
What Faircloth liked about Seco was that Brian Joshlin was always there. "Brian came in about once a month; he'd basically stand there and train me. Not only did he say this tool would work, he showed us how," says Faircloth.
To clinch the relationship, he had been calling around to various tooling suppliers to find a large tap needed to produce a sole-plate component. Previously manufactured by outside suppliers, Bradleys' was bringing the part in-house now that they had acquired the new vertical mill. The plate, which measured 20 x 14 x 2" (508 x 356 x 50.8 mm) is what very large motors sit on, so it must be rigid enough to allow for secure bolting to the I-beam. This required the creation of a substantial thread, which the Bradleys' suppliers had been achieving by first creating the bolt holes using a 1.25"(31.7-mm) tap, and then threading. The taps would only get through 3–4 parts before breaking.
When Faircloth contacted Seco about the project, Brian Joshlins asked: "Why are you using a hand tap that large when you can threadmill the hole?" He suggested using Seco's threadmills, which helped improve both production and safety on the sole plate. "It may not have been a huge overall efficiency gain," he states, "but it was the catalyst that opened the door to our relationship with Seco."
The clincher was Seco's ability to streamline Bradleys' processes on a unique boring job. Bradleys had a stator frame that was 30" (762-mm) in diam and 46" (1168-mm) long, which required the creation of a 30.313" (770-mm) diam through the entire length of the bore. The company could not find a supplier able to deliver a boring tool that was capable of handling the operation in less than five to six weeks.
Before the new HMC, was purchased, the workpiece was actually placed on end in a vertical turret lathe (VTL) to perform the boring operation. The setup was awkward, and the machining took hours upon hours. "Just imagine having this huge motor sitting on top of a turret lathe, spinning at 200–300 rpm," observes Joshlin. He suggested that Bradleys try Seco's lighter weight aluminum Jumbo Bridge Bars, which can bore out holes up to 7' (2.1-m) in diam.
The CNC milling center's capacity allowed the company to switch the stator boring operations to that equipment, running it at 200 ipm (5 m/min) with a 0.008"(0.20-mm) feed/tooth. "Now, we can bore out the entire diameter in 45 min. Plus, the quality and finish are excellent," says Faircloth.
The Seco Bridge Bar was long enough to enter the frame from one side and go all the way to the center. The boring bar was removed from the workpiece, the frame was rotated 180°, and then the other side was machined to a seamless finish. The tool and the machine were so rigid that there was no visible transition line, and the accuracy was repeatable within a few tenth-thousandths of an inch from part to part.
The investment in the horizontal milling center had been justified when Bradleys decided to start building its own 1500-hp (1119-kW) AC electric motors. This project required the production of stators that need drilling. The company had been accomplishing this task manually, in addition to relying on outsourcing to area machinists. However, each component was taking about a month to produce, and the process was riddled with problems.
The base for the stator requires drilling 1.625"(41.3-mm) holes in the bottom of a plate. "They were using the Seco Perfomax indexable insert drill, but they were not sure how much to push the performance," Joshlin explains. "They were being overly cautious in the machining parameters, and it was taking about an hour to drill the four holes on the new HMC."
"When Brian came in, he told us to increase the rpm from around 800 up to 3000. We were now drilling all four holes within 40 sec. That was exciting," Faircloth says.
The new equipment investments are paying off for Bradleys to the point where it has established a separate facility in Gregory, TX, to handle all the manufacturing work. This new location is home to all the new CNC equipment. One of the largest lathes in Texas, the resident lathe is kept busy almost 8 hr/day, just producing frames for a motor order, motor shafts, and other related parts.
Seco Tools has played a critical role in helping Bradleys develop its machining strategies. The 48-position automatic toolchanger on the horizontal milling machine is currently filled with 33 tools--all Seco-brand. "I do have a few local tools I purchase," Faircloth admits, "but for the most part, we're using about 98% Seco products."
For more information on Seco Tools, go to: www.secotools.com or telephone 248.528.5200.
Software Speeds Time to Market
Using advanced sheetmetal fabrication and machining technology, coupled with rigorous quality methodologies, has enabled Magnus Hi-Tech Industries Inc. (Melbourne, FL) to win customers in the defense, aerospace, medical, and other demanding fields.
Magnus Hi-Tech provides highquality solutions to the full range of its customers' fabrication needs. With a range of products that includes holding brackets and complex components for military simulators, plus housings, struts, mounting blocks, impellers, and military chassis, to name just a few, the company is called on to respond to a diverse array of fabricating and machining needs.
The company's equipment lineup includes laser cutting and EDM as well as CNC turning and milling machines. The newest member of this lineup is a Variaxis 630-5X II five-axis milling machine from Mazak Corp. (Florence, KY). "It's able to machine five sides of a cube in a single setup, drastically reducing changeover times and machine downtime," reports Mike Blake, methods engineer/program manager for Magnus Hi-Tech. The unit also has the ability to perform its own in-machine measurements and data collection with a CMM-type touch-probe, essentially self-adjusting its programming and tooling to ensure that close tolerances are maintained by monitoring tool wear and part-to-part variations.
Part of being good is knowing that you are never good enough, and this commitment to continuous improvement led the company to seek a way to reduce engineering and CNC programming times, and reduce time to market.
The solution was found in CAMWorks solids-based CAM software from Geometric Technologies Inc. (Scottsdale, AZ), a subsidiary of Geometric Ltd. (Mumbai, India). It provides an array of tools to simplify and automate even complex programming tasks, speeding design and programming changes. Its intelligent connection between the solid model and toolpath generation provides associativity between CAD and CAM functions. This allows CAMWorks to identify and recalculate toolpaths based on the changes to the part model.
For example, when the depth of a pocket is changed, CAMWorks can update the toolpath automatically. CAMWorks also supports CNC programming of multiple parts for production machining, and offers an accurate representation of the virtual machining environment. The design and layout of machine components, parts, workpieces, clamps, and fixtures provide a realistic representation of the machining environment. This not only helps the manufacturing engineer as he develops the program, but also the machine operator on the shop floor, who has access to set up documents that show where the parts and fixtures are positioned on the machine.
A key aspect of CAMWorks is its integration with SolidWorks, the features-based CAD program used by many metalworking shops, including Magnus Hi-Tech. "We are a fabrication house that can produce our customers' products from prototype to production," says Blake. That journey from prototype to production is rarely a straight line. Changes frequently occur as problems and opportunities surface, and those changes can be time-consuming.
"We used to have to reprogram the whole part with our previous CAM software," recalls Blake, "or else use the CAD package associated with that software, which would not bring our SolidWorks model up to the new revision."
CAMWorks was purchased in part, in the hope that it would eliminate such problems.
"There have been parts, for instance, where a customer has needed to move some hole positions, or a pocket was moved to a different location. We used to have to reprogram the model. With CAMWorks, which can work inside SolidWorks, we just change the model to the new revision, automatically regenerate the toolpath, then repost it to our Mazak mills, and we're ready to run," Blake explains.
"CAMWorks' ability to automatically accommodate changes to the part model, eliminating a lot of time-consuming CAM-system rework due to design updates, makes true associative machining possible," says Blake. "Time savings are considerable."
One of the ways in which CAMWorks is able to speed CNC programming is through Intelligent Machining, a suite of tools that automates the generation of toolpaths. Within this suite, Automatic Feature Recognition (AFR) has the potential to cut hours off the time it takes to move from design to finished part, through its ability to automatically identify and define prismatic machinable features.
AFR Technology does this by analyzing the solid-model geometry and identifying mill features such as holes, slots, pockets, and bosses; turning features such as outside and inside profiles, faces, grooves, and cutoffs; and wire EDM features such as die openings. AFR recognizes these features regardless of the CAD system in which they were created.
Further speeding the design-tomachining process is Geometric Technologies' TechDB (Technology Database). Using knowledge-based machining technology, the database associates tooling, machining strategies, and parameters to the features. When operations are generated, CAMWorks applies these settings automatically. Significantly, the rules in the TechTB are fully customizable, enabling companies to incorporate their best practices.
"I routinely use Automatic Feature Recognition in creating fixtures for our machining operations," notes Blake. "Together with the Technology Database, it enables CAMWorks to automatically select the right drills and taps. We used to spend most of the day programming fixtures—not anymore."
Production of a military chassis required machining a series of complex prismatic parts, a job that had to be done accurately and on time. Using CAMWorks, Magnus Hi-Tech was able to create complex machining programs for its Mazak five-axis mill, quickly make any required revisions, and generate designs and toolpaths for the needed fixtures.
Blake notes that CAMWorks' tight integration with Magnus Hi-Tech's SolidWorks environment facilitates true associative machining, so that any revision to a part design updates the SolidWorks solid model, as well as the CAMWorks file, permitting CAMWorks to automatically generate the new toolpaths, the tool list and, if required, the fixture modifications as well. This has resulted in timesavings on revisions ranging from 20 to 60%.
Forging Company Sees Saw Advances
By utilizing a new billet-cutting saw, a midwest forging company is realizing faster throughput on its billet blank preparation with a high degree of accuracy and an anticipated 20-year service life, without major rebuilding.
Clifford-Jacobs Forging Co. (Champaign, IL) is a supplier to aerospace, off-road construction, mining, forestry, truck, military, rail transit, and the oil/gas equipment markets worldwide. The company's forgings are used in products as diverse as giant machines that tunnel deep into the earth and military aircraft that fly at supersonic speeds.
Founded in 1919 by Cass Clifford and David Jacobs, the origins of the company tell a remarkable story of tenacity and determination to succeed. Following a fire that nearly destroyed the business and the onset of the Great Depression, Jacobs and the company's one employee cut, forged, and trimmed an order of 300 service hubs for Chevrolet—at fifty cents apiece. To save additional shipping cost, the men loaded the product into wheelbarrows and hauled them to the local rail station in Champaign.
Today, the company focus is clearly on the forging process, which employs 1500.25,000-lb (680.11,340-kg) steam hammers, but the billet-blanking saw department is where the process begins. Here, one of the original Metalcut billet-cutting saws, the sixth one ever built by Willy Goellner in 1971, still functions, cutting billets up to 12" (305-mm) diam to prepare the blanks for the forging process.
Goellner designed and built these saws for Metalcut at his company, now called Advanced Machine & Engineering Co. (AME; Rockford, IL). Today he remains chairman, running the business along with his sons. He has since designed a new generation of saw called Amsaw for today's cutting needs, based on state-of-the-art machine technology.
AME still supplies its billet-cutting saws to Clifford-Jacobs, and has recently installed one of its latest developments, the Amsaw S300, for use on 3–12" (76–305-mm) billets, though the customer here primarily uses it for 6–9" (152–229-mm) stock.
"We process a very wide variety of materials here at Clifford-Jacobs, and we use the Amsaw for all but some aerospace and stainless grades," says Mike Snell, vice president-manufacturing. "Materials include carbon, alloy, and bearing steels, calcium-treated, VIM-VAR, and customer-supplied proprietary grades from such leading companies as Caterpillar, Westinghouse, GE, and Boeing Aerospace."
In the sawing department, long bar stock is offloaded by overhead crane and fed directly onto the saw tables. On the new Amsaw S300, a PLC maintains the precise feed settings and monitors the loading system. According to AME, this particular style of carbide billet-cutting saw outperforms a bandsaw by a factor of eight at less cost per square inch of material cut. Snell says that, while Clifford- Jacobs has not studied that particular comparative aspect of the saw's performance, he is certain the Amsaw makes a discernable difference in the overall output of the sawing department at his company.
The same grind is used on all saw blades, and though Clifford-Jacobs uses a local source for new blades and resharpening, all machine service and the rebuild/upgrading work on the AME saws is purchased through the manufacturer, as part of a scheduled predictive maintenance procedure in place at Clifford-Jacobs.
"Our contact at AME, Steve Swanson, has been with Willy [Goellner] at the company almost since the beginning. We can call on him and know our work is being handled by someone who is familiar with us, our needs, and the particular requirements of our process," says Snell, who has been with Clifford-Jacobs for 21 years.
Beyond this personal closeness in the working relationship, the performance of the Amsaw is what most appeals to Snell, who says they can hold ±0.010" (0.25 mm) or better tolerances routinely on the material blanks, including the hardest materials processed at Clifford-Jacobs. He credits the design of the Amsaw machine, using pivot point rather than older way technologies, for the unit's ability to maintain this consistent cutting action.
The Amsaw S300 at Clifford-Jacobs was one of the first such machines installed, and Snell admits there were some difficulties at the outset. "The initial problems took some time to solve, but AME and C-J stuck with it and, in the end, we got exactly what we wanted from the machine. That's a credit to both AME and us. When you've relied on a supplier for so long, it's worth having them as a cooperative partner. We'd like to think our customers have the same attitude towards us."
The smaller saws in the department have been rebuilt approximately every eight years, according to Snell, who predicts the Amsaw S300 might go 20 years before requiring a rebuild. "We use the machines constantly about 50 hr each week, with only a routine maintenance shutdown every July."
The new equipment and the training that AME provided for the three operators in the Clifford-Jacobs sawing department was thorough and allowed nearly immediate production to occur. Says Snell: "Our Total Quality program mandates continuous improvement in management tasking, production reporting, and especially in equipment upgrades to maintain the highest level of quality and consistency possible, all of which were realized in the training and acquisition of the Amsaw S300."
For more information on Advanced Machine and Engineering, go to www.ame.com or telephone 815.962.6076.
Robotic Trimming for High-Tech Plastic
Trimming a strong, lightweight fiberglass bonded to a thermoformed part presented a significant challenge to the developer of the Tool-less Engineered Composite (TEC) system. Plastics Unlimited (Preston, IA) manufactures custom-thermoformed products including automotive and recreational vehicle trim, shipping pallets, packaging materials, covers, and shrouds.
Established in 1993 by Terry and Nancy Kieffer, the company has since grown into a 67,750 ft2 (6294 m2) facility. Its capacity was expanded in 2004 with the acquisition of Fabri-Glass Composites (Moline, IL), which specializes in composite molding, molded fiberglass insulation, and waterjet cutting.
The TEC system allows fiberglass to be bonded to a thermoformed part, creating a product with a Class A finish that is lightweight and extremely strong. Dropping a concrete block from 20' (6.1 m) doesn't damage or mar a part as large as a small riding-mower cover. The toolless process uses the thermoformed shell as the tool surface in a closed-mold process to produce a durable product with a high-gloss finish.
The strength and durability of the TEC material are exactly the source of Plastics Unlimited's problem in trimming the materials with its robotic router. Each time a spindle needed to be replaced, the system would go down for a week, and cut quality would suffer as the router bits would begin to wear.
After receiving a large order from a new customer for TEC parts, management recognized the need for increased trimming capacity, and began to look for a reliable trimming solution that would improve part quality and increase production. Ben Clarke, design manager, says that the company had seen KMT Robotic Solutions (Auburn Hills, MI) at a number of industry trade shows, and was impressed with the company's capability and process technology.
After reviewing process requirements with KMT's engineering and sales teams, Plastics Unlimited sent parts to KMT's Process Solution Center to be tested on both waterjet-cutting and router-trimming systems. The company selected the KMT JetTool waterjet cutting system. "The waterjet trimmed the material much more easily than the router," says Clarke.
The waterjet trimming process reduced the amount of part finishing and sanding required by 60%, and eliminated the need for a dust-collection system. The waterjet cutting system also included KMT's system calibration tools, AccuFind and CamPro offline programming software. AccuFind is a combination of hardware and software used specifically on parts that tend to warp, bow, or shrink from their original dimensions. It uses a sensor to determined the location of the part's critical features, and then automatically offsets the robot program accordingly.
"The AccuFind system has been a godsend," says Clarke. "We probably couldn’t cut our parts without it, because they are intricate and vary in shape." The parts are made of a combination of plastic and a durable fiberglass backing, with plastic on the A side. The fiberglass is applied manually and tends to be inconsistent.
"Because we have AccuFind, we are able to fixture the parts on the B side instead of the A side," Clarke explains. "This allows us to trim the parts three times faster. The quality of the waterjet cut compared to the router is much better on our EC material."
The waterjet cutting system also includes KMT's CamPro software, which seamlessly converts CAD/CAM-generated trimming and milling paths into complete six-axis robot programs. It took a week to program two parts on the routing cell, which resulted in a week of downtime. Clarke estimates that it would have taken two team members about six weeks to program the twelve parts on the routing system without CamPro.
"CamPro is definitely the way to program a robot. The machine is running production while you're making changes to the program," says Clarke. "With the implementation of CamProwe were able to program the twelve parts and set up the robot in about three weeks." Clarke expects that programming time will decrease even more as operators become increasingly familiar with the CamPro software.
Since installing the JetTool waterjet trimming system, Plastics Unlimited has been able to increase trimming capacity, flexibility, and production quality. The waterjet system is currently trimming about 100 parts in an 8-hr period. The newfound flexibility has enabled the company to quote larger-volume projects and expand into new markets.
The company is planning to add more parts to its waterjet cell, and is looking into retrofitting the legacy router trimming system with KMT's accuracy enhancement tools and CamPro offline programming software. Clarke says that KMT's specialized training classes have helped Plastics Unlimited team members improve their part programming, intensifier maintenance, and software skills.
This article was first published in the February 2010 edition of Manufacturing Engineering magazine.