Technology Transformation at Croix Gear & Machining
Croix Gear & Machining leverages Gleason’s total solutions package to exceed customer expectations for spiral bevel gear quality and delivery.
When Wisconsin Governor Scott Walker criss-crossed his state earlier this year to pitch Wisconsinites on his ambitious “Blueprint for Prosperity” plan for tax relief and worker training, he made a point of visiting Croix Gear & Machining. The Hudson, Wisconsin, gear jobber, the governor said, “continues to invest in new technology, equipment, and its employees to ensure quality products for its customers. This is a great example of a company that depends on a competitive tax climate and a skilled workforce to continue to thrive in Wisconsin.”
Gov. Walker singled out Croix’s new Gleason Phoenix® 280C Bevel Gear Cutting Machine as exactly the type of technology investment that his plan is meant to encourage among all Wisconsin manufacturing companies. Today, Gov. Walker’s Blueprint for Prosperity has been signed into state law, and Croix’s 280C is more than living up to the governor’s generous praise, according to Croix Facility Manager Matt Johnston (and third-generation member of the family that founded and still owns the nearly 50-year-old company).
“‘To be exact’ is our company motto, and the promise we keep to our customers relative to quality, deliveries, and service,” Johnston said. “When capacity constraints necessitated making an investment in new technologies for producing spiral bevel gears, we bought the best — the 280C, along with the other Gleason technologies we purchased in a total package. They’ve transformed our operations in amazing ways.”
Phoenix and PowerDryCutting™: Faster Production, Quieter Gears
Like many manufacturers of spiral bevel gears worldwide, Croix Gear had long relied on its array of Gleason manual machines and Gleason solid cutters to produce spiral bevel gearsets using the continuous face milling method. While these tried-and-true machines have done the job for years, explained Johnston, many drawbacks now outweigh very few benefits.
“For example, we were using five of these older machines to produce large volumes of an important gearset for use in a commercial refrigeration unit gearbox,” Johnston said. “The customer’s low noise criteria for these gears could not be met with the quality levels (around AGMA Class 9) we were producing, so an additional lapping operation after heat treat was needed to remove high spots and generate an acceptable dB level. With installation of the 280C, we’ve significantly reduced cycle times for these gears, easily doing the work of all five of the older machines and achieving AGMA Class 12-13 quality, thus eliminating the need for a lapping operation downstream.”
The Phoenix 280C is ideally suited for PowerDryCutting, the Gleason process that combines high cutting feeds and speeds and dry cutting conditions with, in this case, Gleason’s Pentac® Plus Cutter System. Phoenix’s monolithic column is cast from an advanced polymer composite material for the thermal stability and damping needed for dry machining, and its clean work chamber and simplified guarding ensure that high volumes of hot chips are easily collected away from the cutting zone. It’s a superb platform for the Pentac Plus, a cutter system that couples Gleason’s AlCroNite® Pro-coated carbide stick blades with a cutter head newly engineered to improve the chip removal process and prevent the chip packing that often occurs in dry, high speed cutting. The end result: more productivity and longer tool life, according to Johnston.
“Not only are we cutting six to eight times faster, but our tools are lasting much longer,” Johnston said. “With the solid cutters, we may have achieved 1,000 pieces per life. With Pentac, we’re getting 450 pieces per sharpening and 70 sharpenings per blade, about 30 times more parts per blade life.”
Cutting Costly Nonproductive Time
Johnston also said that the 280C excels at cutting nonproductive time — absolutely critical at this fast-growing job shop where an expanding array of customers and part numbers necessitates frequent part changeovers.
“It’s like night and day. Changeover on the mechanical machines family to family, member to member, would require three to five hours; now we’ve cut that to just an hour on the 280C,” Johnston said.
Part of the savings in downtime is related to the design of the machine itself. While the 280C is the “jobber” version of the line’s more automated 280CX model, which comes with auto loader and chamfer spindle for chamfering in parallel with cutting, it does share in common with the 280CX fast workpiece and cutter changeover. For example, accommodating a new workpiece requires just a simple change to a collet mounted to the front of the spindle itself; a new cutter system is easily loaded on the cutter spindle by torquing a single center bolt. In addition, Croix’s 280C is the first jobber version of the machine to have an on-board chamfer unit. Now, Croix can perform an in-process deburring operation and eliminate both the time and safety issues associated with deburring by hand.
“When extra material is extruded out after a cutter pass in the heel, we can automate its removal with this system,” Johnston explained. “A probe unit touches off the top and root of the heel, teaching the chamfer unit the correct path for that particular gear. The chamfer unit and a ‘bastard file’ work in concert to quickly and effectively remove the material.”
A Complete System to Simplify Setup
But perhaps the biggest savings result from Croix’s use of a complete system of Gleason technologies, all working together, which allows the company to more quickly and accurately ramp up production of new parts. Typically, part changeover in a bevel cutting operation is a time-consuming and tedious process, heavily reliant on the skills and expertise of the operator. An entire part is cut on the machine, rolled with the gear or pinion mating master, and then it’s up to the operator to make an educated guess about how to dial in the machine to achieve the required tooth flank form and pattern. This could take a day or more and generate a considerable number of scrapped parts until it’s right. At Croix Gear, however, that time is now better measured in minutes rather than hours or days, thanks to installation of new Gleason inspection technology and the use of Gleason G-AGE™ bevel gear software to calculate machine corrections based on inspection results. The Croix system, purchased as a package with the 280C, included the upgrade of its existing Gleason Sigma series inspection system with the latest Renishaw® SP80H probes and Gleason’s powerful GAMA™ suite of inspection software, including spiral and straight bevel gear inspection modules. In just the last several months, Croix has added Gleason’s new 300GMS inspection system to its quality room, more than doubling inspection capacity as well as adding worm and worm gear inspection and surface finish measurement (for cylindrical gears only) — all powered by GAMA.
“Compare the old approach to how we’re doing it today,” Johnston said. “Now we cut a single tooth, quickly check it using GAMA, make machine corrections through G-AGE, port it with a thumb drive to the 280C, cut and check another tooth, then move into production. The system is fast, extremely dependable and, most importantly, not heavily dependent on the expertise or experience level of the operator.”
The Croix package also included a Gleason CB Cutter Build Machine, an advanced computer controlled bevel gear cutter setup and measuring unit. The machine is used to build and “true” Croix’s array of different diameter Pentac Plus cutters in as little as 45 minutes and to a high degree of accuracy. Blade re-sharpening and re-coating for the Pentac Plus cutters is performed at the Gleason Cutting Tools facility in Loves Park, Illinois.
“Regarding the 280C, anyone here who has operated the machine is in love with it,” Johnston said. “The significant gains we’ve made in capacity and quality gives evidence every day that our decision to purchase a total solutions package from Gleason was exactly the right one.”
Big Plans for Titan at Columbia Gear
Columbia Gear continues to expand its large custom gearing production capability with the addition of a new Gleason hobbing machine and advanced Gleason gear production and inspection technologies.
At 235,000 square feet, Columbia Gear’s central Minnesota-based custom gear production facility is one of the largest in its field. More impressive still is the investment the company has made in putting the full array of productive new manufacturing capabilities under its roof. With a customer base that’s a Who’s Who of all the major OEMs in everything from energy to agriculture, earth moving to mining, and the ability to produce a vast array of small, medium, and large spur, helical, and spline gears to AGMA 15 quality, Columbia Gear relies heavily on advanced technologies to both meet demand and separate itself from the competition. Today, the company is pushing the technology envelope yet again — this time with a new 2-meter gear diameter production capability and investment in Gleason’s new Titan® 1200H Hobber.
More Capacity, Three Times Faster Machining
Columbia Gear’s investment in a Gleason P 1600/2000 Hobbing Machine in 2012 gave the company an important new capability: the ability to meet surging demand for gears up to 2 meters in diameter. Even better, the machine is equipped with a highly productive internal hob head that, when equipped with the latest indexable-carbide insert gasher cutter technology, enables Columbia to produce internal gears three or more times faster than possible with a typical shaping operation. The performance and potential have been so impressive, said Columbia Gear Manufacturing Engineer Ken Stommes, that the company raised the bar even higher this year with the purchase of a Gleason Titan 1200H Hobbing Machine, for gears with diameters up to 1,200 mm.
“If the P 1600/2000 is good, then we expect the Titan to be even better,” said Stommes, a 35-year Columbia Gear veteran. “Investment of this kind is the only way we know to stay competitive. Couple that with Gleason’s track record at Columbia of good service and support from both Ludwigsburg and Rochester, and the Titan purchase made perfect sense.”
While the Titan is just now in the early stages of production, both Stommes and Columbia Manufacturing Engineer Chad Grewe speak highly of the new machine and its many capabilities. Most important, of course, is the machine’s ability to operate with the high speeds and feeds required to squeeze optimum performance out of the latest indexable-insert carbide cutters. This requires exceptional machine stiffness, rigidity, and vibration damping that’s already in evidence, according to Grewe.
“On the gear we’re cutting right now on the Titan (a timing gear for locomotive application), we’re using a carbide insert hob in an aggressive roughing cut on tough 4140 steel at many times the speed possible than with its HSS counterpart, and then fine finishing in a second pass, with no need for hard finish grinding downstream,” Grewe said. “Accuracies are phenomenal too; on this particular part, lead tolerances of .002 inch were required, and we’re achieving .0006 inch.”
Grewe also likes the way the Titan’s work area is designed both for ease of operator access and for optimum chip disposal — a key factor considering the high metal removal rates that can be achieved and the need to keep the work area and workpiece free from chip contamination.
“Whether we’re cutting dry with carbide or wet with conventional HSS hobs, Titan is very well designed and puts the chip disposal in the ideal spot, right in front of the work table and below the hob head,” Grewe said. “We’ve had experiences with older machines in the past, where we’ve set up for dry machining and chip evacuation was a nightmare.”
It’s important to note too that both the Titan and the larger P 1600/2000 are equipped with a retractable tailstock, a “steadyrest,” and what Stommes calls a clamshell.
“This is handy because we can accommodate even very tall shafts where it’s not possible to put a center into the end,” Stommes said. “Instead, the clamshell wraps around the end to secure it.”
Fast and Intuitive Programming and Operation
With the new Titan, Gleason has introduced an advanced new operating interface that supports the latest generation of control systems and the powerful new Siemens 840D Solution Line — all with the mission of making setup and operation faster and more efficient regardless of operator experience. Operators are led through the setup and manufacturing sequence using simple, highly intuitive menus. A continuous plausibility check helps ensure the safety of the operator and protect the machine from damage. If the P 1600/2000 was easy to operate, Grewe said, then Titan does it one better.
“The process of putting in the inputs is similar but the way the screens are set up makes it even easier and more intuitive to use,” Grewe said. “That’s important for our operators, given the wide variety of work we do here, and the need to bring operators up to speed quickly.”
Shaping — Without Mechanical Guide Limitations
While some of the large internal gear cutting previously done on Columbia’s shaper machines will be done more productively on the new hobbing machines, shaping is still a key technology in Columbia’s extensive production repertoire, according to Stommes.
“For particularly tight-tolerance parts or where the part is dead-ended with a shoulder, or where the part diameter is so small that gashing isn’t an option, then we, of course, use our Gleason Shapers,” Stommes said. “In fact, in just the last year, we’ve added a Gleason P 1200/1600 S with a hydraulically driven cutter spindle for very large internals, and two P 600/800 ES Shapers with electronic guide technology, so shaping is still a very important process.”
According to Stommes, the Gleason ES Shapers give Columbia a particularly significant competitive advantage for the production of larger internal helical gears, since the mechanical helical guides used on many conventional gear shaping machines present the user with significant disadvantages by comparison.
“With the ES Shapers, we can produce the desired helix angle without the high cost, long lead times, and long changeover time required to change a guide,” Stommes said. “Instead of waiting three or four months and spending thousands on a mechanical guide, we can do the helical internals on the fly with ES programming changes and, in addition, achieve phenomenal accuracies.”
Finishing First with Gleason Profile Grinders
According to Stommes, the trend toward quieter, smoother running, highly reliable gears in every industry means that finish grinding after heat treat is becoming even more prevalent.
“Even the farmer sitting in his cab has his stereo on these days and wants a quiet running tractor,” said Stommes. “And in the case of wind turbine applications, quality requirements are particularly stringent, when you consider that changing out a failed gear can cost upwards of $100,000. So we’ve invested as well in Gleason Profile Grinders, helping us achieve accuracy levels as high as AGMA 15.”
Columbia Gear has P 1200 G and P 1600 G Profile Grinders, purchased in 2009, and two P 600/800 G Grinders that date back about 10 years. According to Stommes, these machines share a simple programming capability and high levels of productivity as a result of Gleason’s powerful software. The shop-oriented, user-friendly Gleason dialogue program, for example, supports the entire machining process. The machine operator calls up the required workpiece, tooling, and technological data on a familiar Windows-based user interface. The NC part programs are generated automatically, eliminating the need for typical time-consuming programming.
Making Gear Inspection Look Easy
Columbia Gear Inspector Don Ostendorf brings 21 years to Columbia’s impressive quality assurance lab. But he says an operator with far less experience could easily handle many inspection jobs on their new Gleason 3000GMM Analytical Gear Inspection System for gears as large as 3 meters in diameter.
“It’s a smooth running, highly accurate, and particularly user-friendly machine,” Ostendorf said. “But what’s impressive is how easy it is to program. Used to be you’d have to have a lot of knowledge about all the different standards we run through here, like ISO, AGMA, ZF 5005, and about 10 others. Now the GAMA software makes it so easy, anyone can do it. Just select ISO, for example, put in the class, lengths, and the usual part parameters, and off you go.”
In addition to the GAMA operating software, Ostendorf also makes daily use of a host of other software, including “journal reference” to speed setup, “root scan,” and “root tip diameter” to help define inspection parameters, “unknown gear,” and others.
“Years of experience, good service and support, and proven results give us a comfort factor with Gleason,” Stommes said. “Their technology solutions and, most importantly, willingness to support them, make all the difference.”
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