Rotary Transfer For
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AUGUST 2002 / VOLUME 54 / NUMBER 8 BY ALAN RICHTER, MANAGING EDITOR Rotary transfer machines provide high-volume flexibility. hen it comes xxBrown noted that to high- the company’s ma- Wvolume, chines need oil extended-length pro- coolers for some de- duction runs of complex manding runs. parts or families of parts, eliminating secondary opera- Setting Up tions is highly advantageous. It pre- The setup requirements for a vents tolerance build-up, reduces parts rotary transfer machine depend on handling and maximizes machine effi- the workpiece material, part complex- ciency and profit. For this type of production, ity and the type of part the machine was rotary transfer machines excel. The flexibility of previously running. Brown said setup takes 2 this type of machine also makes it appropriate for to 3 hours when switching a part within the smaller parts quantities. same family and two to three shifts when changing Brown Manufacturing Co. Inc., Plainville, Conn., is a outside a family of parts. case in point. “We were one of the first to use a CNC rotary Since an RTM can be an alternative to a high-volume transfer machine in a job shop environment for smaller quan- production run on a multispindle screw machine, it makes tities rather than dedicated to a certain job,” said Douglas sense that screw-machine shops are some of the biggest Brown, company president. In 1993, the company purchased consumers of RTMs. But screw machinists often don’t have its first CNC rotary transfer machine from St. Louis-based Hy- the proper mindset when it comes to rotary transfer tech- dromat Inc. (The 12-station machine was the second CNC nology, Brown said. RTM the machine tool builder produced.) Brown Mfg. cur- “Initially, the screw-machine guys were skeptical of a ro- rently has three Hydromats. tary transfer machine’s ability to produce parts,” he said. Started almost a half a century ago making precision parts Brown said the company worked around the skeptics by with traditional screw machines and centerless grinders, choosing people who weren’t familiar with screw machines Brown Mfg. turned to rotary transfer technology to finish a for the initial RTM training. “With rotary transfer, there’s a part completely with a single machine. “We first tried mini- different philosophy about machining parts,” he said. “We workcells on wheels, but there was still parts handling and didn’t want people with preconceived notions about what parts damage,” recalled Brown. would and wouldn’t work.” In addition to reducing parts handling, the company was able To become proficient, Brown indicated that it takes 6 to to downsize its cam-driven screw-machine department from 38 12 months of training. to 12 machines. Brown said those machines still play an impor- tant role, because some parts are not complex enough for RTMs. From the Get Go “The Brown & Sharpes are for simple parts that we don’t With two generations of family involvement in the screw- want to tie up the high-cost equipment with,” he said. machine business, Troy Pohlman seemed destined to be- For parts whose complexity and size fell between the two come a manufacturer of precision parts. In 1989, he founded types of machines, the company acquired two CNC live-tool- Component Bar Products Inc. in a shop a short stretch down ing indexing machines with back-working capability. the road from Hydromat. CBP began producing parts using But when it comes to running a family of parts, Brown said two Hydromats. Familiar with equipment from his father’s there’s no better way than a rotary transfer machine. “The ma- experience with the technology, Pohlman figured it chines don’t like to cool down,” he said. “They like to run and was ideal for making consistent, high-quality parts cost- cut metal.” effectively. “The Hydromat rotary transfer ma- chine is an alternative to running a screw machine and two or three secondaries. Anytime you have multiple people han- dling a part, variation is introduced into the product,” Pohlman explained. By plowing profits back into the op- eration, the company grew to occupy its current 60,000-sq.-ft. facility in St. Charles, Mo. The building houses 30 RTMs: 24 Hydromat horizontals, 2 Hy- dromat VM-16 verticals, three Mikron rotary jaw/chuck machines plus a one- of-a-kind miniature model of a Hydro- mat—complete with moving parts. Another machine tool the company has is a Walter CNC tool and cutter grinder. CBP uses it to make all of its carbide and HSS cutting tools. The Photos: A. Richter company also designs its tools in-house, Brown Mfg. Co.’s Douglas Brown (left), president, and Les Brown, vice president, con- while outsourcing the coating work. tinue the family-owned business founded by Howard Brown in 1955. Although designed to accept a max- 3 imum diameter of 1 ⁄4", Pohlman said sition and cut off at the appropriate piece’s backside can be machined. CBP is able to push the capabilities so length until the finished part is dis- A Hydromat 16-station RTM, for ex- one RTM model can accept 2"-dia. bar charged through a chute at the 11:30 ample, could perform 16 horizontal stock. position, a virtually infinite combina- plus eight vertical operations, for a total The company can produce parts up to tion of machining operations can be of 24. Since the spindle units are mod- 6" long for a plethora of industries, performed. Individual stations can be ular, an individual operation can be from HVAC to automotive, made of designed so that each independently switched from, say, tapping to boring. any bar shape and a wide array of ma- controlled spindle performs its required In addition, a worn drill can be switch- terials. “The machine provides infinite operation vertically, horizontally or at ed for a new one in about 1 minute with flexibility from one station to the next any angle. In addition, the hydraulically the quick-change tooling attached to and is capable of running all flavors,” controlled machine can have an invert- the end of the spindle. Without quick- Pohlman said. ing station to allow the workpiece to be change tooling, switching a worn tool From the time the bar stock is fed taken out of its collet, inverted and takes 15 to 20 minutes. into the machine at the 12-o’clock po- placed back into the collet so the work- Although Pohlman said CBP’s pub- lished minimum run is 50,000 parts, the contract manufacturer has gone down to 2,500-piece runs for select customers. Being flexible helps justify the in- vestment, since the machines are de- signed for “the long run,” with a 10- to 20-year outlook, Pohlman said. “There are not many jobs that will pay for the machine in 3 to 5 years,” he said. “Not many home runs like that.” As previously stated, RTMs run long and hard, so preventive maintenance and machine reconditioning are essen- tial ingredients for seeing an ROI. Pohlman said CBP performs teardowns and reconditioning work in-house on its RTMs after 100 million cycles. “We can recondition a machine in as little as Troy Pohlman, president of Component Bar Products, started the company in 1989 with 8 weeks.” two rotary transfer machines and is of the belief that CBP is the contract manufacturer Depending on the job and the part’s with most Hydromat RTMs under one roof in the Western Hemisphere, with 26. cycle time, he noted that a single ma- chine can produce up to 5 million parts annually. A rotary transfer alternative to single-machine production CBP also does all repairs and modifi- cations in-house, Pohlman said. He es- rotary transfer machine’s design builder’s main offering, he said, with timated that maintenance costs less than Amakes it easily adaptable to a prices ranging from $200,000 to $1 $10,000 annually for each machine. wide array of applications, but that flex- million. Jamieson also offers the Ro- ibility doesn’t come cheap. Depending tamat line of RTMs, which are smaller Variation on a Theme on the number of stations on an RTM than the SR series machines. Shops Not all types of rotary transfer ma- and the types of operations it performs, with in-house machine-building ca- chines are an alternative to producing a new machine can cost well over $1 pabilities can save money by choos- parts on screw machines. Larger million—and the sky’s the limit. ing the components system instead RTMs, such as the Imasflex machines Having the RTM perform the sec- of ordering a turnkey machine. from the Italian machine tool builder ondary operations after the work- The company’s RTMs are available Imas, substitute having a line of CNC pieces have been turned on a separate with up to 15 stations, with horizon- vertical or horizontal machining cen- machine is a lower-cost alternative to tal and/or vertical units in each sta- ters for high-volume production of a doing everything with a single ma- tion. They can accept part sizes up to part or family of parts. chine, said Wolfgang Kesselring, vice 4"x4"x8". This is the scenario for Duro-Life president of Jamieson Mfg. Co. Inc., Kesselring said most of the ma- Corp., Algonquin, Ill. Timothy Heag- Torrington, Conn. chines are pneumatically/hydrauli- ney, general manager, said the company “Depending on the part quantities cally actuated but can also be actu- purchased two Imasflex eight-station and type of part family, it’s cheaper ated by cam, hydraulics or servomo- RTMs about 6 years ago to make a fam- to have a standard turning center tor, which is becoming more popular.