New - CNC Machine Classifieds
Click Here to get free $20 instant credit to list your CNC
Click Here to get free $20 instant credit to list your CNC
Best CNC Resources:
Training and Technology on the Press Brake
|
|
Tom Abeyta stepped onto a fab shop floor in June 33 years ago thinking it would be a summer job. It turned out to be a career. Last year he sold his stock as co-owner of one of the top five metal shops in the Portland, Ore., area, Integrated Metal Components, a company with a reputation that many a company manager would kill for: a 95-percent employee retention rate. That's no small feat for a 33-person shop fighting rising health-care, raw-material and operating costs. The key, he says, beyond fair pay, of course, is training—and no where is that more important in a sheet-metal shop than at the press brake. No matter how well a part is punched or cut, the customer won't walk away happy unless the part is formed up correctly. (Abeyta has since started a new company that will market a new product he invented and for which he recently filed a patent.) The equipment has come a long way from 33 years ago, when machines were innately inaccurate. Finding the proper bend allowances could (and at times still can) cause migraines, particularly for material with inconsistent thicknesses. The old mechanical brakes featured wide operating clearances between ball joints, rocker arms and other elements. An operator couldn't accurately air bend because the machine wouldn't close in all those gaps, so coining ruled the day. They still had to shim, of course, because they used planed, not ground, tooling. Fast-forward 33 years and some companies are boasting 95 percent uptime, two shifts a day. "In the past, that wouldn't be possible," says Casey Schlachter, press brake product manager for Bystronic, Hauppauge, N.Y. What does make it possible is offline software. Software ties lasers, punching and bending together. If a certain V die is changed, the tool can be entered into the offline software, which will "change the whole flat layout for the laser [and other processes] and change dimensions automatically for the new bend allowance," Schlachter says. Software saves hundreds of part programs. No longer must operators rely on a bend-allowance chart, set the backgauge and perform manual crowning and other skills learned over years. All that "black magic" is now stored neatly in the machine control. But does this mean press-brake operators can become mere button pushers, and companies no longer should worry about hiring, and keeping, skilled personnel? According to many—no. Training for Retention "In my experience, the press brake is the most difficult machine to run in a precision sheet-metal shop," Abeyta says. "You need to think through all the steps, of how to process the part and see problems ahead of time, and that's something I don't think a computer will ever do as well as a person." Finding talent has always been a challenge, even during economic downturns. Companies either find experienced employees, train from within or do both. Of course, quality training brings up a Catch-22: It makes an employee more valuable, yet also hanging fruit for competitors. "But try thinking about it from another perspective," suggests Bill Bossard, president of robotic press brake and fabrication cell manufacturer Salvagnini America, Hamilton, Ohio. "What happens if you don't train employees, and they stay?" Training fostered employee loyalty at Integrated Metal Components. "Yes, good training can hurt retention," Abeyta admits. "But if we took people with a good work ethic and positive attitude, trained them from the very bottom of the ladder to the top, and gave compensation increases as they became more trained on different equipment, then—and only then—did we find that training meant better retention." The company doesn't plunge into training without a good idea of the return on investment. Abeyta notes that the 95-percent retention figure does not include employees during their initial three-month trial. To complete it, workers must show a positive attitude, a desire to do good work and consistent punctuality. "Frankly, we would not even start a training regimen until we knew we had that type of person." The job shop has a mix of low- and high-tech machinery. Entry-level personnel start on simpler machines. They then take blueprint and math classes to learn the fundamentals of flat-pattern layout. With that, the company starts slowly training them on the press brake, shadowing the operator. The operator eventually sheds his shadow, but not completely. The company uses a buddy system built on a simple principle: Two sets of eyes are better than one. After bending a first part and inspecting it, a buddy of equal or higher skill also inspects it. Based on the machine's repeatability and part-tolerance requirements, the operator himself determines how often to inspect the part, be it after a run of 10, 100 or 1,000. "We wouldn't baby sit," he says. "We'd empower the person to have the responsibility to make quality parts." The system has saved the company thousands, if not millions, over the years. Recently, the shop was bending a seat back for a dental chair out of 3/16-inch-thick steel that had recently doubled in cost. The operator read the part dimensions on the drawing and saw a 5.52-inch flange length, strange since the part program saved in the control said 5.25. He corrected the program, bent the part, then called over a buddy—who caught an error. The part program was correct in the first place; the operator had mistakenly transposed the numbers on the drawing. "We probably saved about $5,000 that afternoon," Abeyta says. First, the Basics Jim Cooper arrived at Shimadzu in Portland, Ore., eight years ago to take over both the sheet-metal and machine shop. The company produces a product called the High-Performance Liquid Chromatograph (HPLC), an analytical tool for pharmaceutical companies. If someone wanted to know the recipe for Coke, "this would do the trick," Cooper says. The metal department machines and bends the HPLC's 12 components. Internal ones, mostly stainless, consist of pumps, check valves and other shapes, and are machined with vertical mills and Swiss turning. The sheet-metal shop makes some internal, but mostly external components out of zinc-plated cold-rolled steel and anodized aluminum. Among other equipment, the shop has three press brakes, though only two have advanced CNCs. When the company brings on somebody green, the person doesn't lay a finger on the high-tech controls. Instead, they start with the company's single-axis "one-trick pony," Cooper says, and are shadowed by somebody with greater skill. Only when an operator can build on fundamentals of basic machine operation does he graduate to the advanced brakes with the latest controls and XYZ motion. Operators must "decipher the roadmap" of the press brake, regardless of machine model, Cooper says. Reading that map takes math and blueprint reading, skills employees learn at classes taught either in-house or off-site (provided by the Oregon Precision Fabricators Association, along with a local community college). They must know tooling and dies required to manufacture to a print, read the drawing and know that, say, the bends in "Part 5" hinge on "Part 4." Cooper says he employs an ideal mix of press-brake experience: one with 20 years behind him, another with manual press-brake experience and another brought on totally green. Like at Integrated Metal Products, Shimadzu has the experienced mentor the inexperienced. His training success shows in employee retention. Out of five working in the sheet-metal shop, three have stayed on for more than seven years—and those three represent his most highly skilled. Cooper quips: "Either I'm doing something right, or they like working here despite me." More Automation, More Knowledge Modern press brakes offer the gamut to take the guesswork out of bending, with dynamic bend thickness compensators, automatic springback compensation and the like. But those features add to, rather than subtract from, the knowledge base needed on the shop floor. "More knowledge is needed to just understand the characteristics of a CNC press brake," says Brian Turner, special services manager at Council Bluffs, Iowa-based Automated Concepts, which specializes in robotic solutions for press brakes and other equipment. "It's analogous to an operator knowing the load of a CNC machining center." Sure, the machine is highly automated, but the knowledge base must be there to fully use that automation. Bystronic's Schlachter calls the latest press-brake control software "pretty dirt simple ... You just bring in a 2D file, hit a few buttons and it automatically figures out the bend sequence, where to put the tools and the interfaces." Offline programming and 3D simulation of the bend sequence help make it simple. Even so, most new controls give operators "myriad of options," he adds. "You've got to know how to use these options to make your life easier, make parts better and get more production." Springback compensation provides a prime example; some machines now compensate for it on-the-fly. With the adaptive process turned on, Schlachter says, the machine may add a second bend to each cycle and in some applications has even produced parts within plus or minus half a degree—on 2-inch-thick plate. But, he says, that may add a second to the cycle time, too long for some operations. So the adaptive control can be set up to run for every, say, fifteenth part, and, for the 14 parts in between, it bends based on data gathered when the adaptive control was last activated. Such features make productivity soar, but an operator must know the steps to activate it. It's relatively simple, Schlachter says, but it does require training that wasn't needed before. "Operator training a long time ago was strictly at the press brake," he says, adding that the same on-machine training is needed. "But we've found that's not enough anymore. The controls have become more sophisticated, which requires more training in a quieter environment—in the classroom." Modern equipment still requires operators to know part thicknesses and tolerances, ensure the correct punches and dies are in place, the ram speed is correct, and understand the different bend angles, Automated Concepts' Turner says. "For example, if I know I'm dealing with poor-quality metal, I might actually have to change the bend angle to get the correct angle the print calls for, as compared with 10 years ago," when lesser equipment capability made for simpler (though limited) operation—but resulted in inefficiencies that wouldn't pass muster today. And regardless of how repeatable a ram is, it can't always account for thickness variation, adds Abeyta. "If the metal [thickness] varies plus or minus 0.005 inch or more, the bend angles will still vary a great deal"—and operators, of course, must be trained to recognize that. The knowledge requirements don't go away with robotics. In fact, a CNC background and working with 3D images at the press-brake control come in handy when upgrading to a robot. "CNC knowledge can translate into a robot operation pretty seamlessly," Turner says, "because the language and prompts are similar." The robot may reduce the number of operators required on the floor; one person may control numerous press brake cells. But that one person, say sources, needs experience to do the job right. Not only must personnel understand bend allowances and sequences, but they also must know the capabilities of a six-axis articulated robot, its fortes (big, heavy high-volume parts) and weaknesses (small, low-volume parts). "The nice thing about people is they have eyes and fingers," Salvagnini's Bossard says. "People can manipulate parts by sight and feel. When you take that away [using a robot], then you have to program all of those motions a human would normally do." And to understand the approach angle and other nuances, "it takes somebody with a good deal of experience." For example, once a robotic program is created, skilled personnel must still install it on the shop floor. "And, unavoidably, there are tweaks or refinements that must be done by a qualified person on the shop floor before it's ready to run parts," Bossard says. The robot might, say, pick up a straight panel and place it in between the press-brake tools, as usual. But the panel, depending on thickness, may droop—and the operator, not the robot, knows that droop would cause the operation to crash. So the skilled person intervenes, changing the approach angle slightly. http://www.fandmmag.com/publication/article.jsp?pubId=1&id=66 |
For more information visit CNC Brakes category