Adapt and Conquer – Adaptive controls help CNC machines produce more parts

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It seems that with every new model of CNC lathe or mill, machine controllers get a little quicker and a whole lot smarter. Maybe they haven’t yet achieved HAL 9000 intelligence, but new controls and servosystems process data faster, enable tools to corner more quickly and simultaneously manage more axes than ever before. Some are even capable of monitoring conditions in the machine and adjusting cutting parameters accordingly. It’s like having a virtual machinist with his hand on the feed rate override.

The concept, at least, is nothing new. A 1989 white paper by the American Society of Mechanical Engineers mentioned that Bendix Corp. was researching adaptive-control (AC) optimization as early as 1962. The paper stated that formidable challenges to commercialization of AC technology still existed, including development of reliable sensors, machine tool designs that take into consideration AC requirements and development of stable AC strategies.

Many of the goals of that Reagan Administration-era paper have been met. Laser cutting machines automatically adjust gas and power outputs, EDMs regulate their own sparks and turning and other machining centers slow down or stop when cutters become dull. The pinnacle of AC technology—and something few controls are actually capable of—is the ability to increase feeds faster than programmed when conditions permit, thus autonomously increasing part output.

“There are two basic types of adaptive control technology,” said Thomas Pleuger, account manager for control manufacturer Mitsubishi Electric Automation Inc., Vernon Hills, Ill. “One is look-ahead technology, which relies on a high-gain servocontrol to achieve smooth acceleration and deceleration during changes in machine direction. And then there are adaptive control products that sense spindle load and adjust programmed feed rates up or down according to a set of predefined parameters.”

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Don’t look in the mirror – When cutting thin materials, fiber lasers run circles around CO2


CO2 lasers have long been the 800-pound gorilla in many fabricating shops. But manufacturers are beginning to ignore that hairy ape in favour of fiber lasers, which are often faster and cheaper to operate than their established cousins.

One such shop is Edalica Metal Services Ltd., Mississauga, ON, which recently purchased a fiber laser cutting machine, the Fibermak, built by Turkish firm Ermaksan Machinery and distributed in Canada by Ferric Machinery, Mississauga, ON.

Koen Verschingel, owner of Ferric Machinery, says fiber technology offers many advantages. “Consider energy use—fiber lasers consume roughly one-third as much electricity as do CO2 lasers. So aside from the 60-70 per cent savings in daily operating costs, there’s no need to install an additional breaker or run a new power feed as we’ve seen in some CO2 shops. You can usually just plug in a fiber machine and go.”

Maintenance is another big feather in a fiber laser’s cap. Verschingel explains that, because CO2 lasers require mirrors and a rotating turbine to perform their metal cutting magic, they incur higher costs and downtime: replacement and cleaning of o-rings, filters and optics, as well as mirror alignment and adjustment of the power supply and other components means you’ll be servicing a CO2 laser more frequently than the family car. “With a CO2 laser, you have to start rebuilding it at 12,000 hours, at a cost of $10-$15K per cycle. By comparison, the lifetime on a fiber laser generator is upwards of 100,000 hours, with virtually no maintenance required during that time,” says Verschingel.

There’s also no need for laser gas with a fiber machine, further reducing operating expense. Says Verschingel, “average cost on a fiber runs around $5/hour, while CO2 can run 2-1/2 times that.” Consider as well the increased productivity of a fiber machine—according to the Laser Institute of America’s website, a 3 kW fiber laser can cut 1 mm thick stainless steel at about 30 m/min, whereas a comparably priced 5 kW CO2 machine achieves only one-third of this speed.

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Programming Quality – Knowledge is just as important as the program when measuring with an automated CMM


Clamp the part to the surface plate. Enter a few parameters. Grab the joystick and go. When checking a hole location, or measuring the distance between two machined surfaces, that’s about all you need to know in terms of coordinate measuring machine (CMM) operation. Unfortunately, most inspection procedures are more complex, and good metrology requires a lot more than mastery of a few screen commands. Programming automated measuring equipment needs robust software, a sound program to drive the machine, and some old-fashioned inspection know-how.

Like hand-cranked engine lathes and series I knee mills, manual CMMs are quickly going the way of Gray-Dort Motors. “We still sell a fair number of basic CMMs for general shop use, where people need to do a simple layout or take a few quick measurements for a machine setup, but probably 75 per cent of the CMMs we sell today are automated,” says Peter Detmers, vice president of sales at Mitutoyo Canada, Mississauga, ON. That’s good news for those quality control people who suffer tennis elbow from shoving a probe around all day, but the move to automated CMMs presents a frightful burden: learning how to program.

It’s not as scary as it might sound. CMMs do not require complex G and M code programs to drive them through their elaborate dance. Most if not all CMM software packages offer predefined macros—bolt hole patterns, slots and surfaces, even screw threads can be automatically measured by answering a few basic questions on what you want the machine to do. And automated CMMs can be “taught” how to measure a workpiece by putting the machine into recording mode and manually driving the probe through the first measuring routine. Subsequent workpieces are then measured with the resultant program—take a few manual data points to tell the CMM where the part sits and how it’s oriented, then execute the recording. The CMM software remembers what you did last and drives the machine axes through the same steps.

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Saying Yes – BC steel processor bets on plasma for happy customers


Eric Taylor doesn’t like to say no. As president of Valley Cut Steel in Surrey, BC, he takes pride in providing the best customer service he possibly can. “I used to work on the sales desk at a large service centre,” explains Taylor. “I found myself saying no to a lot of customers, and saw the need then for a small, flexible shop that would provide service the big guys could not.” In 1998, that vision became reality. Taylor opened the doors on a 232 sq m (2500 sq ft) facility, and then doubled it a few years later. “We have 14 people on board today, all of them focused on making our customers happy. Our shop mantra is Find a Way to Say YES.”

Valley Cut Steel offers a number of plate processing services, including flame cutting, forming, rolling, weld prep and beveling. It’s built a reputation on difficult jobs and rush orders, the sort of work Taylor’s former employer would turn down quicker than Mayor Ford’s temper after a night on King Street. But over the past couple of years, Taylor recognized a big shortcoming in his shops’s capabilities. “Most of our cutting has always been done in house on our oxy-fuel machines, but for anything under 3/8 in. [9.5 mm] thick, we’ve had to subcontract it to a plasma or laser house.”

As Taylor explains, this is because oxy-fuel produces poor edge quality and unacceptable accuracy on thinner gauge materials, as well as warpage and a large amount of slag that must be removed by grinding. Worse, sending work to potential competitors was risky, and the added delay and cost made it more difficult to win some business. “We recognized a lack of plasma capacity was holding us back. Buying a machine of our own meant it would be that much easier to say yes.”

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Melting Metal – sintering 3D parts from powdered metal is on the rise

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Acronyms abound: DMLS, MLS, SLS, SLM. All are used to describe technologies that convert powdered metal with the consistency of flour into most any shape imaginable—provided it’s no bigger than a loaf of bread, that is.

The members of the ASTM F42 standards committee—those people who spend their days thinking about additive manufacturing—call it laser sintering (LS). The term “sintering” is a bit of a misnomer, though. Many sintered parts rely on high forming pressures and temperatures slightly lower than the material’s melting point. Laser sintering doesn’t involve application of pressure.

The first step in laser sintering is to electronically slice a 3D CAD model of the part to be fabricated into paper-thin 2D layers. The resultant file is then downloaded to an LS apparatus, which consists of a build chamber fitted with an elevator system. A controller-guided, high-power laser and a scanner sit above the chamber. Powdered metal is placed on the build platform. The laser is then activated and moves such that its beam defines—draws—the outer edge of the part’s bottom. When finished, the elevator lowers the part by the designated layer thickness, which ranges from 0.1mm down to a few microns. Then another layer of powdered metal is rolled across the work zone and the laser outlines that cross section of the part while fusing the second layer to the first. This process continues until the part—built from the bottom up, one layer at a time—is completed.

LS isn’t new. In 1986, Dr. Carl Deckard of the University of Texas filed for the original patent, which describes the process of selective laser sintering (SLS) for powdered plastic, metal and ceramic. He later founded a company that sold SLS machines.

Metal LS has received a lot of attention from major manufacturers the past couple years. “The larger companies, such as General Electric and Boeing, have recognized the competitive advantage this technology gives them,” said Ed Tackett, director of the RapidTech Center at the University of California, Irvine’s Samueli School of Engineering. “As a result, a number of AM equipment suppliers are now actively pursuing this market segment.”

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HMC Transformations: Transforming horizontal machining centers into lean, mean, part-making machines.

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CNC machine shops have it rough. Customers order smaller lot sizes and demand faster turnaround than ever before. More parts are made from nasty materials like Inconel and titanium, with tolerances and geometries so challenging they make even seasoned machinists quake in their steel-toed boots. To stay profitable, many embrace lean and Six-Sigma methodologies, but keeping foreign competitors or even the shop next door at bay takes a lot more than cutting some fat from business processes. Shops must become agile if they want to compete in this brave new world of low-volume, high-complexity machining.

Agile means having the equipment, tooling, software and know-how to respond quickly to changing customer needs while still making a buck. By their very nature, horizontal machining centers are one of an agile shop’s best friends. With built-in pallet changers standard on most machines, efficient chip flow and the ability to hit all sides of a part in a single setup, horizontals increase part throughput while reducing cost compared to their vertical cousins. Add a linear pallet system or pallet pool and a large-capacity tool magazine and shops can simply leave tools and fixtures in the machine indefinitely.

This makes setup for many parts a set-it-and-forget-it affair. And, with options such as broken tool detection and automated parts handling, the transition to lights-out manufacturing becomes a reality for many shops, allowing for unattended production at night and process prove-out during the day.

Of course, it takes more than equipment to become an agile shop. It takes a focused, well-managed plan and having robust processes in place to get there. Let’s pretend, however, that you’re already have the agility of an Olympic triathlete, having addressed the sales and quoting, purchasing, quality control and engineering processes—all key parts of being agile.

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Deep hole drilling that’s “just right” – Goldilocks and the quote for Three Bears


Gabriella Goldilocks had a problem. Her father’s machine shop, G&G Machine, had just received a big drawing package from Three Bears Petroleum Products Inc. in Edmonton, AB. It was a family of components for the new multiport flow selector they were working on. Gabriella did some quick calculations and knew the order would be worth several million dollars, enough work to keep the small shop busy for months.

She examined the first drawing, a small throttle body made of high-strength steel. Her crew would have no problem machining most of it, but those 1/8 in. (3.18 mm) holes through the long axis of the part would make or break the deal. Gun drilling was out—those guys over at Big Wolf Precision would eat up every bit of profit. She needed a better way to drill those holes.

A Google search returned entirely too many options—it seemed every tooling company on the planet had some sort of deep hole drilling solution, and they all said theirs was best. “Always grab the bull by the horns, girl,” came the voice of her father. Gabriella picked up the phone and did just that, calling Kennametal’s regional product manager for Holemaking, Steve Pilger.

Steve was very helpful and after Gabriella explained her problem he suggested she make use of Kennametal’s new manufacturing advisor software, called NOVO. “This is quite a huge project you need to find solutions for. For such complex tasks I would propose to try our NOVO system to get an initial understanding between which manufacturing possibilities you can choose.”

Gabriella was all for software solutions but she didn’t have time right then to download it. She interrupted him. “Not now, Steve. Just find me an 1/8 in. (3.18 mm) drill that can go nearly 4 in. (102 mm) deep in A36 steel.”

Steve steered her towards Kennametal’s line of B27_HPG solid carbide deep hole drills, which according to Steve, remove metal 3-4 times faster than gun drills or high speed steel, in depths up to 30 X diameter. Gabriella pushed. “Everyone makes deep hole drills, Steve. What’s so special about yours?”

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Driven to Perform: Mill-Turn Centers


Where 2-axis CNC lathes were once top dog in most turning departments, mill/turn centers now lead the pack.

With the ability to drill cross-holes, mill complex shapes and sculpt multidimensional surfaces on turned workpieces, CNC lathes with driven, or live, tools are making a big impact on the bottom line of many machine shops, with a commensurate improvement in part quality and delivery time. Despite this obvious benefit, however, driven tools carry the burden of additional tooling costs and a commitment to preventive maintenance of toolholders. This makes it critical for shops to do their homework before embarking on the road to driven tools.

David Fischer, product specialist for Okuma America Corp., Charlotte, N.C., explained that the majority of CNC lathes sold today come with some form of driven-tool capability. Many of these machines offer spindle speeds of 6,000 rpm or higher, with horsepower and torque ratings comparable to small machining centers.

“Compared to 10 years ago, mill/turn centers today have enough power to do some really decent work,” Fischer said. “There’s also an increased focus on shops looking to avoid moving parts from machine to machine, getting things done in one operation wherever possible. Multifunction, [driven tools] on a standard lathe are a big improvement for them.”

Adding that multifunction capability to the purchase of a conventional CNC lathe might be as easy as spending $30,000 for a C-axis spindle option and a live tool-equipped turret. It could also mean investing 10 times that amount or more in a twin-spindle, multiturret monster with more axis letters than a bowl of alphabet soup.

Regardless of how much machine a shop can afford, it’s important to remember the additional cash outlay needed to tool that machine. Where a shop might get away with spending a few thousand bucks on some stick tools and ER collet chucks to tool a 2-axis CNC lathe, properly equipping a mill/turn center will cost far more than that.

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The ABCs of UPM: Freeform machining makes complex parts ultraprecisely

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Today’s CNC machine tools can do things that were only dreamt of a decade ago. Whether it’s a 5-axis machining center or a 9-axis lathe, modern machinery can make increasingly complex parts in less time and more accurately than ever before.

Despite their impressive abilities, however, there is a line that few CNC machines can cross—a line just 1nm wide. “The ultraprecision machine regime is loosely defined as machine tools controlled at a level below 10nm,” said Dr. Jeff Roblee, vice president of technology for machine builder Ametek Precitech Inc., Keene, N.H. “Many of these machines offer 0.01nm resolution, and, with the proper instrumentation, can make repeatable and measurable steps in the 1nm range.”

It’s hard to wrap your head around numbers this small, let alone a machine that can seemingly split atoms. To most machinists, the holy grail of accuracy is holding a few “tenths,” or roughly 10µm. Those who stayed awake during math class know that 1µm equals 1,000nm. Put in everyday perspective, if a sheet of paper measured 1nm thick, 1µm would be thicker than the Machinery’s Handbook.

Figures like this give an entirely new meaning to the word “precision.” Yet, ultraprecision machining, or UPM, means far more than tight tolerances. UPM opens the door to shapes and forms impossible to generate with conventional machine tools, regardless of their capabilities. For example, parts for the James Webb Space Telescope, super-precision medical implants, contact lenses and Blu-ray disc players would be difficult or downright impossible to make without UPM.

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Cracking the Code: Determining when complex turning and multitasking are the right solutions

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While the basic CNC lathe is still a standby in many machine shops, new technology has vastly expanded turning capabilities. For example, live tooling and multiple turrets turn a basic lathe into a multitasking productivity center. When equipped with a large automatic toolchanger, these machines can hold tools for dozens of jobs, reduce setup time, and turn, mill, drill and finish parts in a single setup.

Dual-spindle turning centers can turn both ends of a part in a single setup to minimize operator handling, increase throughput and reduce work-in-process. The opposed spindles support synchronized turning and pass off parts on the fly, reducing overall cycle time. Such machines allow for the creation of more complex parts, and do so more efficiently. But questions like when are such machines needed, what kinds of parts can they produce and how do you justify the increased cost of a “supermachine” should all be taken into consideration before signing on the dotted line.

Eliminating as many operations as possible is the most important consideration for shops looking at a new machine tool, according to Courtney Ortner, chief marketing officer for Lorain, Ohio-based Absolute Machine Tools Inc. “This is why multitasking machines can be so profitable,” she said. “Parts are often ‘done in one,’ eliminating work-in-process and improving quality.”

Ortner argued that turn/mill and other multitask machines reduce setup and fixturing costs while improving employee utilization compared to single-task machines. That’s because with multiple operations, operators do non-value-added tasks, such as part handling, which removes them from the equipment they are supposed to be monitoring and increases downtime. “An idle spindle is no different than going to the front door and throwing money into the wind,” she said. “Because more machining is done per cycle, multitask machines maintain a higher percentage of spindle uptime.”

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