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Shop Solutions: Multitasking Software Turns A Profit

    

Chuck Paul is an optimist who believes hard work will keep operations running through the worst business cycles. He founded Paul Precision Machine (Tulsa, OK) with a conventional lathe and a conventional mill in his garage in 1978. Three years later he purchased a 4000 ft2 (372-m2) building, and in 1988 he moved into his current 18,000 ft2 (1672-m2) facility.

A natural gas cylinder head nears completion on the subspindle of the Puma MX3000S programmed with GibbsCAM at Paul Precision Machine. The MX3000S can rotate its coordinate system along the B axis to act as a vertical mill. The final operation of milling 120° flats is done with a 3" (76-mm) Mitsubishi face mill.In the best of times, he employed over a dozen workers. "In the worst, 1983," Paul admits, "the shop was reduced to another machinist and me." Today, Paul Precision Machine has 12 employees, nine of them in the shop. Paul feels fortunate to have grown up using carbide and HSS in his teens, then experiencing the evolution of tooling and CNC machines his shop uses today. "Even through tough times, it has been a great ride," he says. "I just love it."

In 1996, the shop faced nearly simultaneous challenges. The first involved a start-up natural-gas compressor manufacturer that became his customer. The shop got busy making many prototype parts. The second challenge involved larger CNC lathes that required frequent service. Parts had to be ordered overseas, with long delays. To complicate things, Paul's CAM software supplier ceased operations.   

Unable to afford waiting for repairs, Paul Precision Machine started replacing old lathes with Puma turning centers from Doosan Infracore America Corp. (West Caldwell, NJ). To ensure continuity in programming, a well-known CAM system was tried. Although the machines performed successfully, the software proved to be problematic.

"It was too expensive, much too difficult to use, and the support was terrible," says Paul. "We muddled through it for two years, but our growing workload prohibited wasting time trying to get it to work. We needed to make parts!"

Paul and son Kevin investigated and purchased GibbsCAM from Gibbs and Associates (Moorpark, CA). The GibbsCAM reseller provided training at the shop's equipment supplier. With software and machines working, Paul Precision had a new goal. "We wanted to remove wasted labor and make parts in a single-machine operation, instead of multiple operations on two or three machines," explains Paul. "To achieve that, we used live tooling aggressively. GibbsCAM programming was used on all the Doosan turning centers, and we started generating income and paying off debt."

The shop was still using multiple operations to make a series of 120-lb (54-kg) cylinder heads for its newer natural-gas compressor customer. The parts had angled flanges and hole patterns on each end. The narrower end also had a second hole pattern to accommodate valves. Machining required boring soft jaws for each end, and a special fixture for milling flanges. In lots of 15 or 20 pieces, it took 1.5 hr to make each smaller part, and 2.25 hr to make the larger.

         Chuck Paul (right) discusses a part, one of a pair of bearing-housing covers the shop produces for a railroad repair machine company with Danny Burchfield (left) and Greg Hauth.

Paul had seen a dual-spindle Puma MX3000S, brought into the country for an open house demonstration at the supplier, and thought the machine had potential. He asked if the supplier would use one of his cylinder heads to demonstrate the machine. The supplier agreed, and the successful demonstration led Paul to purchase the second MX3000S sold in the US.

The shop added the GibbsCAM MTM (multitask machining) module, and Kevin Paul, who has since left the shop, started making parts on the MX3000S. Greg Hauth, now the main lathe programmer, says Kevin Paul spent most of his last three weeks at the shop training him on the machine.

"My only formal training was a seven-hour session on the GibbsCAM Production Lathe module," Hauth explains. "Kevin taught me the basics of programming the MX3000. I learned more along the way, and I asked the GibbsCAM reseller a lot of questions. He was very helpful, but GibbsCAM is really straight forward and easy to use. It all makes sense. I don't know how we would program the MX without it."

Programming the MX involves modeling stock material for the left spindle, setting the jaw depth in a GibbsCAM window, selecting tools, and turning the part on the first side. To use the same boring bars and turning tools on the other side, the tools are copied and pasted from the first side onto the other. GibbsCAM then displays how the piece looks in process. Hauth says he can program the difficult gas compressor parts in about an hour.

The machining head rotates from +90° to -90°, and the second spindle can run in reverse, so the same tool setup can be used on both spindles. "On the front side, the chips fly toward the window, and on the back side they fly toward the back," Hauth explains. "The head can spin at 10,000 rpm, so it can drill, tap, and mill, or lock down and turn or bore. No change necessary."

The cylinder heads started as bar stock of 65-45-12 ductile cast iron, then were turned, bored, drilled, and tapped on the main spindle, and transferred to the subspindle, where the other side was turned and bored. Because the MX3000S can mill at angles, it milled the angled flats with a 3" (76-mm) face mill, and the part came off the machine complete.

Parts went from four operations performed on three machines to a single-machine operation. Changeover from one size to another was 30 min, enough to change tools and load a new program. The cost was as much as it was with the previous method, but the shop's income rose, because the production time was reduced by two-thirds.

At peak production, the MX3000S was producing 3200 cylinder heads annually. Now, the customer is in the process of moving, and the shop gets no work from them during the transition. Regardless, Paul remains undeterred, and works hard to keep the CNC mills and lathes making parts. "For CNC turning, I program all seven lathes with GibbsCAM," Hauth adds. "They all have a live-tooling C axis, but multitasking machining with the MX3000 does much more."

As an example, Hauth cites a job he just completed on the MX3000, an order for 1.25.7 (32-mm), round-head, hex-key bolts, 4" (102-mm) long. He began with 1.75" (44-mm) stock of 1040 steel at a length sufficient to make two pieces, which he programmed with heads back to back, so threads could be turned on both ends of the workpiece. He set the main spindle to hold stock at raw diameter, then rough turned, finish turned, and threaded one end, finishing the threads with a deburring operation. Then the subspindle moved across and closed jaws on the finished shank, and the tools rotated to -90o, moved into the subspindle, (now running in reverse), and machined the other end. The double bolt was made in 12 min, then sawn apart, before Hauth used the subspindle to face and broach the heads for a 5/8" (15.8-mm) hex key.

         GibbsCAM Cut Part Rendering is used for all toolpath verification. Cut Part Rendering shows that a part has been completed on the main (left) spindle, while another operation proceeds on the subspindle after the part is transferred.

The productivity resulting from GibbsCAM, live tooling on all lathes, and the MX3000, has all combined to help pay down debt. As a result, Paul has been able to keep equipment current, with no CNC older than three years. He recently converted the shop to a server system, wirelessly networking everything. Six of the nine machinists use GibbsCAM on the network, which provides access to CNC programs and other files. Paul's next goal is providing remote access, so machinists can implement ideas from home, as they think of them.

That's just the beginning in his opinion. "It's no longer just applications in the areas of precision and ultra-precise machining. Today, we have a variety of plate types with optimized cutting angles combined with our extremely wear-resistant, ultra-hard cutting materials that can significantly increase productivity and the quality of products. This applies for all machining technologies, whether milling, drilling, or turning," Becker explains.   

 

Clamping Delivers Process Reliability

Clamping has often proven to be the Achilles heel of hard machining. This held true for tool manufacturer Becker Diamantwerkzeuge GmbH (Landsberg, Germany) until the company started using the TOPlus clamping system from Hainbuch America Corp. (Milwaukee; Marbach, Germany).

Although the founding date of Becker is officially 1987, the firm's origin can be traced to the first half of the last century when its primary activity was manufacturing diamond drawing dies. After the advent of polycrystalline diamond (PCD) and later cubic boron nitride (CBN), the company was considered to be one of the pioneers in the area of ultra-hard cutting materials. At that time, metal cutting applications were fairly scarce, so the market was primarily the jewelry industry.

In the mid 1970s, Werner Becker left the family business and moved to Bavaria to start his own company. Although he initially concentrated on natural-diamond cutting tips, he recognized other possibilities associated with the use of ultra-hard cutting materials.

The TOPlus clamp is used at Becker Diamantwerkzeuge for its own hard-turned parts, for customer trials, and for demonstration purposes."For more than 35 years, we have been involved with the development, production, and sales of precision metal-cutting tools made from materials such as natural diamond, synthetic diamond, and cubic boron nitride," Becker says. "Several years ago, these were still considered exotic cutting materials. Today, we are talking about a market volume of approximately $2 billion."

Technically, the use of diamond cutting tips is relatively problem-free, often only limited by the capacity of the machine. However, machining with CBN does require some experience and skill. Roland Kreuzer, director of application technology at Becker Diamantwerkzeuge, explains: "When using CBN, all relevant process parameters such as cutting values, feeds, and clamping depths must be precisely determined in order to exploit the performance capabilities of the cutting material."

"Results that are achievable in theory are often not achieved—and not achieved by a wide margin—because of poor general setup," Becker says. "To really exploit the strengths of the CBN cutting material—for example when hard turning—we need a rigid total system. In other words, working with unstable machine conditions with the wrong tool system, unsuitable cutting data, and/or using CBN tools with the wrong clamping system, is simply throwing money out the window."

That is exactly where using the right chuck plays a critical role. Diamantwerkzeuge uses the TOPlus chucks for its own hard-turned parts as well as for customer trials and demonstration purposes. Kreuzer recalls that the first thing he noticed about the TOPlus chuck was its hexagon shape.The large-surface support of the clamping segments of the hexagon is more rigid. For the most part, it is vibration-free, allowing cutting values to be run with the TOPlus without sacrificing tolerances on the work piece and the tool life of the blades.

"We have machined identical parts with the same cutting parameters and only changed the chuck. The result was clear. We achieved a 50% increase in tool life right away, and this was achieved with significantly better surfaces," Kreuzer says.

In hard turning, the clamping system must ensure a continuously reliable manufacturing process. The crucial factor for surface quality of the workpiece and tool life is found in the chuck design. The chuck must be rigid so that pressure does not affect it.   

"With hard turning, the tool edge is subjected to pressure of up to 70 kg—bending movement occurs—the chuck cannot give," Becker explains. "Due to the hexagonal pyramidal shape of the clamping head, there is no gap between head and clamping receptacle, which makes the TOPlus chuck resistant to fouling and even the smallest of chips, increasing process reliability significantly."

According to Hainbuch's Joerg Tittel, TOPlus provides planar support and thus sliding friction. "Thanks to the large-surface support of the clamping segments, the hexagon is rigid and for the most part remains vibration-free. This is also why higher cutting values can also be run with the TOPlus without sacrificing tolerances on the work piece and the tool life of the blades. There is no radial offset, which means that even under stress—if bending occurs—the chuck cannot give."

Matt O'Neil of Sandvik Coromant came in to look at the job, and suggested that Nuflo switch to CNMG 432 MM 2025 inserts. Tom Connor, Nuflo manufacturing and operations manager, remembers: "That immediately improved our processes. We then added a wiper insert and saw production increase by another 20%. The wiper achieved a clean enough cut that our finishing operations were significantly reduced."   

 

Staying on the Cutting Edge

In today's manufacturing environment, the sheer quantity of available cutting tools can turn decision-making into a full-time job. With thousands of new products released each year, it can be difficult for any manufacturer to stay informed on the best possible solutions for specific jobs.

For small to mid-size shops, it often proves impossible. For Nuflo Inc. (Jacksonville, FL), establishing a close working relationship with Sandvik Coromant (Fair Lawn, NJ) has allowed it to reap the benefits of new technologies that it might have otherwise overlooked.

Nuflo was founded in 2000 by a group of investors who moved the assets of a struggling shop from New York to Jacksonville to take advantage of contacts within the defense manufacturing industry. The new company was established with a focus on pipe-fitting components for the Navy and commercial marine customers. In less than nine years, the shop grew from 5000 ft2 (464 m2) with a handful of employees to fully occupy a 50,000 ft2 (4645-m2) facility containing 15 CNC machine tools and employing nearly 50 people.

Tom Connor of Nuflo credits Sandvik Coromant with tooling that has improved the company's productivity in machining large dies.Despite its success, the company sometimes had trouble finding the best tooling solutions for its processes. Nuflo's relationship with Sandvik Coromant began in 2006, when it was awarded a $2 million contract for the production of flanges to be used in naval vessels. The shop was experiencing difficulty in machining the components fast enough to meet the necessary turnaround times. Part of the difficulty arose from the fact that the parts were being machined from forgings with a significant amount of scale on them, requiring multiple finishing passes.

Shortly afterward, Nuflo was given the opportunity to be awarded a $3 million contract that required it to produce large dies from pre-hardened tool steel with tolerances of 0.003" (0.08 mm) and a delivery time of eight months. Among other processes, the dies required milling a 12.75" (324-mm) diam hole into the two halves of the die. Nuflo was using a 1" (25.4 mm) diam end mill at 1100 rpm and a 0.075" (1.9-mm) depth of cut. The tool could only handle a maximum feed rate of 20 ipm (0.5 m/min) at these cutting conditions, and the dies were taking over 1300 machining hr to produce.

Knowing that it would be unable to deliver the parts for the job on time at that rate, Nuflo turned once again to Sandvik Coromant. "We were running the job on a 40-taper machine, and it really needed the power of a 50-taper," says Connor. "Our Sandvik rep evaluated it and recommended that we switch over to a CoroMill 210 with a 2" [51-mm] diam. It instantly gave us the heavy-duty performance we needed, without investing in a new machine. The cutting feeds and speeds we're able to get out of that tool are beyond what I would've believed possible."Sandvik Coromant tooling enabled Nuflo to reduce total machining time for a large die component from 1300 to 260 hr.

When the CoroMill 210 was first implemented, Sandvik Coromant recommended machining feeds and speeds of 768 rpm and 60 ipm (1.5 m/min) with a depth of cut of 0.04" (1 mm). These new cutting parameters significantly reduced the time it would take to produce a die. However, Nuflo needed to increase productivity even further if it was to capitalize on the contract, which required production of thirteen dies in an eight-month period.

Nuflo began experimenting with the cutting parameters to see if the tool could be maximized even further. By shifting to 1100 rpm and 90 ipm (2.3 m/min) with a 0.04" (1-mm) depth of cut, productivity was improved, but tool life suffered, as the higher heat levels impaired the life of the inserts. After further testing, Connor upped the cutting data to 1480 rpm and 190 ipm (4.8 m/min), with the depth of cut remaining at 0.04" (1 mm) and the tool buried 1.3" (33 mm) into the material at all times.

 The results were surprising. "When we were running at 768 rpm and 1100 rpm, a lot of heat was going into the tool and the inserts were very hot to the touch when changing them," says Connor. "When I moved to 1480 rpm and 190 ipm (4.8 m/min), the heat started to transfer into the chips. When cutting at these speeds using forced air only, with no coolant applied, the inserts lasted longer and were cool to the touch when changing them."   

In addition to faster metal removal rates, the move to the CoroMill 210 also allowed more accurate roughing, greatly reducing the amount of finishing operations required. Total machining time for the component dropped from over 1300 hr to approximately 260 hr per die. This boost in productivity proved vital to achieving the turnaround time necessary to meet the customer's demand.

       

Rush to Profits with Software

In today's competitive metalcutting arena, progressive companies realize that to maximize the productive and profit-making potential of their advanced machine tools, they need advanced software as well.

A case in point is Roush Industries (Livonia, MI). The company, which provides engineering, testing, prototype development, and manufacturing services, is closely associated in the public mind with motorsports. But it also serves automotive clients, as well as aviation, electronics, medical equipment, and consumer-products companies. As a result, Roush's machining operation is called on to process a diverse range of parts with widely varying lot sizes, lead times, and levels of complexity.

To efficiently handle this demanding workload, Roush invests heavily in advanced technology. Its most recent capital acquisitions are several new machines from Mazak Corp. (Florence, KY), including an Integrex e-420 five-axis mill-turn center. It was brought in, in part, to handle the growing demand for complex cylinderhead porting operations.

One of the keys to engine performance is a properly designed cylinder head with ports that allow air and fuel to flow efficiently, producing a good burn pattern in the combustion chamber. Modifying these ports is called, appropriately enough, "porting," a technique that is done for racing engines and for prototype engines for conventional vehicles as well. Specifically, it involves fine-tuning the shapes of the ports and the thickness of the cylinder walls, along with ensuring a superior surface finish. The design objective is to reduce or eliminate flow turbulence, allowing the air/fuel mixture and exhaust to move quickly through the ports for more horsepower.

Generating these complex curves and fine finishes with a three-axis machining center is a time-consuming operation, one that typically requires a secondary positioning operation or another machine, as well as hand finishing.

The five-axis Integrex, by comparison, can complete the operation in a single setup, dramatically speeding the process. In addition, the fine finishes generated with the new system have largely eliminated the need for handwork, also reducing labor costs.

However, as anyone familiar with real world machining knows, it was not a simple plug-and-play success story. "The CAM software we'd been using on our three-axis machines couldn't take full advantage of the greater efficiencies the Integrex made possible," says Rob Mank, job planning supervisor for Roush Industries. "For example, the old software just didn't work well when the secondary turning application was added in, which really gets quite complicated. We needed software that would support this type of machine and this type of work."

CAMWorks simplifies complex programming tasks for the porting operation.

Chosen to maximize the productive potential of the new machine tools was CAMWorks 2009 software from Geometric Technologies (Scottsdale, AZ), a subsidiary of Geometric Ltd. Roush Industries had consulted knowledgeable users of similar equipment, many of whom were using CAMWorks. "After investigating, it seemed like CAMWorks had just what we needed," recalls Mank. CAMWorks is a solids-based CAM solution that provides an array of tools to simplify and automate complex programming tasks, such as associativity to speed design and programming changes.

The latest version, CAMWorks 2009, heightens the software's ability to quickly generate three-to-five-axis toolpaths as a separate thread, and in separate processes. This allows users to continue working in other areas, or on other CAM models. The key here is the system's knowledge-based database, which employs automatic feature recognition (AFR) to automatically define prismatic machinable features, and a technology database (TechDB) to define machining operations. As a result, complex toolpaths can often be automatically generated, eliminating hours of programming time.

In tandem, CAMWorks and the Mazak Integrex e-420 mill-turn process the cylinder heads for peak engine performance.The new machines and the new software were both installed at Roush at the beginning of 2009. "It was a pretty big undertaking for us," says Mank, "but we had strong support from CAMWorks." They aided with training and in ensuring that Roush had postprocessors that would support the Integrex's milling axes and turning capability.

Speed and accuracy have reduced Roush's programming times for complex jobs like cylinder head porting. "In the past, before we had the Integrex, we had to create a program for the milling operations and another for the turning. Now, with CAMWorks, we can program the job as one operation or we can program it as two operations, and then merge the two programs together once they are proven out and run them as one," says Mank.   

"We've gone from approximately 45 min doing this in the standard conventional way with two machines to 12 to 15 min with the Integrex and CAMWorks," notes Mank, an improvement of as much as 73%.

Programming speed is also increased by CAMWorks' intuitive user interface, part and machine simulation, and library options. "You can enter cutter paths in the library with associated tools, feeds, and speeds," says Mank, who finds this particularly helpful for contours that recur on numerous jobs. It helps ensure the accurate reproducibility of complex five-axis cuts like cylinder head ports, and aids operators in quickly and accurately preparing jobs. "You can really personalize the system," he adds.

Speed, too, is behind Roush's decision to purchase two seats of CAMWorks 2009. Mank adds, "Having two seats comes in handy during times of extra work and when something requires quick turnaround. During rush periods this helps us get programs out to the machines as quickly as possible, which is crucial because you don't want machines sitting idle."

 

This article was first published in the October 2009 edition of Manufacturing Engineering magazine. 


Published Date : 10/1/2009

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