Shop Solutions: Mining Boom Spurs Innovation
The demand for mining equipment has never been greater, driven by high commodity prices and skyrocketing demand from China and India. Mining equipment manufacturer, P&H Mining Equipment Inc. (P&H; Milwaukee) has sought ways to take advantage of the market surge and satisfy its customers by improving delivery times.
P&H Mining Equipment is part of Joy Global Inc., which also includes the underground mining equipment company, Joy Mining Machinery. P&H produces its three main product lines of surface mining equipment, which includes electric mining shovels, rotary blasthole drills and walking draglines, at its headquarters in Milwaukee.
P&H is a global leader in the manufacture and service of large excavating and drilling machines used to mine copper, coal, iron ore, silver, gold, diamonds, oil sands, phosphate, molybdenum, potash, and other minerals and materials. Ninety percent of the world's surface mines utilize P&H equipment.
In an industry where downtime can cost thousands of dollars per minute, delivery, quality and reliability are vital. P&H has chosen an approach to manufacturing called QRM (Quick Response Manufacturing), whose overriding principle is lead-time reduction. (Please refer to sidebar on page 77.) Implementation of QRM and the acquisition of 13 new machine tools have produced an overall reduction in lead times of 40–50%.
"We didn't just go out and spend $12 million on capital equipment; we completely changed our manufacturing philosophy," explains Walt Wiedmann, facilities manager and capacity expansion project leader. Over an 18-month period the project team, which included both management and hourly employees, selected equipment, negotiated the purchases, reorganized the factory, moved machines into cells, educated employees on QRM principles, installed the equipment, and trained operators on the newly installed machine tools.
"Partnerships and teamwork were the keys to our successful implementation of this project," Wiedmann says. P&H Mining has a union workforce. The changes required in the QRM philosophy would not have been possible without the union's cooperation.
"We negotiated a cellular manufacturing agreement with the union. To their credit, they recognized that for P&H to remain competitive and keep skilled union jobs in Milwaukee, changes were needed. The days of one employee operating one machine and performing one operation are no longer cost-effective or efficient," Wiedmann explains.
Workers within a QRM cell are responsible for the entire job from scheduling to machining, assembly and inspection. They also multitask, taking on several roles within the cell. In anticipation of the change, a great deal of time was spent training employees on team-building as well as the equipment and processes within their cell.
Before selecting equipment, P&H took a hard look at the machine-tool companies themselves. "We didn't want a typical vendor/customer relationship", says Wiedmann, "We narrowed the field to those companies that could work with us every step of the way, from part processing through service support." Giddings & Lewis (G&L; Fond du Lac, WI), a Cincinnati Technologies Group MAG IAS company, was selected as the partner for vertical turning centers. Among the vertical turning centers purchased were a VTC 1600 used in the large gear roughing cell, a three-pallet shuttle 1600-mm vertical in the small roughing cell, and a large 2500-mm vertical turning center that is part of a support cell for large, tight-tolerance parts.
Structuring the manufacturing process into cells and restricting part movement out of the cells is fundamental to the QRM objective of lead-time reduction. P&H manufacturing cells are organized around families of parts. The large round cell produces the shipper shaft pinions and rollers. Both arrive at the cell as raw forgings. The cell contains a Mazak HMC, two internal shapers, and a Giddings & Lewis VTC 1250. Two people on each shift run the cell operations. Except for heat treat, all processes are performed in the cell. Lead time for the two families has been reduced by 40%.
The pin cell, which has been in production for about one year, is a good example of the results possible employing the QRM philosophy. There are three machines in the cell. Crawler shoe pins are faced and centered or drilled and tapped on a Giddings & Lewis HMC, and turned at RC 40 on a lathe. The pin is then induction hardened and tempered to RC 55/60.
P&H changed from untreated bar stock to pre-heat-treated bar stock so that the pin never leaves the cell. As a result, movement of the parts was reduced from 2200 to100' (670–30 m), and the cycle time improved from 20 to 2 hr. Six operators were involved in the old process compared to one per shift in the new process. Each mining shovel uses 180 pins.
Most of P&H's production is not high volume like the crawler shoe pins. A quantity of two is the average lot size. QRM purports to handle variable demand and highly-engineered products such as planetary transmissions more effectively than lean or JIT approaches.
"Planetaries are the heart of our shovels and an area of core competency for our company," states Wiedmann. As part of the buying process, P&H supplied the part prints to ensure that G&L could fixture and tool the parts to the close tolerances required. A runoff at the Giddings & Lewis plant, demonstrated the versatility of the VTC's live spindle and the capabilities of a special tool from Kennametal Inc. (Latrobe, PA) called a Tuneable Bar.
With the Tuneable Bar, P&H can machine two bores inline, 19" (482-mm) apart, to extremely tight bore diameters and clocking tolerances. This precision boring bar with extended reach requires a stiff connection between the spindle and the tool. Giddings & Lewis vertical turning centers use a company-designed tooling system called WedgeLock. As the name implies, a wedge system secures the tool at a 6.3" (162-mm) diam gage line with 33,000 lb (146,784 N) of clamping force. "We're very pleased with the accuracies. WedgeLock is a rigid system and holds close tolerances well," Wiedmann confirms.
Accuracy and repeatability were not the only considerations in the selection of VTCs. Improved quality and increased capacity were also important both from the standpoint of machine availability and machining capacity. Redundant capacity is a significant concept in the QRM system. In the past, the company had one vertical turning center in the large turning and shaping cell to handle critical components such as planetary carriers and large planetary ring gears. This became a manufacturing bottleneck and caused lead times to lengthen. With the G&L VTCs, additional capacity is available for these critical components. Parts for mining equipment are by nature large. P&H chose the extended column heights on two of the VTCs purchased and use the 1600 and 2500-mm VTCs to their maximum swing capacities.
Eight cells are currently running at P&H. Ultimately the company plans to have nine cells in operation in its rotating factory. "The underlying benefit and reason for the changes is our constant goal of satisfying our customer," Wiedmann adds. "But we also appreciate the benefits of the partnerships we've established with our Union committee, our workers, and our machine tool suppliers."
Precision Machining Opens New Markets
Continental NH3 Products Co. Inc. (Dallas, TX) has been in the manufacturing business for more than 50 years. Founded in 1955, the company specializes in manufacturing equipment for the agriculture industry, and is well known for meters, valves, fittings, adapters, couplings, and manifolds for handling anhydrous ammonia.
In the past few years, Continental's president, Judd Stretcher, has pursued a policy of sound growth. In 2005, Stretcher formed Continental Manufacturing to help the company expand into non-agriculture-related precision-turned products. Continental Manufacturing occupies a 28,000 ft2 (2601 m2) facility, which features high-volume multispindle automatics, CNC turning and milling machines, multi-axis lathes with live tools, Y-axis with subspindle and CNC Swiss machines.
Its production capabilities include production work handled on multi-spindle automatics, as well as CNC turning and milling, multiaxis lathe machining with live tooling, and Swiss turning. Secondary operations are supplied by drill presses, turret lathes, and manual mills and lathes. The facility also includes an onsite tool-grinding shop where it fabricates form tools and sharpens drills.
One of the first contracts awarded to Continental Manufacturing was to produce take-down pins for the M-16 rifle. Over the past eighteen months, Continental manufacturing has re-engineered the traditional process from the ground up and eliminated secondary operations to achieve what many thought impossible, a complete take-down pin in less than sixty seconds. The manufacturing process for the key defense component resulted in a 56% reduction in cycle time and improved part quality.
Machined from 86L20 stainless, these 1.01" (25.6-mm) long parts had been a headache to manufacture. Operations required to complete the part included facing, turning, drilling, hole chamfering, and slot milling. Drilled and chamfered holes on one side of the part added another level of complexity by making it difficult to produce the part in one chucking.
A number of manufacturing process sequences were attempted with varying degrees of success. "We began using multispindle automatics to blank the part before taking them to a milling machine, placing them one by one in a custom-built fixture for milling and drilling operations," Stretcher explains. While the cycle time was acceptable, multiple setups made staying within the 0.0005" (0.013-mm) tolerance challenging. "It is extremely challenging to maintain a 0.0005" [0.013-mm] tolerance once you re-chuck."
Recognizing the need to machine the part complete from bar stock, Stretcher consolidated the two operations on one gang-tooled lathe with live milling tools. This approach had the desired effect, yielding a slightly faster cycle time, and producing parts within tolerance. With pneumatic milling attachments, the lathe began to struggle with the extensive cross milling of an 0.0725" (1.84-mm) slot. The machine's poor thermal compensation characteristics caused parts to grow throughout the day.
"We found that our parts at the beginning of the third shift were within tolerance and by the next morning a substantial number had exceeded tolerance," Stretcher says. The need to run untended and consistently produce parts within tolerance led him to seek a more permanent solution using the company's recently installed Tsugami BS26C Swiss-turn from Rem Sales Inc. (East Granby, CT).
Feasibility of manufacturing the part on the BS26C Swiss-turn was assigned to operator Rodney Grabatin, who was familiar with the Fanuc control. Grabatin immediately set to work programming the BS26C, which is a rigid machine with Swiss capabilities, including subspindle and 5000-rpm cross rotary tools, for the part. The result was that the Tsugami BS26C Swiss-turn was soon cutting the parts to print in 1 min 26 sec. Subsequent tweaking, including adjustments to tool positioning, reduced the final cycle time to 1 min 2 sec.
The transition from multispindle automatics to the more flexible Swiss platform virtually eliminated down-time. "Changing a tool on a Swiss machine usually involves throwing an insert away and replacing it with another. To do the same thing on an automatic requires removing the tool, regrinding it, reinstalling, and retouching it." With a better understanding of exactly how the company could benefit from Swiss-turns, Continental soon sold one of its standard lathes, using the proceeds to purchase a new Tsugami BE19.
Awarded the take-down pin contract for a second time, Stretcher decided to make two additional changes to further reduce the cycle time. The first change was to machine the part on the new Tsugami BE19. Featuring 8000-rpm cross rotary tools, the Tsugami BE19 proved to be a significant improvement over the Tsugami BS26C for this job. Continental handed over the reins of the BE19 to their latest employee, Kody Dill, who came to Continental with previous Swiss machining experience. "This time around we were able to reduce the slot-milling operation by around 75%."
The second change was to reorder the processes. Typically the two drilled and chamfered holes on the take-down pin are completed after the facing, turning, and slot milling operations. In the end, with the help of Continental's tooling specialist, Don McWhirter, they decided that by using a single form tool, the holes could be drilled and chamfered with one tool. In the subsequent operation, the slot milling would reduce the length of the now chamfered hole to tolerance.
In the final analysis, Continental was able to reduce the cycle time to 38 sec, a savings of 56%. By thinking creatively, continually seeking improvement and utilizing the latest Tsugami Swiss-turn technology, Continental produced parts more efficiently, improved part quality and grew its business. "We are very happy with our Tsugami. That BE19 will hold one or two tenths all night long,h Stretcher concludes.
CAM Programming Meets Need for Speed
Ed Pink founded his business in 1959, gradually expanding it into the 23-employee R&D company that Ed Pink Racing Engines (EPRE; Van Nuys, CA) is today.
Operating from a 15,000 ft2
) facility, EPRE is well-known in racing circles or, more accurately, on racing ovals, for high-performance engines and components. Among its many clients have been GM, Ford, Nissan, and Toyota.
Salient projects include turbocharged Cosworth and Buick V6 engines for Indy car racing, and turbocharged Porsche engines that have run in the 12-hr Sebring and the 24-hr Daytona sports car races. EPRE's products have been in nearly all the major series including the Indy Racing League, Champ Car (formerly known as CART), USAC, and NASCAR. EPRE has taken stock engines that have been in production for many years, and made them run at 10,000 rpm, with nearly 800 hp (597 kW).
All racing organizations impose dimensional and weight restrictions on cars, engines, and components. Ed Pink, EPRE founder and owner says, "NASCAR is the most diligent enforcer. Their rules make it difficult for anyone to gain an edge, but they make good business for us."
EPRE's core business is R&D, designing, testing, and developing high-performance engines and components for racing. Production of the noncustom components that are generally used is outsourced. They include camshafts, connecting rods, engine bearings, pistons, valve trains, water pumps, dry-sump oil pumps, and cooling, air-intake, ignition, and exhaust systems.
It was in making prototypes that EPRE encountered an apparently insurmountable challenge. Although its machine shop, occupying about 7500 ft2 (697 m2), was well equipped with conventional machines, (three lathes, four vertical and two horizontal mills, and a tracer mill), EPRE found it lacked equipment to manufacture parts on a timely and consistent basis.
Traditional reliance on outsourcing became a very frustrating problem. "It's tough to find reliable shops able to meet your quality and delivery requirements. When you do, they sometimes charge a prohibitive amount. Being held hostage many times, we decided we needed a change. We had to find a better way to machine our parts," Pink explains.
Armed with a problem and little knowledge of CNC machine tools, Pink's team investigated several machines, selecting a VF3 VMC from Haas Automation Inc. (Oxnard, CA) with Haas CNC control. To take full advantage of the machine, and compress the prototype-to-production cycle, EPRE needed the right software.
"We attended the WESTEC Show and looked at countless software packages as complete novices," Pink laughs. "Most of the vendors treated us as a nuisance, except Gibbs and Associates [Moorpark, CA]. Bill Gibbs, himself, saw us as serious buyers, educating us, showing us the software, and answering our questions. Their patience demonstrated that they were likely to provide the service we would need as we moved up the learning curve," says Pink.
Mastering GibbsCAM was easy, according to Mike Johnson, the EPRE design engineer whom Pink credits for most product development. "We use SolidWorks almost exclusively for design. I can send the model to Doug Nealy, our programmer and machinist who loads it into GibbsCAM, and it's nearly ready to go," says Johnson. "GibbsCAM is very easy to use and very accommodating. We can literally load a part and run. The conventional machines are slowly gathering dust, and our scrap rate is very, very low."
GibbsCAM enables reading SolidWorks models directly, and its associativity between part geometry, processes, and toolpath accommodates most incremental changes in the model. A GibbsCAM plug-in for SolidWorks allows models to be transferred directly from SolidWorks to GibbsCAM.
"We run the model in Gibbs-CAM's process simulation, and we take a very careful look, to check for potential problems and see what shortcuts we can take," Johnson explains. "Often, you see where changing a machining process or tooling will save time. We've cut our scrap rate, our costs, and delivery times significantly.
The greatest benefit of GibbsCAM has been the ability to machine a new component design, take the component to the test lab, check its performance, and quickly make modifications. "Before, we would have to wait weeks. Now I can have a perfect functional part, tested and ready for production, within a couple of hours," Nealy says.
An unexpected benefit is the ability to machine parts from billet, parts previously made through EDM or casting. One of many examples is a rotor, a key component of a new dry-sump oil pump designed by Johnson and now in the final stages of development for several NASCAR racing teams.
The pump is intended to improve racing engine oil management and lower power consumption by reducing drag and resistance. Unlike most other dry-sump pumps, EPRE's design uses two rotors in each scavenge (or retrieval) section, keeping gears only in the pressure section. The Pink team concluded that rotors scavenge more efficiently, and generate a high negative pressure in the engine crankcase, which helps pull oil off moving parts that don't need lubrication.
Although the pump contains some unique and EPRE-patented parts, Pink claims it's not a re-invention of the wheel, but merely optimization through applied knowledge and expertise.
Even so, applying their knowledge was not easy. The former rotor production process would encompass four vendors and begin with 2" (50.8-mm) thick, 2' (0.6-m) square aluminum plate, which would be sent out for Blanchard grinding to achieve flatness. Then, 100 two-lobe rotors would be laid out on the plate, which was sent out for boring center holes on the rotor layouts, and drilling and tapping a 10-24 hole on the end of each lobe. Finally, the plate would move on to an EDM shop to form individual rotors, returning as 20 bars, each holding five rotors.
Each rotor would be cut free, and each rotor end would be partially machined. Then a half-cylindrical groove would be broached into the edge of the center hole. A matching groove would be EDMed into the separate rotor shaft, enabling the placement of a steel dowel to lock the rotor onto the shaft. "At the end of this laborious process, four months would have passed, and we would have $100 invested in each rotor," says Pink.
One of the new Ed Pink Racing oil pumps for the NASCAR V8 race engines has five scavenge sections: four serving two cylinders zones each of the crankcase and one serving the upper section of the engine. For this one pump, the cost of ten rotors alone was $1000, but Pink is quick to emphasize that the delays were as bad as the cost.
Now, EPRE uses GibbsCAM and its three-axis CNC VMC to make rotors. Starting with a square billet, the CNC does the complex profile on the outside, bores the hole through the center, drills and taps the 10-24 holes, and completes the rotor by boring the dowel pin groove next to the center hole.
Pink is elated with the result. "To get 100 rotors from our outside multiple vendor process would take us four months, from start to finish. Now we make 100 rotors in-house in a week. GibbsCAM and the CNC let us do that. We use the rotors in our other pumps with great results. The inhouse produced rotors are more dimensionally precise resulting in more scavenging performance of the pumps by reducing operating clearances. An additional benefit is our ability to modify the rotor lobe shape, bench test the new design, and then incorporate the change into our inhouse production."
But what about cost? Says Pink: "This shattered my experience, which was that, to make a component better or faster, it costs more. Not now. We cut the cost of our rotors from $100 to under $25, saving $750 dollars per pump. We eliminated previous outsourcing combined with long manhours on conventional mills, and we're making better, more accurate parts, and doing it a lot faster."
While EPRE's conventional machines are increasingly idle, Ed Pink and his team continue to look for new, exciting projects, hoping to generate sufficient business for dry-sump oil pumps and other components, "to add more CNCs to our arsenal of one, so we can do our own production. There's only so much one machine can do...even driven by GibbsCAM...even running 24 hours a day.
Thread Mill Cuts Aerospace Part Processing
Gentz Industries L.L.C. (Warren, MI) is a world-class provider of complex turbine engine components for the commercial and military marketplace. With over 50 years of manufacturing to its credit, the company's commitment to quality is reflected by its ISO 9001:2000 and AS9100 registrations.
Gentz typically produces low-volume, high-precision parts from expensive and hard-to-machine materials such as Inconel, titanium, and stainless, among others. Due to the high cost of these materials, there is no margin for error due to scrap or waste.
When Belinda Smith, application engineer for Seco Tools Inc. (Warren, MI), approached Mark McWilliams, Gentz purchasing manager, and asked him to consider switching to a 0.156" (3.9-mm) Threadmaster thread mill on a combuster case component made of Inconel 718 heat-treated to RC 42, she was met with just a bit of skepticism.
"We had already tested five competitive 0.156" [3.9-mm] size thread mills on this application, which requires the creation of 52 #10-32 thread holes," explains McWilliams, "All resulted in tool breakage. We weren't real confident when Smith said 'ours is better,'" says McWilliams.
To perform the thread milling operation, Gentz had settled on using a 0.170" (4.3-mm) thread mill, which created undersize holes. Each of the 52 holes then had to be individually hand-tapped for finishing. To perform the entire threading operation required two thread mills making three passes and about 15 taps to hand tap the part. Total time per component clocked in at 154 min of machining time plus another one or two hr for hand tapping.
Not the most efficient process, but it had proven to be stable, and stability is crucial on high-value components. When the forged combustor ring arrives on Gentz' floor, it is already worth $14,500 per unit. Then add to that about 14 more hr of machining time before it gets to the final thread milling operation. The Gentz team, understandably, was not very keen about messing with a process that was producing good components.
"We have a long-standing partnership with Seco and enjoy a great relationship," says Jim Stevens, Gentz OEM manufacturing manager. "But experience had taught us that the 0.156" thread mill was just not suited for the job. It took about a year of Belinda confronting us on this process before we finally agreed to give Seco's solid-carbide Threadmaster a whirl," Stevens says.
Part of what makes Threadmaster different from other solid thread mills is a TiCN coating and micrograin structure that provide both toughness and wear-resistance.
Once Gentz agreed to the trial, Curt Hassan, Seco regional manager, then insisted that Gentz more than double its feed rate from 78 to 194 ipm (1.9–4.9 m/min). Additionally, he wanted to run the OKK KCH500 four-axis twin pallet machining center from OKK USA Corp. (Glendale Hts, IL) to its 5000-rpm capacity; over three times the 1500 rpm Gentz had been using.
"We were very skittish about speeding up," says Stevens. "I couldn't imagine the thread mill doing anything but falling apart on the Inconel."
It's because of Mark and Jim's support along with the rest of the Gentz team—Paul Jones for programming and machine operators Mike Namel and Simon Street—that we were able to try and run the Threadmaster at this speed and feed," says Hassan. "Our numbers were so much higher that it just scared everyone."
The new Seco Threadmaster 0.156" was able to complete the thread milling operation in 53 min with only two passes, saving an hour in machining time and one complete pass. Additionally, the hand tapping time was reduced from 90 min average per component to 30 min. And, this is only done to check and see if any of the threads are snug.
Programming parameters were modified with Seco's Thread Milling Wizard software to help compensate for the increased feed and speed. With the Wizard, the operator need only enter the type of thread, diam, depth, and material group they are working in. The software then generates the machine code, greatly reducing setup time and creating a perfect thread from the very first cut.
Gentz also switched from the current hydraulic chuck system to a shrink-fit thermal toolholding system offered by Seco. "This helped us achieve less runout, better tool life, and more even tool wear," adds Stevens. "The machining center is really humming at 5000 rpm and the rigidity of the thermal toolholder helped us achieve better tool balance." An added bonus is that the shrink-fit system has worked so well, that Gentz is now going to apply it to other applications.
Hassan is modest about the success of this thread milling application, although the two hr/part savings equates to 44 hr/month that can be spent manufacturing other hardware. "The Threadmaster 0.156" is providing a great cost-savings to Gentz and increasing throughput," says Hassan, "but, I think we are only in the infancy of gaining efficiencies in the machining of this part, which spends about 16 hr on the Gentz shop floor."
"Just eliminating the hand-tap time was worth the change in this process," emphasizes Gentz COO Roger Bartolomei. "Most of the hand labor is gone and now we are threading to size, which improves quality. And, you can't scoff at almost $62,000/year in savings."
Seco is currently studying the other operations performed on this component—turning, rough milling, deburring, heat treating, and finish milling—using its Productivity Cost Analysis (PCA) program. PCA measures a process or workpiece as it moves through production with the software manipulated to achieve the stated objective, whether it is reduced cost or increased output. With PCA, Seco can evaluate a single-machine tool process or the complete path that a workpiece takes on its journey through the shop floor.
Seco and Gentz, along with distributor E&R Industrial, have opened a monthly forum during which the group reviews what has been accomplished on the Gentz shop floor and develops action items that need to be addressed. "We've really seen a lot of good things come out of this forum," says McWilliams.
"Through these meetings, we help Gentz to identify their hot spots... the areas where they need help. This helps us focus on what is important to them," says Seco Tools' Hassan.
"We are a fast-growing company, so it is critical for us to work with suppliers that know how to help us improve efficiencies," concludes Bartolomei. "One thing I know for sure, Seco understands the meaning of partnership."
CAD Takes Models to Mold Fast
Innovative Casting Technologies Inc. (ICT; Franklin, IN) is a small, ISO-certified agile company that claims it can accelerate its customers' product development cycles and help them reduce time to market.
ICT's business includes fast-turnaround on prototypes and low-production castings in grey iron, ductile iron, and aluminum for customers such as Cummins, Deere, Tecumseh, Caterpillar, and Parker-Hannifin. Services include NC programming and machining, CMM verification, and use of CAD/CAM software to speed product turnaround.
One of the major tools it uses to accomplish its mission on a daily basis is CAD/CAM software from Delcam International (Windsor, ON, Canada).
ICT specifically uses PowerMILL CAM software and PowerSHAPE, to manipulate the surface form of CAD models so that the company can ship machined prototype parts within three to four weeks of receiving the customer's CAD file.
According to ICT, the Delcam software allows it to create models and secondary tooling in a day or even hours in some cases. Since 2005, the company has used the Delcam software to deliver cost-effective prototypes to its customers to check form, fit, function, and to evaluate a new product design visually. Most of the prototype work is manifolds and brackets of various descriptions.
"For a customer who needed parts for an engine right away, we shipped five six-port exhaust manifolds 13 days after receiving the CAD file," says owner Jack Laugle. He is a second-generation pattern-maker with experience at another casting company before starting his own company in 1997 to make patterns and prototype castings.
Once a pattern is designed, the company uses a series of machining centers to create patterns, core boxes, and finished machined castings. Haas mills are used to machine the patterns, and two Mazak machining centers are available for prototype machining. Castings and machining can be verified with a Brown and Sharpe CMM, comparing the measured data to the CAD file.
"Previously we used another software package, but have found that the options available through Delcam PowerSHAPE make the pattern design and machining process much easier, including creating surfaces for the parts," says Tony Luenebrink, pattern designer.
"When we get a pattern to work with, such as bracket or manifold, we bring the customer's part file into PowerSHAPE, usually from Pro-E. We then easily break out the component parts, [cores, the outside shape and the core boxes] in order to create a pattern we can use to produce the prototype parts," Luenebrink explains.
PowerSHAPE saves hours of pattern design time at ICT with a feature called Smart Surfacing. It blends fillets and radiuses automatically. PowerSHAPE has always provided a number of alternative methods for constructing a surface from a given set of lines, arcs, or points. But with Smart Surfacing, the choice of method is made automatically by the software to give the best possible (smoothest) surface.
Smart Surfacing also permits the software's selection to be updated automatically as information is added to the design. As any additional lines or points are inserted into the model, PowerSHAPE reviews the chosen surfacing method and regenerates the surface automatically, giving an alternative solution if a better one exists.
"Then, once the file is imported into PowerMILL," Luenebrink says, "it is easy to program the machining in layers to suit the lengths of our cutters. Many of our patterns can be 10–12" [254–305-mm] tall, and our cutters are 4–5" [101.6–127-mm] long, so programming in layers allows us to program the machining efficiently, avoiding cutting air. This saves all kinds of time, which is important to our business of speed.
"The programming time is similar to our previous method, but once we start machining, that's where we can really see the difference," says Luenebrink. "The machining strategies in PowerMILL help us avoid cutting air, so machine time is chip-making time. The result is that the whole pattern-making cycle is much shorter so we can turn around a pattern 30% faster. For example, a pattern that used to take us 12 hr to program and machine on our Haas mill now takes us less than 8 hr."
ICT usually produces 3–5 different patterns a week, depending on the size and complexity of the patterns. The machining programs take less time because they are shorter. "You can tell they are shorter," Laugle says, "because there are many fewer lines of code. It's just more efficient software than what we had been using. Toolpaths are much more concentrated."
To assure safe, time-saving machining, PowerMILL automatically checks for potential collisions of the cutting tools, while contact-point analysis allows ICT to ensure that only the cutting edges touch the pattern or prototype part.
Once a prototype casting is delivered and evaluated by the customer, its file can be changed and returned to ICT. "The Delcam software makes its easy to overlay the 3-D model from the customer and to see any changes in the new casting file we get back," says Luenebrink. This is a big advantage to the prototyper. It makes it easier to select the areas of a pattern that only need machining then to modify the PowerMILL file accordingly, so the machine will concentrate only on the area of concern—saving a lot of time in reprogramming and machining.
Patterns are machined in the ICT building, and transferred to the foundry next door. Castings are then returned to ICT for finish machining, painting (if needed), and final shipment. According to Laugle, production of the system can be up to 25 molds/hr, depending on the size and number of cores.
"With the pattern-making, prototyping, and foundry capability, we can compress leadtimes and sell speed. With our own foundry, we are a 100% turnkey operation, which has permitted us to compress the leadtimes," Laugle says. "And the Delcam software is a major tool in taking time out of deliveries to our customers."
As a matter of fact, according to Laugle, sometimes sales can't keep up with the ability of his staff to turn around patterns and prototypes. That helps ICT stay competitive, which is good, because the company has competition. Not so much from foreign sources as much as from larger domestic companies that have reduced their volume requirements. With the help of Delcam, ICT is sure of meeting the challenge and remaining a successful, turnkey prototype foundry.
Quick Response Manufacturing
QRM is a strategy whose main tenet is the pursuit of lead time reduction for competitive advantage. Some of the organizational principles of QRM include:
- Overall lead time minimization as the goal rather than a focus on "touch" time or the time required for individual processes such as machining or assembly.
- Simple, product-oriented cellular structures run by teams.
- Strategic planning for spare capacity ultimately reduces lead times.
- POLCA strategy (Paired-cell Overlapping Loops of Cards with Authorization), a material control system, combines the best features of push (MRP) and pull.
The Center for Quick Response Manufacturing at the University of Wisconsin—Madison has a membership of nearly 40 manufacturers of various sizes, products, and locations. Professor Rajan Suri is the Director of the QRM Center. Additional information may be found at www.engr.wisc.edu/centers/cqrm.
This article was first published in the March 2007 edition of Manufacturing Engineering magazine.
Published Date : 3/1/2007