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Shop Solutions: Custom Cutting Tools Deliver Productivity Payoff

 

Since its inception in June 2001, Genesis Machining Services (Calgary, Alberta) has been manufacturing the TorqStopper, a custom torque anchor for use in progressive-cavity pumps in the oil and gas industries. Available in a variety of sizes, TorqStoppers are marketed by Advantage Products Inc., one of Genesis' largest customers.

In operation, progressive-cavity pumps can produce thousands of foot-pounds of torque. A torque anchor stabilizes the pump in the well bore, reducing pump and casing wear. The Torqstopper's design wedges the pump stator against the casing, and can be serviced quickly and on-site using only an Allen wrench. The unit can be installed in production tubing or casings from 2 7/8 to 10 3/4" (73 - 273-mm) diam.

       

           
                 

            Advantage Products says the patented device has captured 80% of the heavy oil market in Canada and 70% of the coal bed methane market in the US. It's used in gas and oil wells around the world, from Venezuela and Brazil to Ireland, Australia, Oman, and Western Siberia.

Advantage Products says the patented device has captured 80% of the heavy oil market in Canada and 70% of the coal bed methane market in the US. It's used in gas and oil wells around the world, from Venezuela and Brazil to Ireland, Australia, Oman, and Western Siberia.

Far from being a static part design, the TorqStopper underwent a major evolution last year. Advantage designers incorporated a D-slot into the main body of the torque anchor to prevent the body's door detail from being torn off if a power wrench is used.

The problem for Genesis Machining was that there was no standard tooling available for machining the D-slot efficiently. "We supply several thousand TorqStoppers per year," says general manager Ned Polancec. "In the prototype stage for the new model, we used a regular brazed carbide single-point fly cutter. We soon realized this just wasn't going to work on larger production runs."

The company's first option was to supply its own cutting tools. "For the maiden production run of 200, we made four six-toothed cutters, incorporating six brazed-on carbide inserts, that were sent out for grinding to match the D-slot profile," Polancec recalls. "This improved quality and machining time substantially from the prototype stage, but tool life was nowhere near what we needed. The cutters were good for maybe 10 or 20 TorqStopper bodies at most, and we were spending way too much time changing cutters and running measuring probes to ensure that tolerances were within specifications."

Investigating custom tooling suppliers via the Internet, Genesis Machining came across US Tool Inc. (Farmington Hills, MI). "We sent them a concept drawing of the milling cutter and indexable inserts we wanted," Polancec says. "Within a day, they provided us with detailed drawings for both cutter and inserts along with pricing and a delivery schedule."

Genesis Machining found the pricing and delivery acceptable, and placed an initial order for three milling cutters and 50 indexable inserts, 25 of which were TiAlN-coated.

"The day they arrived, we put them in use and realized significant performance improvements," Polancec says. "We were able to increase speeds and feeds by 100% and went from a five-minute cycle time down to two minutes for the D-slot profile." Tool life is well over 100 TorqStopper bodies before inserts require changing, he adds.

Genesis also takes advantage of US Tool's Ready 2 Ship program, which lets users place volume orders for several months' worth of tooling. US Tool then manufactures the tools and stores them, releasing them to the customer on an as-needed basis. The user gets a volume discount because the entire order is manufactured at once, and receives an invoice only for the amount shipped.       

End Mills Pump Milling Productivity 

Circuits and Systems (also known as Arlyn Scales; East Rockaway, NY) manufactures electronic weighing scales for industrial and commercial applications. With products that can weigh components weighing from a few grams to 20,000 lb (9000 kg), the company has 22 employees who work in a 6000 ft2 (560 m2) facility.The company machines load sensors--electro-mechanical devices that convert the weight on a scale to an electrical signal through a strain gage--in a variety of different sizes depending on the scale.       

Transducers start out as rectangular bar stock in sizes ranging from 0.75 X 1" (19 X 25 mm) to 1.5" (38 mm) square with varying lengths. The bars are machined with pockets and slots. "In some cases, we do plunge milling using the entire length of the cutter going through the whole part in one pass," company president Arnie Gordon says. "Other times, we take multiple passes." The company produces about 5000 transducers annually, he adds.

To boost milling productivity in the tough 17-4PH stainless material, Gordon checked out solid-carbide end mills from Dura-Mill (Malta, NY). Dura-Mill tech personnel recommended a 1/2" (12.7-mm) diam WhisperKut end mill with three flutes for machining the precipitation-hardening stainless.

Milling is done on a twin-spindle VMC with 7.5-hp (5.6-kW) spindles. "We use double vises to hold eight parts at a time," Gordon explains. "We run the end mills at about 1500 rpm, depending on the part."

Previously, Arlyn was using a 1/2" diam three-flute end mill for both rough and finish cutting. Speed and tool life were issues.

The new tools are used for several different operations. "In one operation where the previous cutter took about five minutes, the WhisperKut is doing it in 90 seconds," Gordon says. "We took faster feeds and speeds and a deeper cut, and we didn't have to use both a roughing and finishing cutter. That saved a tool change, eliminated the tool change time, and allowed us to add another tool in the changer." Machining time for another operation was cut from 30 to 15 seconds, he adds. 

 

                                    

CAD/CAM Makes for Better Biking 

   

Tucked away in Van Buren, ME, just a stone's throw from the Canadian border, is a small company that manufactures some of the most high-tech bicycle frames on the planet.

According to production manager John Desjardins, Aegis is "one of the bicycle industry's best-kept secrets." Despite that, the company has attracted some 12,500 customers around the world--a number that's growing by 5% a year.

That's not bad, considering there are no bike shops where cyclists can buy a complete Aegis bicycle. The company makes the frame, fork, and seat post, but not the other components that make up a finished bicycle, such as gears, shifters, handlebars, seat, tires, brakes, and rims. Rather, a customer walks into a dealer and custom-designs his or her bicycle from the ground up. Price tags of $4000 - $5000 are common, but the customer gets a very light, fast, and durable bicycle.

So how does a nine-person company compete against much larger bicycle manufacturers? The keys to Aegis' success are its mastery of carbon fiber, cutting-edge design, and innovative manufacturing, including technology solutions such as SurfCAM CAD/CAM software from Surfware Inc. (Westlake Village, CA).

"We need to be extraordinarily self-sufficient," Desjardins says. "We're a very small company, and we're based in a very rural area. On the plus side, employees get to wear a lot of different hats, and no two days are alike. But on the downside, we need everything to work perfectly day-in and day-out. We get that kind of reliability and dependability with SurfCAM."

Aegis has used the software to design bicycle geometry and aluminum molds for the carbon composites, and to create NC toolpaths, for more than a decade. Company engineers sketch out the geometry for a new bicycle frame using the package's 2-D design capability.

"Bicycle geometry is essentially two triangles put together," explains Desjardins. "One triangle represents the bicycle main body, while the other represents the seat stay and chain stay.

"Once the basic geometry is set, we insert library figures representing the wheels and other critical components so we can check for potential interferences." Aegis engineers then use SurfCAM to design aluminum molds used to produce the carbon composite bicycle frame and to generate NC toolpaths to machine the molds.

After production of the main triangle and the seat/chain stays, the two frame triangles are glued together using an alignment jig--also designed and machined using SurfCAM--to create a complete frame. "Once the frame's taken out of the jig, we reinforce the joint areas by brushing them with what we call a wet lay-up--a mixture of dry carbon, fiberglass, and epoxy," Desjardins says. "The lay-up mixture cures at room temperature."

SurfCAM enables Aegis to keep all manufacturing in-house, according to Desjardins. "We make our own jigs, fixtures, connectors, pins--a variety of milled aluminum parts that we need for our manufacturing process," he says. "If we didn't have SurfCAM and had to go outside and buy these parts, it would add $200 or $300 to the cost of our bicycle frames. So we'd be less price competitive, and it would take us longer to get each bicycle frame out the door."

 

Clamping System Cuts Setup, Production Time 

Engineers at The Boeing Company's Auburn, WA, Fabrication Division plant achieved a big reduction in setup times and increased productivity using a universal clamping system to fixture airframe components.

In one operation, fixture change time on a large gantry for airplane flaps was cut from nearly two hours to 20 minutes. Another changeover for smaller parts (trunnions) that used to take an hour is now completed in seconds using the Unilock universal clamping system from BIG Kaiser Precision Tooling (Elk Grove Village, IL).   

At Auburn, a series of Unilock clamping chucks mate with a series of clamping knobs to hold the fixture or workpiece. Each chuck can provide up to 11,240 lb (50 kN) of clamping force and achieves repeatability of 0.0002" (0.005 mm) or better. The system provides a solution for two tough setup problems: repeatability of location from one fixture or workpiece blank to another and transfer of work from one machine tool to another.

A Unilock demonstration impressed Boeing engineers with the system's speed, repeatability, accuracy, and ease of use. Even more important, Boeing retained the ability to build its own fixtures and mating receivers with standard Unilock components.

The modular system adapts to workpieces of virtually any shape or size. Zero point clamping chucks are available in different configurations for use with mills, lathes, grinders, and EDM machines, as well as measuring equipment such as CMMs. Standard pallets come in steel and aluminum, or customers can produce their own pallets by purchasing the positioning components. Position and clamping elements can also be mounted directly to workpieces or existing fixtures.

In one operation, Boeing is using the system to hold flaps for the 777 commercial airliner during machining. The operation involves machining separate flap halves, then fastening them together. "It used to take us two hours to change out the fixtures," says process engineer Steve Martin. "With the Unilock, we just clean off the fixtures and put them back on the machine. It takes about 20 minutes."

Another operation involves machining trunnions for the 757. "The parts require seven different media for roughing, finishing, and other operations. We flip parts over to work on both sides and use several different tools. Unilock always works. The center locator is precision-ground and uses a diamond pin. We know that's where it's going to be every time," says Boeing NC programming manager Miles Olson.

"We have long run times on these parts--anywhere from 45 minutes to four hours," Olson continues. "We have six fixture changeouts per shift. Unilock has cut our clamp and unclamp time, but it's not just the speed that makes a difference. It's accuracy and repeatability. When we clamp the fixture, we're done. We hit cycle start and cut the part, knowing we are getting accurately machined parts with side A and side B matching precisely."

Boeing is using a Unilock riser plate to hold fixtures on a five-axis Makino machining center. Engineers conducted a test that involved lifting the fixture off the riser plate, then reclamping and cycling it back into the machine. "We achieved a simultaneous nesting surface for the fixture to the riser surface and Unilock chucks within 0.0002" [0.005 mm]," Olson reports. "Tooling pin locations on the first fixture probed within 0.0002" on the first check.

"We have reduced fixture clamp and unclamp time for this pallet to zero," he adds. "It also eliminates the need to re-adjust the fixture location on the pallet to get it within our fixture probing tolerance. Fixture locating accuracy and repeatability are now under control."

Boeing typically performs multiple operations--turning, milling, and grinding, for example--on the same workpiece, using several different machine tools. Typical tolerances are plus or minus a tenth or two, according to Olson and Martin. Boeing needed a central datum for transfer of a single workpiece from operation to operation and machine to machine.

With Unilock, a workpiece reference location need only be established once. Alignment is from the chuck centerline, and the location data are captured electronically and kept in the machine's CNC. Engineers can run any fixture at any time, giving Boeing a universal system for use throughout the shop.

"Operations that used to take days are now completed in minutes or hours. The system gives us much more versatility to make our commitments," Olson says.

 

This article was first published in the April 2004 edition of Manufacturing Engineering magazine. 


Published Date : 4/1/2004

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