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Shop Solutions: Military Manufacturing Ready to Rock

 

The Rock Island Arsenal (RIA) Joint Manufacturing & Technology Center (Rock Island, IL) operates like a combat-ready military outfit. It has a strategic plan in place and is well-equipped with the latest technology to carry out its mission to provide world-class manufactured products, services, and logistics specifically in support of the US Army. RIA, however, is now looking to expand and diversify beyond its Army manufacturing roots. Its goal is to support all the Department of Defense (DoD) branches and, through public/private partnerships, reach out to meet private industry needs as well.

Currently, RIA’s support involves a variety of different military programs. Some include armor plating, building components, and assembling the M119 Howitzer and producing spare artillery parts for the M109 and the big M198 Howitzer. Components for a variety of small-arms weapons like the M240, M249, M16, and M2 machine guns are also produced at RIA.

RIA gives program decision makers options of choosing to stay within the government called the Organic Base, or opt for commercial companies large or small. In any event, RIA markets for every hour of work that comes into its plant, even the military jobs. The facility has a goal of $400 million in business annually and has operated near that level for several years.

RIA has 20 individual shops or "skills sets" under one roof and offers customers all types of precision machining, in addition to titanium casting services, foundry work, investment casting, heat treating, welding and fabricating, assembly and painting. Over the past six years, the facility has bolstered its highly skilled workforce—blue and white collar—from 750 to its present size of 1750.Largest Mazak machine at Rock Island Arsenal is the Versatech V-140N multisurface, five-axis double-column machine with a table size of 10 x 20 (1.5 x 3 M) shown machining three baseplates for an M7 machine gun pedestal on a military personnel vehicle

Since the 1990s, RIA has transitioned to become a lean, agile shop, as substantiated by three Shingo Awards, ISO certification, and the installation of the latest advanced machine tool technology. Being agile, according to all those at the facility, is the key to keeping RIA competitive and critical to winning shorter-run, job-shop-type work.

At the heart of RIA’s lean and agile initiative is the incorporation of innovative machine-tool technology, much of which was acquired from machine tool builder Mazak Corp. (Florence, KY). Among the more than 60 Mazak machines of varying sizes and types at RIA, those providing multitasking capabilities have had the most significant impact. This particular advanced machine tool technology is what has allowed RIA to increase cost efficiencies and effectively compete for work.

Multitasking machine technology has allowed RIA to reduce part operations by performing turning operations and five-axis machining on the same machine tool. This consolidation of manufacturing operations reduces tooling costs and numerous part transfers from machine to machine. Reducing tooling is important because approximately 20% of a new order cost at RIA is in tooling and fixturing. Multitasking machines also allow RIA to standardize its tooling, which is especially beneficial for cutting complex part geometries, using standard tooling and reducing the need for expensive special form tools.

"When we eliminate some of the tooling or fixturing, which the multitasking machines do, those savings are passed on to our customers," explains Travis Themas, branch chief in manufacturing at RIA. "We also need quick changeover capability and fast setups to help us adhere to lean principles. We are currently moving to operate more like a job shop with just-in-time manufacturing. To stay competitive, however, we can’t increase our cost of doing so. That is where multitasking machine tool technology really helps."

RIA gets into production much quicker these days, thanks to its multitasking machines. RIA machinists were able to reduce the time spent tooling up for three or four separate machine tools before starting a job. In most instances, they can have one Mazak multitasking machine set up in one-third of the time it takes to do so for standard conventional machine tools.

Themas also points out that multitasking machine technology forces his people to think outside the box. They are moving beyond the traditional mindset of fixtures, lathes, and mills and developing new and different ways to process parts and improve overall production. RIA’s Mazak machine models include the Integrex i, Integrex e and Integrex IV Series as well as several models from the Hyper Quadrex, Versatech, Quick Turn Nexus, Vertical Center Nexus, and Horizontal Center Nexus Series.

For example, RIA’s Hyper Quadrex 150MSY model machines do both chuck and bar work. These twin-spindle/twin-turret CNC turning centers with Y-axis capability provide processing speeds that are much faster than conventional turret lathes. "It’s not so much the speeds and feeds of the machines, but more the capability to input raw material and output completed parts," Themas explains. "On conventional machines, such double-spindle part work would have to be done on two separate operations, with double the setup time. Having twin spindles/twin turrets, we do both first and second operations at the same time to cut our throughput times by half. This kind of technology will soon be giving Swiss-style machines a run for their money."

Once it is determined that a product will go into production, a plan is developed for how to most efficiently process that product. Part programs are then written and presented to the process planner and machinists involved with the prove-out. Together they run the 3-D simulations to ensure that speeds and feeds are correct, verify that selected tooling is the best for the job, and resolve any other concerns before the parts get to a machine tool. RIA can run 3-D simulations on 18 of its different Mazak machines.

For day-to-day scheduling, the facility uses a computer system that automatically signals the production controllers to release orders to the shop floor. The same system tracks raw material and parts as they progress through the shop. During the manufacturing process, material expediters log material/parts in and out of the various departments according to tagged part numbers, so RIA knows exactly where individual components are at all times.

Raw materials processed at RIA range from titanium to aluminum to composites to every type of steel imaginable. Sizes of parts can be as small as the tip of a human finger or as big as a fully armored military vehicle. There are no "typical" parts/jobs at RIA. Each differs in size, material, and machining requirements. From raw to finished machining, complex wheel suspension assembly components for the M119 Howitzer that previously could have taken up to 11 months are now done in less than a week using Mazak Integrex e-1060 V-II Multi-Tasking machine at Rock Island Arsenal

Many of RIA’s parts require tolerances of ± 0.005" (0.13 mm), and some a bit tighter at ± 0.0005" (0.013 mm). RIA can easily hold these on its Mazak machines. Such capability has even allowed for the elimination of grinding in some instances. Within its small arms gage production, RIA holds 20-millionths of an inch tolerance.

RIA relies heavily on the knowledge and skills of its workforce to produce its precision parts and has taken advantage of advanced training programs offered by Mazak. RIA conducts a Department of Labor certified Apprentice Program and has partnered with Mazak to establish on-site training programs. The software-simulated courses teach basic milling, Mazak Integrex multitasking machining, and advanced milling. The goal is to impart machinists with the skills needed to do part prove-outs and help with process planning.

"We are teaching our people the capabilities of all our Mazak machines to improve overall part processes," says Lon Lukavsky, division chief of machining at RIA. "A lot of our parts and products are very expensive, and we can’t afford mistakes. Some components cost $100,000, and the Mazak training gives our people the confidence to work on such expensive parts."

Themas adds that the training is especially beneficial for RIA to get the most out of its Mazak Palletech manufacturing systems. He says that students learn how to exchange pallets between machines without losing data. Just as important, students learn the similarities and differences between the various Mazak machine models.

Among RIA’s newest Mazak machines are its Integrex e 1060 V-II Super Multi-Tasking systems, which have slashed the number of machining operations for a wheel suspension assembly for the M119 Howitzer from 17 to just 3. The forged part secures the gun’s wheel and attaches to the rest of the suspension system. It previously could have taken up to 11 months to machine the component. Now it is done in less than a week.

One Integrex e 1060 V-II rough cuts, turns, faces, and drills the suspension parts, which then move to another Integrex e 1060 V-II for subsequent turning and finishing operations. This second machine is outfitted with a wide array of different tooling, including burnishing tools, required for the numerous challenging part features. It performs some of the more complicated part operations, such as machining an ID spline bore and turning a spindle/shaft, which requires the large odd-shaped part to spin at about 450 rpm.

Another Integrex e 1060 V-II is paired with Mazak’s Palletech manufacturing system with five pallets, which Themas says allows the shop to run a variety of different projects on the machine. "The beauty of the Palletech system is that it stays set up. When we are ready to run a certain part, we simply call it up and load it." He also points out that RIA uses the Palletech technology wherever applicable throughout the facility. However, the facility’s projects/components are constantly changing, so it must carefully consider how long to leave pallet real estate set up for jobs that may or may not repeat.

Most of the automation used at RIA is what is available with the design of its machines, such as bar feeders, part grippers, and the Palletech system. External robots are not typically practical for the type of jobs RIA performs due to the varied lot sizes and frequent jobs changes. In most instances, the "natural" automation from the various Mazak machine designs allows one RIA machinist to run multiple machines simultaneously. ME

For more information on Mazak Corp. go to www.mazak.com or phone 859-342-1700; on Rock Island Arsenal-Joint Mfg. & Technology Center, phone 309-782-6854 or visit https://ria-jmtc.army.mil.

 

Toolholder Prevents Aero Variance

Reliability is critical in the airline industry. Passengers expect it. Manufacturers demand it, and machine shops can’t live without it. In the case of machine shops, variance in manufactured parts can be the difference between profits and attrition. To ensure reliability, shops are constantly reviewing every aspect of the aerospace manufacturing process. "The challenge for aircraft manufacturers is making enough airplanes. Efficiency is the answer," explains Peter Boucher, president, 3V Precision Machining Inc. (Tacoma, WA).

3V Precision Machining specializes in supplying complicated and precise aerospace components machined from the most demanding alloys, metals, or plastics. The shop is on a constant mission to ensure reliability in every aspect of the manufacturing process, right down to the toolholder. "When we have toolholders that keep things more reliable, we win more jobs and stay more competitive," explains Boucher. "We are really picky on consistency here. Variance is the devil."

In aerospace applications, where machining titanium is a common challenge, achieving desirable consistency can be a struggle. "The high-speed machining of titanium requires the use of accurate tooling to hold concentricity and keep tool life up there as much as possible," says Boucher. There are different schools of thought on how to tackle a material as tough as titanium. "Titanium creates a lot of heat. Other shops will rough a part out, then take it out, stress relieve it, and then finish it old-school style," comments Boucher. 3V Precision, on the other hand, machines the part at high speeds, with fewer steps and without inducing stress into the part.3V Precision Machining President Peter Boucher (left) with lead machinist Eric "Red" Reitan, and IMCO Carbide Tool representative Patrick Clewis with the Lyndex-Nikken 3 Lock toolholder which provides a rigid connection for machining

A rigid machine fitted with a rigid toolholder enables the shop to attain high speeds and efficiency while maintaining high levels of concentricity. 3V Precision was introduced to the rigid 3-Lock Toolholder System from Lyndex-Nikken Inc. (Mundelein, IL) 12 years ago. A Kitamura representative recommended the holders for their machines. When 3V Precision first began using the 3-Lock Holder, tool life increased by 20% and accuracy and finishes grew by a staggering 30%.

"The rigidity of the 3-Lock plays an important part in what we do," Boucher says. With the 3-Lock, 3V Precision was able to turn an 8-hr machining job into one taking only 3 hr. In February of this year, 3V Precision was approached by Boeing, and was able to win the bid against other Tier 2 shops. This particular job required machining a part that attaches to the wings of a Boeing 737 aircraft. 3V Precision begins with a 25 lb (11.25-kg) rectangle of titanium and machines it down to 5 lb (2.25 kg). To achieve this, they use a ¾" (19-mm) end mill with a 2 ¼" (57-mm) length of cut, at 1260 rpm, and 45 ipm (1143 mm/min), 0.070" (1.78 mm) on radial stepover each time they take a pass. "If done the old-school way, it would have been 200 rpm, and 2 ipm [51 mm/min], rough stress relief, and then finish," Boucher says.

Other toolholder manufacturers have challenged the 3-Lock Holder, but Boucher, who welcomes the competition, is not looking for a replacement. This year, Boucher has been approached by three representatives of competing holders. In each case, the wear on the contact patch was 30% on the face and the taper, contrasted with 90% when using the 3-Lock. "I gave each of them an ample 12-hr part test, and they didn’t get the same tool life [as the 3-Lock]. They get one chance and that’s it. A lesser toolholder isn’t able to do it," continues Boucher. "We need something highly reliable to be successful at lights out."

The 3-Lock’s design enables it to achieve the cutting performance and tool life so important to shops like 3V Precision. It uses internal expanding pressure to maintain the correct taper to flange ratio and achieve full face contact of the flange to the spindle. The 3-Lock Holder is designed to counteract the centrifugal forces produced on the machine spindle during high-speed processes.

The 3-Lock system consists of a main body with an internal taper configuration housed inside a taper cone. The taper cone is shaped to deform to a 7/24 external taper. This taper cone is pre-loaded on the body with disk springs. The combination of the taper cone and the disk springs creates a dampening effect that reduces cutting vibration and extends cutting tool life. When the tool is clamped, the taper cone slides slightly in an axial direction to absorb any minute gage-line errors. During a tool change, the internal taper of the 3-Lock body expands. The internal taper of the holder continues to expand until the flange of the toolholder makes contact with the spindle face. The combination of the taper expansion and the contact between the flange of the holder and the spindle face results in maximum pull force of the machine tool.

3V Precision has also had success machining 625 Inconel using a corn-cob rougher held in Lyndex-Nikken’s 40-taper 3-Lock. With a 1–2" (25-51-mm) length of cut, the run out of the tool is less than 0.0001" (0.003 mm). Previously, the shop was using a tool that flexed too much, wobbling from side-to-side, causing the cutter to fail prematurely. While most shops would choose to use a 50-taper machine for such an application, 3V Precision has found that the 40-taper 3-Lock performs more like a 45 taper, and gives their 40-taper machine what amounts to 45-taper strength. ME

For more information about the 3 Lock System, go to
www.lyndexnikken.com, or phone 800-543-6237.

 

This article was first published in the December 2011 edition of Manufacturing Engineering magazine.  Click here for PDF

 


Published Date : 12/1/2011

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