Using a strategy that would have made its founder proud, Colt has cut production costs and improved the quality of its guns by moving away from transfer lines and towards flexible machining cells.
Colt makes the M4 carbine at its West Hartford facility.
The M-16 is produced for the U.S. government.
Nakamura-Tome WT-250 multispindle turning centers produce barrels and barrel extensions at Colt.
In 1851, Samuel Colt built a factory, which, according to the company's own history, housed the most up-to-date metalworking machinery available at the time. Precision machine tools produced metal parts for Colt's handguns, over 80% of which were interchangeable — a pretty newfangled idea for its time. Reportedly, Colt, inspired by the technological might of his machines, once said, "There is nothing that can't be produced by machine."
Almost 150 years later, another Colt plant, located in West Hartford, Conn., is continuing the tradition of using technologically advanced machine tools. Over the past four years, Colt Manufacturing Co. Inc. has spent several million dollars on capital equipment upgrades, aggressively moving away from transfer line machines to state-of-the-art machining centers and flexible cells. This strategy has helped Colt respond quickly to design changes, make accurate parts, and cut production costs.
The Hartford facility makes revolvers, semiautomatics, rifles, and replacement parts such as upper receivers, bolt carriers, and complete barrels. It also is the main manufacturing facility for the government-issued M-16 automatic rifle and its cousin, the M-4 carbine. In addition, the plant makes the descendent of what is arguably the best-known gun in the world — the Single Action Army Colt .45, also known as the "Gun that won the West" or the Peacemaker.
The Colt facility machines mainly aluminum alloys and gun-quality stainless steels. It regularly partners with firms such as Carpenter Steel to ensure that materials meet Colt specifications. The company also works with forgings rather than castings because, as Ashot Ghokasiyan, manager of capital and reengineering, explains, "Forgings outperform castings in our applications."
Ghokasiyan keeps a close eye on all the machines at Colt. To determine if a machine should be replaced, he studies maintenance logs and quality reports from various departments. If he finds machines that don't meet required tolerances or are down a lot, he schedules them for replacement.
For example, when the company decided to manufacture different variations of the internal mechanism of one of its weapons, it decided to replace a transfer line with Makino A66 machines arranged in a flexible cell.
Ghokasiyan considered retooling the transfer line, but decided it would be too costly. Another problem was that if one head on one machine went down, the entire transfer line was out of commission. In contrast, if a machine goes down in the flexible cell, Colt can quickly insert a duplicate system, minimizing downtime.
The company evaluated a number of machines before selecting the Makinos, considering such factors as cycle times and machine accuracies. Ghokasiyan wanted a high-speed turnkey with a 60-tool automatic tool changer for Colt's CAT 40 tooling. The A66s met all of Colt's requirements.
The A66 is designed to manufacture high-volume, commodity production pieces. A standard machine has a rapid traverse and feedrate of 1,575 ipm and a 20-in. 2 pallet with a maximum workzone of 31.5 35.4 in. A 14,000- rpm, 30-hp spindle runs CAT 40 tools for high speed applications or HSK 63 tooling for more rigid applications.
The machine features a standard tool change of 0.9 sec with CAT tooling and 0.7 sec for HSK. Chip-to-chip time is 3.4 sec.
Another recent acquisition involved the replacement of machines that produced barrels and barrel extensions. Colt bought Nakamura-Tome WT-250 multispindle turning centers outfitted with K&C automatic barfeeders. A standard WT-250 is a five-axis system with a maximum swing of 9.840 in. The bar capacity on the main spindle is 2.000 in. (2.050 in. on the sub-spindle). These machines feature both a main spindle and a subspindle, which, working together, slash cycle times simply by eliminating extra setups. Interestingly, in this case, Colt kept its older equipment up and running so that it could gradually train workers on the new machinery. To boot, the older machines are there for skilled machinists who may feel more comfortable using them.
Over the past four years, Colt has made several other acquisitions. In one application, it cut out a secondary operation by replacing a transfer line that was making bolt carriers. After parts came off the system, they went to grinding machines for finishing. Now, Colt hard turns the parts in one setup on a Wasino LG7. In another case, two Daewoos replaced an old cam system. The company has also added Mazak HTC-400 horizontal machining centers, several Chiron VMCs, and Star Swiss-turn SV-20s (8 axis) to its arsenal.
The trend towards hard turning
One way Colt has improved production is by eliminating finish grinding as much as possible. Grinding obviously adds the cost of a secondary operation as well as the costs of abrasive and coolant. The machines also need constant realignment for optimum operation.
Hard turning eliminates these costs and saves time. However, the challenge of hard turning is in dealing with parts that can have hardnesses of 62 to 65 Rc and severe interrupted cuts. Ghokasiyan reports that, in many cases, Colt has overcome these problems with the right machines and tooling.
The company regularly tests tools to see if they can handle these tough jobs. "We've held a 16 or better finish with CBN tooling made by J&M Diamond Tools and a 32 or better finish with some Mitsubishi and NTK cermets," says Ghokasiyan.
Besides being responsible for purchasing machines for Colt's commercial and military products, Ghokasiyan also selects tooling. "You can have the best machine in the world, but the worst tool," he says. He wants the best combination to remove material quickly, and nowhere is this more true than in hard turning.
He says that over the last year, the manufacturing group has worked closely with the design team to make parts and production more cost effective. Not only have they redesigned parts so that Colt's machines can make them better and faster, but they have worked to eliminate the need for special tools in many operations.
Although the company may use a few Kurt hydraulic vises here and there, it does, however, use elaborate, specialized fixturing to hold a good number of round or irregularly shaped parts during machining operations.
The Hartford plant has an amazing amount of manufacturing might under one roof. In addition to its machine tools, the company has a full metallurgical lab for steel analysis and a heat treatment facility on the premises. However, one part of Colt's quality control program isn't found at the average machine shop — a firing range behind the manufacturing facility. This is where every gun is test fired before being shipped out. Walking through the plant, one can occasionally hear the sound of gunshots over the din of the machine tools.
As one would expect, the gun maker uses a number of gun drilling and broaching machines. For example, in the cylinder manufacturing area, Colt uses El Dorado and DeHoff gun drilling machines, many of which have been retrofitted with CNCs. The plant also uses varieties of gun drills made by Star Cut and Drill Master. Ghokasiyan points out that gun drilling is one area where standardizing tooling would be impractical; about 90% of Colt's gun drilling operations require special cutters.
As for the broaching machines, Colt is happy with what it is currently running and has no plans to replace anything soon. One of the machines, as a matter of fact, is even a Colt-designed broaching machine, specially built for its own applications.
According to Ghokasiyan, one operation that a machine — currently — can't match involves hand shaving of parts. He says the company tried using diesinkers, but found them too slow. In addition, the EDMs simply did not provide the finishes Colt wanted.
One area the company is looking to improve is its polishing operations. Because the company does a tremendous amount of hand polishing, it is currently looking for a robotic system to speed production.
Colt's manufacturing history
1836: Sam Colt receives a patent for a firearm with a revolving cylinder that holds up to six bullets
CNCs help riflescope manufacturer hit production targets
According to company lore, during World War II, Marcus Leupold was hunting on the rainy side of Oregon's Cascade Range when he had a good shot at a Blacktail buck. Unfortunately, he missed the target because his riflescope lacked accurate field adjustment and had fogged up in the damp morning air. He then embarked on a mission to develop a more reliable and accurate riflescope. In 1947, the company introduced the Plainsman, a weatherproof, accurate, and field-adjustable riflescope. Some 50 years later, Leupold & Stevens Inc. is recognized as the dominant optical gunsight manufacturer and is one of only two U.S. manufacturers of riflescopes, spotting scopes, and binoculars.
Much like Colt, the company has pursued a manufacturing-driven competitive strategy that puts quality above all else. Since 1989, the Beaverton, Oreg.,-based firm has reinvested anywhere from $2 million to $4 million every two years in new machine tools, controls, and software. This program has accommodated expanding demand and market growth primarily through productivity rather than capacity gains. The result has been reduced production costs and tremendous profitability for the company.
The company's riflescopes are made primarily from grade 6061-T6 round aluminum stock. Manufacturing engineering technician Mike Brown, a 30-year company veteran says, "With the exception of the optical glass and some rubber seals, we manufacture all component parts."
Each riflescope has dozens of pieces that are designed on a CAD/CAM system. These files are then downloaded to CNC multiaxis mill/turn systems, milling machines, vertical and horizontal machining centers, and lathes. Piece production on the various machines runs from 25 parts on certain machines to some 300,000 per year on others.
According to Brown, turning machines, most of which are built by Index of Germany, produce the bulk of the company's parts. However, he credits CNCs — most specifically Siemens systems — for the company's most recent gains in cost control, productivity, and quality. Now, when the company orders new machines, it specifies Siemens controls. For instance, it recently ordered a number of Index MS-32 32-axis milling machines, all of which were fitted with Siemens 840D controls.
Manufacturing Technician Supervisor John Karge has been busy specifying, acquiring, and installing new machines at the rate of two or three a year over the last 10 years. "This year, we've installed three new Siemens-equipped Index machines," says Karge.
Karge echoes Brown's remarks when he describes the effect the new machines have had on production over the years. "We're not so much as adding capacity," Karge finds, "but gaining productivity." He recalls that in 1989, Leupold needed to find a machine to fabricate one-piece scope main tubes: "At the time, ours consisted of five pieces, but the competition introduced a single-tube design. Index was the only tool builder that had a machine capable of this — the GSC — and it could do it in two operations."
Soon thereafter, Leupold had six GSC machines fabricating main tubes. However, the company soon bought newer Index machines that took advantage of Siemens advanced control and drive technology. The Index G300, with a Siemens 840C control, makes the main tube in one pass, reducing cycle time by 30%. "We now have three G300 machines doing what the six did before," says Karge.
With the addition of CNC machining technology, the company has also cut down on overtime, rework, and scrap. "We know it's as much the control as the machine, and if you put the effort into controlling the machine properly, the return on your machine investment is going to be there. We have 16 fewer people making as many parts or more," says Karge, "and quality has increased tremendously."