Folding money: Mini drops its top; Available across the line for an extra 4,500, the Mini Convertible aims to set the standard in the premium compact convertible segment.

(1) Mini doesn't cut the top off its standard cars to create the convertible, it starts with stampings specific to the topless model, thus saving the time, effort, and money of altering an existing body-in-white. A tubular steel reinforcement is added to the A-pillar, a lower brace adds rigidity to the rear struts, and the floor and sills are strengthened via lower B-pillar cross bars and pan stiffeners to meet side impact requirements. Otherwise, the chassis is standard Mini, which was designed from the start to include a convertible model. Aluminum hoops behind the rear seat provide roll-over protection and act as upper mounts for the three-point rear seatbelts. The lack of a hardtop does reduce the number of airbags offered by two, however, leaving front and seat-mounted airbags, but eliminating the side-impact head bag found on the three-door.

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(2) Engines are the same as the hardtop's, though the supercharged "S" model gains five horsepower (to 168 hp), while the non-boosted 1.6-liter four-cylinder soldiers on with 115 hp. Where the base engine gains, however, is in the replacement of the previous MG Rover-sourced five-speed gearbox with a Getrag transmission with the same number of speeds. Not only is the shift action on the new gearbox lighter and more precise, the gear ratios are more closely spaced for better off-the-line and in-gear performance. The six-speed Getrag used on the Mini Cooper S convertible also has closer ratios.

(3) Oasys Systems, a joint venture between Webasto and Pininfarina, designed and developed the convertible top. It has a heated glass window, multiple fabric layers, and does away with the need for a cover when lowered. A power sunroof is integrated into the top, and the first section of canvas-about 16-in.-slides back along the top rails when the top button is pressed the first time. It can be opened or closed while driving at speeds up to 75 mph. Holding the top button causes the roof to fold completely, with a "Z-mechanism" in the rear quarters Folding it such that it stows neatly behind the seats while leaving 4.2 [ft.sup.3] trunk space. (There's 5.8 [ft.sup.3] with the top up.) The sunroof section rests on top, protecting the rest of the top from dirt, dust, and debris. The sunroof and top can be opened via the keyless remote, or closed by inserting the key into the door lock and holding it in the lock position. Unlike most small convertibles-and a number of larger, pricier soft tops-the Mini Convertible's top is fully automatic, and does not require the opening or closing of latches along the header. To preserve trunk space, the rear of the top can be unlocked and raised to 35[degrees] to increase the size of the rear opening. The outer-hinged trunk lid drops down for loading and can hold 175 lb.

(4) The front and rear fascias are subtly modified, and the light housings updated across the Mini line. Headlights receive a new reflector and bezel design, and a new reflector design increases the amount of light that reaches the road. The optional Xenon headlamps receive new teardrop-shaped light ports around the edge of the Xenon element. This not only delineates the more-expensive lighting unit from its more prosaic brother, it brings a new interpretation of the "Angel Eyes" lighting units found on BMW-badged vehicles. The taillights also are new, and include integral reverse lights, which eliminate the central light previously found on the lower rear bumper fascia. Because of the wide sail panels, all Mini Convertibles come standard with parking sensors mounted in the rear fascia.

COLLABORATIVE HORSEPOWER

Collaboration could be a competitive advantage in engine manufacturing. That seems to be what will be realized by GEMA--the Global Engine Manufacturing Alliance--which brings together DaimlerChrysler, Hyundai, and Mitsubishi in the development and production of a family of four-cylinder engines (1.8-, 2.0- and 2.4-liter units). These engines will be built in five plants: two in Dundee, Michigan, and one each in Asan, South Korea; Hwasung, South Korea and Shiga, Japan. The annual capacity will be on the order of 1.8 million engines.

How effective can this be? Consider: Compared with a similar DCX engine produced in Saltillo, Mexico, Bruce D. Coventry, president of GEMA, estimates an annual total material cost savings of $100-million.

According to Coventry, the engine program is one that has followed the lead of Hyundai. There was a Hyundai engine design that had been developed. The partners examined it, but determined that based on specific attributes it was the "wrong engine." Six weeks later, the partners returned. The necessary adjustments had been made.

The process engineering for the engine also had a Hyundai lead. Coventry says that because Hyundai has a machine tool division, much of the necessary equipment for engine production has been secured from it. In addition to which, he says, there is extensive deployment of machinery from Mitsubishi Heavy Industries. One of the advantages of this approach was, clearly, economical sourcing. What's more, not only was five plants' worth of equipment purchased (from a "friendly" supplier base, as it were), but because of the duplication of process, the process engineering was only done a single time, which is a great money saver in itself.

Speaking of the manufacturing approach being deployed, Coventry states, "Flexible machining centers in a hospital-clean manufacturing environment are the basis to the GEMA business model. Compared to the traditional transfer line process, this model incorporates part recognition and automatic changeover features to allow different products to flow down the line seamlessly, even allowing for a batch size of one. An even greater benefit that machining centers give us over transfer lines is uninterrupted flow, even if there is machine downtime."

The first plant in Dundee will go into production in '05 and the second in '06.--GSV

THE OFFICE

While the number of rapid prototyping machines is growing as designers (especially) and engineers become increasingly interested in having solid, physical 3D representations of products under development, an alternative to making models with polymers or sintered metals will become available during Q1 of '05: The means to produce actual parts with the bona fide materials in one's own office.

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This is the possibility provided by the "Office Series" of machines from Haas Automation (Oxnard, CA; www.haascnc.com). There are two machines in the lineup, the OL-1, a lathe with a 5C collet spindle and a 5-hp, 6,000-rpm spindle motor, and the OM-1, a mill with an 8-in.[.sup.3] work envelope and a 270-W electric spindle motor.

Interesting aspects of the machines: they are designed so that they can be moved through a standard 36-in. office door, and require just 240-V power and air (1 scfm @40-70 psi). Base price: $34,999.--GSV

PAYING FOR PARTS, NOT THE MACHINE (PER SE)

What do you do when you need to produce parts on a new VMC but don't want to invest in the equipment? Chiron America (Charlotte, NC; www.chironamerica.com), a specialist in CNC vertical machining centers, has launched a program wherein parts suppliers that don't want to carry big capital investments on their books agree to pay a per-part fee based on their unit production rather than paying upfront for a machining center. Chiron installs the machine in a supplier's plant but actually sells it to a third-party lender who charges the supplier a per-part fee. A portion of the fee goes toward what is essentially a service contract in which Chiron guarantees an agreed-upon percentage of uptime and set throughput numbers in exchange for a five-year commitment from the supplier. At the end of the five years, the supplier can buy the fully-depreciated machine for a nominal sum (the end value is determined when setting the per-part fee). Chiron is targeting tier one automotive suppliers with very high production outputs who are looking for creative ways to shift some of the investment burden that has been placed on them by OEMs.--KEW

MAGNETIC FIXTURING FOR AGILE MACHINING AT GM

When it comes to engine parts machining, one of the most important aspects is something that tends to get far less attention than its importance merits: the fixturing. The fixtures that hold the workpiece in place during machining must not only provide accurate positioning so that the component can be cut with micron-accuracy (~20 microns), but they must be sufficiently robust to keep that component in place as the cutting tools engage the metal with terrific forces. This goes to explain why fixtures are (1) long-lead time items, (2) expensive, (3) designed to work on particular parts (i.e., are "dedicated").

Consequently, the excitement of Pulak Bandyopadhyah, group manager, GM R & D Plant Floor Systems, and Yhu-tin Lin, staff research engineer at the GM Technical Center, is understandable as they describe the flexible fixture that they and their GM R & D colleagues have developed, as it provides the ability to make rapid configuration changes so that it can be setup to accommodate the machining of workpieces of varying sizes, such as 4-, 6- and 8-cylinder engine parts. Consider: they're performing in excess of one-billion machining operations per year at GM, so that means a lot of fixtures.

So what they've created is a fixture that is based not on hydraulics, as is typically the case in production machining, but on magnetic force. That's right, they're using an electromagnet to hold the components that hold the part in place. The pull-resistance is on the order of 12,000 lb.; the sliding resistance is on the order of 3,000 lb. Which means that what gets put in place stays in place. The rare-earth electromagnet (sourced from Tecnomagnete; Sterling Hgts., MI) is one that the magnetic force is generated once the power is removed, so that if there was machining and a power failure, the workpiece and fixture components wouldn't fly away. (Actually, there is a series of 1-in. magnets that are put together to form one large magnet.)

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In the test setup--and plans are to put the fixture into a plant during the first quarter of '05--the fixture is a tombstone mounted on the table of a Makino A99 horizontal machining center. The backside of the fixture has a series of slots into which the fixture components (clamps, guide rails, supports) are fitted. When a fixture is to be constructed on the front of the plate, the machining center's spindle is used to select the appropriate pieces from the slots in a way analogous to selecting cutting tools from a toolchanger. In effect, the fixture is put together through instructions from the CNC control. According to Bandyopadhyah and Lin, this use of the tombstone fixture to store the tooling elements will not be used in the production setup, as the select component-rotate table-insert component-rotate table-select component ... routine is far too time inefficient. For production, they're looking at a five-minute fixture change. Compare that to the months it takes now.

Apparently, they've been trying all manner of ways to fixture parts in place and while people have thought about the magnetic approach, it had seemed as though it wouldn't be up to the rigors of machining. Clearly, that challenge has been overcome.--GSV

HYUNDAI GOES FLEX IN ALABAMA

When the engine plant at the Hyundai Motor Manufacturing Alabama (Montgomery, AL) opens next year, it will be one of the most modern, flexible operations found anywhere. Engineered to produce the new Lambda 3.3-liter V6 engine that will be used in the Sonata sedan and the Santa Fe SUV, the production operation is based largely on machining centers: both the block and head lines consist primarily of horizontal machining centers from Cincinnati Lamb (Chesterfield, MI; a UNOVA Industrial Automation Systems company). The machines in question are the HPC-500TS, a 500-mm pallet machine fitted with two machining spindles, and the rugged HPC-500ZS, another 500-mm machine that's specifically built to handle even cast iron (although the Hyundai engine features an aluminum block and head). The head line features 220 adapter plates that are used to move the parts through the system. According to Edward J. Irvine, a Cincinnati Lamb account executive who is working on the project, "The plates provide a common interface to accurately locate and handle the parts throughout the entire system." He adds, "If they want to change the part at a future date, this makes it much easier for retooling." Irvine says that the 52 twin-spindle HPC-500TS machines on the Hyundai head line make it the biggest installation of any line the company has engineered. The adapter plates, or pallets, are not used on the block line. The part itself moves through the stations. While each of the adapter plates has an RFID tag on it to identify the part moving through the operations, in the case of the blocks, RFID tags are screwed into the aluminum. One of the areas where there is additional fixturing on the block line is for machining the valve seats. This is done to keep the part solidly in place so that there isn't movement that could cause a cutting tool to crack. Crankshafts for the engines are going to be produced on five CNC grinders from Landis Gardner (Waynesboro, PA; another UNOVA company). In-process automation for the line, final assembly, and hot and cold testing equipment is being supplied by Lamb's Assembly and Test operation in Rockford, IL.--GSV

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