chisels, tibia alignment guides, patella clamps, and acetabular shells and inserters. “We developed an important niche in spinal implants, such as replacements for discs,” says Marr. As a contract manufacturer serving many industries, they
found they needed to organize their facilities differently than a dedicated manufacturer. Each portion of the plant, or pod, is dedicated to machine types—grinding, milling, or lathe/mill- turn. Te company’s South Building, for example, is shaped like an “H”—180,000 ſt² (16,722 m²) on 46 acres—with each leg containing four pods of over 20,000 ſt² (1858 m²). “Our volume is not high enough in most cases in any one part to make dedicated workcells attractive for us,” says Marr. Tis means a lot of material flowing around their plant as each job moves from operation to operation.
One such system C&A uses for this is an OASIS opti-
cal profile inspection system supplied by George Products Company (Middletown, DE). Tey program this 2-D digital shadowgraph to measure critical features for a particular part, which is stored in a library. “During production, we simply place the part on the machine and it automatically identifies the part from its library and gives a go/no go on each critical dimension,” says Marr, requiring no fixturing for speedy, ac- curate measurements. “Tis machine is sometimes described as an optical com-
parator on steroids,” says Jeff Palmer, a manager with George Products. Te system is accurate to ±0.0001" (2.54 µm), ac- cording to the company. “When a part program is created, the OASIS looks at the edges of the part using what we call Tool Windows,” explains Palmer. “It searches through all the stored parts programs to see what lines up best with that part. If there are similar parts, it may offer up to three different files of part pro- grams that are close for the user to choose.” He reports the system as frequently used by medical device manufacturers, for parts with maximum dimensions of over 6" (152.4 mm) down to less than 0.5" (12.7 mm), such as dental implants. In some respects, the GD&T requirements
C&A Tooling distributes QC labs equipped with CMMs and other quality equipment in each of its dedicated equipment pods as well as at a final inspection point.
Each pod contains its own metrology laboratory, typi-
cally outfitted with one or two Contura CMMs from Carl Zeiss Industrial Metrology, LLC (Brighton, MI), and optical comparators from Optical Gaging Products (OGP, Rochester, NY). Tey use Zeiss CALYPSO soſtware for programming their CMMs. Each CMM is equipped with touch probes and scanning analog probes. “We are looking into noncontact sensing, like laser scanning, for our CMMs, but have not made that decision yet,” says Marr. Teir noncontact sensing is in equipment such as Zygo Corporation (Middlefield, CT) surface profilers. Multiple quality labs scattered around the facility reduce the amount of time required to move pieces (and people) away from important machining operations to inspection. Cutting and grinding is still where the money is. In fact, metrology at the machine is the ideal. “Utopia is if our skilled associates do not have to walk away from the machine to measure a part,” Marr says.
66 Medical Manufacturing 2013
for medical devices are not very different from other industries, such as aerospace, according to Gary Meyer, C&A’s go-to-guy for medical quality. While each part requires a thorough first-article inspection, like many other industries, the dif- ference is the depth and breadth of documenta- tion. Tey tend to rely on the expertise of their customers, the medical device OEMs, to know the details of meeting regulatory requirements. “I just had one assembly submitted for first-article approval with 250 pages of documentation—for
that one assembly. It only had eight or nine component level parts,” he explains. Joe Huelsenback, the medical machining go-to-guy for the
company notes that tolerances for spinal implants are typically 20 µm. A 10:1 gage R&R means they need inspection capabil- ity down to 2 µm. A product they like to use near machinery on the shop floor is an IM-6500 Series image dimensions measurement system from Keyence (Itasca, IL). Useful for 2-D measurements, the integrated measuring
system with display is designed for convenience, to operate fast, and with no fixturing. It adjusts automatically for location and orientation of parts. With optional soſtware, the machine is programmed with actual parts, prints, or off-line using CAD. “It is especially good for measuring parts where contact might affect the result,” says Sergie Shirokov, project manager for Key- ence. “Parts that are very thin or have precise etchings, where you cannot get a stylus into. Tese include soſt parts that are