Technology in Action Founded in 1964 by the late David Lilja and now under
the second-generation leadership of his son, Patrick, Lowell specializes in manufacturing implantable medical devices such as orthopedic implants for the spinal, trauma and extremity markets and cardiovascular parts for mechanical circulatory support and valve repair. Tese are typically very complex multicomponent assemblies like pedicle screws, cervical plates, cross connectors and leſt ventricular assist devices (LVAD). Almost all are multiple-piece systems in which indi- vidual components must function properly when combined with each other. Plus, designs vary from customer to custom- er, so basically every job at Lowell is a custom one. On top of this, medical OEMs continue to redesign their
implants to provide increased flexibility in the operating room. In spinal fusion procedures, for instance, surgeons can now readily adapt an implant to a patient’s anatomy—resulting in less time on the operating table and better outcomes.
Machining Challenges Tis demand for customization and adjustability, along
with smaller devices for minimally invasive surgery, present notable machining challenges for implant manufacturers such as Lowell. Once the shop figures out how to hold these very small parts, it must then machine tiny, intricate, highly com- plex features into them—regularly using cutting tools smaller than 1 mm in diameter. To tackle its most challenging parts, Lowell recently
installed three Mazak Integrex i-150 multitasking machines and grouped them together in a cell configuration. Te machines provide complete done-in-one part processing capability to eliminate manual operations and increase overall throughput. Tey simplify workholding to just collets and chucks; easily handle parts that vary from one customer to the next; and, in many instances, reduce part machining cycle times as well. Each Integrex i-150 features a C-axis CNC-controlled turn-
ing spindle, vertical B-axis milling spindle and backworking vise/part support center for done-in-one turning, multiface, multiangle and full five-axis contouring. Lowell opted for the high-speed 20,000-rpm milling spindles and 72-tool-capacity front-loading tool magazines for its machines as well. Milling spindles tilt from -10 to +190°, and C-axis chucks
feature ample through holes that accommodate bar stock diameters up to 65 mm. For off-centerline operations, the In- tegrex i-150s deliver Y-axis ranges of ±100 mm. Axis travels of 370 mm in X, 435 mm in Z and 400-mm diameter maximum swing allow the machines to process a wide range of part sizes and shapes—all within a space-saving 2.3 × 2.5-m footprint. With the three machines configured identically and ar-
ranged in close proximity of one another, machinists can easily move from machine to machine without having to learn a completely different machine or programming language.
62 Medical Manufacturing 2014
Lowell’s Integrex i-150 features a C-axis CNC- controlled turning spindle, vertical B-axis milling spindle and back working vise/part support center.
“Prior to the Mazaks, our programmers would have to
conceptualize what the workholding needs would be in addi- tion to programming for the part itself,” explained Spah. “Plus we had to use a lot of form tools as well because our standard vertical and horizontal machining centers, for instance, were unable to access every intricate part feature.”
Options to Enhance Performance On the Mazaks, Lowell generates practically all parts from
bar stock 0.375 to 1.250" [9.52–31.75 mm] in diameter. LNS Quick Load Servo 65 bar feeders automatically feed 1-m long bars into the machines. Te shop chose several machine options that further enhance machine performance. Tese include coolant chillers, scales on all axes and advanced CNC control features for high-speed machining. According to Ron Spah, engineering director at Lowell,
the Mazaks streamline the entire part machining process, especially programming and set up. For instance, he said that the machines, once installed, immediately eliminated the need to spend between two and six weeks designing and program- ming workpiece fixturing.
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