New Knees

Its no secret that todays medical shops are constantly under pressure to improve quality and increase volumes while staving off the competition. Succeeding in such an environment, especially for shops making high-demand orthopedic knee implants, takes systems and processes that provide product
differentiation, shorten development cycles, and produce high-quality components at low manufacturing costs. Two such systems are the HS154R-4X4 and HS-154R-M from Huffman of Clover, S.C.

The HS154R-4X4 sports two grinding spindles and two work spindles. Each work spindle accommodates
an arbor with two workpieces, so the machine grinds four components in one grinding cycle. Cycle times range from five to 10 min or 1.25 to 2.5 min/part. Grinding four components simultaneously also means the system uses one-fourth the manufacturing floorspace of alternatives.

As a multiaxis machining system, the HS-154R-M performs high-speed milling on a precise, durable, superabrasive-grinding platform. This multitasking machine reduces setups, throughput time, and cost while increasing part quality by combining operations into one machine cycle.

The machines high-speed superabrasive wheels grind articulating surfaces of implants. Then its high-speed milling spindle machines part areas unreachable with large-diameter grinding wheels - areas like the PS box located between condyles.

Programming the two Huffman machines is done in CAD/CAM systems, and the company offers 4, 5, and 6-axis post-processors that work with a variety of such systems. This CAD/CAM integration, according to the company, dramatically reduces cost and time for product-development cycles. And shops can test and prove out CAD-model changes on the grinders in minutes.

More than machines

The successful deployment of Huffman machining systems results from collaborative efforts between the machine tool builder and its end users. This cross-functional team approach typically involves project management, design engineering, manufacturing engineering, programming, quality, production, and maintenance.

To further ensure a successful system, Huffman uses computer simulation to develop and test an end users machining process virtually prior to running it on an actual machine. Within a virtual environment, the company creates a scaled, solid model from mechanical CAD models of the machine, fixtures, grinding wheels, and parts.

Simulation software then interprets CNC part programs and simulates machine motion to check for interference conditions and programming errors. This lets Huffman and its implant-manufacturing customers test and debug ideas before actually building a machining system.