TRIANGLE PRECISION ACHIEVES "HANDS OFF", ONE SETUP MACHINING

Triangle Precision Industries Inc. has reached a milestone in manufacturing; true art-to-part production with one setup. The company is showcasing this in medical implants with tight tolerances and delicate, flawless surfaces, maximizing CAD-to-CAM automation in what has become known as hands-off machining.

At Triangle's Ohio base, Kettering, geometry that is sent in by medical supply companies, surgical hospitals and research institutions is readied for machining. This is accomplished with virtually no changes in a computer- aided machining (CAM) software package, EdgeCAM from Pathtrace Systems Inc. Programmer Bryan Hunt uses EdgeCAM to program machining operations, avoiding all manual handling—all sides of the part are machined in a single step. Hunt uses computer numerically controlled (CNC) machines with integrated milling and drilling capabilities on additional spindles. The machines are known as mill-turn machines, and can be programmed as either 3-axis mills or 2- or 4-axis turning centers, or both.

Triangle chose EdgeCAM, in part, for its pioneering developments in programming mill-turns, which have up to nine axes to be coordinated, and for fully automated programming known as machining form the solid. Together, they add up to hands-off machining. Mill-turn machines can be costly, but hands-off machining is a good way to get the machines to pay off—integrating turning and milling in a single setup. EdgeCAM handles this with its Mill/Turn package. Triangle utilizes mill-turn machines from Mori Seiki (SL253BMC) and from Star Turn (SR20).

TAKING JOBS OTHER SHOPS TURN DOWN
The biggest challenge facing Hunt is Triangle Precision's preference for jobs that other shops refuse to quote. In exchange for less price competition, Triangle takes on tougher technical challenges. The majority of jobs are prismatic and relatively simple to program and to machine. In contrast, many of the new medical and aerospace work have compound surfaces that are curved in two directions, like saddles and organic surfaces, as in implants that are entirely freeform.

In the medical fields, the major challenge is visually perfect surfaces. Because of the ever-present risk of infection, surgeons reject any implant or cut guide with visible flaws, regardless of specifications and tolerances. "Because surgeons will reject anything that might harbor an infection, the aesthetics of the implants are life-and- death to us," Hunt commented.

Many of the surface flaws that Triangle encounters are due to rough handling between machine setups. The avoidance of dings in delicate finishes is a major justification for Triangle's mill- turns. The machines can rough-and- finish-machine every surface of a part in a single setup, resulting in virtually no handling. Deadlines are tight and engineering changes are frequent for these parts. Hunt praises EdgeCAM for handling changes in a matter of minutes. "We are able to reprogram so quickly and so accurately that there is no need to treat prototype and production jobs differently," he said.

ZEROING IN ON GEOMETRY
When dealing with the medical business, a new challenge presented itself. The medical business is full of curves, unlike print heads, which had few, if any curves. To deal with this, Triangle has six EdgeCAM seats. Four are networked, and drive the three mill-turn machines, plus 14 machining centers, a laser cutter and seven EDMs. The other two EdgeCAM seats are dedicated to the tool- and die-makers.

In his multi-axis mill-turn work, Hunt opens EdgeCAM from within SolidWorks from Dassault Systèmes. This eliminates "importing" and "exporting" of product geometry and the risk of a translator error. As Hunt gets ready to machine medical parts, he opens EdgeCAM from with SolidWorks using the SolidWorks toolbar. Then, working in EdgeCAM, he lays tool paths over the solid model, and finally post-processes the job to the specific machine tool.

Also packed into Triangle's 24,000ft2 shop are: 18 Bridgeport milling machines; four surface grinders; welders; riveters; saws; a blast- cleaner; and a deburrer, plus presses, shears and press brakes for sheet metal fabrication. Triangle also has a well-equipped inspection department with coordinate measuring machines (CMMs).

MILL-TURNS AND SIMULATION
Simulations produced by EdgeCAM lend a hand in determining whether a job can be run on one of the mill-turn machines, rather than a machining center. For instance, mill-turn jobs must be done with no more than 10 tools, the most that can be mounted in the particular machines that Triangle uses. Many have special head configurations with buttons and knurled knobs that mill- turn machines handle well. Triangle's mill-turns also produce surgical drive wrenches that have one end turned and the other end milled.

MORE BUSINESS IN A COMPETITIVE MARKET For Hunt, the overall benefit of using EdgeCAM is increased business in a market that grows more competitive every year. "We get a lot more work now because EdgeCAM helps us cut costs and be more competitive," said Hunt, adding that, "short-run machining and prototyping are very competitive."

TRIANGLE'S BENEFITS INCLUDE:

• Enhancing and accelerating the diversification away from the printing/ graphics business.
• Doing a better job of serving other, longtime customers such as with high- precision, short-run, fast-turnaround work.
• Supporting the ongoing business transformation to "single-sourcing". At Triangle, this means almost any conceivable metalworking operation can be done in-house. The benefit to the customers is that they no longer have to worry about what is happening to their parts as they are moved from one specialized shop to another.

Perceiving the success at Triangle Precision, other shops master the intricacies of medical, surgical markets, or hire the skills necessary. Then, they follow in the footsteps of Triangle, investing in machining innovations like mill-turns and trunnions, and in turn saving time, lowering costs and boosting quality.