Turbocharging your toolpath

Since the dawn of machining, part manufacturers have looked for ways to squeeze greater efficiencies out of existing equipment, materials and labor. CAM and CNC machining were huge steps in the right direction several decades ago. But in recent years, the improvements in machining productivity haven’t been as large.

This is because productivity-enhancing research focused primarily on computerization to streamline toolpath generation and toolpath optimization software, slowing feed rates at corners to reduce stress on tools. Nearly all innovations assumed a parallel-offset toolpath used for roughing parts, not realizing this was the real bottleneck. Ultrahigh- performance toolpath (UHPT) software changes this and improves the way tools cut through material, using high-speed continuous tangent motion rather than sharp, interrupted movements.

Imagine driving through a neighborhood without arterial streets. At each corner, you must slow down or stop at a stop sign, make a turn and proceed for another block while encountering changing traffic conditions. It’s maddeningly inefficient.

That’s how basic toolpaths drive CNC machines. Modeled on manual methodology, existing toolpaths are derived from the geometry being machined. They start with the material boundary and keep stepping in, following the shape of the material until the path collapses on itself. In other words, the tools follow a path regardless of the amount of material they encounter. This is hard on machines and tools.

Now, imagine the same neighborhood is redesigned on a circuitous route, with banked roundabouts and smooth curves instead of corners and stop signs. The amount of traffic is steady; it almost never slows down and never stops. You drive at a high average speed until you reach your destination. Yes, you might travel more distance. But the time and fuel saved and the reduced wear and tear on the car make the circuitous design worthwhile. This is the underlying concept behind UHPT software.

The software works on any shape, open or closed, with any number of features, and integrates with any CAM system. It plans the toolpath based on abilities designed into the machine and cutting tools. By taking advantage of the capabilities of modern machining hardware and avoiding sharp directional changes, it generates toolpaths that assure the machines and cutting tools are used at peak efficiency given existing conditions.

Courtesy of Celeritive Technologies

A standard toolpath (left) makes parallel cuts, requiring numerous stops and starts. UHPT software designs toolpath cuts in continuous motion.

Currently only offered as a 2.5-axis product called VoluMill from Celeritive Technologies Inc., Cave Creek, Ariz., UHPT software is ideal for prismatic parts. The software cuts pockets, steps, slots, channels and other shapes. It can be used with any cutting style and workpiece material, including the hardest metals.

Traditional toolpath technology forces machinists to accommodate worst-case machining conditions to prevent damaging the spindle and prematurely wearing out the cutting tool. Abrupt changes in the amount of material being encountered put excessive force on the part and machine. So programmers and machinists select slower feeds and speeds or make shallower cuts.