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Advanced CAM programming techniques can make significant differences in the cycle times and costs of jobs, but creating tool paths with these techniques has historically been a time-consuming process, limiting their use to mid- and high-volume parts. Or at least, this was the case in 2010 when 91ÊÓƵÍøÕ¾ÎÛ spoke to Tom Funke, a CAM and applications specialist at Sandvik Coromant for the aerospace, space exploration and defense markets. Fifteen years later, Funke says CAM applications have evolved to include canned cycles that make advanced programming techniques accessible to a wider range of users.

Funke works with Sandvik customers to reprocess parts and set up processes for new components, typically in the aerospace market but also in other markets working with difficult metals such as nickel alloys, titanium, and stainless steels. As part of this role, he says he has learned that parts require very different approaches and methodologies depending on the setup. These can include advanced CAM features, which Funke says no longer require specialized programs and complicated, time-consuming programming techniques. Many of those he spoke of in 2010 are now included standard in today’s CAM packages.

From Specialized to Standard

Funke points to the idea of “rolling into the cut” as one that has become far simpler in recent years. Rolling into the cut — programming a tool path to engage a part in the same direction as the tool’s rotation — grants users better control of chip thickness on cutter engagement and exit, minimizing tool wear and increasing tool life. In 2010, CAM support for this was relatively limited in scope and restricted to a handful of CAM software packages. Funke says most contemporary software packages only allowed users to roll the tool in the opposite direction of the tool’s rotation. Nowadays, Funke says CAM software companies give users more control over the arc of engagement’s direction.

Ramping down (that is, creating tool paths that move down to the next Z-layer at the end of each pass to ensure constant tool engagement, which Funke says is especially useful for milling pockets) has also received better CAM support. Whereas programmers in 2010 would need to manually create rest milling tool paths for corners, now they can use specialized tooling with canned cycles like VoluMill, Dynamic Milling, Adaptive Milling or Waveform Machining. Instead of needing to manually calculate the radial engagement for each slice into a corner based on the angle of the corner, Funke says software can automatically calculate this and optimize feed rates as tools change cutter engagement in a feature.

Trochoidal turning, a way to turn pocket groove features which was particularly time-consuming to program around 2010, has also gotten much simpler. Instead of groove turning, a round insert is used with a zig-zag tool path motion arcing in and out at the beginning and end of each pass. The insert never leaves the material in this approach, and as such lasts longer. Funke also says this approach maximizes metal removal rate and tool life by using both sides of an insert. While software could only support trochoidal turning in a limited way in 2010, Funke says the last five years have seen CAM software implement canned cycles trochoidal turning techniques such as Adaptive Turning, Dynamic Turning and VoluTurn.

New Programs for New Techniques

In addition to some of the techniques Funke discussed in the 2010 article, he says there are several more recent programming techniques that are as well-supported as they are useful.

Five-axis dynamic milling is chief among these. Funke describes this as similar to three-axis dynamic milling, but with five-axis simultaneous motion to follow the curvature of a component’s surface. He says this technique is particularly effective for convex part floors, on aerospace brackets and on conical bands for aerospace engine cases, as well as other parts that would have traditionally relied on 3+2 machining or turn-milling. Performing this kind of milling used to be time-consuming, but Funke says the past five years have seen CAM software such as Siemens NX and Mastercam support the technique and improve shops’ ability to program tool paths along the curvature of a part.

Simultaneous, continuous B-axis turning is a turning technique that Funke says was possible in 2010, but it typically required operators to employ workarounds in the postprocessor — Funke specifically recalls needing to trick the machine controller to move the B-axis like a five-axis milling tool while it was in a “turn” mode (that is, spinning the main turning spindle). Now, some CAM packages provide support for the technique, and there are canned cycles expressly dedicated to it.

Further turning updates include Sandvik’s PrimeTurning concept, which combines cutting inserts designed to work at high feeds with tool path techniques and software supporting this approach. Funke says this type of turning maximizes the chip thinning effect while boosting metal removal rates. While the company debuted these tools around 2017, he says their implementation has become simpler after CAM software packages began including canned cycles around 2020.

OptiThread is another technique developed in-house at Sandvik, this one changing the cutting tool path during thread turning to ensure the insert is moving in and out of the cut like a wave. Funke says thread turning operations typically have difficulties breaking chips, especially in heat-resistant superalloys and stainless steels. This means chips grow and wrap around the part, potentially causing damage. Changing the tool path to operate in a wave pattern forces the chip to break as the tool moves in and out of the cut, he says, improving chip control and part quality. In its earliest implementations, Funke says that this required a Sandvik-developed code generator, but after several collaboration efforts with CAM providers, support is catching on within CAM software.

Funke also mentions simultaneous Y-axis turning on the Y-Z plane rather than the X-Z plane as a newer technique. In it, he says the forces are directed through the B-axis where the machine is most rigid, enabling the cutter to run more aggressively. Users tip the tool to do simultaneous turning, performing roughing and finishing on complex shapes. Moreover, this is a continuous process, eliminating the seam lines caused by retracting a cutting tool for finish passes. Funke says this is great for aerospace engine components and other high-tolerance parts where seam lines are at risk of fracture. This particular technique is still in its infancy, he continues, with CAM software developer partners still developing functions to support it and Sandvik developing tools specializing in the technique.

The Power of Simulations

These are all potentially useful CAM techniques, but Funke credits the expansion of simulation software with much of their success. In particular, he points to how support for ISO 13399 3D models has gone a long way to standardizing tooling nomenclature. He also reports that it improves solid model tool support, and the combination of solid model tooling support and universal nomenclature standards makes it simpler for operators to assemble tools online and import them directly into the CAM software. This improves the accuracy of simulations, and gives programmers confidence in their programs.

Funke also says machine kinematic simulation has drastically improved over the past 15 years. According to him, these advancements have particularly impacted multitasking machines with multiple spindles, but other improvements such as the implementation of force simulation are a boon for all machining. Funke says simulating force used to require dedicated, expensive collision detection or finite element analysis software in addition to simulation software, but now toolpath simulation software packages can recognize cutting forces. Built-in force modules such as Vericut Force improve visibility into potential collisions, kinematic motions and the forces being enacted on any cut. This also includes a lack of force, Funke says, and these modules can detect when a tool begins to transition between cutting material or air. The software can then optimize accordingly, making wear more predictable and improving tool life. As the software also knows the material, type of cutter and depth of cut, Funke says recent simulation software can also suggest improvements that cut cycle times. According to him, the software has been able to cut the cycle times of his own programs by 15 to 30 percent.

Into the Future

In 2010, Funke noted there tends to be a gap between the capabilities of new tooling technologies and techniques and what CAM software can support. This still exists now, Funke says, but in recent years Sandvik has its increased efforts to collaborate with the R&D teams at CAM software companies, speeding along the development of canned cycles for advanced programming techniques.

While Funke does not currently use AI in CAM programming for his job, he is watching AI software such as ’s CAM Assist with interest and believes it will provide time-saving benefits. He notes that automized programs have been around for a long time in the form of feature-based machining and logic trees. Building these out, however, has required large amounts of data — large enough that only certain, higher-volume kinds of job shops could benefit. Funke predicts that AI could streamline the process of building a code base from which to run feature-based machining and data-driven processes.

In a way, this means AI in CAM programming could act like the canned cycles of today, which have brought the efficiency and efficacy of advanced programming techniques to a wider range of shops.