As featured in Fabricating & Metalworking Online - August 13, 2008
The only real limitations in machining are people's misconceptions about what is possible.
That's about to change, because a new software/cutter combination technology is rewriting what is possible.
By Stephen Diehl, Surfcam, Inc. and Steve Swift, Swift-Carb Cutting Tools
Traditional CAD/CAM software employs the 'shallow depth' version of high speed machining (HSM),
or 'constant stepover machining'. All previous tool path systems using this approach have the same fundamental flaw:
they use a fixed stepover to calculate the path, which always leaves them buried in the corners.
Now a new technology is literally turning the corner on this issue by taking a totally different
approach. TrueMill® toolpaths are very different from any tool motion seen before. This approach effectively eliminates
all corners, all the sharp directional changes. The tool never plows into a corner. The algorithm embedded in this
technology works on all part shapes. Rather than generating toolpaths based on a given stepover value and the shape of
the geometry being machined, the software manages tool-engagement angles to produce superior toolpaths. The net result
is that much more aggressive cutting parameters can be used, resulting in dramatically reduced cycle times.
The core problem in milling has always been the inability to control the cutting tool's engagement
with the material. This makes it physically impossible to keep the load on the tool constant and forces machines to be
run at far less aggressive cutting parameters than they are capable of, resulting in longer cycle times. By employing the
patented 'engagement angle' or 'TEA' method to calculate the tool path, this software achieves what all tool path
systems have been trying to accomplish from the beginning: it solves this core problem.
The motion of the toolpath is designed with consideration for the in-process material boundary
everywhere along the toolpath to ensure that the tool is never over-engaged. The tool stays as close as possible to the
desired engagement angle without ever exceeding it. Controlling the engagement angle and using smooth motions allows the
tool to run at an exceptionally fast and consistent feed rate, resulting in an exceptional reduction in cycle time.
The software application is a primary component of this new combination system, but another side
of the equation involves the new end mill technology that resulted in a tool specifically designed to optimize the
software's toolpath and further increase its productivity and benefits.
The design of this new end mill technology began by assessing the limitations of standard high
performance end mills to determine where these tools begin to fail. As such, it new cutter technology is designed using
engineered geometry that won't fail in those particular areas. The difference between the TrueMill Certified series end
mill compared to others lies in the substrate, geometry, and coatings used. A tool like this has essentially never been
This combination of software and cutting tool technology is currently being marketed in several industry
niches, with the formal release planned for the IMTS show in September. The biggest challenge in offering this sort of system to
users is to literally remove their misconceptions about what is possible by getting them to "forget what they think they know"
about machining. For example, in one case where "forgetting" yielded some fairly impressive results, a shop was drilling and
finish boring 2-1/2 in holes through 2 in thick steel plating with traditional machining practices and averaging 3 to 5 minutes
Using the new software/cutter combination, they now rough and finish the hole in less than 50 seconds
with no tool change.
Traditional cutter paths won't allow this kind of speed. This software/cutter combination can go faster than
shallow depth machining or traditional HSM, eliminate the harmonics and leave a better finish as well.
As the overall economy slows down, companies are investigating new things that will enable them to quote jobs
more aggressively. They must look at newer, faster ways to manufacture their parts in order to remain competitive. They cannot afford
to miss out on going 30 or 40 percent and, in many cases, 100 percent faster.
In other words, their only real limitation in machining is their misconception about what is possible. It's
only a matter of turning the corner.
Steve Swift is the president of Swift-Carb Cutting Tools, a New Tech Cutting Tools, Inc. company, 633
Central Avenue South, Kent, WA 98032-6110, 800-227-9876, Fax: 800-225-9876, www.swiftcarb.com.
Stephen Diehl is the president and CEO of Surfcam, Inc., 100 Camino Ruiz, Camarillo, CA 93012, 818-991-1960,
Fax: 818-991-1980, www.surfware.com.