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As featured in Manufacturing Engineering Online - October 13, 2008
Stephen Diehl is president and CEO of Surfware Inc. (Camarillo, CA), developer of SURFCAM software
"Because TrueMill maintains consistent chip geometry without changing the feed rate throughout the toolpath,
it enables significantly higher material removal rate (MRR) overall while extending tool life by a factor of two to four." |
Stephen Diehl |
Manufacturing Engineering: Your company recently was granted a patent for its TrueMill
engagement milling capability: describe the process and what it offers to users.
Stephen Diehl: TrueMill controls the amount of material in contact with the tool circumference
everywhere along the toolpath. Whether you measure this as an angle along the tool circumference and call it the tool-engagement
angle (TEA), or whether you measure it as the actual or projected width of the material being cut by the tool at any location
in the toolpath and call it the 'true stepover' or some other term, it is the same thing. When you combine controlling the
TEA with use of a constant feed rate and constant depth of cut, you completely control the geometry of the chip that is produced.
Because TrueMill maintains consistent chip geometry without changing the feed rate throughout the toolpath, it enables a
significantly higher material removal rate (MRR) overall while extending tool life by a factor of two to four.
ME: How does your TrueMill system differ from other companies’ approaches, such as toolpath optimizers
or feed-rate optimization techniques?
Diehl: Feed-rate optimizers vary the feed rate to compensate for parallel offset toolpaths. Changing
the feed rate on parallel offset toolpaths changes the chip geometry, which unavoidably changes the load on the tool. Equally
important is the fact that optimizers fail to control the tool’s critical cutting edge temperature; the tool is no longer cutting
optimally. To cut optimally means to cut with the optimal chip geometry everywhere. Furthermore, due to momentum of the moving
table and workpiece, it is not possible to change the feed rate fast enough so as to achieve a constant chip load and/or constant
material removal rate. TrueMill on the other hand not only maintains a constant chip load and a constant material removal rate,
it does so without having to vary the feed rate. It is the only CAM product designed from the ground up to actually achieve a
consistent chip geometry. The proof is in the cutting--TrueMill will outperform any other technology by a very wide margin,
especially on difficult to machine materials where it is essential to have cut with a consistent chip geometry.
ME: Are there concerns that other developers may encroach on this technology?
Diehl: Of course, the law provides strong protections for a company's confidential information and
trade secrets, as well as its patents. Surfware has taken - and will continue to take - appropriate steps to protect its
intellectual property, which is our bread and butter.
ME: What industries or applications can best use your TrueMill engagement milling process?
Diehl: Any industry or application that needs to rough out a large amount of material will benefit
from the TrueMill approach. Also any workpiece made of tough or hard material, where large deep pockets are required, will benefit
tremendously from this technology. Because the load on the tool is controlled by controlling the chip geometry throughout the entire
toolpath, TrueMill can cut titanium and other exotics, as well as mild steel, with large depths of cut up to two times the diameter
of the tool and more using small or large diameter tools.
ME: What other new capabilities are you developing for your SURFCAM Velocity software?
Diehl: The next release of Surfcam will be Velocity 4 and it should be available shortly. A great many
improvements have gone into our next release. Our three-axis product now has new high-speed finishing strategies featuring automated
rest-machining, multiple processor support, adaptive step-down machining, automatic arc filtering, support for all standard and custom
tools. The superior surface finishes increase productivity by reducing secondary processes and makes hard-die milling more efficient.
Our four and five-axis product has precise control over every aspect of multiaxis machining ensuring safe tool motion in the most
challenging applications. Advanced gouge avoidance strategies for drive and check surfaces, flexible retract styles, and an enhanced
swarf cutting method are some of the highlights.
The TrueMill technology continues to evolve. A significant improvement to the feed rate is now handled by default,
a large reduction in rapid motions has been implemented, and more. Less than a third of the ideas in the patent have been implemented in
the software to date. These ideas are now actively being developed for future releases of TrueMill to provide ever increasing levels of
productivity.
ME: What other key technical advances are helping CAM users increase productivity?
Diehl: Machine tools, cutting tools, holders, and fixturing are all better than ever. Until TrueMill, the
weakest link in the chain has been the toolpath. TrueMill automatically creates a toolpath for any shape workpiece, including pockets with
any number of islands. The user simply sets a few parameters and TrueMill creates an efficient toolpath. You don’t have to choose from a
multitude of possible routines to machine a pocket more efficiently than ever before, and this is a true productivity gain.
ME: What is the current business climate?
Diehl: The current business outlook is excellent for both Surfware and the CAM industry in general. The aerospace
industry in particular has a huge backlog of parts to be built requiring roughing out large amounts of material, often times in exotic
materials at large depths of cut. This is ideal for TrueMill, and several Tier One aerospace companies are actively pursuing an investment in
the TrueMill technology.
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