Where will new cam technology have the largest impact on manufacturing?
Diehl: The two main areas where CAM software can affect the profitability of a company come down to
saving machine cycle time and saving time creating the NC code. In general, the cost to machine a part far out
weighs the cost of creating the NC code. So reducing the cycle time provides the greatest productivity
advantage. This is particularly true with large-lot runs.
What are some new technologies you are developing?
Diehl: Our patented TrueMill technology, which dramatically reduces cycle time, is being made
easier to use and has been further enhanced. These improvements will be available this Fall as part of
our SURFCAM Velocity® 4 release. Through our maintenance program, all qualifying customers will receive
SURFCAM Velocity 4 when it is released.
TrueMill toolpaths are very different from any tool motion you’ve seen before. We’ve effectively eliminated
all corners, all the sharp directional changes. The tool never plows into a corner. This algorithm, 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, we manage tool-engagement angles to produce toolpaths that are far
superior to anything on the market today. The net result is that much more aggressive cutting parameters can
be used, resulting in dramatically reduced cycle times.
It seems to be a trend, where the software adjusts to how much material is removed.
Diehl: Adjust is the commonly used description, but it doesn’t apply here. Adjust implies that you
take a standard toolpath and modify it to avoid burying the tool in areas with excess material, or you slow the
feedrate down in those areas. That’s what you see with the so-called trochoidal toolpaths, morphing toolpaths,
feedrate optimizers and other similar processes. Such adjustments seek to address specific symptoms of the
overall problem without treating the problem itself and have achieved relatively little success. We are not
doing that at all!
The core problem is 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.
TrueMill 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.
We don’t need to adjust the toolpath because the tool will never be buried in the first place. We stay 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 feedrate resulting in an exceptional reduction in cycle time.
That sounds totally different.
Diehl: It is totally different. If you look at these toolpaths on the screen, you will instantly
notice that they do not look like anything you’ve ever seen before. The toolpaths are engagement-angle
driven, not geometry driven. In other words, the shape of the geometry doesn’t dictate the flow of the
toolpath. Rather, each cut is made such that the next cut can be made at the desired engagement angle.
The part shape is ultimately produced, of course, but it doesn’t really become apparent until the final
passes of the tool. Because of this smooth, flowing, engagement-controlled motion, we’re able to run at
feedrates, spindle speeds, depth’s of cut and stepovers that at first glance might seem crazy. The cycle
time reductions are dramatic.
One of the most impressive characteristics of these toolpathis is the way they sound on the machine.
The even tool load produces a quiet, constant pitch that seems out of synch with the aggressive material
removal rates. When you look at the current approach to high-speed machining, you’ll notice that they’re
taking very light cuts. TrueMill enables you to run at high speeds with much heavier cuts. Also due to
the even loads, there is less stress on the machine and the cutting tool. Tool life is actually extended
while cycle times are reduced. These two concepts used to be mutually exclusive.
Can this toolpath replace all other specialized toolpaths?
Diehl: Yes, TrueMill replaces them all. Specialized toolpaths are usually the result of treating
a symptom of the problem, rather than solving the problem itself. Some CAM systems offer eight or ten ways
to machine a pocket. Each of these options addresses one symptom of the problem, but more often than not
introduces other problems that didn’t exist before. For example, adding self-intersecting loops in sharp
corners is a popular method of allowing a stepover of greater than 50 percent of the cutter diameter without
leaving uncut material. But doing this adds length to the toolpath, forces the tool to be engaged at 180
degrees for extended periods of time and cuts conventionally when exiting the loops. So it treats one issue,
but introduces three new problems to the toolpath each of which is detrimental to the machining process.
With TrueMill, we have solved the core problem that produced all of these symptoms in the first place. Since
there are no symptoms to treat, there is no need for multiple, gimmicky toolpath options. There is just one
strategy that works in all cases. It even removes the distinction betwenn pocketing and contouring or
profiling. You just select your geometry and TrueMill knows what to do.
This sounds like a great way to run machines unattended.
Diehl: Right. Since the tool engagement angle is accurately managed, the tool load never exceeds a
known threshold. Therefore the machine operator no longer needs to stand there with his hand on the
feed-override control. Using current technology, shops tend to back way off on the cutting parameters when
running lights-out. This is because they don’t want to risk breaking a tool in the middle of the night and
come back in the morning to find they wasted the whole shift. With TrueMill, you can run lights-out with even
faster speeds than you would today with an operator standing by.
Will this new toolpath work on a standard machine lacking high-speed capabilities?
Diehl: Absolutely. It will enhance the productivity of any machine. Historically, the limiting
factor in material-removal rates has not been the machine tool or the cutting tools, though that has been the
popular belief. The toolpaths themselves have been the limiting factor. Traditional toolpaths force tools
into corners; they plow into excess material, spiking the tool engagement angle thereby spiking the load on
the tool. These toolpath flaws dictated the cutting parameters that had to be used. The oldest, most basic
numerically controlled machine you can find is capable of producing the motion of a TrueMill toolpath. That’s
good news; shops can increase their throughput with their existing equipment. The even better news is that the
better the equipment you invest in, the higher your productivity will be. TrueMill will match the capability
of your hardware, not limit that capability.
Will this new toolpath work with any material? What about titanium?
Diehl: TrueMill will work well on any material. The harder to machine the material, the greater the
advantage that TrueMill offers. Harder to machine materials have a narrow range of cutting parameters for
quality cutting and long tool life. TrueMill ensures that the cutting takes place within this narrow range
of optimal parameters everywhere along the toolpath. Results with titanium are spectacular. Cycle times
have been reduced by more than a factor of two when machining titanium.
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