Material Properties in MillMax
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In MillMax we use two material properties that you have never seen before. Cutting Stiffness and Process Damping Wavelength. Together we often refer them as the Force Model.
Cutting Stiffness is the amount of force it takes for the cutter to cut through that particular material. It is measured in Pounds per Square Inch (PSI).
A high cutting stiffness is shown in blue and a low cutting stiffness in shown in red. High cutting stiffness limits the depth of cut.
Note, that though the depth of cut is limited the stable speeds are identical regardless of the material.
The Cutting Stiffness can also change by the direction of the cutting force of the milling tool.
With 90 degree mills the cutting force is radial. Feed mills move the majority of the cutting force axially.
Process Damping Wavelength is the amount of vibration energy that is absorbed, primarily by the geometry of the cutter. Process damping is measured by the length of the wave. The longer the wave, the less it vibrates.
Edge prep or eccentric relief increases Process Damping.
Perhaps the largest source of Process Damping is variable pitch endmills. Tooth 1 and 3 are doing most of the cutting. Tooth 2 and 4 are followers and act like shock absorbers.
Process Damping increases the low speed stable range. Figure 2 has higher Process Damping than Figure 1.
Because we could not possibly know the exact properties of every material and the process damping of every cutter/material combination we have to make assumptions. Sometimes, when tapping an existing tool and material that a customers has had years or months of trial and error adjustments, the resulting dashboard shows red where the customer is currently stable. We can calibrate the Cutting Stiffness and Process Damping to the known stable condition and then optimize the process. We do this by stepping through different database settings: