src/Mod/Material/Resources/Materials/Machining/HardWood.FCMat

General:
  UUID: "ba2474ee-f62c-45f5-b388-823ea105847f"
  Author: "Jonas Bähr"
  License: "CC-BY-3.0"
  Name: "Hard Wood"
  Description: >-
    Prototype for various hard woods, with densities around 0.75 g/cm^3 (beech, oak, ...).
    Wood is highly anisotropic and here data is provided only for the single
    cutting direction that is the toughest: the crosscut (direction A, as
    defined by Kivimaa).
    The surface speeds given here are conservative values and can be increased up
    to 4x on capable machines with sufficiently large tools.
    In addition, the numbers here use the cutting force model from B.Ettelt,
    which is less accurate for smaller chip loads, but has the advantage of being
    compatible with the model from O.Kienzle commonly used for metals.
    Another source of uncertaintly is the unknown base rake angle.
    Together with the natural inhomogenities of Wood the numbers given here can
    only serve as an initial estimate.
    Source: Zerspanung von Holz und Holzwerkstoffen, https://www.hanser-fachbuch.de/fachbuch/artikel/9783446477698
Inherits:
  Wood:
    UUID: "1850ac4a-0df2-43cd-9934-e59e95b9526f"
Models:
  Father:
    UUID: '9cdda8b6-b606-4778-8f13-3934d8668e67'
    Father: "Wood"
  MaterialStandard:
    UUID: '1e2c0088-904a-4537-925f-64064c07d700'
    KindOfMaterial: "Wood"
  Machinability:
    UUID: '9d81fcb2-bf81-48e3-bb57-d45ecf380096'
    # ISBN 978-3-446-47769-8, 2. Edition 2023, P. 66
    # for contour milling, a wide range from 10m/s to 40m/s (up to 120m/s for HSC)
    # is provided, without differentiation on the cutting material or type of wood.
    # Here we take the lower end, based on the assumption that mainly hobbyists will
    # apply this information. Here, smaller tool diameters are common, thus higher surface
    # speeds are not achievable.
    SurfaceSpeedHSS: '600 m/min'
    SurfaceSpeedCarbide: '600 m/min'
    # ISBN 978-3-446-47769-8, 2. Edition 2023, P. 120 (again citing work from B.Ettelt, 1987)
    # provided is the mean of the upper bounds of the ranges given for beech (26..40) and
    # oak (22..44), for direction A. (values for direction B are 12 and 10; for direction C
    # 7.5 and 7 respectively)
    # Unfortunately, it is unknown with which rake angle the values have been obtained.
    # The choice of 20° is arbitrary and needs revision. It should prevent underestimation
    # of the calculated cutting force when expecting a value normalized for 0°.
    # i.e. 42 / (1 - 20/100) is 52.5
    # NB: Ettelt's model uses 'N/mm^1.5' because it does not normalizes the chip thickness,
    # however, the definition of FC's Machinability-model requires this normalization.
    UnitCuttingForce: '52.5 N/mm^2'
    # Ettelt's model uses the square root of the chip thickness, i.e. an 0.5 as exponent
    ChipThicknessExponent: 0.50