HEIDENHAIN CNC Pilot 4290 Pilot - Manual (Page 24)

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Help commands fo
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Feed rate reduction factor G38-Geo
G38 defines a special feed rate for G890.
Parameters
E:
Special feed-rate factor (0 < E † 1) – default: 1
(special feed rate = active feed rate * E)
Attributes for superimposed elements G39-Geo
G39 influences the machining of G890 for the superimposed
elements (form elements):
✲■ Chamfers/rounding arcs (for connecting base elements)
■ Undercuts
■ Recesses
Influence on machining:
■ Special feed rate
■ Peak-to-valley height
■ Additive D compensation
■ Equidistant oversizes
Parameters
F:
Feed per revolution
V: Type of surface texture (see also DIN 4768)
■ V=1: general roughness (profile depth) Rt1
■ V=2: average roughness Ra
■ V=3: mean roughness Rz
RH: Peak-to-valley height (µm, inch mode: µinch)
D: Number of the additive compensation (901 † D † 916)
Basics of programming
■ G38 is a non-modal function.
■ G38 is programmed before the contouring
element for which it is destined.
■ G38 replaces another special feed rate or a
programmed peak-to-valley height.
The ”special feed rate” applies only for basic
contour elements.
P: Finishing allowance (radius)
H: (Translation of P) absolute / additive – default: 0
■ H=0: P replaces G57/G58 allowances
■ H=1: P is added to G57/G58 allowances
E: Special feed-rate factor (0 < E
† 1) – default: 1
(special feed rate = active feed rate * E)
Basics of programming
■ G39 is a non-modal function.
■ G39 is programmed before the contour element
for which it is destined.
■ G50 before a cycle (MACHINING section) switches
G39 oversizes for this cycle off.
Only use peak-to-valley height (”V, RH”),
finishing allowance (”F”) and special feed
rate (”E”) alternately!