Operation Manual

HEIDENHAIN CNC PILOT 4290 165
4.8 Attributes for Contour Description
Feed rate reduction factor G38-Geo
G38 activates the special feed rate for the finishing cycle G890. The
“special feed rate” applies only to basic contour elements.
Attributes for superimposed elements G39-Geo
G39 influences the finishing feed rate of G890 with the form
elements:
 Chamfers/rounding arcs (for connecting basic elements)
 Undercuts
 Recesses
Affected machining: Special feed rate, surface roughness, additive D
compensation, equidistant oversizes.
Parameters
E Special feed factor (default: 1)
Special feed rate = active feed rate * E (0 < E <= 1)
 G38 is a non-modal function.
 Program G38 before the contour element for which it is
intended.
 G38 replaces another special feed rate or programmed
surface roughness.
Parameters
F Feed per revolution
V Type of surface roughness (see also DIN 4768)
 V=1: General surface roughness (profile depth) Rt1
 V=2: Surface roughness Ra
 V=3: Surface roughness Rz
RH Surface roughness (µm, inch mode: µinch)
D Number of the additive compensation (901 <= D <= 916)
P Oversize (radius)
H P applies as an absolute or additive value (default: 0)
 H=0: P replaces G57-/G58 oversizes
 H=1: P is added to G57-/G58
E Special feed factor (default: 1)
Special feed rate = active feed rate * E (0 < E <= 1)