Siemens SINUMERIK 840D sl Function Manual

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Supplementary conditionsAxis-specific feed stop/axis disableAxis-specific feed stop and axis-specific axis disable are ignored by LookAhead.If an axis is to be interpolated that should on the other hand be made stationary by axis-specificfeed stop or axis disable, LookAhead does not stop path motion before the block in questionbut decelerates in the block itself.If this response is not wanted, an axis-specific feed stop can be transferred to a channel viathe PLC to stop the path immediately (see also Section "Clamping monitoring (Page 86)").4.3.4.2 Free-form surface mode: Extension functionFunctionThe "Free-form surface mode: Extension function" is an extension of the Look Ahead standardfunctionality and is used to calculate the path velocity profile during free-form surfaceprocessing (see also Section "Free-form surface mode: Basic functions (Page 224)").Its use optimizes the continuous-path mode as follows:● Symmetry between the acceleration and deceleration profiles● Uniform acceleration process, even with changing jerk or acceleration limits● Uniform acceleration process of target velocity profiles, irrespective of the degree to whichthey can or cannot be started with the specified dynamic response limit● Look Ahead braking to lower setpoint velocitiesUniformity and compliance with the dynamic response limit guarantee that the setpoint velocityprofiles are smoothed to a homogeneous velocity profile on the part. This serves to minimizethe effect of following errors on the quality of the surface.Advantages● Greater uniformity in the surface of the workpiece● Lower machine loadApplicationsThe "Free-form surface mode: Extension function" is used to process workpieces whichprimarily comprise free-form surfaces.NoteAs better results are not achieved for standard processing applications, standard Look Aheadfunctionality should be used in these cases.B1: Continuous-path mode, Exact stop, Look Ahead4.3 Continuous-path modeBasic Functions206 Function Manual, 01/2015, 6FC5397-0BP40-5BA2