Siemens CNC Milling | SLOT1 | Slots on a Circle

In this article, we describe how to use SLOT1 to machine slots arranged on a circle in Siemens CNC controlled milling (machine centre) machines with all details and examples.


SLOT1 Introduction

The cycle SLOT1 is a combined roughing-finishing cycle.

Use this cycle to machine slots arranged on a circle. The longitudinal axis of the slots is aligned radially. In contrast to the long hole, a value is defined for the slot width.
NOTICE:¬†The cycle requires a milling cutter with an “end tooth cutting across center” (DIN844).

Note: A tool compensation must be programmed before the cycle is called. Otherwise, the cycle is aborted and alarm 61000 “No tool compensation active” is output.

If incorrect values are assigned to the parameters that determine the arrangement and size of the slots and thus cause mutual contour violation of the slots, the cycle is not started. The cycle is aborted and the error message 61104 “Contour violation of slots/long holes” is output.

You may be interested also:
“Siemens CNC Milling | LONGHOLE | Long Holes located on a Circle”
Siemens CNC Milling SLOT1 Contour Violation

Supported CNC Series

Siemens CNC 802D, 810D, 840D, 840D sl, 840Di, 840Di sl series controllers.

SLOT1 Format



RTP = Retraction plane (absolute)
RFP = Reference plane (absolute)
SDIS = Safety clearance (enter without sign)
DP = Slot depth (absolute)
DPR = Slot depth relative to the reference plane (enter without sign)
NUM = Number of slots
LENG = Slot length (enter without sign)
WID = Slot width (enter without sign)
CPA = Center point of circle, abscissa (absolute)
CPO = Center point of circle, ordinate (absolute)
RAD = Radius of the circle (enter without sign)
STA1 = Starting angle
INDA = Incrementing angle
FFD = Feedrate for depth infeed
FFP1 = Feedrate for surface machining
MID = Maximum infeed depth for one infeed (enter without sign)
CDIR = Mill direction for machining the slot
(Values: 0: Down-cut milling (corresponds to direction of spindle rotation); 1: Down-cut milling; 2: with G2 (independent of direction of spindle rotation; 3: with G3)
FAL = Finishing allowance at the slot edge (enter without sign)
VARI = Machining type (enter without sign) Values :
UNITS DIGIT: Machining process
0: Complete machining
1: Roughing
2: Finishing
0: Perpendicular to G0
1: Perpendicular to G1
3: Oscillation with G1
MIDF = Maximum infeed depth for finishing
FFP2 = Feedrate for finishing
SSF = Speed when finishing
_FALD = Finishing allowance at the slot base (enter without sign)
_STA2 = Maximum insertion angle for oscillation movement

SLOT1 Examples

SLOT1 CNC Program Example – 1

This program realizes the same arrangement of 4 slots located on a circle as the program for long hole machining (see Programming long holes located on a circle – LONGHOLE).

The slots have the following dimensions:

Length : 30 mm
Width : 15 mm
Depth : 23 mm
Safety clearance : 1 mm
Finishing allowance : 0.5 mm
Milling direction : G2
Maximum infeed in depth : 10 mm

The slots must be machined completely with an oscillating insertion motion.

Siemens CNC Milling SLOT1 Program Example

N10 G19 G90 S600 M3 ; Specification of technology values
N15 T10 D1 ;
N17 M6 ;
N20 G0 Y20 Z50 X5 ; Approach start position
N30 SLOT1 (5, 0, 1, -23, , 4, 30, 15, 40, 45, 20, 45, 90, 100, 320, 10, 2, 0.5, 30, 10, 400, 1200, 0.6, 5) ; Cycle call, parameters VARI, MIDF, FFP2 and SSF omitted
N40 M30 ; Program end

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