Fundamentals of approach and departure functions
Approach and departure functions allow you to avoid dwell marks on the workpiece because the tool gently approaches and departs from the contour.
Because the approach and departure functions encompass multiple path functions, you get shorter NC programs. The defined syntax elements APPR and DEP make it easier for you to find contours in the NC program.
Overview of the approach and departure functions
The APPR folder of theInsert NC function window contains the following functions:
Symbol | Function | Further information |
---|---|---|
APPR LT or APPR PLT Use Cartesian or polar coordinates to approach a contour on a straight line with a tangential connection | ||
APPR LN or APPR PLN Use Cartesian or polar coordinates to approach a contour on a straight line perpendicular to the first contour point | ||
APPR CT or APPR PCT Use Cartesian or polar coordinates to approach a contour on a circular path with a tangential connection | ||
APPR LCT or APPR PLCT Use Cartesian or polar coordinates to approach a contour on a circular path with a tangential connection and a straight line |
The DEP folder of the Insert NC function window contains the following functions:
Symbol | Function | Further information |
---|---|---|
DEP LT Depart contour on a straight line with a tangential connection | ||
DEP LN Depart contour on a straight line perpendicular to the last contour point | ||
DEP CT Depart contour on a circular path with a tangential connection | ||
DEP LCT or DEP PLCT Use Cartesian or polar coordinates to depart a contour on a circular path with a tangential connection and a straight line |
You can switch between entry of Cartesian and polar coordinates in the form or by pressing the P key.
Approaching or departing a helix
The tool approaches and departs a helix in the extension of the helix by moving on a circular path that connects tangentially to the contour. Use the APPR CT and DEP CT functions for this.
Positions for approach and departure
- Program a feed rate other than FMAX before the approach function
The control uses the following positions when approaching and departing a contour:
- Starting point PS
The starting point PS is programmed prior to the approach function without radius compensation. The starting point is located outside of the contour.
- Auxiliary point PH
Certain approach and departure functions require an additional auxiliary point PH. The control automatically calculates the auxiliary point using the entered information.
In order to determine the auxiliary point PH, the control requires a subsequent path function. If no path function follows, then the control stops the machining operation or simulation with an error message.
- First contour point PA
Program the first contour point PA within the approach function, along with the radius compensation RR or RL.
- Tip
If you program R0, then the control may stop the machining operation or simulation with an error message.
This reaction is different from the behavior of the iTNC 530.
- Last contour point PE
You program the last contour point PE with any path function.
- End point PN
The position PN is located outside of the contour and arises from the information entered within the departure function. The departure function automatically cancels the radius compensation.
- Program a suitable pre-position
- Check the auxiliary point PH, the sequence and the contour with the aid of the graphic simulation
Definitions
Abbreviation | Definition |
---|---|
APPR (approach) | Approach function |
DEP (departure) | Departure function |
L (line) | Line segment |
C (circle) | Circle |
T (tangential) | Continuous, smooth transition |
N (normal) | Perpendicular line |