Approach functions APPR LCT and APPR PLCT

Application

The control uses these functions to approach a contour on a circular path with tangential connection and a straight line. You use APPR LCT to define the starting point of the contour with Cartesian coordinates, and APPR PLCT for polar coordinates.

Description of function

8H000_41
  • The control approaches the contour as follows:
  • On a straight line from the starting point PS to an auxiliary point PH
  • If you program the Z coordinate in the approach block, the control simultaneously moves the tool from the starting point PS to the auxiliary point PH.

  • On a circular path in the working plane from the auxiliary point PH to the first contour point PA
  • The circular path is connected tangentially both to the line PS to PH as well as to the first contour element. Once this information is entered, the radius R suffices to unambiguously define the tool path.

 
Tip

The feed rate programmed in the approach block is effective for the entire path that the control traverses in the approach block. If no feed rate is programmed before the approach block, the control generates an error message.

Programming APPR LCT and APPR PLCT

 
Tip

If you want to program this path shape with polar coordinates, then you must first define a pole CC.

Polar coordinate datum at pole CC

  1. To define the approach function:
  2. Use any path function to approach the starting point PS
ApprDep

  1. Select APPR DEP
  2. The control opens the Insert NC function window.
ProgramApprLctIcon

  1. Select the path shape, for example APPR LCT
  2. Define the coordinates of the first contour point PA
  3. Define a positive value for the radius R of the circular path
  4. Select radius compensation RR/RL

Example APPR LCT

11 L X+40 Y+10 R0 FMAX M3

; Approach PS without radius compensation

12 APPR LCT X+10 Y+20 Z-10 R10 RR F100

; PA with radius compensation RR, radius of the circular path: R 10

13 L X+20 Y+35

; End point of first contour element

14 L ...

; Next contour element