Approach function APPR PCT

Application

With the NC function APPR PCT, the control approaches the contour on a circular path tangential to the first contour element.

Coordinates of the first contour point are programmed with polar coordinates.

Requirement

Description of function

This NC function encompasses the following steps:

  • A straight line from the starting point PS to the auxiliary point PH
  • The distance of the auxiliary point PH to the first contour point PA arises from the center angle CCA and the radius R.

  • A circular path from the auxiliary point PH to the first contour point PA
  • The circular path is defined by the center angle CCA and the radius R.

  • The direction of rotation of the circular path depends on the active radius compensation and the algebraic sign of the radius R.

The table shows the relationship between tool radius compensation and the algebraic sign of the radius R and the direction or rotation:

Radius compensation

Algebraic sign of radius

Direction of rotation

RL

Positive

Counterclockwise

RL

Negative

Clockwise

RR

Positive

Clockwise

RR

Negative

Counterclockwise

 
Tip

If you change the algebraic sign of the radius R, then the position of the auxiliary point PH changes.

The following applies regarding the center angle CCA:

  • Only positive input values
  • Maximum input value 360°

Input

11 APPR PCT PR+15 PA-90 CCA180 R+10 RL F300

; Approach the contour on a tangential circular path

To navigate to this function:

Insert NC function All functions Path contour APPR APPR PCT

The NC function includes the following syntax elements:

Syntax element

Meaning

APPR PCT

Syntax initiator for a circular approach function tangential to the contour

PR

Polar coordinate radius

Entry: absolute or incremental

Optional syntax element

PA

Polar coordinate angle

Entry: absolute or incremental

Optional syntax element

CCA

Center angle as a fixed or variable number

Entry: absolute or incremental

Optional syntax element

R

Radius as a fixed or variable number

Optional syntax element

R0, RL, RR

Tool radius compensation

Tool radius compensation

Optional syntax element

F, FMAX, FZ, FU, FAUTO

Feed rate

Feed rate F

Fixed or variable number

Optional syntax element

M

M function

Miscellaneous Functions

Fixed or variable number

Optional syntax element

Note

Example APPR PCT

11 L X+5 Y+10 R0 F300 M3

; Approach PS with R0

12 CC X+50 Y+20

; Set the pole

13 APPR PCT PR+30 PA+180 CCA40 R+20 RL F300

; Approach PA with CCA40 and RL; distance PH to PA: R+20

14 LP PR+30 PA+125

; Complete the first contour element