Format Specifications for Turning Centres

The part programming format used in turning centres is similar to that used in machining centres. We will look at a typical format used in Fanuc controls, which are the most commonly found in many industrial machines. The other controls used such as Sinumeric and Haidenhain have similar formats. We will use most of the common facilities, which will be similar with other controls as well. The following is for metric units.

N04 G03 X ± 053 U ± 053 Z ± 053 W ± 053 I ± 053 K ± 053 F050 S04 T04 M02 ;

N04   

The identification of the block is done with the N word address that can have a total of 4 digits with    leading zero suppression.

G03      

G code or Preparatory function is used for specifying the geometric nature of the part program.

X ± 053 and U ± 053

Word address used for specifying the X-axis coordinates. The U word address is used to specify the incremental X-coordinates while X is used for absolute coordinates.

Z (W) ± 0.53              

Similar to the above but for Z-axis.

For axis dimensions both decimal point and leading zero suppression are permitted. The controller automatically identifies a dimension as leading zero suppression if no explicit decimal point is present. Care has to be exercised while giving the axes coordinates.

R 053              Radius value for circular interpolation

I 053                {Centre coordinates in incremental format from the start point of

K +053            {an arc for circular interpolation

42                    F 032   Feed specification in mm/rev

F 050               Feed specification in mm/min

S 04                 Spindle speed specification in direct RPM or constant surface speed in   m/min

T 04                 Tool function

M 02                miscellaneous functions

The inch format will be similar in most cases except for those with dimensions that need to have an extra decimal place.

Besides these word addresses, certain other word addresses are also used while programming such as A, B, C, E, P, Q, O, etc., and they are discussed when actually encountered.

Operator messages and comments can be included in a part program by enclosing them in parentheses. Any legal ASCII character can be used when writing a comment. The Block Skip (/) code inserted at the beginning of a data block is used to cause that particular block of data to be ignored by the control when Block Skip is activated by the machine operator. When Block Skip is not active, the data block will be executed. There is no particular sequence of word that should be followed in a block. However, it is generally recommended to follow the sequence:

       /, N, G, X, Z, U, W, B, C, I, K, P, Q, R, A, F, S, T, M