Creating And Writing Programs - HEIDENHAIN TNC 426 B User Manual

4.5 Creating and Writing Programs

Organization of an NC program in HEIDENHAIN
conversational format.
A part program consists of a series of program blocks. The figure at
right illustrates the elements of a block.
The TNC numbers the blocks in ascending sequence.
The first block of a program is identified by "BEGIN PGM, " the
program name and the active unit of measure.
The subsequent blocks contain information on:
The workpiece blank
Tool definitions, tool calls
Feed rates and spindle speeds as well as
Path contours, cycles and other functions
The last block of a program is identified by "END PGM, " the pro-
gram name and the active unit of measure.
Defining the blank form — BLK FORM
Immediately after initiating a new program, you define a cuboid
workpiece blank. This definition is needed for the TNC's graphic
simulation feature. The sides of the workpiece blank lie parallel to
the X, Y and Z axes and can be up to 100 000 mm long. The blank
form is defined by two of its corner points:
MIN point: the smallest X, Y and Z coordinates of the blank form,
entered as absolute values.
MAX point: the largest X, Y and Z coordinates of the blank form,
entered as absolute or incremental values.
You only need to define the blank form if you wish to run
a graphic test for the program!
The TNC can display the graphic only if the ratio of the
short side to the long sides of the BLK FORM is less than
1:64!
HEIDENHAIN TNC 426 B, TNC 430
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Block:
10 L X+10 Y+5 R0 F100 M3
Path function Words
Block number
Z
MAX
Y
MIN
X
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