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4 creating and writing programs, Define the blank: blk form – HEIDENHAIN TNC 620 (340 56x-01) User Manual

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4.4 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

„

Approaching a safe position

„

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 program name
and the active unit of measure.

Define the blank:

BLK FORM

After initiating a new program, you define a cuboid workpiece blank.
To define the workpiece blank, press the SPEC FCT soft key and then
the BLK FORM soft key. 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.

10 L X+10 Y+5 R0 F100 M3

Block number

Path function

Words

Block

After each tool call, HEIDENHAIN recommends always
traversing to a safe position, from which the TNC can
position the tool for machining without causing a collision!

You only need to define the blank form if you wish to run
a graphic test for the program!