HEIDENHAIN iTNC 530 User Manual page 482

12.1 Execution of CAM programs
If you create NC programs externally using a CAM system, you should
pay attention to the recommendations detailed below. This will enable
you to optimally use the powerful path control of the TNC, and as a
rule create better workpiece surfaces with shorter machining times.
Especially noteworthy is that the TNC achieves very high contouring
accuracy despite the high machining speeds. The basis for this is the
HeROS 5 real-time operating system of the TNC, which is also very
good at processing NC programs with high point densities.
From 3-D model to NC program
Here is a simplified description of the process for creating an NC
program from a CAD model:

CAD: Creation of the model
Design departments prepare a 3-D model of the workpiece to be
machined. Ideally the 3-D model is designed for the center of
tolerance.

CAM: Path generation, tool compensation
The CAM programmer specifies the machining strategies for the
areas of the workpiece to be machined. The CAM system uses the
surfaces of the CAD model to calculate the paths of the tool
movements. These tool paths consist of individual points calculated
by the CAM system so that each surface to be machined is
approximated as nearly as possible while considering chord errors
and tolerances. This way, a machine-neutral NC program is created,
known as a CLDATA file (cutter location data). A postprocessor
adapted to the machine and control generates a machine- and
control-specific NC program, which can be processed by the
numerical control, from the CLDATA. The post processor is the link
between the CAM system and the CNC control.

TNC: Motion control, tolerance monitoring, velocity profile
The TNC uses the points defined in the NC program to calculate the
motions of each machine axes as well as the required velocity
profiles. Powerful filter functions then process and smooth the
contour so that the TNC does not exceed the maximum permissible
path deviation.

Mechatronics: Feed rate control, drive technology, machine
The motions and velocity profiles calculated by the TNC are realized
as actual movements of the tool by the machine's drive system.
482 Programming: Execution of CAM Programs, Multi-axis Machining