HEIDENHAIN TNC 620 Programming Station, User Manual

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Running CAM programs 12.6
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HEIDENHAIN | TNC 620 | ISO Programming User's Manual | 9/2016
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12.6 Running 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. Despite high machining speeds, the
TNC still achieves very high contour accuracy. The basis for this is
the real-time operating system HeROS 5 in conjunction with the
ADP
(Advanced Dynamic Prediction) function of the TNC 620. This
enables the TNC to also efficiently process 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: Model creation
Construction 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 post processor generates a machine- and
control-specific NC program, which can be processed by the
CNC control. The post processor is adapted according to the
machine tool and the control. 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 control, drive technology, machine tool
The motions and velocity profiles calculated by the TNC are
realized as actual movements of the tool by the machine’s drive
system.