HEIDENHAIN TNC 640, User Manual, Page: 643 / 948

Multiple-Axis Machining | Running CAM programs
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HEIDENHAIN | TNC 640 | Conversational Programming User's Manual | 10/2017
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13.7 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 motion control
functionality provided by the control and usually create better
workpiece surfaces with shorter machining times. Despite high
machining speeds, the control still achieves a 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 640. This enables the control 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.
Control: Motion control, tolerance monitoring, velocity
profile
The control uses the points defined in the NC program to
calculate the movements of each machine axis as well as the
required velocity profiles. Powerful filter functions then process
and smooth the contour so that the control does not exceed the
maximum permissible path deviation.
Mechatronics: Feed control, drive technology, machine tool
The motions and velocity profiles calculated by the control
are realized as actual tool movements by the machine’s drive
system.