Siemens SINUMERIK 840D sl Turning Operating Manual page 701

The advantage is that you reduce your production time. Further, when machining, the cutting
forces are better distributed.
Technological function
2-channel machining is available for the "Parallel stock removal" technology.
Leading channel/following channel
Define the leading channel when programming workpieces that you wish to machine utilizing
multiple channels. As a consequence, you define the channel-specific machine and setting
data that are used to create the stock removal programs.
Turning always starts in the leading channel. The second channel, also known as the following
channel, starts with the second depth infeed as soon as the leading channel has removed stock
by a specified "stock removal distance" (offset). If cuts are obtained that are shorter than this
offset, then machining is only carried out in the leading channel.
Offset
If the offset is not equal to zero, then a dedicated stock removal program is generated for each
channel. Automatically generated WAIT commands are used to synchronize both programs.
If the offset is equal to zero, then only one stock removal program is generated. This program
is started in the leading channel. Axis coupling is used to generate the motion of the following
channel.
For multi-channel lathes, the name of the generated stock removal program is extended by
identifier "_C" with a subsequent two-digit channel number.
Roughing
When roughing, typically there is an offset between the channels when machining (channel
offset DCH).
● When the parameter is positive, then the leading channel machining is executed before the
following channel by the channel offset.
● When the parameter is negative, then the machining sequence is interchanged. The
program generated for the leading channel is in this case, started in the following channel.
● When the parameter is equal to zero, then the workpiece is machined without offset (refer
to the paragraph "Finishing balance cutting").
Note
Constant cutting rate
When using a constant cutting rate, ensure that the offset (DCH) is not too high.
Tools
The difference between the two cutting radii of the tools must not exceed the allowance.
Turning
Operating Manual, 06/2019, A5E44903486B AB
Multi-channel machining
11.2 Multi-channel support
701