
5. FEED FUNCTIONS
5.8
Speed Control at Comers of Blocks
5.8
Speed Control at Corners of Blocks
For linear acceleration/deceleration after interpolation, the acceleration or deceleration
is applied in feed start and feed stop, automatically with a time constant so that the
machine tool system is not jarred.
Therefore, this need not be considered when
programming.
Because of automatic acceleration and deceleration, corners are not cut sharply. In
.
this case, deceleration command (G04;) must be commanded at the corner to cut
sharp.
For example, if the tool moves along the X axis only in one block and along the Z axis
in the next block, the feed rate for the X axis decelerates while motion along the Z axis
accelerates and the actual tool path is as follows.
Insert a deceleration command here
- Programming path
- + Actual tool path
If the deceleration command is inserted, the actual tool path matches the programmed
path
. The faster the feed rate and the larger the acceleration/deceleration time
constant, the larger the error at the corner.
(Note 1) The following chart shows feed rate changes between blocks of information specifying different types
of movement.
Positioning Feed Not moving
Positioning X X X
Feed
I
X
I I
0
X
Not moving 1 ---x -p---r x
x :
The next block is executed after commanded rate has decelerated to zero.
0 : The next bl
oc
k * IS executed sequentially so that the feed rate is not changed by very much.
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