Installation manual
CNC 8060
CNC 8065
CONCEPTS.
9.
(REF: 1402)
·489·
Configuration of the HSC mode (High Speed Cutting).
9.9.3 Procedure for analysis and adjustment of the HSC.
To adjust the HSC mode, the CNC axes must have parameters G00FEED, ACCEL, LACC1,
LACC2 and ACCJERK already tested and adjusted to the maximum value allowed by the
dynamics of the machine. The following procedure is meant for analyzing the behavior of
the CNC while machining and evaluate whether the result may be improved or not by
adjusting a parameter. The steps to follow are.
1 Evaluate the time the CNC has for its calculations and if the blocks are supplied properly.
2 Evaluate the feedrate on the path in case there are irregularities from one pass to the next.
3 Analyze the problems occurring at specific points.
The CNC has a set of variables that, when analyzed while machining, help find aspect of
the HSC that may be improved in terms of execution time and machining quality. The
oscilloscope will serve as a tool to analyze the evolution HSC while machining.
Evaluate the time the CNC has for its calculations and if the
blocks are supplied properly.
An improper supply of blocks forces to lower the feedrate unnecessarily. The CNC offers the
following variables to check whether the HSC has a proper supply of blocks or not.
In order to ensure a proper supply of blocks to the HSC, the following variables must return
a value near 100%.
In either case, parameter PREPFREQ may be increased to increase the supply of blocks
as long as the system has enough time; in other words, the percentage of cycle time used
by the CNC is not too close to the total cycle time (about 50%). This information may be
checked with the following variable.
To properly analyze this aspect, parameter FEEDAVRG must be set to ·No· to prevent the
CNC from limiting the feedrate depending on the supply of blocks.
Evaluate the feedrate on the path in case there are irregularities
from one pass to the next.
For similar machining passes, the velocity graph should look the same. However, in some
passes, the feedrate could decrease even more and the machining could be less symmetrical
Variable. Meaning.
V.[ch].G.PERFRATE Percentage of blocks managed by the CNC in block preparation, with
respect to the best possible.
V.[ch].G.DROPRATE Percentage of reduction of the maximum feedrate possible.
V.G.NCTIMERATE Percentage of loop time (cycle time) used by the real time portion of
the CNC.
V.G.LOOPTIMERATE Percentage of loop time (cycle time) used by the position loop.
V.[ch].G.CHTIMERATE Percentage of loop time (cycle time) used by the channel.
V.[ch].G.PREPTIMERATE Percentage of loop time (cycle time) used by the channel for block
preparation.
V.[ch].G.IPOTIMERATE Percentage of loop time (cycle time) used by the interpolator of the
channel.
V.[ch].G.PERFRATE A value lower than 100 means that the CNC can process more
blocks.
V.[ch].G.DROPRATE A value lower than 100 means that the CNC could increase the
feedrate if it had more blocks.
V.[ch].G.NCTIMERATE With a value lower than 50, parameter PREPFREQ may be
increased.
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