Impax 2000, Manual

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Chapter 5 - Tolerance Setting Guide
MANUAL TOLERANCE
AUTOMATIC TOLERANCE
IMPAX
tolerance limits are adjustable because every forming job is different. If a machine is running
well and making high quality, consistent parts, a low tolerance number can be used. If the job is
sloppy, or the material is inconsistent, or the quality of the part is not critical, a higher number
may be chosen. Tolerance selection is a compromise; there are several factors to consider. The
best compromise is a tolerance setting which is slightly wider than the normal force variation;
unnecessary stopping is minimized, but all real problems will be caught.
Consistency is important. IMPAX works best when the forming forces are unchanging.
Sometimes this may be improved by careful setup, tight tooling, and uniform material. This also
improves the quality of the finished part, which is an objective of any good manufacturing
operation.
Unnecessary Stops must be prevented. If the tolerance is set too tightly, productivity may
actually go down. When IMPAX stops a machine frequently for no reason, the tolerance setting
is too low (or the job is too sloppy; see paragraph above). When IMPAX catches every problem
but seldom stops when nothing is wrong, the tolerance is set properly.
To set the tolerance on a new job, begin with a fairly high number such as 7, 8, or 9. Watch the
job and, if it runs well, set the tolerance lower after each few thousand parts are made. Look at
the force display to see how close the limits have been set. When the IMPAX begins to stop the
machine and no problem is found, ‘back off’ by raising the tolerance setting. Check the force
display occasionally to be sure the force limits are as close as they can be; adjust the tolerance as
needed. Also, check the tolerance display; it may indicate that a different tolerance setting may
be used. (The current variation may change slightly over a time.) These adjustments should be
made slowly, over a period of time.
This option may also be used to learn the settings for a new job. This is helpful if you are busy,
or if the machine has many stations. To use Auto-Tolerance, enter a * instead of a number when
setting up the tolerances for the job (see Chapter 3). IMPAX will automatically adjust the limits
on that station. The tolerance information display will then show the equivalent tolerance which
has been set, for instance; “CHANNEL 1 *(5)” would mean that, for Channel 1, Auto-Tolerance
has set a tolerance level equal to 5 on the scale from 1 to 9.