
Why AgMon? What's the Difference?
______AgMon
is a program that makes use of statistics to project
changes in the gradation of your aggregate products. It
differs from other programs in this category in several
important ways.
______First,
since you already note the percent passing for
all
of
the screens, AgMon reports the results for
all
of
the screens. This is instead of requiring you to select
so-called key screens to represent the entire product. Less
guesswork is good.
______Second,
it computes the independent probability that each screen is
in spec and then uses those probabilities to estimate the
likelihood that the next load from your stockpile, or the
next sample from your belt, will be in spec.
______Third,
AgMon serves as your QA log. You enter the test and
identification info, and AgMon prepares the log sheet which
you may, if you wish, print and put in a binder for
reference or review.
______Fourth,
it prepares process control charts for all of the screens,
with one-button ease. In addition, it prepares a composite
control chart as a visual summary. These are also readily
printed or transmitted by email.
______Fifth,
it allows you to print customer reports for faxing, or pdf
format reports that you can email. You care about this
because better informed customers can make better
decisions, which makes customers that are happier with you
and your products.
______Is
that enough? There are a few other things listed later
under "Special Features" which both your QA and QC people
may find interesting. (The
download link for the AgMon demo is at the bottom of the
page.)
How it works
______This
can be divided into two groups: the stuff you see, and
the stuff you don't see. Except for a small comment on
the math, we'll focus on the stuff you can see.
______One
of the first things you'll notice is that entering the
data is very similar to entering the data on a paper QA
form. But it's easier. Your tech doesn't have to do the
calculations, eliminating one major source of mistakes.
Also, the electronic form is more secure because you
can backup thousands on a single CD, and store it off
site. Fire at the office? You still have your data; ten
thousand test results on a ten cent piece of plastic.
If you take advantage of the backup features, your data
will survive things that could destroy your building.
______We
are not yet decided on this, but are considering
whether to offer on-line backup options, so you don't
even have to burn the occasional CD. If we do this, it
will be added as a one-click feature in the program.
______Your
technician starts using AgMon the moment the first test
result is available. When he finishes with one
aggregate type, the statistics can be run, emailed to
the production personnel who control your production
process so they can see, very quickly, what the current
trends are and make tweaks to keep the production as
near to the center of the specified gradation as
practical. Of course, nearer to the center means that
you stand a lower risk of product hitting the stockpile
out of spec. If your QA technician notes an alarming
abrupt change, the email can and should be backed up by
a telephone call.
______In
addition to the usual mean-based analysis of sample
results, AgMon-8 allows you to click once to see
trends, visually, on a sieve by sieve basis; and to
click again to see an estimate of the composition of
your "well-rolled" pile. (The first was also done by
AgMon versions 1.0 through 1.10 and is well
established.)
A Little Math Stuff
______The
trend analysis performed by AgMon is adapted from
standard techniques. (If you want to read more about
it, go to the National Institute of Standards and
Technology web site, math
section, for a
thorough discussion.) The mean line is determined by
a conventional "best fit" approach. The Standard
Deviation about the mean line is estimated to equal
the SD about the ordinary mean. When the slope is
small - as in a well controlled process - the error
is trivial and conservative. When the slope is
large, the error increases somewhat, but it doesn't
matter because your process is clearly out of
control.
______This
analysis estimates the probability that your next
sample, for each screen, will be "in spec." Then,
making the conservative assumption of statistical
independence, the program computes the probability that
the next sample will be in spec for the entire
gradation.
______Estimates
made by statistical methods are just that, estimates.
Estimates made by AgMon are slightly conservative
within the range where calculations are useful. If your
goal is 96% across the board gradation spec compliance,
and AgMon reports that you are achieving this level,
you are actually doing slightly better than indicated.
If your process is poorly controlled, AgMon will return
estimates that are progressively more conservative.
That is, if you are actually running at 80% compliance,
AgMon may report 70%. If you are running at 50%
compliance, AgMon may report 30%. Considering how AgMon
is used illustrates the insignificance of this sort of
error. When your process is in good control, the more
accurate estimates allow you to fine tune, and to
exercise control proactively. When your process is
badly out of control, your interest is in the direction
you must shift the results. Fine tuning is not very
important when the house is on fire.
Click here
to download the AgMon demo
file.
Click here
to purchase
AgMon-8.
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