CTG Six Sigma Project.pdf - Chemtool

CTG Six Sigma Project

PURPOSE / DISCUSSION
• The purpose of the study was to follow-up of the trial of
Nusol 177-M cupper lube at a typical can-making plant
as part of a Six Sigma study to reduce tear-offs. The
tear of rates, while statistically reduced, did not show the
major improvements seen at other locations.
• The overall average T/O rate for a seven day time period
(3/22 - 3/28/07) that the plant has experienced (both
cuppers converted) running Chemtool 177M is
0.128/10M.
• The seven day T/O rate prior to the start of this trial (3/13
- 3/19/07) was 0.147/10M.
• At this point, the Chemtool product does show
statistically valid improvement in T/O rates with an
overall 12.5% reduction for the two time periods (see the
Two Proportions Analysis below).

Test and CI for Two Proportions
(C1A vs. 177M)
• Sample X N Sample p
• C1A 758 52348754 0.0000147
• 177M 648 50466446 0.0000128
• Difference = p (1) - p (2)
• Estimate for difference: 1.639595E-06
• 95% lower bound for difference:
4.409649E-07

Test for difference = 0 (vs > 0): Z =
2.25 P-Value = 0.012
• It appears that the cup conveyor mat is a major factor in
the MEMP tear-offs. When either line backs up, cups
accumulate in ‘dead spots’ on the cup conveyor, and the
conveyor continues to run. This leads to a situation
where the cup lube can be physically removed from the
cup exterior. The plant confirms that when there are
extended down periods (1-2 hours), they dump the cups
(6000 cans) rather than fight the F/E issues. This ‘root
cause’ naturally affects product performance as well.
Cupper 2 appears to have more inherent issues than
Cupper 1 (missing cup elevator pins, heel dents, lower
cup lube weights), yet consistently has better tear-off
performance. This appears to be due to more consistent
running, with fewer back-ups. The 12 B/Ms of line 2 (vs.
10 on line 1) contribute to more consistent running as
well.

The corrective action(s) would
appear to be as follows:
• Variable speed cup conveyor drives
• Sensors to modulate drives
• Auto-stop the cup conveyors on back-ups

Corrective Action Discussion
• These steps were reviewed with plant personnel, and
they indicated that corrective action would occur. Given
the plant’s excellent TO rate, this will likely reduce them
into single digits per million cans, even with the current
product. Chemtool would expect to reduce that number
even further, as has occurred at other locations, and
pointed that out.
• Some additional issues were raised, including
“instability” in tramp levels and pH, inconsistent cup lube
weights, and possible issues with can top wall
concentricity. Excellent cooperation with Corporate Six
Sigma provided the plant with “data driven” answers to
everything as follows:

Cup Lube Weights
• The data summaries below indicate that the cup
lube weights were actually more consistent
during the NuSol 177-M trial than previously with
the competitive product on line. Chemtool
identified major variations to the plant during the
trial that led to solenoids being replaced on both
Applicoaters, as well as a situation on cupper 1
where the wick was not touching the bottom of
the coil (exterior of the cup). These corrective
actions certainly contributed to the improved
consistency in the cup lube weights across the
width of the cupper during the trial.

Cup Lube Weights (cont.)
Cupper 1 - Overall Comparison
Lube Mean StDev Minimum Maximum Range
177M 15.631 3.488 6 26 20
C1A 13.714 4.261 -12 20 32
Cupper 2 - Overall Comparison
Lube Mean StDev Minimum Maximum Range
177M 16.167 2.924 8 27 19
C1A 15 3.383 8 27 19

Coolant pH
• Coolant pH increased to closer to 9.0 (avg)
during the trial, which is difficult to rationalize as
NuSol 177-M related (pH @ 20%
concentration8.1-8.6). It should be noted the
plant was running ‘trial’ Arco aluminum during
this period, so some of the issues may be from
that ‘noise’ as well.
• Review of the data with the plant led to the
admission the pH was in fact “more stable and
capable” with NuSol 177-M.

Coolant pH (cont.)

• The table embedded
below shows a
precipitous reduction in %
tramp, simultaneously
with an increase in %
cupper lube (177-M).
Note: The data is from
the plant QC testing. The
same phenomena
anecdotally occurs with
C1 (higher cup lube
weights increase the %
cupper lube in the
system, and the tramp oil
level decreases).
Tramp Level

Coolant Sample Results
• A coolant sample was obtained from the Womack system and sent to the Crystal
Lake laboratory for analysis. Results were:
• Refractive Index FTIR
• % NuSol 177-M 1.4% 2.1%
• % Competitor EP 1.2% 2.3%
• These results are consistent with the fact that no change was made to gear oil usage
(~100 GPD), and that the plant added 80 gallons of Competitor EP to raise the level
based on the QC results.
• The Chemtool analysis uses a ‘salt split’ to separate the oil. The Competitors
procedure uses Seaquest 100 to split the oil. An experiment was run with NuSol 177-
M, Competitor EP, Seaquest 100, and the plants Brix refractometer. This showed the
use of the Seaquest dramatically skewed the readings toward the % cupper lube. A
50:50 tramp:cupper lube mix gave a reading of 70:30 when Seaquest was added.
This same phenomena occurs with C1.

% NuSol® 177-M in Oil Split
% NuSol 177-M in Oil Split (BRIX)
NuSol 177-M = 5.26558 - 0.0652284 Brix
S = 0.0120906 R-Sq = 99.9 % R-Sq(adj) = 99.9 %
1.0
NuSol 177-M
0.5
0.0
65 70 75 80
Brix
NuSol 177-M can easily run in the same ranges as the competitor, and did in
this trial, so keeping the cup weights in a 12-18 mg/cup range should not
cause any future issues with the readings.

Concentricity
• Analysis was done on midwall and topwall
data for 3/13 - 3/19/07 (C1A) and 3/22 -
3/28/07 (177M). The overall variability
(can-to-can) that impacts random spoilage
rather than BM specific concentricity
(within can) that will also impact camera
spoilage but is easily identified. The 2-
variance chart below shows no statistical
difference in the overall variances for
these two time periods.

Connectivity (Cont.)
Looking at the overall descriptive statistics of topwall (below), shows no differences.
MEMP Concentricity Data Summary
Variable Mean TrMean StDev Minimum Maximum Range
C1A 0.006046 0.006045 0.000111 0.0056 0.00646 0.00086
177M 0.006053 0.006053 0.000109 0.00567 0.00644 0.00077
Again the data indicates less variation with NuSol
177-M, and the plant acknowledged that.

SUMMARY
• The plant rejected an Arco “test” coil on the
afternoon of 3/29, and admitted to running ‘new’
Arco plate for a ‘flatness’ issue. In spite of the
trial coil rejection, running a metal having altered
finishing passes, raising tramp levels above the
ideal settings, cup conveying mat issues, the
lower Applicoater injector solenoid falling three
times and a 8.5 hour power failure that yielded a
rash of T/O's upon plant restart, we have still
seen a 12% improvement in T/O rates through
3/28/07, and this will be reflected in the
customer’s Six Sigma report on the trial.