'On-the-fly' can line checking.
Columbia Beverage Co., Tumwater, WA, is a cooperative owned by 9 members, including packers of Pepsi-Cola, Seven-Up, Dr. Pepper, Squirt, and A&W. To achieve optimum filling efficiency and container integrity, canning operations require periodic checking of can seams and fill levels.
At Columbia, an operator would stop the canning line once every two hours to remove and identify one can from each seamer head in order. Inspection staff needed to know which can was filled by each valve and closed by each seamer head in order to pinpoint problem sources and make necessary corrections. Each line stop translated to about 15 minutes downtime, and each sample can seam analysis took about 45 minutes.
As can-line speeds increased at Columbia Beverage, line shut downs to take off checking samples became even more significant in terms of lost production. To deal with this difficulty, management decided to initiate improvements to upgrade the two existing canning lines.
The company installed a can-line control system that monitors and precisely controls filling and seaming functions and eliminates the downtime previously required for pulling samples for QC inspection.
The system automatically removes a string of cans, starting at seamer head or filler valve No.1, while running at production speed (1050 cpm). The data is accumulated by a single, multi-function electronic inspection head and accessed through an industrial-hardened video monitor with touch-screen.
The system also monitors and tracks the performance of each filler valve for under- and overfills. As needed, the production supervisor or QC technician can bring up screens that show which valves are trending out of adjustment. If even a single valve is trending over- or under-tolerance, the technician can punch in the valve number and get its individual performance record. Adjustments are made on the specific out-of-range valves.
The system provides three pieces of information for each valve: number of underfills from that valve, average performance, and variance in fill accuracy. This data is useful in alerting machine maintenance personnel when a single valve needs overhauled. If the average fill level for all fill valves shows excess variance, the yearly filler teardown-rebuild process is scheduled accordingly.
An automatic shutdown feature nips can line fill or foamer problems in the bud. When 6 underfills are detected in sequence, the line shuts down, thus preventing a longer string of bad fills before the operator reaches the machine.
Time is saved, and opportunities for human errors reduced. Downtime to pull can samples has been eliminated. Likewise, downtime due to filler or seamer performance problems has been minimized, as these problems can be detected and corrected before they get out of hand.
Continual line-efficiency monitoring homes in on individual valve and head malfunctions, vastly increasing overall line performance ratings. Adjustment of every filler valve and seamer head is kept closely in range, hour by hour. A production summary report with trend graphs is printed out daily.
An additional intrinsic bonus of on-the-fly sampling is that it alleviates wear-and-tear shock on the canning equipment. Subtle problems increase when sophisticated machinery starts and stops unnecessarily.
Push-button can seam analysis
Close monitoring of can seam dimension accuracy has become more critical as line speeds have increased and metal can sidewall structures have become thinner. Manual measuring is too slow and inaccurate. Hand positioning and tightening of each individual micrometer setting leads to inconsistent data from one to another operator. Micrometers are accurate to .001". However, manual operating influences blur that accuracy--within a .002" band. In contrast, electronic probes are precise to .00001".
In the Columbia Beverage QC lab, a computerized seam control system now is used in place of laborious can strip-down and time-consuming manual recording of a 6 measurements per can.
With the computerized system, the precise measurements remain consistent regardless of the operator. Each can is exactly positioned in a fixture and measured for seam height, thickness, countersink depth, body hook, overlap, cover hook, and tightness. Dozens more cans can be measured and evaluated per day than before. Data entry is by push-button. Hand-plotting is eliminated. Software does it better.
The software analysis package generates trend data that accurately exposes even the subtlest inconsistencies such as 1) seaming head setting changes which may occur over time, and 2) tooling weardown which also occurs over time. Likewise, any head that goes wildly out of range is quickly pinpointed for immediate attention.
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|Title Annotation:||includes related article; replaces manual inspection at Columbia Beverage Co.|
|Date:||Aug 1, 1992|
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