|Injection molded polypropylene switch plates are placed on the start of the conveyor manually.|
If you're a molder who slaps barcodes on your injection molded products, you know that customers are getting pickier and pickier about their readability. GE was finding that out the hard way, thanks to a 20-year-old packaging system operating in its AcuÃ±a, Mexico plant.
In AcuÃ±a, just across the Rio Grande River from Del Rio, TX, GE molds wall plates for electric outlets; the company produces about 100 varieties with different outlet holes, screw holes, colors, and other variations. Packaging efficiency is a must, as each variety must be labeled and barcoded differently than the others. The 20-year-old packaging system had become sensitive with age, requiring delicate adjustments with every package change. Even when operating at peak levels, the old system could package no more than 40 items per minute. An added problem was that label readability for each product was not assured. This created the risk that a product might be shipped to a customer wearing an imperfect barcode.
To bring itself up to speed, GE turned to Columbia Labeling Machinery (Danielson, CT) and the CPA-250, a computer-controlled label printer/applicator. The device uses a DOS/Windows-based system to store part numbers and the barcode information that will appear on the labels.As parts change, the operator simply calls up the part number on the computer and the CPA-250 shifts gears to apply the correct barcode. Columbia says it takes about an hour to train operators to use the software and only a few minutes to learn to enter new part numbers.
The machine operates in direct thermal, or thermal transfer mode. Labels up to 4.5 by 10 inches can be printed and applied. Other variable options include formats, fonts, and character lengths. You can even apply a logo or label in a non-English language.
On-the-fly changeovers aside, what attracted GE was the machine's quickness: 100 labels per minute, 6000 per hour (although higher speeds have been recorded). At AcuÃ±a the machine routinely runs at about 80 labels per minute, 4800 per hourâthat's twice as fast as the 20-year-old machine.
|As the switch plates pass beneath it from right to left, the CPA-250 prints barcode and alphanumeric information, blows the cut label onto wrapped switch plates, and scans the barcode for legibility and accuracy.|
GE was also impressed by the fact that the CPA-250 actually does its own quality assurance. After a label is applied to each part, it passes through an optical scanner similar to those found in your local grocery store. If that scanner cannot read the labelâbecause of a crease or other flaw in the paper stock, for exampleâa blast of compressed air blows the offending part off the conveyor into a hamper beside the line. With this system, GE guarantees that every outlet cover that leaves the AcuÃ±a plant is scannable. Offending parts are re-fed through the labeler by hand before being sent out.
At the AcuÃ±a plant, outlet plates come off the press and are wrapped with mounting screws in polypropylene film. They then pass through a heat tunnel to shrink wrap the film before they go to the labeler. Labels at the AcuÃ±a plant are .875 by 1.875 inches and consist of an eight-character stock identity code and a five-character part description. The pressure-sensitive self-adhesive labels are applied to the outlet covers by a blast of compressed air to allow for consistent application, even on rough or uneven surfaces. GE reports that the CP-250 applies labels to an accuracy within .0625 inch.
As a result of this increased speed and automation, GE reduced the number of workers per shift on the labeler from seven with the old machine to five with the new; GE also reduced the shifts on the labeler from three to two. Based on the savings in labor and increased efficiencies, GE says it expects the labeler to pay for itself within two years. The CPA-250 was installed in AcuÃ±a in April 1995.
If you're in the market for a complete automatic packaging system, be prepared to spend $50,000 to $80,000, of which $15,000 would get you the CPA-250âits printer/applicator, the computer, and the barcode tester. Prices vary depending upon configuration.