The Decoding of Bar Codes
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The Decoding of Bar Codes
Article Introduction
The industrial sector has recently applied bar coding solutions to the manufacturing, warehousing and distribution of goods. The most recognised use of bar code symbols in industry is for compliance labeling.

Article Description
No one except the computer knows the cost hidden behind the bar code. A bar code is a machine-readable representation of information in a visual format on a surface. Originally barcodes stored data in widths and spacing of printed parallel lines, but now they also come in patterns of dots, concentric circle and hidden in images. Bar codes can be read by optical scanners called barcode readers or scanned from an image by a special software. Barcodes are widely used to implement Auto ID Data Capture (AIDC) systems that improve the speed and accuracy of computer data entry.

Manufacturers shipping labels are often designed to meet the needs of their customers. Retailers operating overseas like Wal-Mart and K-Mart require compliance labels on all incoming packaging. Today, many industry groups like AIAG (Automotive Industry Action Group), EIA (Electronic Industries Association), or regulatory/safety bodies such as DOT (Department of Transportation) and NFPA (National Fire Prevention Association) for the chemical industry have mandated compliance labeling. Compliance requirements are also useful within a manufacturers own facility. Bar codes on compliance labels identify the product serial number, and other important product information. Bar code scanners or data collection terminals read this information and communicate with a computer host that processes the data. Bar code scanning improves the accuracy and the timeliness of the data.

Colloquially, there are two types of manufacturing - discrete and process. Discrete manufacturing like automobile manufacturing relies on a Bill of Materials to identify the large number of specific parts, or subassemblies and their quantities. Process manufacturing like chemical processing is formula-based. It relies on weights and measures (pounds or gallons) of raw ingredients. In both cases, bar coding is used to identify component parts or containers of ingredients, work-in-process, finished goods inventory, and products packaged for shipping. Manufacturing businesses depend on a well-coordinated chain of events to make their operations work effectively. Many companies initiated bar code labeling at the shipping dock to support their customers compliance requirements. Todays business software packages like Enterprise Resource Planning (ERP) solutions from SAP, JD Edwards or Baan, depend on bar coding and data collection systems to provide information crucial to the entire manufacturing operation. As more companies turn to enterprise-wide software for process improvement and cost reduction, there is a significant opportunity to help these companies add bar coding throughout the manufacturing facilities.

Step-by-step approach..
After a company zeroes down on bar coding for its facilities, in comes the need to explain how and why bar coding is used.

Step 1: Receiving
Raw materials or sub-assemblies that arrive at a manufacturers receiving dock have bar code labels on their packaging to meet the companys requirements. Otherwise, the receiving department logs in the item and generates a 4" x 6" or smaller bar code label to identify the material, before it is moved to an inventory location or inspection station.

Step 2: Raw material inventory
A warehouse operator transfers the material to an inventory location. These sites often are identified with bar codes printed on reflective labels. The reflective material such as Zebras RetroScan 4000 labels improve readability from fork trucks up to 30 feet away. Bar codes are necessary because the operator scans both the package and the new storage location to complete the transfer operation, and record it in the system.

Step 3: Picking
A work order from the factory floor signals the picking operation to retrieve raw materials, or parts from inventory. The fork truck operator is directed to the exact inventory location where the material is located, and told how many of each part to pick. Bar codes are scanned again to complete the transfer operation. In some cases, inventory labels may need to be updated or corrected in the warehouse to replace damaged labels or to identify a change in quantity. Mobile printers mounted to lift trucks simplify this operation.

Step 4: Work-in-process (WIP)
Picked materials are checked to confirm the right parts, and quantities are picked. Bar codes on each item are scanned for confirmation. As the parts are used in the assembly process, bar codes enable part tracking throughout the process - showing that it was consumed in an assembly, or was set aside due to a defect or other issue. As parts become assemblies, additional bar code labels pertaining to the new part number can be added to identify and track the assembly. In some process manufacturing, bar code labels are used to identify transitions between lots or batches. For example, in paper, film, or coatings manufacturing, splices are required between batches to complete a master roll of material. The splice point is identified with a bar code label that identifies the time and batch number of the new material.

Step 5: Product identification
Thermal transfer printing also is used to print nameplate identification labels on-demand with serial number information and/or UL/CSA regulatory content. Synthetic label materials ensure the durability of the image, and the labels longevity. For electrical products, labels with UL/CSA logos or content are unique because only specific label supplies tested by UL or CSA are approved. More than 300 combinations of Zebra® labels and ribbons are tested and UL/CSA-approved for this purpose. Pre-approved label and ribbon combinations from Zebra can save manufacturers extensive paperwork and product delays when they need a new type of label or one for a new application.

Step 6: Finished Goods
At the completion of the packaged assembly in discrete manufacturing, or the packaging of the product in process manufacturing, bar codes are used to identify the package contents. If no sales order for this product exists, the fork truck operator collects the package and takes it to a finished goods warehouse location for inventory. Bar codes on the product, and at the warehouse location are scanned to complete the transfer operation. A customers sales order signals the picking operation to retrieve the product from finished goods inventory. Thanks to the information retrieved from the bar code, the operator knows the precise inventory location, and picks the inventory for shipping. Bar codes are scanned to confirm if the correct item was picked, and to record the transfer to the shipping department.

Step 7: Shipping
The bar code on the package is scanned in the shipping department to acknowledge receipt. New labels are printed with shipping information. These labels are typically 4"x6" paper labels with customer, or carrier-specific compliance formats. Compliance formats may include 2D symbols such as PDF-417 found in the latest GM 1724A Compliance Label Mandate, or UPS Maxicode. If a number of labeled packages are combined on a pallet and shrink-wrapped, a larger, master label is often required for the pallet. Paper labels are commonly used for these applications, but synthetic master labels should be specified if the shrink-wrapping is recyclable (such as Zebra PolyO™ 2000). Other regulatory or environmental requirements may impact the label format and content, or the label materials. Local and federal US Department of Transportation (DOT) and National Fire Protection Association (NFPA) regulations, for example, mandate the labeling of chemical packaging and containers used in transportation. Although many of these labels contain fixed information, and on-demand, thermal transfer printing on to it, preprinted label materials can provide a substantial cost savings by reducing the storage of expensive label inventory and waste that occurs when adhesive degrade. Technology because of the initial investment required.
Posted : 10/21/2005

The Decoding of Bar Codes