Resources

By David P. Tryling
July, 2008

The United States is all about capitalism. Capitalism depends on and is based on buying and selling in an open and free market. For better or worse, we are a society of consumers. Long gone are the days where you could go into a local grocery store, walk up to the counter and discuss with a clerk exactly which product you wanted and how much of it you needed. Now everything in retail is about prepackaged items. Marketing and sales strategies are based on getting consumers interested in purchasing these prepackaged items. This makes the way they are packaged and the cost of their packaging very important to a manufacturer. Because there are so many consumers there are large quantities of products being manufactured and delivered to our local stores through a myriad of distribution processes. How do manufacturers and retailers keep track of all of these products? How does a manufacturer know how many different kinds of things it produces and the quantities of each type?

Certainly each manufacturer has part numbers or item numbers or some other method of identifying the types of products that they have. But in high speed manufacturing processes, reading numbers and characters is a very slow and cumbersome process and until recently, was difficult even for electronic devices to do. Hence the birth of barcoding.

How It Works

Barcoding can look confusing on the surface – an array of lines and spaces that appear indecipherable but the very basics of barcode are extremely simple. It’s all about the width of the black bar and the width of the white space. These varying sizes can be put together in groups to represent a sum of information which will relate to a specific character in the character set. The difference in the codes then becomes the range of the sizing, the number of groupings put together and how the groupings are linked. The barcode scanner or reader passes a laser light across the code. It receives back more (from the white spaces) or less (from the black bars) reflected light as the laser passes across the code. As this light increases or decreases, the timing determines the length and width of the bars and spaces. The scanner then interprets this and decodes it into various groupings of numbers. Because this is a laser process, it is extremely fast.

Scanners

There are many types of scanners. The scanners you see in the grocery store send laser arrays from multiple directions. These arrays are “waiting” to find a readable barcode. They are set up so that as you pass a product over the counter, one of the lasers will likely encounter the code and successfully decode it. Scanners used in manufacturing are more unidirectional. Usually they send out a single laser array, which is aligned toward a specific location on a carton, package or product as it is passing down an assembly line or through a packaging area. While we may think of the grocery store scanners as fast, their industrial brothers can be significantly faster. This is mainly based in their processing time.

Barcode Types

There are a number of different kinds of barcodes. These have evolved over time for various needs, although probably the most prevalent type and the one that you see most often in the store is called the UPC (Universal Product Code). The UPC has been used in retail since 1973. The product code not only allows for the identification of the product but also the manufacturer. While there are variations of the UPC, there are mainly just two versions that are in widespread use, Version A and Version E with the most common being Version A. An example of a Version A UPC code is below. The code is divided into sections. The first digit defines the use of the code, the next five digits define a manufacturer number. This manufacturer number is assigned by the Uniform Code Council or the UCC. Following the manufacturer number are five digits for the product code from the manufacturer. And finally, a checksum digit is established on the end to assist in error detection as the code is read. By using this system, any registered manufacturer of a product can apply UPC coding to their product and work within the universal supply chain.

While UPC is prevalent in retailing, there are a number of other codes used throughout manufacturing for other purposes such as tracking and quality control. These codes are structured differently from UPC with the government and military applications as some of the driving forces behind these code formats. Below is an example of Code 128 which allows for full use of the 128 character ASCII set. Code 128 is prevalent in many manufacturing applications because it has no restriction on the number of characters permitted in each barcode symbol.

Next is an example of Code 39. This code is also referred to as Code 3 of 9 or sometimes Code 3 from 9. This is a discreet code, meaning that there is a fixed pattern of bars and spaces to represent each character available in the code specification. Each character has five black bars and four white bars in a particular spacing pattern. Code 39 has a total of 43 characters supported and only uppercase characters are used in this code set.

Now that you have the very beginning of the basics, the logical question is how you might translate this into an application on one of the machines in your facility or how you might suggest this to one of your customers. You might want to follow the following five steps.

  1. Determine the type of barcode. More than likely, but depending on the type of the product, barcoding may already be implemented somewhere else in the process and if so, you will need to establish what that barcode is. However, if there is no barcode already being used in the facility, choose one that fits your application best. A true UPC code will require some registration, but a Code 128 or 39 can be applied within your organization however you wish.
  2. Determine the application method. Are you going to print a barcode label and apply it to the product? Are you going to print the barcode directly onto the product? There are various options for each choice all with pluses and minuses depending on your product.
  3. Determine how fast your process is. Remember, you not only have to decide what the barcode is and where it goes, but what will read it and what will handle the code number data on the product. This will involve PLC’s, computers, printers and other hardware. The requirements will be significantly different if you’re going to do one product per minute or 400 products per minute.
  4. Establish your data strategy. What is the structure of your barcode numbering system? What does it mean within your organization? How are you going to use it? How are you going to store it? How are you going to convey the information to the rest of the organization?
  5. Do a little testing. Before you run headlong into a full-blown barcoding project, test a few samples. This gives you the opportunity to work out both the data end and the scanner end of the barcoding.

Product identification is extremely important, both in retail and in manufacturing. But for manufacturers, the use of product tracking information is expanding as continuing pressure for efficiency in the manufacturing process require more and more process data. Tracking products through the process and ultimately the growing importance of traceability in the supply chain continue to drive the expanding use of barcodes and other tracking methodology.