Machine Vision, RFID Technologies Combine to Meet Tracking, Tracing Challenges
Applying tracking and tracing technologies as part of manufacturing and supply chain operations provides the full range of functions companies need to ensure product safety, alleviate product liability, and promote product value.
By Control Engineering Staff
Handling the rigors of tracking and tracing products and parts is easier today thanks to the combined benefits of machine vision and RFID systems. The need to “serialize” items with unique identifiers during production and throughout the supply chain presents an ever-growing and ever-more-critical challenge to manufacturers. Applying these technologies, however, provides the full range of functions companies need to ensure product safety, alleviate product liability, and promote product value—the critical factors driving tracking and tracing initiatives.
The value of these technologies is best illustrated through two applications, one from the pharmaceuticals industry, the other from the military/defense world. In the pharmaceutical industry, there is widespread and growing concern about drug counterfeiting and drug diversion (using drugs for other than their intended purposes, including illegal distribution). “The Internet,” observes Siemens’ Machine Vision Specialist Randy Kemmerer, “has made just about every drug imaginable available worldwide. Some estimates say that 40% to 50% of these drugs are not even real. It is one of the reasons the [U.S.] Food and Drug Administration (FDA) and some states are mandating that drugs be serialized.”
Enhancing drug safety
The tracking requirements state that every “saleable” unit of medication—the smallest unit that can be sold to the distribution channel—must have a serial number, typically in the form of a Datamatrix code, associated with it. This identification system is not a per-pill requirement; it refers to the lot size that a pharmacist would typically receive in a shipment. “Pill level,” explains Kemmerer, “is called the unit dose level. We have not reached that point yet. That would involve marking every pill and the technology is just not there yet. But one day it will be. Marking saleable units is a place to start.”
Tracking and tracing directives in the pharmaceutical industry are referred to as ePedigree laws. Attaching a serial number to each saleable lot allows a significant amount of information to be associated with it. Looking up that serial number reveals where a saleable unit was manufactured, by whom, all the places at which it changed hands, and where it went into the distribution channel. At present, the database is being maintained by a cooperative called EPC Global (electronic product code). Details are yet to be worked out, but plans include developing a repository funded by various industry participants.
Although steps are being taken to address them, serious privacy and HIPAA regulation concerns do exist, especially if compiled drug information can be tied to a specific patient. Despite these drawbacks, however, the benefits are enormous. If a saleable unit is counterfeit, no accurate data would be available, thanks in large part to the combined impact of machine vision and RFID technologies. A case of legitimate drugs would be fitted with an RFID tag to give it an identification number and associated information, while all the items in it—for example, each bottle—would carry a machine-vision-readable code. Repository data would reveal which bottles were in which case, and subsequently each case can be linked to the pallet it was on or the batch from which it came. The term “pedigree” is drawn from this ability to trace the relationship of a drug to its origins.
The goal, of course, is to discourage counterfeiting and diversion. Without an ancestry, counterfeit drugs would be easier to spot and uncover. Although security breaches are always an issue, proponents believe a system operated with due diligence would establish an extensive and secure protective net. Adds Siemens’ Kemmerer, “States and the regulatory bodies look at these situations from the standpoint of‘Is public health and safety better served by having this tracking and tracing system in place?’ In this case, the answer is ‘yes.’”
Accounting for inventory
The U.S. Department of Defense provides another example of using machine-vision-readable codes and RFID tags to track and trace product. Its UID (universal identification) program was initiated after the government encountered problems with unaccounted inventory during the first Gulf War. For instance, a unit in need of an automotive part would have it shipped from the United States when a unit a hundred yards away unknowingly had six of the needed parts. The question became: “Where is our inventory and how can we procure it quickly?” Under wartime conditions, these circumstances become even more critical.
As a result, the DOD created a system that requires any item worth more than $5,000 or deemed “mission critical,” have a UID associated with it. The number is applied as a two-dimensional Datamatrix code; its associated information is stored in a DOD-maintained database. As items move through their lives and through the supply chain, they can be tracked and traced. As parts are palletized, an RFID tag is affixed to each pallet so that it can be tracked. Once again, combining the two technologies provides full and comprehensive tracking and traceability.
Assessing the benefits
The global concept of track and trace—the process ofits are significant and diverse. In the first case, the reduction of drug counterfeiting and diversion protects the public health. In the second, inventory tracking heightens efficiency and reduces costs. Although there are security concerns in both situations, all parties believe the greater good is served through such systems.
Track-and-trace is expected to extend into other industries and to spread around the world. Track-and-trace concepts already exist in the European Union, and although not as much activity is underway in Asia yet, it is expected to follow suit in the future. Similarly, moves are underway to launch serialization systems for other industries—for example, spice manufacturing, which harbors significant product liability potential. This and other industries are recognizing the inherent benefit of knowing where product is and how it is being used at all times. Most industries see the advantage of policing themselves.
Tracking and tracing doesn’t always start with the finished product. Many times, it must begin with the raw materials. In some cases, companies may be called on to trace products back to raw ingredients. Indeed, recalls are more easily managed if the offending ingredients can be unquestionably isolated. In the area of RFID technology, points out Ed Housler, Siemens Factory Sensors Business Manager, “we see a lot of interest in tracking internal supply chain logistics to help ensure that what manufacturers are sending customers as finished goods are indeed what the customer has actually purchased and that they meets the specifications. RFID technology is useful for that level of quality assurance.”
The automotive industry provides an excellent example. During final assembly of a product as complicated as a car, it is critical that correct accessories and components come together as planned. “When incorrect parts are put in,” adds Housler, “especially if they are not caught until the car is completed, the cost of re-work is huge. Errors, if they are going to occur, need to be caught as early as possible. Tracking and tracing all components through machine vision and RFID technologies can help error-proof the operation so that such problems don’t happen at all.”
Bringing it all together
RFID and machine vision technologies are critical elements to the tracking and traceability process of applying and verifying serial numbers. Each has its advantages and are designed and intended to complement each other.
Small, durable Datamatrix machine vision codes can be etched directly on all kinds of items and surfaces. Redundancy (error correction) is built into them so that machine vision systems can read even partially damaged codes accurately. In some cases, one product might contain both a Datamatrix code and an RFID tag having the same serial number. The two technologies can then, in some ways, cross check each other. RFID does not require line-of-sight; it operates using radio waves. Thus it is more viable with pallet operations. When the Datamatrix product codes are covered by packaging, RFID tags can still be read.
The product serialization systems that make up tracking and tracing bring manufacturers advantages beyond what is required by regulation. It not only increases product safety and reduces product liability, but provides the added value of knowing where and how products are flowing through the supply chain.
Combing the well-proven, mature technologies of machine vision and RFID is all about validation, about making visible the factory floor, the warehouse, the distribution center, and the retail store to show where product is, where it came from, and the attributes that were added. At the end of the day, data from both systems can be gathered for analysis and review by a higher-level information system, bringing full circle the comprehensive methodology that ensures that the product made, ordered, bought, and consumed is what was intended—accurate, high-quality, and genuine.
To read more about machine vision's role in industrial tracking and tracing, click here ; to read about the use of smart cameras in machine vision applications, click here .
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