Which RFID Technology is Best for Your Traceability Application?

There are a lot of articles on using RFID for traceability, but it’s hard to know where to begin. Examples of traceability include locating an important asset like a specific mold that is required to run a machine or verifying a specific bin of material required to run production. Spending time looking for these important assets leads to lost time and production delays. RFID can help but understanding the different RFID capabilities will narrow down the type of RFID that is required.

Not all RFID technology is the same. Each RFID technology operates differently and is categorized by the frequency band of the radio spectrum, such as low frequency, high frequency and ultra-high frequency. In low and high frequency RFID, the read range between RFID tag and reader antenna is measured in millimeters and inches. The read range on ultra-high frequency (UHF) RFID technology can range from one meter to 100 meters. Typically, inventory traceability is done using ultra-high frequency band of the radio frequency spectrum, due to the need to read the asset at a further distance so it does not interfere with the production flow. Also, there are cases where there needs to be a reading of multiple tags in an area at the same time to determine where an asset is located. UHF RFID technology allows for simultaneous reading of multiple RFID tags from a single antenna reader.

There are two types of UHF RFID, passive and active.  Passive UHF RFID means that the RFID tags themselves have no additional power source. The UHF reader antenna sends out an electromagnetic wave field, and the RFID tags within the electromagnetic field have an internal antenna that receives the energy which activates the integrated circuit inside the tag to reflect the signals back to start communicating. The read distance between the passive RFID tag and antenna reader is determined by several factors, such as the size of the electromagnetic wave field generated out of the reader antenna and the size of the receiver antenna on the RFID tag. Typical read ranges on passive UHF systems can be anywhere from one to 12 meters, where the larger the power and RFID tag, the longer the range.

Active UHF RFID systems do not require the tag to reflect signals back to communicate because the active RFID tag has its own transmitter and internal battery source. Because of this, with active UFH RFID you can get read ranges of up to 100 meters. There are active tags which wake up and communicate when they receive a radio signal from a reader antenna, while others are beacons which emit a signal at a pre-set interval. Beacon active tags can locate in real time the location of the asset that the RFID tag is attached to. However, a downfall to active RFID tags is the battery life on the tag. If the battery is dead, then the asset will no longer be visible.

Figure 1

Once the strengths and weaknesses of each type of UHF RFID system is known, it’s easier to work with the constraints of the system. For example, the application in Figure 1 shows a reader antenna for reading bins of material placed a few feet away so that its’ not in the way of production. A passive UHF RFID system will work in this case, due to the distance between the antenna and the RFID tag on the bin a few feet away. There is no need to worry about battery life on the passive RFID tag.

Figure 2

If the exact location of a production mold is required in a large facility, then using an active UHF RFID system is likely a better fit. Incorporating an active RFID tag that sends out a beacon at a fixed interval to a data center ensures the location of all assets are always known. With this setup, the exact location of the mold can be found at any time in the facility.

Examining the different types of RFID technology can help determine the correct one to use in a traceability application. This includes analyzing the pros and cons of each technology and seeing which one is the best fit for the application.

Using Long-Range RFID for Metal Stamping Die Identification

Using incorrect dies for metal stamping operations can result in lost time and production as well as severe damage to the presses and a risk to human lives.

In recent years, there was a case where the use of the incorrect die caused catastrophic press damage resulting in significant downtime and, because the press was so large, it had to be cut up before it could be removed and replaced. These types of occurrences can prove disastrous to the survival of a company.

When not in use, dies are generally stored in specified storage areas. Often, the die is in the wrong place, and the crane operator needs to know what he/she is retrieving for the next process in the correct die.

To help ensure that these types of errors do not occur, some manufacturers use long-range UHF RFID technology. This can ensure that the correct dies are chosen when they are staged outside of a press. And with handheld devices, it can help the operator find the correct die in storage if it has been misplaced.

Since long-range UHF RFID technology allows the verification of the correct dies from as little as one foot away to as far as several meters, it can be used in both large and small stamping presses. The long-range allows the reader antennas to be placed in strategic locations where the correct readings will be possible but in positions where they will not be damaged by the operation of the press and dies.

I recently assisted with a metal stamping operation that first brought this idea to my attention. This manufacturer was having the problem of the wrong dies being staged for installation into the press. So far, none of the dies had made it past the staging area and into the press. Still, the possibility of that happening was clearly present, and they were experiencing lost production due to having to remove the incorrect die and find the correct one.

The manufacturer wanted to interlock the press so that if the incorrect dies were not in place, the machine would not be able to run. He also wanted to know ahead of time of a wrong die so that it could be replaced promptly to not impact production.

The solution we developed was to place multiple reader antennas at multiple staging locations at the press and interlock the RFID reads with the PLC that controlled the press.

Additionally, he incorporated handheld readers to help find misplaced dies in the storage area.

This solution required testing and tuning of the UHF RFID system to ensure that all die RFID tags were being read when the dies were staged. But once this was completed, it proved to work effectively and reduce the errors and downtime.

It should be noted that due to the physics of UHF RFID technology versus other types of RFID technology, implementing long-range UHF RFID systems in any application should be preceded by a feasibility study that tests the system in the real world environment of the plant.

RFID Minimizes Errors, Downtime During Format Change

Today’s consumer packaged goods (CPG) market is driving the need for greater agility and flexibility in packaging machinery. Shorter, more customized runs create more frequent machine changeover. Consequently, reducing planned and unplanned downtime at changeover is one of the key challenges CPG companies are working to improve.

In an earlier post, I discussed operator guided changeover for reducing time and errors associated with parts that must be repositioned during format change.

In this post, I will discuss how machine builders and end users are realizing the benefits of automated identification and validation of mechanical change parts.

In certain machines, there are parts that must be changed as part of a format change procedure. For example, cartoning machines could have 20-30 change parts that must be removed and replaced during this procedure.

This can be a time consuming and error-prone process. Operators can forget to change a part or install the wrong part, which causes downtime during the startup process while the error is located and corrected. In the worst scenarios, machines can crash if incorrect parts are left in the machine causing machine damage and significant additional downtime.

To prevent these mistakes, CPG companies have embraced RFID as a way to identify change parts and validate that the correct parts have been installed in the machine prior to startup. By doing so, these companies have reduced downtime that can be caused by mistakes. It has also helped them train new operators on changeover procedures as the risk of making a mistake is significantly reduced.

Selecting the correct system

When looking to add RFID for change part validation, the number of change parts that need to be identified and validated is a key consideration. RFID operating on the 13.56 MHz (HF) frequency has proven to be very reliable in these applications. The read range between a read head and tag is virtually guaranteed in a proper installation. However, a read head can read only a single tag, so an installation could need a high number of read heads on a machine with a lot of change parts.

1

It is also possible to use the 900 MHz (UHF) frequency for change part ID. This allows a single head to read multiple tags at once. This can be more challenging to implement, as UHF is more susceptible to environmental factors when determining read range and guaranteeing consistent readability. With testing and planning, UHF has been successfully and reliably implemented on packaging machines.

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Available mounting space and environmental conditions should also be taken into consideration when selecting the correct devices. RFID readers and tags with enhanced IP ratings are available for washdown harsh environmental conditions. Additionally, there are a wide range of RFID read head and tag form factors and sizes to accommodate different sized machines and change parts.

 

 

Manufacturers Track Goods, Reduce Errors, Decrease Workload with RFID

More and more, retailer sellers are starting to require that manufacturers place RFID tags on their products before they leave the production facility and are shipped to those retail locations. From high-end electronics all the way down to socks and underwear are being tagged.

These tags are normally supplied by the retailer or through a contracted third party. Typically disposable UHF paper tags, they are only printed with a TID number and a unique EPC that may or may not correspond to the UPC and barcode that was used in the past. Most cases I have seen require that the UPC and a barcode be printed on these RFID tags so there is information available to the human eye and a barcode scanner when used.

While this is being asked for by the retailers, manufacturers can use these tags to their own advantage to track what products are going out to their shipping departments and in what quantities. This eliminates human error in the tracking process, something that has been a problem in the past, while also reducing workload as boxes of finished goods no longer must be opened, counted and inspected for accuracy.

A well-designed RFID portal for these items to pass through can scan for quantities and variances in types of items in boxes as they pass through the portal. Boxes that do not pass the scan criteria are then directed off to another area for rework and reevaluation. Using human inspection for just the boxes that do not pass the RFID scan greatly reduces the labor effort and expedites the shipping process.

I recently assisted with a manufacturer in the garment industry who was having to tag his garments for a major retailer with RFID tags that had the UPC and a barcode printed on them. The tags were supplied through the retailer and the EPCs on the tags were quite different then the UPC numbers printed on them.

The manufacturer wanted to know how many garments of each type were in each box. Testing showed that this could be done by creating a check point on his conveyor system and placing UHF RFID antennas in appropriate locations to ensure that all the garments in the box were detected and identified.

In this case, the manufacturer wanted was a simple stand-alone system that would display a count of different types of garments. An operator reviewed the results on a display and decided based on the results whether to accept the box and let the conveyor forward it to shipping or reject it and divert it to another conveyor line for inspection and adjustment.

While this system proved to be relatively simple and inexpensive, it satisfied the desires of the manufacturer. It is, however, possible to connect an RFID inspection station to a manufacturing information system that would know what to expect in each box and could automatically accept or reject boxes based on the results of the scans without human intervention and/or human error.

Traceability of production material with RFID

As we progress toward a more automated factory, the need to more efficiently manage what happens prior to the production process has become apparent. Tracking of raw material and production components from the dock door to the warehouse is quickly evolving from a best guess estimate to real-time inventory levels driven by production. Essentially, we are moving from a practice of holding just-in-case inventory to Just-in-Time (JIT) inventory. The JIT concept helps to optimize the amount of in-house inventory based on production. In addition, the entire supply chain benefits because the levels of raw goods inventory upstream can be managed more efficiently and forecasted with more accuracy.

RFID and barcode technology have played a critical role in the actual production process for decades, but its benefits are currently being leveraged in other areas of the plant as well. Whether its tracking every item or every pallet that comes into the receiving dock, ID traceability provides visibility where it did not exist before.

Traceability of production material 

Upon receiving a pallet with raw material, the 2D matrix code on the shipping label is read by a barcode scanner. The relevant data needed for the further traceability process is transferred onto the stack of trays which contain UHF carriers. The number of carriers is saved together with the traceability data in a database. This process takes place at one single station and the data is updated immediately to represent the inventory level.

Transmission of incoming goods data on the transponder

Automated review of loaded pallets

Based on the material number, the system contains a standard load for the number of trays on the pallet. An automatic screening takes place to determine if all transponders on the pallet are registered. In case of a difference between the registered data and the expected data, an error message pops up to indicate the need for manual intervention. This process allows for proactive management of inventory to prevent false inventory levels or goods that cannot be accounted for.

Key Features of a traceability solution:

  • Corresponds to the global ISO standard
  • Suitable for attachment to major control systems via bus interfaces and higher level IT systems
  • Variety of accessories available for easy integration into different applications

To learn more about RFID technology, visit www.balluff.com.

How RFID Can Push Your Automotive Production Into the Fast Lane

The automotive industry is one of the technological trendsetters in the manufacturing industry. In 1913 Henry Ford invented the assembly line and forever changed automotive production. Now a bit more than a century later the automotive industry is again facing one the biggest innovations in its history.

The complexity of different models and the variety of equipment variations are enormous. This individuality comes with great challenges. The workers in the assembly process are confronted with countless, almost identical components. This requires accurate tracking of all items to avoid mistakes. Safety-relevant components are, therefore, often provided with a barcode that has to be scanned manually.

The major advantages of RFID over barcodes in automotive production

Another technology could relieve employees of this routine task and give them the security of having installed the right parts through automatic testing: RFID. These are the big advantages of RFID over barcodes:

  • While the barcode only contains the information about which type of product it is, the RFID tag provides additional information, such as in which vehicle the car seat is to be installed.
  • While the barcodes have to be read out manually one after the other with a handheld scanner, the RFID tags can all be detected simultaneously and without contact via a scanner – even if the parts are already installed.
  • RFID tags can be used to retrieve information in seconds at any time. During the production process, it can already be checked whether all the required components are installed –  provided they are all equipped with an RFID tag. Without RFID, this was only recorded in the final inspection, using visual inspection and paper list.
  • Additionally, nowadays it is indispensable for the automotive industry to make the production parts traceable and thereby assign them a unique identity. RFID has the advantage that without visual contact or even after a repainting of the component, the information can be easily retrieved. The function is not lost with dirt or oil coverage. Furthermore, tags with special encapsulation can retain their function even under high mechanical, thermal or chemical loads.

How does RFID work?

RFID is the identification of objects by electromagnetic waves.  A reader generates a high-frequency electromagnetic field. If a data carrier (also called “tag”) is brought into the vicinity of the reader, the specific structure of the tag ensures a change in the field and thus transmits individual information about itself – contactless.

RFID Tag and Reader
Functional principle of an RFID system

Increase process reliability and profitability with RFID

Several thousand parts are needed to build a car. But only those parts that are safety, environmentally or testing relevant get an RFID tag. For example, the motor cabling would get a tag that can be read out automatically. Without RFID a worker would have to manually enter the label in a database and errors can easily arise. RFID detects the part automatically and you don’t have to look for labels in transport boxes, etc.

With RFID you know exactly where a component is located at any time – from the moment of delivery until the belt run of the car. With this information you can react flexibly to changes in the process, such as delays in certain areas, and can reschedule at short notice. In addition, you can always retrieve the current stock and know whether the right component is mounted on the right vehicle. So it can significantly increase process reliability and efficiency. An RFID solution eliminates several manual steps in the documentation per vehicle, and it brings more transparency to the logistics and production processes. That means the effort is reduced and the profitability increases.

The implementation starts with the suppliers

Ideally, the implementation of RFID starts with the automotive suppliers. They attach the RFID tags to their components what allows them to use the technology within their own logistics and manufacturing facilities. On arrival to the car manufacturer, the parts are driven through an RFID gate that reads out the tags automatically and adds the parts to the inventory. If the car leaves the assembly hall after manufacturing you can screen again by the RFID gate. At the push of a button it can show which parts are under the hood.

Automatic configuration with UHF for your convenience

The processes in the automotive industry are versatile, but a broad selection of innovative RFID products can push your automotive production into the fast lane.

For more information on RFID, visit www.balluff.com.

UHF making a big impact on manufacturing

RFIDUltra-High Frequency (UHF) RFID is quickly becoming the go-to identification system for flexible manufacturing lines around the world. While it was once considered to be a system designed primarily for distribution centers and retail stores, UHF technology has evolved to meet the rigors of the manufacturing environment.

Not long ago I was in a discussion with one of my customers who had been using RFID for almost 25 years. He was caught in a tough spot because he had an application which required reading tags from as little as six inches away to as far as two feet away. The HF system he had could easily meet his needs for the six inch read range, but reading at two feet away limited him to using UHF. When I explained that, his bewildered look indicated to me he was reluctant to consider UHF as a real option. He went on to explain that about ten years prior he conducted tests in his plant with UHF and found a host of limitations with the technology. His main concern was how the operators’ two-way radios interfered with the UHF operating frequency of 902-928MHz. Having heard this from other manufacturing organizations who were early adopters I knew right away that he wasn’t aware of how the technology has evolved over the last decade.

Frequency hopping has pretty much eliminated interference with other radio signals. In addition to overcoming radio interference, being able to read and write to tags which are mounted on or near metal and liquids has become a reality with recent advancements. These improvements have led to more flexible read ranges which are a requirement in today’s flexible manufacturing applications.

In a nutshell, the demands of flexible manufacturing have spurred advancements in the process as well as the supporting technology. As it applies to identification of parts or pallets in the manufacturing process, the flexibility of UHF RFID enables manufacturers to gain visibility in their process and provides actionable data that is used to make complex business decisions.

You can learn more about the technology in Balluff’s white paper, What Makes RFID Systems Industrial Strength? or by visiting our website at www.balluff.us

Barcode and RFID, A one-two punch when it comes to sequencing

UHFRFIDAll too often I read about RFID replacing barcode as an ID technology. No doubt, there are cases where RFID is used to replace a barcode system due to a harsh environment or there is a need to “de-centralize” information etc., but more often than not I see both barcode and RFID being used together to address an application. It doesn’t have to be one or the other.

One application where the two live in harmony is sequencing. Sequencing is referred to by many different names and acronyms and is synonymous with automotive assembly plants and their tier suppliers. In a nutshell, the goal is to deliver the exact number of components in the exact order they will be used. When this is done efficiently the result is a WIN-WIN-WIN. A win for the supplier because they decrease the amount of in-process inventory and carrying costs; A win for the manufacturer because they maximize their floor space and spend less time hunting parts and components to complete a build; And a win for the consumer because they get their new car faster.

As one can imagine there is a great deal of communication and data sharing that must take place in order for this to operate smoothly. This is where the one-two punch of RFID and barcode come into play. The most common method is to identify the parts with barcodes and write the barcode data to the RFID tag which is fixed to the carrier. The information on the RFID tag identifies the carrier and identifies the components on the carrier. Rather than explain how this works, it makes more sense to look at a real-life example of how a major automotive supplier achieved their sequencing goals by using the one-two punch. Read Balluff’s Application Spotlight on UHF RFID Sequencing to learn more.

UHF RFID, One Size Fits All! – Really?

With the proliferation of UHF (ultra-high frequency) based RFID in the commercial and consumer markets, UHF has been seen as the mainstay now for many low-cost, long-range RFID applications. And in recent years with the desire for longer range application flexibility in the industrial sector, naturally users want to gravitate toward technologies and products with a proven track record. But can you really take the same products developed and used for the commercial and consumer logistics markets and apply them reliably to industrial applications like asset tracking, EKanban, general manufacturing or logistics?
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A Bolt For RFID

In many cases, RFID tags are only as good as the package that carries them. In recent years with the explosion in the use and acceptance of RFID, many different types of tag packaging have become available. In these cases, these new packages have been based around low-cost labels. But when it comes to the industrial use of RFID, strength and reusability are an absolute must and there is a package for that too.

Databolt examples.

This package is called the Databolt™. The Databolt is most likely what you might picture when you hear that name in reference to RFID. It is literally an industrial grade bolt with an RFID tag embedded inside. Usually the tag is located in the head of the bolt. The bolt body is usually made of a type of tooling steel which has been treated or hardened for maximum longevity. In several automotive applications today, the Databolt is screwed into a part, typically metal, programmed with data as needed and then erased and removed only to be taken back to the beginning of the process and used again. But there are new applications where a Databolt can be screwed into a part like an oil or gas valve, cylinder or plate as a bolt for example, and then used as a track and trace method for things like field servicing once the device is installed or in use.

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