DMC vs. RFID in Manufacturing

The increasing discussions and regulations on complete traceability and reliable identification of products is making identification systems an inevitable part in manufacturing. There are two specific technologies that are very well received: The Data Matrix Code (DMC) and Radio Frequency Identification (RFID).

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One critique of RFID is the market maturity regarding practicability and price-performance ratio is not reached yet. Compare this to DMC; DMC is practical and cost-effective which is an advantage over RFID. In order to choose DMC or RFID for your application, you have to understand the fundamental differences between the two technologies. Both have their advantages and disadvantages, and the wrong decision could have costly consequences. The technology you choose will mainly depend on the object being identified. The decision will be based off of size, shape and the environmental conditions.

A New World of Opportunities with DMC

A Data Matrix Code is a two-dimensional data point pattern that has a variable, rectangular size in the form of a matrix. The matrix consists of symbol elements with a minimum of 10×10 and a maximum of 144×144 . It is a binary code that is interpreted with zeros and ones and can hold up to 1,556 bytes.

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A horizontal and a vertical border describe a corner, which serves as orientation for the reading – called the “Finding Pattern”. On the remaining sides, the border must alternate with light and dark square elements in order to describe the position and size of the matrix structure – the “Alternating Pattern”. The data storage area is inside the symbol.

Advantages of DMC

This machine-readable coding form was invented to encode higher amounts of data in smaller areas compared to 1D code. Camera scanners can already reliably read dot patterns of only 2mm by 2mm. Thus DMC is suitable for very small products or round surfaces where there is little room for marking on the product.

With the technology of DMC you can place a lot of information in a very small area. Article or batch numbers, manufacturing or expiration dates as well as other important manufacturing data can be stored permanently on the work piece across all processing steps.

A particular strength also lies in the fact that the code can be directly applied to a part (without a label) using different printing or embossing methods. It can be needled, lasered or printed with inkjet or thermal transfer printing. It works with various materials: plastics, papers, metals and many more. Since you have to use special cameras to read the DMC, not barcode scanners, they can be read in any orientation (from 0°-360°).

Additionally, the error correction when reading a DMC is very high due to information redundancy and error correction algorithm, even 25-30% contamination or damage of the data field can be fully compensated.

Disadvantages of DMC

As it is not possible to read a DMC with linear barcode scanners, you have to use camera-based image processing systems that are more expensive. In addition, it is imperative that the entire surface (not just a part of it) is decoded, because the arrangement of the modules on the surface determines the contained data. Otherwise you don’t get any valuable information.

Although DMC can accommodate low-contrast printing (20% contrast are sufficient), glossy surfaces are difficult to handle because either the light used by the camera for reading is not optimally reflected or it is too scattered. The angle at which the camera is mounted can also play a role.

Last but not least, the location of the DMC or its attachment determines whether it is readable or not. Unlike RFID, a DMC can only be read with visual contact. A hidden DMC cannot be read by the cameras. Even if there is a line of sight you can read the DMC only within a specific reading distance.

Gain Visibility into the Manufacturing Process with RFID

This technology makes it possible to identify every item that is equipped with an RFID data carrier contactless and unambiguously. An RFID system in manufacturing consists of thousands of data carriers (also called tags or transponders) and a minimum of one read/write device (usually called a reader) with an antenna.

The reader generates a weak electromagnetic field via its antenna. If you bring a tag into this magnetic field, the microchip of the tag is supplied with energy and can send data (without contact) to the reader or store new information on the chip. If the tag leaves the magnetic field, the connection to the reader breaks off and the chip is inactive again. The stored data will remain in the tag memory.

RFID tags are available in many different designs, it can be just a simple adhesive tag but also a hard tag as a disc, bolt or glass tag. Only a few millimeter tags can be used for tool identification and very large transponders for container identification.

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Advantages of RFID

An RFID tag has 3 main advantages:

  • The tag can be read or written contactlessly without visual contact to the reader
  • The tag has almost unlimited rewritability
  • Several tags can be read simultaneously (multitag/bulk reading)

These features open up completely new possibilities that DMC cannot provide. If the RFID tag is integrated in a pallet or tool and you can’t even see it, it can still be identified. RFID tags can also be read with the greatest possible contamination as no visual contact is needed. With the rewritability of the tags you have the chance to change, delete or supplement the data on the chip – at any time.

Once an RFID system is integrated into a process, the system can be run with just minimal human participation. For a new order, the new information is written automatically on the tag. This can be up to 128 kbyte of data on a single tag. The detection of RFID-equipped parts happens within less than a second, much faster than using a barcode. This leads to reduced administrative errors, increased transparency and significant increase of speed.

With RFID, even after a post-treatment, parts can be tracked down for a lifetime. Every production step can be documented, read and written directly on the RFID tag in or on the part. To avoid security issues, data can be encrypted, password protected or set to include a “kill” feature to remove data permanently.

Disadvantages of RFID

RFID also has some disadvantages. Depending on the used frequency, physical conditions are often the reason for issues. For example, metal containers or contents made of metal can create problems or even non-readings as metals reflect and shield. Products with a high proportion of water absorb radio waves and it could cause the reader to not detect certain objects.

Another sore point is the cost. RFID tags are always more expensive than a DMC because even with a large amount, the integrated antenna and the transponder must be paid. However, with having almost unlimited read and write capabilities, the higher initial acquisition costs pay off over the time with tens of thousands of uses of the tags – at least with closed-loop applications.

Different frequencies for different applications

There are 3 established radio frequency ranges that have specific characteristics:

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The application determines which frequency you should choose. As Low Frequency (LF) systems only have a moderate sensitivity for potential metallic reflections they are designed for applications where the tag has to be mounted flush in metal, for example, with tool identification. High Frequency (HF) systems score with a high transmission speed for large volumes of data and are therefore ideal for work in progress (WIP) applications. High reading ranges make Ultra High Frequency (UHF) very attractive when the plant or process does not allow a close proximity between reader and tag, RFID tags on various positions on an item can be read with just a single UHF antenna. As all tags can be read out almost simultaneously in the read range of a reader, UHF systems are ideal for detecting complete pallet loads.

Main Differences Between DMC and RFID Tags

Here is an overview of the most important differences between Data Matrix Code and RFID:

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Which Option is Better for Your Application?

Ultimately, the decision to opt for one or the other technology is always a case-by-case decision. Here are some fundamental questions you can ask yourself in order to choose the right one:

  • Will the marked object be reused or will it be lost at the end of the processing chain? → closed-loop application = RFID, open loop application = DMC
  • Is there only a one-time marking or a repeated writing/ change of the stored data needed within the processing chain? → One-time marking = DMC,  rewriting = RFID
  • How big are the detection distances? → Short = DMC, large = RFID
  • What about the data volume on the object? → Low = DMC, high = RFID
  • Should process data be stored on the object? → Yes = RFID, no = DMC
  • What about the processing speed? Not relevant = DMC, high = RFID
  • What about the lighting conditions and contrasts? → Good = DMC, bad = RFID
  • How big is the space available for the marking? → Small = DMC, sufficient = RFID
  • Is the direct line of sight to the object difficult? → Yes = RFID, no = DMC
  • Are there potential sources of interference like dirt or damage? → Yes = RFID, no = DMC
  • Are there potential sources of interference like metals or liquids? → Yes = DMC, no = RFID

It’s Not Always About “Either/Or”

DMC and RFID do not necessarily have to compete. Sometimes it may be beneficial to have a combination of both technologies. An example of a combination solution is an RFID label with a printed DMC. While the DMC can be read directly on the object with a scanner, the RFID tag fulfills further tasks. Thanks to the special technology, goods can be identified even when packaged. In addition, all relevant process data can be stored on the RFID data carrier and offer added value throughout the value chain.

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

RFID for Work in Process (WIP) – Empowering people to make complex business decisions.

traceability_1From the concrete of the production floor to the carpet in the executive offices, RFID technology provides actionable data which allows organizations to make complex business decisions. Making decisions based on actual data opposed to “best guess” data…I don’t even need to explain that. The trick is collecting that data and making it available for the organization. That is where RFID comes into play.

Work in Process is one of many applications within a plant in which RFID improves overall process efficiency. It helps to enable flexible manufacturing, tracks the work process, and helps to maintain regulatory compliance. Simply put, RFID technology is responsible for collecting the data, but it is up to the humans to use the data.

What is the data that is being recorded and collected?

  • Build Data: What are we trying to build? (for flexible MFG)
  • Process Data: How well did we build it? (Error Proofing or Poka Yoke)
  • Lineage Data: Where did the parts come from? (Tracking sub-assemblies and parts to their origin)

How does this data benefit the manufacturing organization?

Build Data:  Consider a company who is manufacturing seats for an automobile. The number of options on seats today is mind boggling. A few options include: Heaters, automated controls, weight sensors, specialized foam, specialized covers, etc.  The problem is they all look the same to the human eye. When tagged with an RFID tag all that data is written to the memory in the beginning of the process and then the data is read at every work station along the line to identify exactly what needs to be done based on what the finished product is going to be. In the old days, the operator at each station would have to read through a couple reams of paper to determine what needs to be completed. Now an automatic data transfer informs the operator what needs to be completed.

Process Data: At the same seat manufacturer, let’s say there are twenty stations (processes) that a seat must go through in order to be completed. Now, let’s say there was an error installing the heating mechanism in station three. The seat then proceeds through the remaining seventeen stations getting many other things added to it along the way. Then, prior to shipping, it goes through final inspection and the heater problem is identified. Now, that final seat needs to be either scrapped or needs to go back through the rework line. That’s what used to happen in the old days. Nowadays there are error checks in between each station that quickly identify problems immediately opposed to waiting until the end of the line resulting in lost labor and time. As the seat moves from station three to four the error check occurs and either a go or no-go is written to the tag. If the reader in station four reads a no-go off the tag the operator is notified immediately and the production error can be corrected immediately without having to tear the seat apart to fix the problem. Additionally, the entire production process is written to the tag along the way and at the end of the line the information is uploaded to a database.  The tag can then be erased and written to all over again.

Let’s say the seat manufacturer receives a special order that has to be run ASAP. All twenty seats currently on the line need to be removed to make way for the special order. After the special order is completed it’s now time to put the seats back in their respective stations. RFID takes the guess work out of that process because now they can just read the RFID tag and it will tell them the exact station it belongs in.

Lineage Data:  All those seat variations mean many different components coming from many different suppliers. RFID is used to track those parts back to their origin in case of recall or repetitive part failure. Now instead of bringing the entire assembly back and scrapping the seat they can identify the faulty component, replace it, and hold their suppliers accountable to their quality promise.

Ultimately, from the concrete to the carpet, RFID helps manufacturing organizations make high quality products, eliminate un-planned down time, and improve overall efficiency. By allowing operators and executives to make decisions based on actual data, RFID is helping drive manufacturing organizations to the next level.

For more information on RFID solutions visit balluff.us/rfid.

How to Make Plant-based Assets Smarter

 

traceability…add RFID

Pallets, bins, shipping containers, machine tools, hand tools, calibration equipment, neumatic and hydraulic cylinders, etc, etc, etc can all be given some level of intelligence which would make life easier within the plant. Plant-based assets are truly assets because they make our job easier or they allow us to be more efficient. When workers are efficient they are more productive.

Really it all comes down to the questions that we need answered. Here are a few that I have run into in a plant:
Where are all of my pallets and shipping containers?
How much longer can I use this machine tool before the tolerances are out of range?
Has this gauge been calibrated? when? by whom? what are the parameters?
I need to re-order this part or order spare parts and the manufacturer information has been worn off. What is the serial number, when was this part manufactured, what is the location of this asset within the plant?

Ultimately, if your assets can answer a few questions your life becomes a little less complex. All of the answers are simply written to the RFID tag and when you have a question you can read the information from the tag with an RFID reader, sometimes called an interrogator for obvious reasons. It’s that simple.

For more information on RFID as a solution visit our website at www.balluff.us/rfid

“Team” Spells Success In Traceability

If you’ve ever considered a traceability project, like asset tracking for instance, you’ve probably also done some homework into the different technological ways to implement it, from barcoding to using RFID (radio frequency identification). And possibly, while doing that research, you may have seen some presentations or read some articles or whitepapers that have talked about the “team” of stakeholders required to implement these projects, especially if involving the scale required for a facility, or even multiple facilities. Well if you’re a manager reading this and involved with such an endeavor, I’m writing to tell you, take this stakeholder team thing seriously.

In many respects, there are rational fears in getting a stakeholder team together in the early stages of these projects, like the conceptualization stage for example. These fears include: Blowing the project out of proportion; Creating mission creep; Even derailing the project with the others self-interests. Again, all can be valid and even come true to a certain extent, but the reality is that most, if not all of the time, these same stakeholders will also identify the potential opportunities and pitfalls that will either help build the REAL ROI case, and/or help prevent the unseen wall that will prevent success.

These stakeholders can range from operational management (warehouse to manufacturing, depending on the target), IT, financial, quality, and engineering, just to get the ball rolling. You must always be careful of allowing the project to slip into “decision by committee”, so hold the reins and have the project lead firm in hand. But by bringing their input, you stand to satisfy not only your goal, but likely the shared goals they also have, validating and strengthening the real ROI that will likely exist if traceability is the requirement. You will also likely find that along the way you will bring improvements and efficiencies that will benefit the broader organization as a whole.

Once you’ve established the goal and the real ROI, reinforced by the stakeholder’s inputs, that is the time to bring in the technology pieces to see what best will solve that goal. This is many times were the first mistake can be made. The technology suppliers are brought in too soon and the project becomes technology weighted and a direction assumed before a true understanding of the benefits and goals of the organization are understood. Considering a project manager before bringing in the technology piece is also a great way to be ready when this time comes. When you’re ready for this stage, this will typically involve bringing in the vendors, integrators and so forth. And guess what, I’m certain you’ll find this part so much easier and faster to deal with, and with greater clarity. If you have that clear picture from your team when you bring in your solution providers, you will find the choices and their costs more realistic, and have a better picture of the feasibility of what your organization can implement and support.

Not to kill the thought with a sports analogy, but a team united and pulling for the same goal in the same direction will always win the game, versus each player looking out for just their own goals. So get your team together and enjoy the sweet taste of ROI success all around.

For more information on Traceability visit www.balluff.us/traceability.

RFID ROI – Don’t forget the payback!

traceability_1Just recently, while visiting a customer wanting to implement an RFID asset tracking solution, it occurred to me that ROI (return-on-investment) should always be the ultimate goal for most uses of RFID. What brought this to mind? It was because we were discussing technology before understanding what the ultimate ROI goal was. I’m sure you could say this was failure from a sales perspective, but I’m sure at some point you have also found yourself caught up in the technology seeming so promising and exciting in terms of its benefits, that you lost track of why you were there in the first place. Also, many times, the technology stage is where equipment suppliers and/or integrators are brought in.

As with most projects of this nature, they get started because someone says something like “why don’t we do XXX, it will save us money, time, trouble, loss or get us in compliance” or all of the above and likely more. But this same thought can get lost going through execution. RFID projects are no exception. Many successful RFID implementations show it can bring large benefits in short and long-term ROI not just in asset tracking, but manufacturing, warehousing, supply chain and so on. But the implementor must always keep track of the ROI goal and be willing to share this with their internal stakeholders, supplier and integration partners to be sure everything stays on track and technology does not take over for technologies sake.

Unfortunately the ROI is not always calculated the same for applications. Typically ROI can simply be measured in time period until the investment is paid back or the money saved over a given period of time. The most simplistic way of calculating payback or ROI is: Cost of Project (calculated at the beginning) / Annual Cash Revenues (expected savings) = Payback Period. Unfortunately the rub comes in when calculating the detail in the two factors. This can be because the cost of the project is not totally encompassing and/or revenue does not take into consideration factors like interest costs or variations in production, for example. As this will ultimately become the measure of successful projects, really understanding ROI is critical.

Factors in Annual Cash Revenues are factors the implementer needs to understand and grasp as the reasons for undertaking a project. These factors will typically involve several aspects of their business, including savings from greater efficiency, lower cost in storage or inventory, less scrap, higher quality standards (less failure returns), compliance benefits, etc. In fact, this part is difficult to encompass here in this forum. But Cost of Project has some factors I can point out. In the example I raised in the beginning, the customer needed to not only address the read/write equipment and tags (including handheld’s), but also the cost of installing all the possible variations in tag types used during manufacture, common database/software needed, bringing distributors and field service on board, integration providers costs (internal also), training needs, software licensing, start-up and support cost, and so on. So in a manufacturing line, it starts with the new equipment, but must include the PLC/database programming, pallet modifications, station installation, spare parts, start-up and training for example. In warehousing, it might include new equipment, loss of facility equipment like forklifts or warehouse area, facility modification like electrical for example, ERP and WMS implementation or integration, commissioning and training.

One thing to consider toward understanding these factors before implementing a total enterprise solution, whether in warehousing, supply chain or manufacturing is to consider a pilot or test/trail program to determine as many factors as possible and test the results before committing to the full investment of the complete project.

So in your next project, remember to include your stakeholders and partners in your end goals, try to encompass all the factors and don’t forget the payback!

To learn more about RFID visit us at www.balluff.us/rfid.

RFID – Keep it Simple!

traceabilityMost of us drive an automobile and use a PC daily. However, very few of us could accurately describe the intricate details of how each of those work. They help us get to work and help us do our work. There is not a need for us to know and understand the algorithm that allows us to compose and save an excel spread sheet. As well, there is not much use in knowing the coefficient of friction when using snow tires compared to standard tires. While those factors play a major role in the tools we use every day, we do not necessarily need to be an expert or scientist to reap the benefits.

Much like a car or PC, RFID systems enable us to be more efficient and productive. Specifically, RFID systems in manufacturing enable full visibility into the process. RFID technology provides actionable data to an organization. Having access to actionable data allows an organization to make critical business decisions with a great degree of confidence. Essentially, it takes the guess work out of the process.

So, how does it work? Very simply, a reader reads the information that has been written to the memory of a tag. Yes, it is that simple.

Check out this webex sponsored by SME. This is a very basic introduction to RFID and how it is used in manufacturing.
https://smeweb.webex.com/smeweb/lsr.php?RCID=c517f86066227766f9e36668c2325aa8