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.

Be Driven by Data and Decrease Downtime

Being “driven by data” is simply the act of making decisions based on real data instead of guessing or basing them on theoretical outcomes. Why one should do that, especially in manufacturing operations, is obvious. How it is done is not always so clear.

Here is how you can use a sensor, indicator light, and RFID to provide feedback that drives overall quality and efficiency.

 

Machine Condition Monitoring

You’ve heard the saying, “if it ain’t broke, don’t fix it.” However, broken machines cause downtime. What if there was a way to know when a machine is getting ready to fail, and you could fix it before it caused downtime? You can do that now!

The two main types of data measured in manufacturing applications are temperature and vibration. A sudden or gradual increase in either of these is typically an indicator that something is going wrong. Just having access to that data won’t stop the machine from failing, though. Combined with an indicator light and RFID, the sensor can provide real-time feedback to the operator, and the event can be documented on the RFID tag. The machine can then be adjusted or repaired during a planned maintenance period.

Managing Quality – A machine on its way to failure can produce parts that don’t meet quality standards. Fixing the problem before it affects production prevents scrap and rework and ensures the customer is getting a product with the quality they expect.

Managing Efficiency– Unplanned downtime costs thousands of dollars per minute in some industries. The time and resources required to deal with a failed machine far exceed the cost of the entire system designed to produce an early warning, provide indication, and document the event.

Quality and efficiency are the difference makers in manufacturing. That is, whoever makes the highest quality products most efficiently usually has the most profitable and sustainable business. Again, why is obvious, but how is the challenge. Hopefully, you can use the above data to make higher quality products more efficiently.

 

More to come! Here are the data-driven topics I will cover in my next blogs:

  • Part inspection and data collection for work in process
  • Using data to manage molds, dies, and machine tools

Tag, You’re It: Choosing the Right Type of Tags for Your RFID System

Many companies have already discovered the benefits of implementing RFID into their systems. Traceability within the manufacturing process provides a competitive advantage of both efficiency and profitability. RFID tags are a major component of this technology. But it’s important to select the correct type for your specific application. These tags are classified into categories based on how they obtain power and how they use that power. The three categories are as follows:

  • Passive tags
  • Semi-passive tags
  • Active tags

Understanding the difference between these can help narrow down your decision when looking into implementing RFID systems to your process.

Passive tags do not have their own power source. The tag receives power only when the RFID reader is in range. These tags are limited since the power supplied is minimal. The biggest advantages of passive tags are that they are small and inexpensive. They can be useful in specific applications where space is limited. Also, if the environment in which the tag is being placed is harsh, the passive tag may be a good option because it can be cheaply replaced if damaged. Since these tags do not generate power, their read distance of just a few inches to about two feet is much shorter than others. Passive tags are also limited to the amount of data storage they possess. Depending on the application this can be an advantage or disadvantage.

Semi-Passive tags, as the name implies, are similar to passive tags in that they do not have an active transmitter. They still require an RFID interrogator to be in range for the device to work, although the semi-passive tags have their own battery to power the IC. If you are looking for longer read ranges than the passive tag, this could be an option. Since the read range of the passive sensor is solely based on how far away the interrogator can power the device and not the signals coming in, adding a battery unit to the semi-passive tags increases this distance. These distances can range up to 100 feet. Another advantage is the amount of data they can store. These added features do come with added costs. The onboard power supply also makes these tags larger and heavier. The electronics inside the tag are susceptible to harsh environments like high or low temperatures, resulting in shorter lifespans.

Active tags have both a battery and transmitter built within their housings. The typical read range is again increased to around 300 to 750 feet depending on the battery power and the antenna. This allows the tags to store more data with their increased memory capacity. Active tags display the most configurability in comparison to passive and semi-passive tags. They can be set up to conserve battery power when the interrogator is out of range and respond only when the reader is within range. They can also be set up as a beacon, which is when the tag does not wait until it receives a signal from the interrogator. Instead, the active tag can be configured to send the information in set time intervals. Since active tags contain an active transmitter, they can contribute to radio noise. They are also more expensive and usually larger in size and weight due to the increased electronics within its housing.

It’s important when selecting a tag for your RFID system to consider the application needs and the advantages and disadvantages of these different options.

Add Transparency and Traceability with RFID

How can traceability and easy data collection help make the assembly line more transparent and efficient? I’m sure if you ask any manufacturing engineer if being able to track vendor and lot information is going to benefit them in some way, they are going to say yes! All companies have some type of ERP system set up to track parts coming in and products going out, but what goes on between those lines? If a customer reports a missing or faulty component how do you easily know where it came from?  How do you know when the product was made or who made it?

This is where RFID comes in. RFID read/write heads and data collectors can help you track and control production on the assembly. These data collectors or “tags” come in various shapes and sizes. They can be small chips attached to the workpiece carrier or they can even come as a bolt that you screw right into your part. Read/write heads also come in different sizes and have variable read/write distances or frequencies (i.e. low frequency, high frequency, and ultra-high frequency). The read/write heads connect to a processor unit that ties directly back to the PLC. Once the PLC receives this information, it can provide it to the ERP system. This takes all the information on the floor level and makes it available to the management system.

For example, say you have an unexperienced line worker on your assembly line. You are producing large diesel engines and he has the job to put together the pistons at the front of the line. Many times, he snaps the O-rings putting them on. Other times, the rings aren’t put completely in place, but he still sends the engine to the next station. When customers start calling faulty O-rings, you need an easy way to locate the source of the problem.

If you have 10 different lines changing out various engines every day, it could be difficult to narrow down the source of the problem. But if you have RFID read/write heads at each station on the line and a tag on each engine, you can look into your ERP system and track down on which line the engines in question were assembled and who was responsible for putting together the pistons.

You can then determine if the problem was human error or if the cause was due to poor quality parts, and take steps to rectify the situation. If it is determined that the rings are poor quality, you can easily determine every engine that these rings have been used on and recall only those engines. This is just a small example of how RFID can help with transparency on the assembly line. If you are looking for better ways to track inventory, vendors, or just make data more accessible to you and your company, then RFID is your answer!

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.

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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.

Palletized Automation with Inductive Coupling

RFID is an excellent way to track material on a pallet through a warehouse. A data tag is placed on the pallet and is read by a read/write head when it comes in range. Commonly used to identify when the pallet goes through the different stages of its scheduled process, RFID provides an easy way to know where material is throughout a process and learn how long it takes for product to go through each stage. But what if you need I/O on the pallet itself or an interchangeable end-of-arm tool?

Inductive Coupling

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Inductive coupling delivers reliable transmission of data without contact. It is the same technology used to charge a cell phone wirelessly. There is a base and a remote, and when they are aligned within a certain distance, power and signal can be transferred between them as if it was a standard wire connection.

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When a robot is changing end-of-arm tooling, inductive couplers can be used to power the end of arm tool without the worry of the maintenance that comes with a physical connection wearing out over time.

For another example of how inductive couplers can be used in a process like this, let’s say your process requires a robot to place parts on a metal product and weld them together. You want I/O on the pallet to tell the robot that the parts are in the right place before it welds them to the product. This requires the sensors to be powered on the pallet while also communicating back to the robot. Inductive couplers are a great solution because by communicating over an air gap, they do not need to be connected and disconnected when the pallet arrives or leaves the station. When the pallet comes into the station, the base and remote align, and all the I/O on the pallet is powered and can communicate to the robot so it can perform the task.

Additionally, Inductive couplers can act as a unique identifier, much like an RFID system. For example,  when a pallet filled with product A comes within range of the robot, the base and remote align telling the robot to perform action A. Conversely, when a pallet loaded with product B comes into range, the robot communicates with the pallet and knows to perform a different task. This allows multiple products to go down the same line without as much changeover, thereby reducing errors and downtime.

Not All RFID is Created Equal: Is Yours Built for an Industrial Environment?

The retail environments where products are sold look nothing like the industrial environments where they are produced (think of the difference between a new car dealership and an automotive manufacturing plant). Yet the same RFID products developed for retail stores and their supply chain operations are still marketed to manufacturers for production operations. These products may work fine in warehouses, but that does not necessarily qualify them as industrial grade.

IO-Link_RFID

So what are the differences between retail and industrial RFID?

Production environments often require a level of ruggedness, performance, and connectivity that only purpose-built industrial equipment can reliably satisfy. For example, general-purpose RFID equipment may have the physical Ethernet port needed to connect to a PC or server, but will not support EtherNet/IP, Profinet or other industrial protocols that run on PLCs and other industrial automation control equipment. Many retail grade readers need to be supported with an additional protocol conversion, which can require external hardware and slow system performance, and adds to implementation time, difficulty, and expense.

When evaluating RFID equipment, it is essential to make the distinction between what is possible for use in the environment and what is optimal and, therefore, more reliable. There are three fundamental qualities to consider that can determine if RFID systems will perform reliably in demanding production environments:

  • Will the RFID system integrate seamlessly with industrial control systems?
  • Will it provide the reliability and speed that production and their information systems tied in require?
  • Can it maintain uptime and performance long term – will it last on the production line?

RFID is often marketed as a “solution,” however in manufacturing operations, it is almost always used as a supporting technology to provide data and visibility to the MES, ERP, e-Kanban, robotics, asset tracking, material handling, quality control and other systems that run in production facilities. Failure to accurately provide data to these systems at the reliability and speed levels they require eliminates the value of using RFID.

The physical environments in industrial and supply chain settings cause RFID technology to perform differently. Tag density can be a consideration for industrial RFID users like retail, but an industrial environment has much more challenging and powerful potential interference sources, for example, the presence of metal found in most industrial products and environments.

When determining whether RFID products are suitable for a specific environment, it is important to look beyond published marketing hype and misleading specifications. Consider the design and construction of the product and how it could be affected by various work processes. Whenever possible, you should test the products where they will be used rather than in a lab or demonstration area, because the actual work location has interference and environmental conditions that may be overlooked and impossible to duplicate elsewhere.

The key attributes that differentiate industrial RFID equipment from supply chain-oriented alternatives include:

  • Native support for industrial protocols;
  • High tag read reliability and the ability to continuously operate at speeds that won’t slow production systems;
  • Durable housing with secure connectors with IP65 or better rating and relevant certifications for shock, vibration and temperature resistance;
  • The ability to support multiple RFID technologies and supporting devices as needed, including sensors, PLCs, IO-Link, and other industrial automation equipment.

Compromising on any of these criteria will likely result in unnecessary implementation time, support, and replacement costs and increase the risk for system failure.

RFID for Improved Operator Accountability

One of the most fascinating parts of my job is making site visits to manufacturing plants across the country. Getting a first-hand look at how things are made in a modern manufacturing facility is nothing short of amazing. Robots whirling, automatic guided vehicles (AGV’s) navigating the floor, overhead cranes and gantries lifting tons of material over-head, flames shooting from ovens, and metal chips flying create an exciting, but sometimes dangerous, work environment. To some people this may seem like a good reason to avoid these places, but if you are fitted with the appropriate personal protective equipment (PPE) the chances for injury are minimal.

The safety of every human in the plant is the top priority.  This is why there are requirements to wear PPE that is suitable for the environment and the hazards within. The challenge is confirming that everyone is aware of the required equipment, and that they indeed are wearing that equipment.

This can be accomplished with a simple RFID kiosk system. When an operator scans their ID they are asked a series of questions to ensure they are wearing the correct PPE. If the operator confirms they are wearing all the required gear, they can begin work in the area they are assigned. If not, a supervisor will be notified so the correct equipment can be obtained. This method can serve as a daily reminder for what needs to be worn while holding the operator accountable.

Ultimately, it is up to the plant and occupational safety organizations to define what needs to be worn and where it should be worn, but it is the responsibility of the operator to actually wear it. The same system can be used for vendors, visitors or anyone else who ventures out on the plant floor.

Using RFID to Create Transparency in Production

To meet today’s requirements for fast delivery and infinite flexibility, many productions are already set up as flow production with work steps distributed to workstations. As a result, products can be individually adapted in order to optimally meet customer requirements.

The basic prerequisite for this is to continuously know where a product is in the process. Additionally, information should be available about the next workstation and the subsequent work step. Without technical assistance, the required information can only be generated by the employee with much effort. Additionally, you run the risk of production steps being confused and time delays occurring in the production process. One solution to meet the requirements with minimum effort and maximum reliability is to install automated product recognition by using an RFID system.

 
Automated product recognition with an RFID system

To install an RFID system one important prerequisite must be fulfilled. Each product that is planned to be tracked needs a compatible RFID data carrier. This enables an individual connection between the order number and the product, which is then stored in a database.

During the product creation, the stored connection is called up multiple times. Each time it is supplemented by further information. In this way product traceability can be ensured. The connection is initiated by an antenna of the RFID system, which recognizes the data carrier and its ID. The resulting data shows which product is at the workplace, the time stamp, the place of recognition and the order number, all of which are noted in the database.

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Communication between RFID system, database and production employee

 

Reduction of error rate and increase of efficiency in the production

In addition to ensuring traceability, the installation of an RFID system can also significantly reduce the failure rate in the production. The connection to the database allows information to move in two ways. On one hand additional information is provided, while on the other further information is created that can be processed by other systems.

The storage of the time stamp enables an analysis of the duration of each work step. This makes the identification of potential ways to improve in the production possible. If this analysis and the implementation of the system is done consequently, the efficiency in the production can be improved continuously.