RFID in the Manufacturing Process: A Must-Have for Continuous Improvement

There is quite an abundance of continuous improvement methodologies implemented in manufacturing processes around the globe. Whether it’s Lean, Six Sigma, Kaizen, etc., there is one thing that all of these methodologies have in common, they all require actionable data in order to make an improvement.  So, the question becomes: How do I get my hands on actionable data?

All data begins its life as raw data, which has to be manipulated to produce actionable data. Fortunately, there are devices that help automate this process. Automatic data collection (ADC), which includes barcode and RFID technology, provides visibility into the process. RFID has evolved to become the more advanced method of data collection because it doesn’t require a centralized database to store the data like barcode technology. RFID stores the data directly on the product or pallet in the process, which allows for much more in-depth data collection.

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RFID’s greatest impact on the process tends to be improving overall quality and efficiency. For example, Company X is creating widgets and there are thirty-five work cells required to make a widget. Between every work cell there is a quality check with a vision system that looks for imperfections created in the prior station. When a quality issue is identified, it is automatically written to the tag.  In the following work cell the RFID tag is read as soon as it enters the station. This is where the raw data becomes actionable data. As soon as a quality issue has been identified, someone or something will need to take action. At this point the data becomes actionable because it has a detailed story to tell. While the error code written to the tag might just be a “10”, the real story is: Between cells five and six the system found a widget was non-conforming. The action that can be taken now is much more focused. The process at cell five can be studied and fixed immediately, opposed to waiting until an entire batch of widgets are manufactured with a quality issue.

Ultimately, flawless execution is what brings success to organizations.  However, in order to execute with efficiency and precision the company must first have access to not only data, but actionable data. Actionable data is derived from the raw data that RFID systems automatically collect.

Learn more about RFID technology at www.balluff.com.

 

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The Evolving Technology of Capacitive Sensors

In my last blog post, Sensing Types of Capacitive Sensors, I discussed the basic types of capacitive sensors; flush versions for object detection and non-flush for level detection of liquids or bulk materials.  In this blog post, I would like to discuss how the technology for capacitive sensors has changed over the past few years.

The basic technology of most capacitive sensors on the market was discussed in the blog post “What is a Capacitive Sensor”.  The sensors determine the presence of an object based on the dielectric constant of the object being detected.  If you are trying to detect a hidden object, then the hidden object must have a higher dielectric constant than what you are trying to “see through”.

Conductive targets present an interesting challenge to capacitive sensors as these targets have a greater capacitance and a targets dielectric constant is immaterial.  Conductive targets include metal, water, blood, acids, bases, and salt water.  Any capacitive sensor will detect the presence of these targets. However, the challenge is for the sensor to turn off once the conductive material is no longer present.  This is especially true when dealing with acids or liquids, such as blood, that adheres to the container wall as the level drops below the sensor face.

Today, enhanced sensing technology helps the sensors effectively distinguish between true liquid levels and possible interference caused by condensation, material build-up, or foaming fluids.  While ignoring these interferences, the sensors would still detect the relative change in capacitance caused by the target object, but use additional factors to evaluate the validity of the measurement taken before changing state.

These sensors are fundamentally insensitive to any non-conductive material like plastic or glass, which allows them to be utilized in level applications.  The only limitation of enhanced capacitive sensors is they require electrically conductive fluid materials with a dipole characteristic, such as water, to operate properly.

Enhanced or hybrid technology capacitive sensors work with a high-frequency oscillator whose amplitude is directly correlated with the capacitance change between the two independently acting sensing electrodes.  Each electrode independently tries to force itself into a balanced state.  That is the reason why the sensor independently measures  the capacitance of the container wall without ground reference and the capacitance of the conductivity of the liquid with ground reference (contrary to standard capacitive sensors).

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Up to this point, capacitive sensors have only been able to provide a discrete output, or if used in level applications for a point level indication.  Another innovative change to capacitive sensor technology is the ability to use a remote amplifier.  Not only does this configuration allow for capacitive sensors to be smaller, for instance 4mm in diameter, since the electronics are remote, they can provide additional functionality.

The remote sensor heads are available in a number of configurations including versions image2that can withstand temperature ranges of -180°C up to 250°C.  The amplifiers can now provide the ability to not only have discrete outputs but communicate over an IO-Link network or provide an analog output.  Now imagine the ability to have an adhesive strip sensor that can provide an analog output based on a non-metallic tanks level.

For additional information on the industry’s leading portfolio of capacitive products visit www.balluff.com.

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Hydraulic Valves – Customize your Feedback

Hydraulic actuators can be used to open and close a valve’s position.  In automation architectures, a linear position sensor is used within the hydraulic actuator to provide continuous position feedback.

The linear position sensor is installed into the back end of the cylinder.  The sensing element resides in a cavity that has been gun-drilled through the piston and cylinder rod, Image1extending the full length of the mechanical stroke. A magnet ring is used as a position marker and mounted on the face of the piston.  As the piston (and the position marker) move, the linear position sensor provides a continuous absolute position by way of an analog or digital signal.

In some applications, a cylinder’s position may only be moving across a small portion of the overall stroke or a specific portion of the stroke.  The end user could benefit from altering the transducer’s signal based on the application’s specific stroke requirements instead of the entire cylinder’s stroke, thereby maximizing available position resolution.  When this situation arises, most transducer manufacturers offer the ability to customize or “teach” a modified output of the stroke via push buttons or from wiring inputs.  When this is done, the process does require the cylinder (and position marker) to move to these defined locations for a “teach”.

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A more user-friendly and repeatable approach for customized stroke lengths with linear position sensors is to use a graphical software package. The software can be connected
from a PC via USB to a compatible linear position sensor. Starting and ending stroke values can be precisely entered into the software and a graphical representation of the output curve is created.  For a more straightforward approach, you can also drag and drop these stroke points by a click of a cursor. The file can be saved on a PC and downloaded to the transducer. In either case, the cylinder’s piston doesn’t need to be actuated.

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In projects where multiple, identical actuators and linear position sensors need to be customized, the setup would only need to be done once, the file saved, and simply uploaded to all the sensors for the project.  A great time-saver over manually teaching each and every sensor.

Another benefit to using software with linear position sensors is to be able to upload programs for replacement units in a safe user environment (e.g. lab station or office) and shipping them to various job sites.  These different locations (or locales) can be in harsh environmental conditions (extreme cold or heat) or areas that contain ignitable or explosive gases or dusts which may be difficult to work in.

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Other software features include inverting the output curves, offering position or velocity outputs, and more.

For more information on Balluff’s Magnetostrictive Linear Position Sensors, visit www.balluff.com.

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The Benefits of using RFID or Barcode for E-Kanban or Automatic Replenishment

Electronic Kanban (E-Kanban) is a messaging system that uses a mix of technology to trigger the movement of components and materials within a manufacturing facility. Electronic Kanban differs from traditional Kanban in that it uses technology to replace traditional elements, such as Kanban cards with barcodes and RFID.

A typical electronic Kanban system will see inventory marked with barcodes or RFID. The inventory is scanned at various steps in the manufacturing process to signal usage levels that are sent back to an ERP system for replenishment. This method ensures a constant flow of material while keeping inventories to a minimum.

An additional benefit of E-Kanban is the integration of outside suppliers through an ERP system. By relaying this information, the entire supply chain can be optimized for Just-In-Time inventory flow.

Benefits include:

  1. Reduce inventory levels, carrying cost
  2. Savings in material transfer, labor cost
  3. Increase in inventory replenishment, decrease down time and line stoppage due to stock out

Automatic replenishment, Ekanban, and end-to-end pull, are all names that describe a system in which parts and sub-components are automatically replenished in a manufacturing environment. While most manufacturing organizations have some form of replenishment system in place, I have found that just about every company does it differently. While some are more effective than others, the ones that truly want to automate the process utilize automatic identification.

For more information, visit www.balluff.com.

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How to Develop and Qualify Sensors for Arctic Conditions

The climatic conditions in the arctic are characterized by cold winters and short summers. There is a large variability in climate and weather: Some regions face permafrost and are ice covered year-round with temperatures down to -40°C / -40°F (and lower), other land areas face the extremes of solar radiation up to +30°C / +86°F in summer.

As oil and gas exploration, as well as renewable energy (e.g. cold climate versions of wind turbines) move into arctic areas, the need grows for sensors designed to deal with the extreme conditions and to perform reliably over their whole life cycle.

One option is the implementation of a Highly Accelerated Life Test (abbreviation HALT) in the development process. The basic idea of HALT is the accelerated aging of electronic products (including sealing gaskets, potting compound, housing etc.) with the aim of detecting their possible weak spots as early as possible and to correct them at the development stage.

Example of a sensor in the HALT test facility (Balluff magnetostrictive linear position sensor BTL)

The item under test is subjected to higher and higher thermal and mechanical stress in order to cause failures. The limits where the product will fail functionally or be destroyed are determined in order to push these limits as far out as possible, and so achieve a higher reliability for the product.

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Product operational specs = data sheet values

The HALT procedure – in brief:

a) Analysis of weaknesses already known, definition of failure criteria, establishing the stress factors

b) Stressing the test specimen beyond the specification to find the “upper and lower operating limits”, and the “upper and lower destruct limit” for temperature, rapid change of temperature, vibration, combined vibration and temperature stress

c) Determination of the causes of failure

d) Devising a solution to eliminate the weaknesses

e) Repeating of steps b) to c)

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Example: Temperature step test – cold and hot

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Example: Combined vibration test and rapid temperature changes

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Example: Cowan Dynamics E2H Electro-Hydraulic valve actuator Photo: Cowan Dynamics (Canada)

In contrast to other environmental tests, HALT is not qualification testing according to specific technical standards (as  ISO/IEC etc.), but it applies stimuli to the items under test until they fail, so weak spots will be revealed. A HALT test is not an exam you can pass!

However, if sensors are implemented into more complex automation systems that will be operated in remote areas, this method may help to prevent major faults in the field and is therefore also used in the aircraft and automotive industry.

For more information about Balluff testing methods and the laboratory, please visit www.balluff.com or download our brochure “The Balluff Testing Laboratory”.

 

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Capture vs Control – The Hidden Value of True IIoT Solutions

A few months ago a customer and I met to discuss their Industry 4.0 & IIoT pilot project.  We discussed technology options and ways to collect data from the existing manufacturing process.  Options like reading the data directly from the PLC or setting up an OPC service to request machine data were discussed; however these weren’t preferable as it required modifying the existing PLC code to make the solution effective.  “What I really want is the ability to capture the data from the devices directly and not impact the control of my existing automation equipment.”  Whether his reason was because of machine warranty conflicts or the old adage, “don’t fix what ain’t broke” the general opinion makes sense.

Capture versus Control.

This concept really stuck with me months after our visit that day.  This is really one of the core demands we have from the data generation part of the IIoT equation; how can we get information without negatively impacting our automated production systems?  This is where the convergence of the operational OT and network IT becomes critical.  I’ve now had to build an IT understanding of the fundamentals of how data is transferred in Ethernet; and build an understanding of new-to-me data protocols like JSON (JavaScript Object Notation) and MQTT.  The value of these protocols allows for a direct request from the device-that-has-the-data to the device-that-needs-the-data without a middleman.  These IT based protocols eliminate the need for a control-based data-transport solution!

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So then truly connected IIoT automation solutions that are “Ready for IIoT” need to support this basic concept of “Capture versus Control.”  We have a strong portfolio of products with Industrial Internet of Things capabilities, check them out at www.balluff.com.

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Solve Difficult Sensing Applications with Ultrasonic Technology

When reviewing or approaching an application, we all know that the correct sensor technology plays a key role in reliable detection of production parts or even machine positioning. In many cases, application engineers choose photoelectric sensors Image1as their go-to solution, as they seem more common and familiar. Photoelectric sensors are solid performers in a variety of applications, but they can run into limitations under certain conditions. In these circumstances, considering an ultrasonic sensor could provide a solid solution.

An ultrasonic sensor operates by emitting ultra-high-frequency sound waves. The sensor monitors the distance to the target by measuring the elapsed time between the emitted and returned sound waves.

Ultrasonic sensors are not affected by color, like photoelectric sensors sometimes are. Therefore, if the target is black in color or transparent, the ultrasonic sensor can still provide a reliable detection output where the photoelectric sensor may not. I was recently approached with an application where a Image2customer needed to detect a few features on a metal angle iron. The customer was using a laser photoelectric sensor with analog feedback measurement, however the results were not consistent or repeatable as the laser would simply pick up every imperfection that was present on the angle iron. This is where the ultrasonic sensors came in, providing a larger detection range that was unaffected by surface characteristics of the irregular target. This provided a much more stable output signal, allowing the customer to reliably detect and error-proof the angle iron application. With the customer switching to ultrasonic sensors in this particular application, they now have better quality control and reduced downtime.
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So when approaching any application, keep in mind that there is a variety of sensor technologies available, and some will provide better results than others in a given situation. Ultrasonic sensors are indeed an excellent choice when applied correctly. They can measure fill level, stack height, web sag, or simply monitor the presence of a target or object. They can also perform reliably in foggy or dusty areas where optical-based technologies sometimes fall short.

For more information on ultrasonic and photoelectric sensors visit www.balluff.com.

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Absolute Position for Incremental Systems

In linear motion applications, it is often desirable to eliminate the need to make a homing run to re-acquire the reference position for an incremental linear encoder. The homing routine may need to be eliminated to save processing time, or it may not be practical…for example, if the machine can’t be moved following a loss of power due to some mechanical consideration. Additionally, to reduce costs and simplify system design, it would also be helpful to eliminate the need for home and limit switches.

Absolute linear encoders offer an upgrade path, however they also require changes on the controller side to more costly and difficult-to-implement serial interfaces like Biss C, EnDat®, SSI, and others.  These obstacles have limited the use of absolute encoders in the majority of linear motion applications.

Recently, an innovative encoder interface called Absolute Quadrature brings absolute encoder functionality to systems with controllers designed to accept a simple and commonly used A-B quadrature incremental interface.

This demonstration video from In-Position Technologies highlights the functionality and advantages of upgrading incremental positioning systems with an Absolute Quadrature encoder.

To learn more about our Absolute Quadrature encoder, visit www.balluff.com.

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How to Balance the IIoT Success Equation

What are the key components to being successful when implementing Industrial IoT?  There are three major components to consider when beginning your pilot project for Industry 4.0: Strategy, Data & Action.  With a clear understanding of each of these components, successful implementations are closer than you think.

Strategy:  What is your plan? What do you need to know?  Who needs to know what?  How do we enable people to make the right decisions?  What standards will we follow?  How often do we need the data?  What data don’t we need?

Data Generation:  Devices need to generate cyclic data giving insight into the process and warning/event data to give insight into issues.  Devices should support protocols that allow requesting data without impacting the control system and structured in a way that’s logical and easy to manipulate.

Data Management:  How are we going to handle our data?  What structure does it need to be in?  Do we need internal and external access to the data?  What security requirements do we need to consider?  Which users will need the data?  Where is the data coming from?  How much data are we talking about?

Data Analytics:  Insight, Big Data, Predictive Analytics, etc.  These insights from an industrial point of view should truly drive productivity for every user.  Predictive Analytics should help us know when and where to perform maintenance on equipment and dramatically reduce downtime in the plant.

Action:  The key component of any IIoT Success.  Without daily decisions based on the strategy by every employee, failure is assured.  Supply chain needs to know that we are interested in not just the cheapest replacement component, but one that can help us generate data to improve our analytic capabilities.  Maintenance needs to be taking action on Predictive outputs and move from randomly fighting fires to purposefully preventing downtime all together.

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Strategy + (Data Generation + Data Management + Data Analytics) + Action = IIoT Success

We have a strong portfolio of automation devices that enable data generation for IIoT applications, check them out at www.balluff.com.

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Precision Pneumatic Cylinder Sensing

When referring to pneumatic cylinders, we are seeing a need for reduced cylinder and sensor sizes. This is becoming a requirement in many medical, semiconductor, packaging, and machine tool applications due to space constraints and where low mass is needed throughout the assembly process.

These miniature cylinder applications are typically implemented into light-to-medium duty applications with lower air pressures with the main focus being precision sensing Image 2with maximum repeatability. For example, in many semiconductor applications, the details
and tolerances are much tighter and more controlled than say, a muffler manufacturer that uses much more robust equipment with slower cycle times. In some cases, manufacturing facilities will have several smaller sub-assemblies that feed into the main assembly line. These sub-assemblies can have several miniature pneumatic cylinders as part of the process. Another key advantage miniature cylinders offer is quieter operation due to lower air pressures, making the work place much safer for the machine operators and maintenance technicians. With projected growth in medical and semiconductor markets, there will certainly be a major need for miniature assembly processes including cylinders, solenoids, and actuators used with miniature sensors.

One commonality with miniature cylinders is they require the reliable wear-free position detection available from magnetic field sensors. These sensors are miniature in size, however Image 1offer the same reliable technology as the full-size sensors commonly used in larger assemblies. Miniature magnetic field sensors play a key role as speed, precision, and weight all come into play. The sensors are integrated into these small assemblies with the same importance as the cylinder itself. Highly accurate switching points with high precision and high repeatability are mandatory requirements for such assembly processes.

To learn more about miniature magnetic field sensors visit www.balluff.com.

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