Sensor Mounting Made Easy

So, you’ve figured out the best way to detect the product shuttle paddle in your cartoning/packaging machine needs a visible red laser distance sensor. It’s taken some time to validate that this is the right sensor and it will be a reliable, long-term solution.

But then you realize there are some mechanical issues involved with the sensor’s placement and positioning that will require a bit of customization to mount it in the optimal location. Now things may have just become complicated. If you can’t design the additional mounting parts yourself, you’ll have to find someone who can. And then you have to deal with the fabrication side. This all takes time and more effort than just buying the sensor.

Or does it?

Off-the-shelf solutions

It doesn’t have to be that complex. There are possible off-the-self solutions you can consider that will make this critical step of providing a reliable mounting solution – possibly as straightforward as choosing the right sensor. Multiple companies offer sensor mounting systems that accommodate standard sensor brackets. Over the years, companies have continued to develop new mounting brackets for many of their sensor products, from photoelectric sensors and reflectors to proximity sensors to even RFID heads and linear transducers.

So it’s only natural to take that one step further and create a mounting apparatus and system that not only provides a mounting bracket, but also a stable platform that incorporates the device’s mounting bracket with things like stand-off posts, adjustable connection joints, and mounting bases. Such a flexible and extensive system can solve mounting challenges with parts you can purchase, instead of having to fabricate.

Imagine in the example above you need to mount the laser distance sensor off the machine’s base and offset it in a way that doesn’t interfere with the other moving parts of the cartoner. Think of these mounting systems and parts as a kind of Erector Set for sensing devices. You can piece together the required mounting bracket with a set of brace or extension rods and a mounting base that raises the sensor up and off the machine base and even angles it to allow for pointing at the target in the most optimal way.

The following are some mounting solutions for a variety of sensors:

These represent only a small number of different ways to mix and match sensor device brackets and mounting components to find a solid, reliable and off-the-shelf mounting solution for your next mounting challenge. So before considering the customization route, next time take a look at what might already be out there for vendors. It could make your life a lot simpler.

Choosing Sensors Suitable for Automation Welding Environments

Standard sensors and equipment won’t survive for very long in automated welding environments where high temperatures, flying sparks and weld spatter can quickly damage them. Here are some questions to consider when choosing the sensors that best fit such harsh conditions:

    • How close do you need to be to the part?
    • Can you use a photoelectric sensor from a distance?
    • What kind of heat are the sensors going to see?
    • Will the sensors be subject to weld large weld fields?
    • Will the sensors be subject to weld spatter?
    • Will the sensor interfere with the welding process?

Some solutions include using:

    • A PTFE weld spatter resistant and weld field immune sensor
    • A high-temperature sensor
    • A photoelectric diffuse sensor with a glass face for better resistance to weld spatter, while staying as far away as possible from the MIG welding application

Problem, solution

A recent customer was going through two sensors out of four every six hours. These sensors were subject to a lot of heat as they were part of the tooling that was holding the part being welded. So basically, it became a heat sink.

The best solution to this was to add water jackets to the tooling to help cool the area that was being welded. This is typically done in high-temperature welding applications or short cycle times that generate a lot of heat.

    • Solution 1 was to use a 160 Deg C temp sensor to see if the life span would last much longer.
    • Solution 2 was to use a plunger prob mount to get more distance from the weld area.

Using both solutions was the best solution. This increased the life to one week of running before it was necessary to replace the sensor. Still better than two every 6 hours.

Taking the above factors into consideration can make for a happy weld cell if time and care are put into the design of the system. It’s not always easy to get the right solution as some parts are so small or must be placed in tight areas. That’s why there are so many choices.

Following these guidelines will help significantly.

Capacitive, the Other Proximity Sensor

What is the first thing that comes to mind if someone says “proximity sensor?” My guess is the inductive sensor, and justly so because it is the most used sensor in automation today. There are other technologies that use the term proximity in describing the sensing mode, including diffuse or proximity photoelectric sensors that use the reflectivity of the object to change states and proximity mode of ultrasonic sensors that use high-frequency sound waves to detect objects. All these sensors detect objects that are in close proximity to the sensor without making physical contact. One of the most overlooked or forgotten proximity sensors on the market today is the capacitive sensor.

Capacitive sensors are suitable for solving numerous applications. These sensors can be used to detect objects, such as glass, wood, paper, plastic, or ceramic, regardless of material color, texture, or finish. The list goes on and on. Since capacitive sensors can detect virtually anything, they can detect levels of liquids including water, oil, glue, and so forth, and they can detect levels of solids like plastic granules, soap powder, sand, and just about anything else. Levels can be detected either directly, when the sensor touches the medium, or indirectly when it senses the medium through a non-metallic container wall.

Capacitive sensors overview

Like any other sensor, there are certain considerations to account for when applying capacitive, multipurpose sensors, including:

1 – Target

    • Capacitive sensors can detect virtually any material.
    • The target material’s dielectric constant determines the reduction factor of the sensor. Metal / Water > Wood > Plastic > Paper.
    • The target size must be equal to or larger than the sensor face.

2 – Sensing distance

    • The rated sensing distance, or what you see in a catalog, is based on a mild steel target that is the same size as the sensor face.
    • The effective sensing distance considers mounting, supply voltage, and temperature. It is adjusted by the integral potentiometer or other means.
    • Additional influences that affect the sensing distance are the sensor housing shape, sensor face size, and the mounting style of the sensor (flush, non-flush).

3 – Environment

    • Temperatures from 160 to 180°F require special considerations. The high-temperature version sensors should be used in applications above this value.
    • Wet or very humid applications can cause false positives if the dielectric strength of the target is low.
    • In most instances, dust or material buildup can be tuned out if the target dielectric is higher than the dust contamination.

4 – Mounting

    • Installing capacitive sensors is very similar to installing inductive sensors. Flush sensors can be installed flush to the surrounding material. The distance between the sensors is two times the diameter of the sensing distance.
    • Non-flush sensors must have a free area around the sensor at least one diameter of the sensor or the sensing distance.

5 – Connector

    • Quick disconnect – M8 or M12.
    • Potted cable.

6 – Sensor

    • The sensor sensing area or face must be smaller or equal to the target material.
    • Maximum sensing distance is measured on metal – reduction factor will influence all sensing distances.
    • Use flush versions to reduce the effects of the surrounding material. Some plastic sensors will have a reduced sensing range when embedded in metal. Use a flush stainless-steel body to get the full sensing range.

These are just a few things to keep in mind when applying capacitive sensors. There is not “a” capacitive sensor application – but there are many which can be solved cost-effectively and reliably with these sensors.

Weld Immune vs. Weld Field Immune: What’s the difference? 

In today’s automotive plants and their tier suppliers, the weld cell is known to be one of the most hostile environments for sensors. Weld slag accumulation, elevated ambient temperatures, impacts by moving parts, and strong electromagnetic fields can all degrade sensor performance and cause false triggering. It is widely accepted that sensors will have a limited life span in most plants.

Poor sensor selection does mean higher failure rates which cause welders in all industries increased downtime, unnecessary maintenance, lost profits, and delayed delivery. There are many sensor features designed specifically to withstand these harsh welding environments and the problems that come along with them to combat this.

In the search for a suitable sensor for your welding application, you are sure to come across the terms weld immune and weld field immune. What do these words mean? Are they the same thing? And will they last in my weld cell?

Weld Immune ≠ Weld Field Immune

At first glance, it is easy to understand why someone may confuse these two terms or assume they are one and the same.

Weld field immune is a specific term referring to sensors designed to withstand strong electromagnetic fields. In some welding areas, especially very close to the weld gun, welders can generate strong magnetic fields. When this magnetic field is present, it can cause a standard sensor to perform intermittently, like flickering and false outputs.

Weld field immune sensors have special filtering and robust circuitry that withstand the influence of strong magnetic fields and avoid false triggers. This is also called magnetic field immune since they also perform well in any area with high magnetic noise.

On the other hand, weld immune is a broad term used to describe a sensor designed with any features that increase its performance in a welding application. It could refer to one or multiple sensor features, including:

    • Weld spatter resistant coatings
    • High-temperature resistance
    • Different housing or sensor face materials
    • Magnetic field immunity

A weld field immune sensor might be listed with the numerous weld immune sensors with special coatings and features, but that does not necessarily mean any of those other sensors are immune to weld fields. This is why it is always important to check the individual sensor specifications to ensure it is suitable for your application.

In an application where a sensor is failing due to impact damage or weld slag spatter, a steel face sensor with a weld resistant coating could be a great solution. If this sensor isn’t close to the weld gun and isn’t exposed to any strong magnetic fields, there is really no need for it to be weld field immune. The important features are the steel face and coating that can protect it against impact and weld slag sticking to it. This sensor would be classified as weld immune.

In another application where a sensor near the weld gun side of the welding procedure where MIG welding is performed, this location is subject to arc blow that can create a strong magnetic field at the weld wire tip location. In this situation, having a weld field immune sensor would be important to avoid false triggers that the magnetic field may cause. Additionally, being close to a MIG weld gun, it would also be wise to consider a sensor with other weld immune properties, like a weld slag resistant coating and a thermal barrier, to protect against high heat and weld slag.

Weld field immunity is just one of many features you can select when picking the best sensor for your application. Whether the issue is weld slag accumulation, elevated ambient temperatures, part impact, or strong electromagnetic fields, there are many weld immune solutions to consider. Check the placement and conditions of the sensors you’re using to decide which weld-immune features are needed for each sensor.

Click here for more on choosing the right sensor for your welding application.

 

Is a Photoelectric Sensor Best for Your Label Detection Application?

Label detection is in every industry of manufacturing. Detecting the placement, orientation, color, or size of a label is critical to product quality and it can even be required for safety purposes. Contrary to what some believe, not every label detection application requires an expensive vision system. This article reviews some common applications that can be solved with just a photoelectric sensor.

As with any sensor application, it’s necessary to specifically tailor the systems for individual applications. In label detection, the label properties dictate the necessary sensor for the job. Using the right sensor will ensure accuracy to the manufacturing process by limiting the possibility of errors or misreads when placing or cutting off the label. The chance for mistakes decreases when labels are designed to have markings used as a point of reference for the sensor to recognize, telling the PLC programming that it is time to cut off or place the label. When looking into a label detection application, several photoelectric sensor types are available.

Through-beam fork sensors

A through-beam fork sensor has an emitter and a receiver built into the same housing which provides a consistent light beam that is simple to configure to many applications. For label detection, fork sensors have teach-in buttons to set the target and background so unique markings can trigger the sensor. This helps find an identification marker that can identify where to cut the label. For applications with consistent markings on different labels, the sensor would not need to be retaught if the color of the identification mark and the background are the same. The common use for these sensors is on flexible manufacturing lines because operators can reteach the sensor to recognize a new label with a different style and color in less than 60 seconds.

Contrast sensors

Providing a high level of accuracy to find labels in an assortment of products, contrast sensors can be taught to identify a target on many different material types, providing an advantage when working with three-dimensional objects. They provide background suppression, allowing for applications using transparent objects, such as glass and plastic and work by distinguishing between objects based on their gray values. This means contrast sensors are highly accurate when detecting objects with similar colors.  

Color sensors

Color sensors are a fantastic choice when working with labels with many different colors. A traditional color sensor can be taught to up to 7 different color parameters to distinguish one label type from the others. Manufacturers with multiple production lines that have labels with various colors can use just one color sensor to detect them all. The more advanced IO-Link-capable color sensors provide an abundance of opportunities to configure many different label types. Using color detection software, one color sensor can be taught up to 256 different color parameters. Users can configure each color setting for the label’s colors and the background.

When it comes to selecting the right sensor for your label detection, you have options. You need to consider the specifics of your application and choose the solution that ensures accuracy and quality during the manufacturing process. For more information about the Balluff photoelectric sensors, visit https://www.balluff.com/en-us/products/areas/A0001/groups/G0103/products/F01325?page=1&perPage=10&searchTerm=.

Custom Sensors: Let Your Specs Drive the Design

Customized sensors, embedded vision and RFID systems are often requirements for Life Science devices to meet the needs for special detection functions, size constraints and environmental conditions. Customization can dramatically raise costs and you don’t want to pay for stock features, such as an external housings and universal outputs, that are simply not needed. So, it comes down to your specification driving the design. A qualified sensor supplier can create custom orders, allowing your specifications to drive the design, building just what you need and nothing you don’t.

It’s as easy as putting a model together.

The process is fairly straight forward. After reviewing your specifications, the sensor supplier develops a plan to supply a functional prototype for your testing phase. Qualified sensing companies can quickly build prototypes either by starting with a standard product or using standard modules. Both methods have advantages.

Standard Product approach: This is the fastest method to get a prototype up and running. Here, the focus is on providing a solution for the basic sensing/detection application. Once testing confirms the functionally, a custom project is started. The custom project ensures seamless integration into your device. Also, cost control measures can be addressed.

Standard Module approach: This will handle the most demanding applications. When a standard product is not able to meet the basic required functionally, we turn to the base component modules. An ever-growing field of applications are solved by combining options from the hundreds of available modules. While this takes more time, the sensing company can deliver a near final prototype in much less time than if they were creating an internal development.

Qualified sensor companies can easily handle the production side as well. With significant investments in specialized automated manufacturing equipment, production can be scaled to meet varying demands. And as components go obsolete, sustaining engineering projects are routinely handled to maintain availability. This can be disruptive for internal production or contract manufacturers. Sensor companies will take on the responsibility of life-cycle management for years to come. It’s part of their business model.

So, make sure your sensor, embedded vision or RFID supplier has a large model kit to pull from. Your projects will exceed your specification and be completed on time without long-term life-cycle issues.

For more information , visit https://www.balluff.com/en/de/service/services/productbased-service/.

 

IO-Link Boosts Plant Productivity

In my previous blog, Using Data to Drive Plant Productivity, I categorized reasons for downtime in the plant and also discussed how data from devices and sensors could be useful in boosting productivity on the plant floor. In this blog, I will focus on where this data is and how to access it. I also touched on the topic of standardizing interfaces to help boost productivity – I will discuss this topic in my future blog.

Sensor technology has made significant progress in last two decades. The traditional transistor technology that my generation learned about is long gone. Almost every sensor now has at least one microchip and possibly even MEMs chips that allow the sensor to know an abundance of data about itself and the environment it which it resides. When we use these ultra-talented sensors only for simple signal communication, to understand presence/absence of objects, or to get measurements in traditional analog values (0-20mA, 0-10V, +5/-5V and so on), we are doing disservice to these sensors as well as keeping our machines from progressing and competing at higher levels. It is almost like choking the throat of the sensor and not letting it speak up.

To elaborate on my point, let’s take following two examples: First, a pressure sensor that is communicating 4-20mA signal to indicate pressure value. Now, that sensor can not only read pressure value but, more than likely, it can also register the ambient temperatures and vibrations. Although, the sensor is capable of understanding these other parameters, there is no way for it to communicate that information to the higher level controller. Due to this lack of ambient information, we may not be able to prevent some eminent failures. This is because of the choice of communication technology we selected – i.e. analog signal communication.

For the second example, let us take a simple photoeye sensor that only communicates presence/absence through discrete input and 0/1 signal. This photoeye also understands its environment and other more critical information that is directly related to its functionality, such as information about its photoelectric lens. The sensor is capable of measuring the intensity of re-emitted light, because based on that light intensity it is determining presence or absence of objects. If the lens becomes cloudy or the alignment of the reflector changes, it directly impacts the remitted light intensity and leads to sensor failure. Due to the choice of digital communication, there is no way for the sensor to inform the higher level control of this situation and the operator only learns of it when the failure happens.

If  a data communication technology, such as IO-Link, was used in these scenarios instead of signal communication, we could unleash these sensors to provide useful information about themselves as well as about their environment. If we collect this data or set alerts in the sensor for the upper/lower limits on this type of information, the maintenance teams would know in advance about the possible failures and prevent these failures to avoid eminent downtime.

Collecting this data at appropriate frequencies could help build a more relevant database and demonstrate patterns for the next generation of machine learning and predictive maintenance initiatives. This would be data driven continuous improvement to prevent failures and boost productivity.

The information collected from sensors and devices – so called smart devices – not only helps end users of automation to boost their plant’s productivity, but also helps machine builders to better understand their own machine usage and behaviors. Increased knowledge improves the designs for the next generation of machines.

If we utilized these smart sensors and devices at our change points in the machine, it would help fully or partially automate the product change-overs. With IO-Link as a technology, these sensors can be reconfigured and re-purposed for different applications without needing different sensors or manual tunings.

IO-Link technology has a built in feature called “automatic parameterization” that helps reduce plant down-time when sensors need replaced. This feature stores IO-Link devices’ configuration on the master port as well as all the configuration is also persistent in the sensor. Replacement is as simple as connecting the new sensor of the same type, and the IO-Link master downloads all the parameters and  replacement is complete.

Let’s recap:

  1. IO-Link unleashes a sensor’s potential to provide information about its condition as well as the ambient conditions, enabling condition monitoring, predictive maintenance and machine learning.
  2. IO-Link offers remote configuration of devices, enabling quick and automated change overs on the production line for different batches, reducing change over times and boosting plant productivity.
  3. IO-Link’s automatic parameterization feature simplifies device replacement, reducing unplanned down-time.

Hope this helps boost productivity of your plant!

The Benefits of Guided Changeover in Packaging

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.

Many packaging machine builders are now providing fully automated changeover, where motors move pieces into the correct position upon recipe change.  This has proven to be a winning solution, however, not every application can accommodate motors, especially those on older machines.

Guided changeover represents an opportunity to modify or retrofit existing equipment to improve agility and flexibility on older machines that are not yet ready to be replaced.

An affordable intermediate step between fully manual and fully automated changeover: 

A measurement sensor can be added to provide position feedback on parts that require repositioning for changeover.  By using indicator lights, counters or displays at the point of use, the operator is provided with visual guidance to reposition the moving part.  Only once all parts are in the correct position can the machine start up and run.

By utilizing this concept, CPG companies can realize several key benefits:

  • Reduced planned downtime: Adding guidance reduces the amount of time it takes to move parts into the correct position.
  • Reduced unplanned downtime: Providing operator guidance minimizes mistakes, avoiding jams and other problems caused by misalignment.
  • Reduced waste: Operators can “dial in” moving parts quickly and precisely.  This allows the machine to be fully operational sooner, minimizing runoff and scrap.
  • Improved operator training: Providing operator guidance helps CPG companies deal with inevitable workforce attrition.  New operators can be quickly trained on changeover procedures.

Selecting the correct sensor

A variety of sensor technologies can be used to create guide changeover; it’s really a matter of fit, form and function.  Common technologies used in changeover position applications include linear positioning transducers  and encoders.  Other devices like inductive and photoelectric distance sensors can be used with some creativity to solve challenging applications.

Available mounting space and environmental conditions should be taken into consideration when selecting the correct device.  Sensors with enhanced IP ratings are available for harsh environmental conditions and washdown.

Analog devices are commonly used to retrofit machines with older PLCs, while IO-Link can be used in place of analog for a fully digital solution, enabling bi-directional communication between the sensor and controller for condition monitoring, automatic device replacement and parameter changes.

Environmental Impacts – Choosing the Right Sensor for the Conditions

Last week’s blog spoke about reducing waste and downtime by implementing LEAN manufacturing procedures. This involves taking a proactive approach to improving efficiencies. This post will focus on selecting the right part for the job to reduce failure rates that lead to avoidable machine downtime and increased costs.

Hardly a day passes by where we are not contacted by a desperate end-user or equipment manufacturer seeking assistance with a situation of sensors failing at an unacceptably high rate.  Once we get down to the root cause of the failures, in most cases it’s a situation where the sensors are being applied in a manner which all but guarantees premature failure.

Not all sensors are created equal.  Some are intentionally designed for light-duty applications where the emphasis is more on economic cost rather than the ability to survive in rough service conditions.  Other sensors are specifically designed to meet the challenges of specific application environments, and as a result may carry a higher initial price.

Some things to think about when choosing a sensor for a new application:

  • What kind of environmental conditions will the sensor be exposed to?  For example:
    • Very low or very high temperatures
    • Constant exposure to or immersion in liquid
    • Continuous vibration
    • Extreme shock
    • Disruptive electrical noise (hand-held radios, welding fields, etc.)
    • Chemical contamination
    • Physical abuse or impact
    • Abrasion
    • High pressure washdown procedures
    • Exposure to outdoor conditions of UV sunlight, rain, ice, temperature swings, and condensing humidity
  • Is it possible to relocate the sensor to move it away from the difficult condition?
  • Is the sensor technology the best choice given the kind of application environment that it must operate in?
  • Is there a way to protect the sensor from exposure to the worst of the damaging effects?

When you reach for a catalog or jump on the internet to look for a sensor, it’s a good practice to just stop a moment first and make a list of the environmental challenges that the sensor could face.  Then you will be prepared to make an appropriate selection that best meets your expected application conditions.

1.jpg

Heavy metal parts being loaded into a welding cell can damage specialty nut detection sensors designed to stick through a hole in a part.  Plunger probes are a better solution.

2

Unprotected and non-bunkered sensors in damage prone areas result in premature sensor failure.

Distance Measurement with Inductive Sensors

When we think about inductive sensors we automatically refer to discrete output offerings that detect the presence of ferrous materials. This can be a production part or an integrated part of the machine to simply determine position. Inductive sensors have been around for a long time, and there will always be a need for them in automated assembly lines, weld cells and stamping presses.

We often come across applications where we need an analog output at short range that needs to detect ferrous materials. This is an ideal application for an analog inductive proximity sensor that can offer an analog voltage or analog current output. This can reliably measure or error proof different product features such as varying shapes and sizes. Analog inductive sensors are pure analog devices that maintain a very good resolution with a high repeat accuracy. Similar to standard inductive sensors, they deal very well with vibration, commonly found in robust applications. Analog inductive proximity sensors are also offered in many form factors from M12-M30 tubular housings, rectangular block style and flat housings. They can also be selected to have flush or non-flush mounting features to accommodate specific operating distances needed in various applications.

Application Examples:

Shawn_1.png

Shawn_2

For more specific information on analog inductive sensors visit www.balluff.com.