The complete guide to proximity and photoelectric sensors

Omron sensors are tailored to specific needs that are common in the automotive industry, particularly with respect to stamp and weld applications. Tell us what your specific issue is, and we’ll suggest a sensor type to help. Here are a few of the common problems our automotive customers face.

1. Experiencing downtime caused by sensor collisions? The extended sensing distances of the E2EW and E2E NEXT prox sensors help reduce sensor damage and boost flexibility by letting you imbed sensors for better protection or move targets further away

2. Seeking a better way to accommodate aluminum part presence detection? Omron E2EW sensors not only achieve longer sensing distance than any other metal face sensor in the industry, but they do so for both iron and aluminum.

3. Having problems with slag buildup on sensors? The proprietary slag resistance coating of the E2EW repels slag better than traditional coatings and is resilient to any scrubbing that is necessary to clean off the buildup. IO-Link can also help identify when it’s necessary to clean the sensor surface.

4. Difficulty locating small parts or holes? The E3AS-HL photoelectric sensors can use both spot and line beams to detect challenging parts.

5. Frustrated with having to set up separate emitters and receivers to detect oddly shaped or colored objects? The E3AS photoelectric sensors offer two different technologies to eliminate the need for a second unit, be it a receiver or reflector. The E3AS-F uses time-of-flight (TOF) technology and a wide spot beam to ensure that incident light is returned to the sensor and detected regardless of target color.

6. Having trouble with gross part detection involving grooved or rough surfaces? The spot/line beam options of the E3AS-HL can help with this as well.

7. Looking to position parts at longer distances with a high degree of precision? The E3AS-HL sensors use a small spot laser beam that can detect pins or holes to help in part positioning. They also include a feature that lets you set narrow detection windows.

Omron sensors push the boundaries of sensing and environmental resistance to outperform in automotive stamp and weld applications. Here we’ll take a look at some of the reasons why this sensing portfolio is unique in its ability to support automotive manufacturers.

1. Advanced sensing technologies that promote flexibility

From exceptionally long sensing distances to techniques that allow for the detection of grooved, multicolor or otherwise complex parts, Omron sensors support production line flexibility by making it possible to use the same sensors on multiple targets and recess sensors farther back within tooling to avoid collisions and slag buildup.

• E2EW sensors lead the industry in metal face prox sensor sensing distances, pushing the boundaries of what was thought possible. They also accommodate mixed metal production lines with factor 1 sensing.
• E3AS-HL CMOS photoelectric sensors use proprietary algorithms and a specialized lens to detect challenging parts. The option to use a spot or line beams adds additional flexibility to selectively detect different objects or parts of objects.
• The E3AS-F family’s time of flight technology and IR laser light source allow for extended range sensing of complex parts without a second unit, thereby reducing wiring, simplifying setup and eliminating alignment issues.

2. Top-of-the-line environmental resistance

Automotive stamp and weld applications are among the most difficult sensing environments that exist. Stamp processes often make prox sensors susceptible to impact from fast-moving metallic parts. Omron overcomes these challenges with environmentally resistant, extended range sensors that maximize system uptime in challenging environments.

• E2EW proximity sensors are built with the harshness of weld environments in mind. Their stainless steel body holds up against impacts, and weld field immunity keeps sensing stable amid magnetic fields. Optional slag resistance coatings keep maintenance needs to a minimum.
• E3AS sensors have unique upgrades to withstand grimy environments. A proprietary antifouling coating repels oil and dirt to keep lenses clear, and an optional air blow unit allows enhances cleaning even further. Protective lens covers are also available.
• E2E NEXT plastic face proximity sensors and E3AS photoelectric sensors are IP67G rated reducing the potential for oil ingress and malfunction. To learn more about the importance of an IP67G rating, check out our white paper on the topic.

3. Intelligence at the sensor level

Omron sensors are getting smarter by the year, and they can now form a key part of your predictive maintenance initiatives. For example, our proximity sensors let you know when there’s too much slag buildup or when parts are close enough to cause damage. This functionality is made possible by IO-Link.

• IO-Link enables condition monitoring for predictive maintenance. You can set alarms on our E2E NEXT and E2EW sensors to indicate potentially damaging target drift towards the sensor, and the E2EW also allows for slag buildup thresholds. With the E3AS sensors, you can set alarms for abnormal light intensity (indicating particulate or liquid buildup).
• IO-Link reduces commissioning time and increases replacement integrity. You can remotely configure multiple sensors, and IO-Link masters can store configuration information as well as part number information to ensure that replacement sensors are configured correctly.
• IO-Link information can be used as input information. Our E3AS-F and E3AS-HL sensors can provide measurement information via this technology that can be used for sensor configuration.

If you’re seeking a better way to protect your stamp and weld equipment investment, you’re likely to find an effective solution in our extensive sensing portfolio. Our latest sensing lines are designed with automotive industry challenges in mind, particularly targeting the need to maximize uptime.

Let’s take a look at a few great options in detail.

Many stamp and weld applications require the detection of a variety of metals, and inductive prox sensors are the ideal choice for metal presence/absence detection. That said, this type of sensor detects each metal type at a different distance, often requiring users to mount their sensors in vulnerable places to detect all the metals being used.

Sensing distances are based on the sensing range for iron, so when users are sensing non-ferrous metals (those that don’t contain iron), a correction factor is used. This typically gives a lower sensing distance, making it impossible to standardize on a single sensor for applications containing both ferrous and non-ferrous metals.

Factor 1 sensing can help overcome this challenge. Factor 1 sensing indicates that the correction factor for sensing a non-ferrous material is 1, meaning that the sensing distance can be used as-is. Not only is it possible to mount sensors in more protected places, but it’s also easy to standardize on sensors that can function in sensing applications for multiple metals.

Ultimately, factor 1 sensing reduces application complexity by eliminating the need for adjustments and special accommodations that would otherwise be required for varied metal detection. All target metals will have the same sensing range, making design and implementation much simpler and less time-consuming.

The sensing range for various metals is not only made constant with factor 1 sensing, but also improved across the board. This allows sensors to be mounted at a greater distance from moving parts to minimize collisions and avoid costly downtime. This also significantly enhances overall layout flexibility.

Both very small objects and targets that are heavily contoured — basically, anything that has lots of ridges or changes in depth — can be quite challenging to detect. For this reason, we’ve made a point of including two types of beams — a spot beam and a line beam — in our E3AS-HL sensors to provide maximum detection flexibility.

Spot beams and line beams have different pros and cons. Spot beams are useful for detecting small objects. Although most of the target parts in stamp and weld applications involve relatively large parts, detecting small parts comes in handy when small holes or pins are used as a reference point to position a larger object in the right orientation.

This is particularly important with respect to riveting, which is a widely used technique in the automotive industry for aluminum-to-steel binding. Manufacturers are using sensors to make sure that the nuts and rivets are in the right spots, and spot beams are very useful for detecting these small items.

Line beams, on the other hand, can be extremely useful in detecting highly contoured targets, such as an engine block. A line beam averages out the ridges and depth changes to achieve a consistent output rather than an inconsistent or flickering output that you would get with a spot beam.

The receiver of a line beam is in a two-dimensional, square-shaped array that provides multiple areas for light to hit. Once light is detected, an algorithm averages out the various intensities that are detected and makes a determination of where the object is located. A spot beam, on the other hand, only allows light to hit a single part of the receiver.

One of the major benefits of the E3AS-HL sensor is that they can do very fine background suppression, so it’s possible to differentiate between two objects that are very close to one another. However, this can also cause the sensor to falsely detect an object with varying topography as multiple objects. This is where line beams can improve overall detection.