Why Use Metal-Faced Sensors that Fail? Use the Ones that Don't!

Why Use Metal-Faced Sensors that Fail? Use the Ones that Don't!

, by Jim Ryan, 3 min reading time

What is that picture above? It looks like an inductive proximity sensor that is impervious to weld slag on one half of its surface but not the other. More on that later.

First, let's look at ordinary metal-faced sensors. They fail in several ways. At the top of the list is that they collect weld slag on their faces. At least the faces don't melt, burn, or otherwise get destroyed by the heat, as plastic-faced sensors do, but that is small comfort because failure is failure, no matter how it comes. Look at the slag buildup on the face of this metal sensor:

If the sensor is mediocre, this is a show-stopper. The slag BBs stuck to the face are made of metal and will  therefore likely keep the sensor in the ON state. If the sensor is of a little better quality, it will continue to operate for a while. However, the slag keeps piling up and when enough BBs are stuck to the face, the sensor will see them as a metallic object and go into its ON state permanently.

Now look closely at the picture again. You see two more problems, don't you? There are BBs at the edge. They seem to like it there. Also, the threads are coated with spatter! When you try to replace the burnt-out prox, you might be unable to get it out of its mount because the threads are no longer usable. You might have to remove and replace the mount! Downtime! I sure hope you weren't planning on actually welding today and had nothing better to do than change out sensors and mounts. Wait, are there any replacement mounts in the storeroom? No?! We have to have some shipped to us?! Can they overnight it? MY WELD CELL WILL BE DOWN FOR DAYS BECAUSE THE SPATTER NOT ONLY RUINED THE SENSOR FACE BUT ALSO ITS THREADS?! AAARRRGGGH! THAT'S OKAY, IT'S NOT LIKE WE HAVE A FACTORY LINE TO RUN!

Okay, everyone got a little upset there. Let's just calm down and evaluate the situation by just looking through pictures of it. Take a sip of coffee and look at these images. They show the problems.

These sensors have been burned out by the welding spatter. Metal-metal faced sensors are a step in the right direction but they need the finishing touch to make them impervious to weld spatter. That touch is ACTIVSTONE coating. This makes a good metal-faced sensor an excellent sensor.

Now let's get back to the half-coated metal-faced prox. Half of the surface was coated with ACTIVSTONE and half was not. Then, the prox was subjected to weld spatter. Take a closer look:

The ACTIVSTONE protected the sensor!

What is ACTIVSTONE coating? How does it make the surface of the sensor able to deflect spatter? Take a look at our ACTIVSTONE page and then come back.

Weld Dynamix's sensors are all coated with ACTIVSTONE. So are our cables and mounts. Stop your weld cell maintenance headaches by using all three in your weld cells. Can't replace your cables? No problem. Just slip on our ACTIVFLEX cable protection tubing. It takes only seconds.

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