Processing Magazine

Sensors Detect Small Metal Objects in Material Handling Applications

April 26, 2010
The ring and tube inductive proximity sensors detect small metal objects used in material flow applications such as feeder processes and parts counting. Metal parts such as rivets, screws, springs and bolts are detected as they travel through plastic tubing. The sensors feature quick response times and high resolutions, according to the manufacturer. Each model offers two output versions: static and dynamic. Static-style sensors generate an output signal when there is metal in the detection zone. These sensors can be used for a variety of feed applications that include detecting falling screws or monitoring for jams. Static-style sensors are also used in wire-break detection applications. Dynamic sensors are used when very small parts with low mass or fast-moving parts need to be detected. As the parts travel past the sensor, the sensor generates an output, which is adjustable from 0.1 to 150 ms. The resolution is also adjustable and will remain stable, even in the case of metal contamination in the tube. Ring sensors are Micro DC units with PNP or NPN outputs, normally open / normally closed and are available in a variety of diameters from 10.1mm to 15.1 mm. Tube sensors are Micro DC units with PNP or NPN outputs, normally open.