Large paper, plastic, textile, and sheet-metal rolls typically consist of multiple segments that are connected or spliced together. When the roll is unspooled and transformed into the finished product, these splices must be identified and removed. Depending on the spooled material’s properties, different sensors are required to detect the splice and stop the feed.
Vinyl and Paper Splice Detection
The UGB-18GM50-255-2E3 thru-beam ultrasonic sensor is designed to detect splices on materials that are thin and consistent in their composition, such as paper or vinyl.
A teach function is performed while the process is running (typically for 10 seconds) with the sensors that are installed in the application. Here, the sensor learns the material thickness, while also taking into account any material inconsistencies and flutter.
Since a splice is thicker than the base material, it creates an acoustic amplitude differential that the sensor uses to trigger a “splice present” signal.
Sheet Metal Splice Detection
Double-sided adhesive tapes are commonly used to splice two metal sheets together. While sheet metals are homogenous, they are often too thick for a traditional splice-detection sensor (like the UGB-18GM50-255-2E3). If sheet metal is the base material, the diffuse-mode UB120-12GM-E5-V1 can be used.
This sensor has a short range and high frequency (850 kHz), which allows it to detect the edge of the overlapping sheet, as seen below. Sensors with a high frequency have a shorter wavelength, which makes them ideally suited to detect low profile edges.
Textile Splice Detection
Textiles are usually somewhat porous, non-uniform materials. This makes it difficult for a splice-detection sensor to establish a baseline to compare the splice against. Thus, the sensors used to detect paper, vinyl, or sheet metal splices will not work. For textile applications, a standard thru-beam sensor such as the UBE1000-18GM40-SE2-V1 can be used.
As seen in the image below, the splice has a higher density than the base material. This makes it easy for this type of sensor to differentiate between the material and the splice.