PDC sensor for paper stack detection
An ultrasonic sensor for paper stack detection is a specialized device that detects whether one, two, or no sheets of paper are present between a transmitter and receiver. These double sheet sensors are essential in printing, folding, and paper processing industries to prevent production errors caused by overlapping or missing sheets. This guide covers the operating principles, applications, and benefits of ultrasonic paper stack detection sensors.
An ultrasonic sensor for paper stack detection, commonly known as a double sheet sensor, is a specialized device that detects whether one, two, or no sheets of paper are present between a transmitter and receiver. Double sheet sensors are used in applications in which sheets or plates are processed, involving industries that process labels, use printing machines, or work with folding machines. Creases, wrinkles, and accumulation of sheets and plates can make a whole process come to a stop. Production errors can be detected early with the use of ultrasonic double sheet sensors and thus can be detected and solved in time to save time and money. The ultrasonic system provides reliable detection of no, one, or two overlapping sheet materials, preferably papers. The sensors are insensitive to printing, colors, and shining surfaces.
PDC Sensor
The working principle of a double sheet sensor is based on through-beam ultrasonic technology. Double sheet detection sensors are unique ultrasonic sensors that are placed in front of each other. The first sensor functions as a transmitter while the second one is a receiver. The material that has to be detected is led through these sensors. The transmitter sends out an ultrasonic soundwave from one side of the material, and the sound wave reaches the sheet. The signal has got through the sheet and is weakened as it reaches the receiver on the other side. The weakened soundwave tells the receiver that there is a sheet present. When a material, paper for example, flaps because of the vibrations from the sent soundwave, it has no effect on the detection. The sensors are available for various detection distances.
Double sheet sensors are available with different configurations and specifications. The UDC-F261-400-3E2-Y268499 double sheet sensor features a sensing range of 38 mm and a transducer frequency of 395 kHz. LED indicators provide clear status: green for single sheet detected, yellow for no sheet detected (air), and red for double sheet detected. The sensor operates on 20-30 V DC and features 3 PNP switch outputs. The sensors are capable of detecting material weights from 10 g/m2 up to over 2000 g/m2. Perpendicular or inclined sensor mounting relative to the sheet plane is possible. The sensors do not require teach-in, with function indicators visible from all directions. The UD18-2 specializes in checking for double layers and splices using ultrasonic technology, operating with precision to determine whether one or two sheets of material – or none at all – are present between its sender and receiver.
Double sheet sensors can be configured for different material types and thicknesses. The recommended mounting distance from transmitter to receiver is typically 40 mm, with the ability to deviate within the range of 20 to 60 mm. The sensor needs a teach-in beforehand for the material used in the application. The sensors are equipped with 3 inputs for teach-in, making it possible to configure three different settings for the materials and the thickness of them. The configurations for different materials are based on the grammage of the sheets or plates that need to be detected. The standard configuration is applied to materials with a grammage from 20 up to 1200 g/m2, with 'thin' configuration for less than 20 g/m2 and 'thick' configuration for over 1200 g/m2. It is possible to switch between configurations during production. In very critical applications, it is possible to teach-in a custom configuration for materials through the three inputs for teach-in.
The applications of double sheet sensors span multiple industries and processes. Double sheet sensors are used for detecting two or more sheets or sheets that partially overlap. This is used in applications such as paper printing machines, folding machines, in the production of silicon wafers, and the processing of labels. The ultrasonic double sheet detection is suitable for paper, cardboard, and foils. Double layer detection is also used for checking for double layers and glued areas in paper, cardboard, metal, and plastic. By detecting the presence of sheets, other processes can be adjusted to the supply of sheets that is led through the machine, which improves efficiency and prevents or resolves errors faster. The sensors provide reliable detection regardless of printing, colors, and shining surfaces. The ongoing development of ultrasonic double sheet sensor technology continues to improve the reliability and versatility of paper stack detection for the printing and converting industries.
