Principle and application of double sensor - Solutions - Huaqiang

Photocoupler

1. During the automatic feeding process, due to various external factors, multiple sheets of material may stick together and be transported simultaneously. This can lead to material waste, product failure, and even damage to the equipment. The purpose of double-sheet detection is to accurately identify when two or more sheets are fed at once, allowing for timely action to prevent them from entering the production line. 2. The principle behind double-sheet detection using a sensor involves an emitter generating a magnetic field that is detected by a receiver. Since most metals are electromagnetic conductors, the magnetic signal weakens as it passes through metal. The system evaluates this weakening and compares it with a baseline signal. If the signal strength changes significantly, it indicates that multiple metal sheets are stacked. Because the induced magnetic field depends on the material's properties and is not affected by external vibrations, the detection is highly stable and reliable. 3. Double-sheet detection is widely used in industries such as metal packaging, home appliance manufacturing, hardware stamping, automotive production, and circuit board fabrication. Among these, tin cans are one of the most common applications in the metal packaging sector. 4. The importance of installing a double-sheet inspection system includes: - Ensuring production efficiency: For example, in printing tinplate operations, there is often an oil layer on the surface. This can cause multiple sheets to be fed at once before printing or coating, leading to misalignment and damage to the rubber belt in the card machine. Installing this safety feature ensures smooth operation by detecting and controlling overlapping sheets. - Reducing labor costs: In some industries, double sheets may occur during stamping or rolling processes. Without automated detection, workers must manually inspect each sheet, increasing workload and the risk of missed defects. An electronic detection system can automate this process, reducing human effort and improving accuracy. - Preventing material waste: Material loss is a common issue in manufacturing, and double-sheet feeding contributes significantly to this problem. A detection system helps avoid unnecessary waste, saving both time and resources. - Protecting expensive molds and equipment: Molds are costly components in mechanical systems, often costing tens of thousands to hundreds of thousands of dollars. If multiple sheets are stamped together, it can easily damage the mold. Installing a double-sheet detection system ensures that only single sheets are processed, protecting valuable equipment. - Ensuring product quality: Quality is the foundation of any successful business. From printing and cutting to seam welding and sealing, every step in the canning process directly affects the final product’s quality. A reliable double-sheet detection system plays a crucial role in maintaining consistent and high-quality output throughout the entire production cycle.