Analysis of application of thin cans sealing technology

At present, China has more than 300 production lines for three-piece cans, with an annual production capacity reaching 23 billion cans. The 202 series (Φ52.3 mm) small metal cans are widely used in food, beverage, and chemical industries. Traditionally, tin cans have been made using materials with a thickness ranging from 0.2 to 0.23 mm. However, starting from the late 20th century, foreign countries began reducing the thickness of tinplate to between 0.14 and 0.16 mm, achieving a material utilization rate of over 30%. This thinner tinplate is known as ultra-thin (SR) tinplate. To maintain mechanical strength despite the reduced thickness, adjustments were made to the steel base composition and heat treatment processes. For instance, Corus in Europe produces class A steel plates with a thickness of δ=0.15 mm by reducing the manganese content (0.18–0.35 wt%) and lowering the annealing temperature to enhance hardness. One of the main challenges in using thin plates for sealing lies in their inconsistent mechanical properties—especially poor plasticity and high hardness. Current roll-seal structures and mold dimensions may not be suitable for such thin materials, leading to issues like inadequate seal tightness and surface defects. When using δ=0.16 mm thin plates, problems such as excessive wrinkling and unstable splice rates often occur during the roll-sealing process. For example, if the wrinkle degree exceeds 50%, it can affect the seal's integrity and cause scratches on the curling edge. Similarly, an unstable splice rate makes it difficult to meet industry standards. The characteristics of thin plate sealing are closely tied to metal plastic deformation theory. Exceeding the forming limit leads to instability and wrinkling, which can compromise the can’s structure and long-term storage capability. Commercial cans generally accept wrinkles up to 50% of the crimped length. Factors influencing wrinkling include plate hardness, thickness, and can diameter. Higher hardness increases elasticity and reduces formability, making wrinkling more likely. Thinner plates also face greater challenges in forming, especially when the can diameter is smaller, as this increases compressive deformation and instability. To address these issues, an experimental plan was developed focusing on reducing deformation. Key measures included adjusting the curling dimensions, optimizing the can body and lid design, refining the curling curve, and improving the indenter settings. These adjustments helped reduce wrinkling and improve the splice rate, ensuring better sealing performance. Additionally, precise machine calibration was crucial, including the installation of rollers and pressure heads, adjustment of the scroll wheel, and fine-tuning of the head burying degree. Through these efforts, the thin double-seaming process for δ=0.16 mm tinplate in 202 series cans was successfully optimized, meeting technical requirements in practical production. The results showed that the process could achieve a splice rate of 60–70% and a wrinkle degree of 40–55%, demonstrating its feasibility for broader application in the industry.

power wrench

Power Wrench,Impact Wrench,Electric Impact Wrench,Electric Wrench

Wuxi Winsun Automation Instrument Co., Ltd , https://www.winsunwx.com