Sealing plastic cups with cover film is a common sealing method for yogurt packaging, which fully utilizes the bonding between the cover film and the cup body boundary when exposed to heat to achieve product sealing and achieve sealing effect. Customers must remove the cover film before enjoying, and the difficulty of removing the cover film directly affects the consumer experience and determines the product image. The opening force of the sealing film for yogurt cups is also known as sealing strength or heat sealing strength. Many dairy companies use increasing the sealing strength between the sealing film and the cup body to ensure the sealing of yogurt cups. If the heat sealing strength is too high, the sealing cover film is not suitable for opening;If the sealing strength is small, it is easy to cause damage and leakage during storage, transportation or trading, which may result in yogurt being unable to continue to be enjoyed or even contaminating other items. So the sealing strength of yogurt cups should be maintained within a scientifically reasonable range, which not only meets the product's sealing standards, but also does not affect the product's opening strength.