What is the German term for blanking cap?

The German term for blanking cap is indeed "Schutzkappe." This term is commonly used in mechanical and engineering contexts to refer to a protective cap that covers an opening or outlet to prevent contamination and protect the components inside from environmental effects. The word "Schutz" translates to "protection," and "Kappe" means "cap," which together aptly describe this function.

The other terms listed do not relate to the concept of a blanking cap. "Entlüften" pertains to venting or releasing air, typically from a system or container. "Befestigungswinkel" refers to a mounting angle or bracket used for securing components. "Buchse" translates to "socket," which denotes a receptacle for receiving something, often in an electrical context. Each of these terms serves different purposes and does not align with the function of a blanking cap, further emphasizing the accuracy of "Schutzkappe" as the correct choice.