There are four kinds of people who study mold design. The first kind is a locksmith who has worked in a mold factory for many years, the second kind is an adjustment master or foreman in an injection molding factory, the third kind is a general worker who knows nothing about molds for many years, and the fourth kind is just out of school and has no social experience. Generally, the first class lasts about 2 months, the second class lasts for 3 months, the third class lasts for 4 months and the fourth class lasts for 5 months. See what kind of person you are.