N'ime nchara zuru ụwa ọnụ, 50 ruo 60% bụ nke a na-eji mpempe akwụkwọ eme ihe, ọtụtụ n'ime ha bụ ngwaahịa emechara nke a na-agbanye ma pịa. A na-edobe ahụ ahụ ụgbọ ala ahụ, mpempe radiator, drum uzuoku nke igwe ọkụ ọkụ, ihe mkpuchi nke akpa, iron isi silicon ígwè nke igwe eletriki na ngwa eletriki, wdg niile bụ akara ma hazie ya. Enwekwara akụkụ dị ukwuu nke stamping na ngwá ọrụ, ngwa ụlọ, dulls ụlọ ọrụ, arịa nchekwa na ngwaahịa ndị ọzọ.