Cov saw hlau pheej yig hauv khw feem ntau yog ua los ntawm roj hmab nylon, vim tias cov khoom siv raw pheej yig, tus nqi ntawm cov khoom tiav yog pheej yig heev. Txawm li cas los xij, qhov kev tiv thaiv kev hnav thiab kev tiv thaiv cua sov ntawm cov saw hlau yas ua los ntawm cov khoom siv raw no tsis zoo heev, thiab lub neej ua haujlwm luv luv. Cov saw hlau ua los ntawm nylon qis tsis tuaj yeem tiv thaiv cov kav dej cable zoo, thiab qhov nce tsis tsim nyog qhov poob. Thaum xaiv cov saw hlau yas engineering, cov neeg siv khoom feem ntau muaj kev tsis meej pem zoo li no: Yuav ua li cas thiaj paub tias lawv xaiv saw hlau zoo lossis phem? Nws tuaj yeem txheeb xyuas los ntawm cov hauv qab no.