Cov ntaub ntawv rau precision machining yog muab faib ua ob pawg, cov ntaub ntawv hlau thiab cov khoom tsis yog xim hlau. Rau cov khoom siv hlau, qhov hardness ntawm stainless hlau yog qhov loj tshaj plaws, ua raws li cov hlau cam khwb cia, ua raws li tooj liab, thiab thaum kawg txhuas. Kev ua cov ceramics thiab plastics belongs rau kev ua cov ntaub ntawv tsis yog xim hlau.
Rau qhov xav tau ntawm cov khoom siv hardness, rau qee lub sijhawm, qhov siab dua qhov hardness ntawm cov khoom, qhov zoo dua. Nws tsuas yog txwv rau cov kev xav tau ntawm hardness ntawm lub tshuab ua haujlwm. Cov ntaub ntawv ua tiav tsis tuaj yeem nyuaj dhau. Yog tias lawv nyuaj dua li cov khoom siv tshuab, lawv tsis tuaj yeem ua tiav. Cov khoom siv yog mos thiab tawv, uas yog tsawg kawg yog ib qib qis dua qhov hardness ntawm lub tshuab qhov chaw. Nyob rau tib lub sijhawm, nws kuj nyob ntawm kev ua haujlwm ntawm cov khoom siv ua tiav thiab cov khoom tsim nyog xaiv ntawm lub tshuab qhov chaw.
Yog li ntawd, ua ntej ua, peb yuav tsum xyuam xim rau qhov ceev ntawm cov khoom. Yog hais tias lub ntom ntom loj heev, nws yog sib npaug rau lub zog hardness, thiab yog tias lub hardness ntau tshaj li lub hardness ntau tshaj li cov khoom siv, uas yuav tsis tsuas yog puas cov seem, tab sis kuj ua rau muaj kev txaus ntshai, xws li cov cuab yeej tshuab dhos ya tawm thiab ua rau neeg raug mob. Yog li, feem ntau hais lus, rau kev siv tshuab, cov khoom siv zoo yuav tsum qis dua qhov hardness ntawm lub tshuab cuab yeej, kom nws tuaj yeem ua tiav.
