Ua ntej tshaj plaws, qhov ua tiav saum npoo thiab qhov ntxhib nto yog tib lub tswv yim, thiab kev ua tiav saum npoo yog lwm lub sijhawm rau qhov ntxhib nto. Qhov ua tiav saum npoo yog muab tso rau pem hauv ntej raws li tib neeg pom kev pom, thiab qhov ntxhib qhov ntxhib tau muab tso rau pem hauv ntej raws li qhov tseeb ntawm qhov chaw micro-geometry. Vim tias ua raws li cov txheej txheem thoob ntiaj teb (ISO), Tuam Tshoj tau lees paub qhov ntxhib nto thiab tshem tawm qhov chaw tiav hauv xyoo 1980s. Tom qab tshaj tawm hauv lub tebchaws cov qauv rau qhov ntxhib nto GB3505-83 thiab GB1031-83, qhov ua tiav saum npoo tsis siv lawm.
Muaj cov lus sib piv sib piv rau qhov ua tiav thiab qhov ntxhib nto. Roughness muaj cov lej ntsuas rau ntsuas, thiab kev sib luag tsuas yog piv nrog tus qauv ntsuas. Yog li ntawd, qhov ntxhib yog kev tshawb fawb ntau dua thiab nruj dua qhov ua tiav.
Qhov ci ntsa iab saum npoo qhia qhov muaj zog ntawm kev nthuav dav nthuav dav ntawm lub teeb ntawm cov khoom. Los ntawm qhov muag liab qab, yog hais tias qhov cuam tshuam qhov cuam tshuam ntawm lub ntsej muag yog qhov muaj zog, nws ze rau qhov tshwj xeeb cov nyhuv, thiab qhov ci ntsa iab siab. Ntawm qhov tsis sib xws, yog hais tias qhov cuam tshuam qhov cuam tshuam ntawm lub ntsej muag tsis muaj zog, qhov ci ci qis. Yog li ntawd, ci tseem hu ua daim iav ci. Qhov muaj feem cuam tshuam ntawm qhov ci ntsa iab yog cuam tshuam nrog lub cev lub cev ntawm cov nplaim thiab cov khoom siv tshuaj lom neeg ntawm cov khoom siv rau saum npoo. Txoj hauv kev txhawm rau txheeb xyuas qhov ci ntsa iab ntawm ib yam khoom yuav tsum siv lub ntsuas qhov ci ci.
