Lub tshuab ntub dej puffing yog ua raws li lub tshuab ziab khaub ncaws kom ua rau lub tshuab ua kom sov, nws lub hom phiaj yog: nce qhov kub ntawm cov khoom, soften thiab ua noj cov khoom, ntxiv ib qho dej. Puffing ntub dej yog qhov ua tau zoo dua li cov puffing qhuav thiab muab kauv, puffing chamber hnav cov khoom nrog lub neej ua haujlwm ntev.
Yog vim li cas yog: yog hais tias cov khoom expansion kub ntawm 130 degree, qhuav expansion ntawm chav tsev kub (20 degree) mus rau 130 degree yuav tsum tau nce qhov kub ntawm 110 degree; Yog hais tias cov khoom ntub dej, tempering kub ntawm 80 degree, tsuas yog yuav tsum tau nce qhov kub ntawm 50 degree ntawm cov khoom, yog li ntawd, ntub expansion ntawm cov neeg kho tshuab zog yuav tsum tau los ntawm qhuav expansion ntawm tsawg, ntau zog yuav siv tau los txhim kho cov zis; vim qhov softening ntawm cov khoom siv kom txo tau cov kauv, nthuav cov kab noj hniav, thiab lwm yam. Vim yog softening ntawm cov ntaub ntawv, nws txo qhov hnav thiab tsim kua muag ntawm cov kauv, nthuav chamber thiab lwm yam hnav, thiab txhim kho lawv lub neej kev pab cuam.
