Inkqubo yokuvelisa:ukubumba okubandayo. Izinto eziluncedo:Iveliswe ngetekhnoloji yokubumba ebandayo, qinisekisa ukusuka kwiimpawu ezibonakalayo zezinto eziluhlaza. iqinisekisa ngokufanelekileyo i-diameter yayo yangaphakathi, i-pitch, i-helical surface kumgca we-peripendicular angle.
