Kubadaha xajisashadu waxay ku shaqeeyaan iyagoo isticmaalaya is jiid jiidka u dhexeeya dariiqyada orodka ee xajka iyo kubbadaha si loo yareeyo khilaafka u dhexeeya shafka iyo xajinta, si loo yareeyo khilaafka ay sababaan taayirrada iyo hagaajinta waxtarka gudbinta. Ficilkan rogrogani waxa uu ka hortagayaa dhaawac soo gaara usheeda in uu is jiid jiid waxana uu kordhiyaa cimriga mishiinka.