Me hanga ki te paura uku parakore-nui, ka hangaia te rakau karamu ma te pehi maroke me te pehi isostatic matao ranei, ka werohia i raro i te pāmahana teitei, katahi ka mahi miihini.Ko nga rauemi uku e whakamahia ana e matou ko Zirconia, 95% ~ 99.9% Alumina (Al2O3), Silicon Nitride (Si3N4), Aluminium Nitride (AlN) me etahi atu.