nā ʻāpana wili kūʻai nui IADC217 17.5 ʻīniha (444.5mm)

ʻO kahi ʻūlili he mea i hoʻopaʻa ʻia i ka wēlau o ke kaula ʻūlili e wāwahi ana, ʻokiʻoki a wāwahi paha i nā ʻano pōhaku i ka wā e ʻeli ai i kahi luawai, e like me nā mea i ʻeli ʻia e unuhi i ka wai, ke kinoea, a i ʻole ka ʻaila.
He hakahaka ka ʻīpuka wili a he mau mokulele e ʻae ai i ka hoʻokuke ʻia ʻana o ka wai wili, a i ʻole ka lepo, ma ka wikiwiki kiʻekiʻe a me ke kaomi kiʻekiʻe e kōkua i ka hoʻomaʻemaʻe ʻana i ka ʻīpuka wili, a no nā ʻano palupalu, kōkua i ka wāwahi ʻana i ka pōhaku.
ʻO nā ʻāpana wili Tricone: Loaʻa i kahi ʻāpana tricone ʻekolu mau wili conical me nā niho i hana ʻia me kahi mea paʻakikī, e like me ka tungsten carbide. Wāwahi nā niho i ka pōhaku ma ka wāwahi ʻana i ka wā e neʻe ai nā wili a puni ka lalo o ka lua wai.
Nā ʻāpana wili PDC: ʻAʻohe ʻāpana neʻe o kahi ʻāpana PDC a hana ia ma ke kahakaha ʻana i ka ʻili pōhaku me nā niho ʻano disk i hana ʻia me kahi ʻāpana daimana synthetic i hoʻopili ʻia i kahi cylinder tungsten carbide.