光洁的

C-timber has no knots in it.

光洁的木料没有节疤。

Compared with that of furane resin bonded sand,the feasibility of phenol resin bonded sand in forming a uniform coating layer in the inside mould surface is studied as well.

本究了砂在铸型中的成型条件及光洁内表面的形成机理，并对比究了覆膜和呋喃自硬砂在铸型内表面形成均匀覆砂层的可行性。