| 摘要 |
<p>A method of manufacturing a drag-type rotary drill bit comprises creating a three-dimensional computerised model of the bit body, employing the computerised model in a computer-controlled process to create a three-dimensional physical model (22) of the bit body from physical material, using the three-dimensional physical model to form an operative hollow mould (23) of complementary shape to the bit body, and then moulding in the mould a reproduction of the bit body in a material suitable for use in an operative drill bit. Alternatively, the method may be used to produce a three-dimensional physical model (26) of a hollow mould, and using this mould to create a bit-shaped former (27) which is then used to create an operative mould (28) for moulding the actual bit body. <IMAGE></p> |
