Drill bit grinding can significantly increase tool life, whilst boosting operating efficiency, according to Goran Lidgren, product manager for grinding equipment of Sandvik Rock Tools

摘要

The obvious argument for grinding cemented carbide inserts in drill bits and drill steels is that a blunt tool has a far inferior performance. And therefore investing in grinding equipment and grinding techniques, will improve performance at the same time as reducing drilling costs. The wear characteristics of rock drilling tools and in this case, cemented carbide inserts, can vary immensely. The differences depend on the properties of the rock to be drilled, although to some extent, the design of the drill bits and the composition of the cemented carbides can help the situation.Consequently, a given drill bit may have service lives differing between 75 drill metres in a hard and abrasive material such as quartzite and thousands of metres in a relatively soft rock like limestone. When drilling in quartzite, the shape of the inserts deteriorates very quickly. Once blunted, the inserts are quickly damaged by the drilling forces. Because the drilling efficiency is reduced, less of the energy is transferred to the rock and these forces can actually end up destroying the inserts. Users can appreciate that restoring the insert's shape as early as possible will help the bit with its job of transmitting the percussive energy from the rock drill piston into actual rock crushing.