I. Weight requirement of diamond composite core bit
1. Initial pressure (10~15min) : 2.5KN. The new drill bit must have a stage of low pressure, low drilling rate and the bottom of the hole. When the drill bit runs into the bottom of the hole, the bit weight should be smaller, and at the same time, the speed should be lower. The main purpose is to maintain the diamond, adapt to the aperture and prevent the edge breakage.
2. Weight on bit should be calculated accurately, first of all, the weight of drilling tool should be calculated or weighed accurately, and the influence of factors such as hole wall friction and hole inclination on weight on bit should be taken into account during drilling.
3. General weight on bit: initial pressure added to a certain time (10~15min), impregnated bit can choose 10~17KN. When drilling into highly abrasive, coarse or broken formations, the weight on bit should be reduced appropriately.
II. Speed requirements of diamond coring bit
Diamond drilling should adopt high speed if the equipment permits. The speed efficiency is also improved, especially the impregnated bit speed should be higher. Impregnated drill bits operate at 350~700 RPM.
Notes for drilling operation of diamond composite core bit:
1. When drilling, the drill tool should be lifted and pulled into the hole without being dragged underground. The rate of decline should be slow to prevent the loss of core from damaging the diamond on the bit.
2. The pressure should be light and the speed should be slow when sweeping the hole. If there is a residual core or a lost block in the hole, it is better to use a needle self-grinding bit to sweep the hole.
3. When reversing the rod, in order to avoid damaging the diamond, the drill tool should be stretched before reversing the rod. When drilling abrasive rock, do not let the bit off the bottom of the hole.
