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Development Of PDC Manufacturing Process Technology-1
- Jul 18, 2018 -

1. The development of the bit machining technology realizes the numerical control of machining, and the CAD computer aided design technology is connected with the CAM computer aided manufacturing technology to realize the CAD/CAE/CAM integrated system, which is the development direction. The processing of the API joints and other parts of the drill bit is gradually processed by CNC machining machines to improve the manufacturing precision of the API joint threads and parts. The inner and outer diameters of the drill bit should be ground to ensure the tolerance of the inner and outer diameters of the drill bit required by the API to further improve the performance and life of the drill bit.

2. Soft Molding Process Foreign advanced bit factory generally adopts soft molding process to manufacture bit molds, which replaces manual operation, greatly improves production efficiency, and has high precision and consistency. Many domestic drill mills have also begun to apply soft molding processes. The rubber mold of the drill bit is made of a silicone rubber material, and the molding material (ceramic powder) is mixed into a slurry and cast into a graphite mold cavity. After the slurry is hardened, the rubber mold is taken out to form a drill bit mold. At present, there are still some shortcomings in the soft mold process, such as complicated process flow; poor thermal conductivity of ceramic materials, resulting in long sintering time, affecting production efficiency and causing loss of polycrystalline performance; weak protective atmosphere during sintering, affecting the quality of impregnation brazing Wait. After the CNC machine tool processing and soft mold forming process of the bit mold are realized, the CNC machining technology can be applied to the newly developed product and the small-scale trial production product, as well as the master mold manufacturing process of the soft mold forming process. Soft mold forming ceramic mold technology. This allows the product to maintain a high level of quality (including the level of delivery) and low production costs in both small and large quantities, and the product has strong market competitiveness.

3. Research to improve the performance of bit matrix The most common PDC bits currently used are mostly carcass. To drill into different types of rock, use a targeted drill bit to achieve good results. The serialization of the drill bit also requires diversification of the performance of the drill bit. It is possible to select carcasses with different wear resistance for different abrasive layers. The performance of the drill bit includes wear resistance, erosion resistance, hardness, coefficient of linear expansion, flexural strength, impact toughness and density. The quality of the drill bit is a comprehensive reflection of these properties.

(1) Evaluation index of carcass performance

1 The coefficient of linear expansion of the bit body should be close to the coefficient of linear expansion of the steel body. Otherwise, the joint strength of the carcass and the steel body is insufficient, and the carcass is likely to fall off.

2 The tensile strength of the drill bit body is about 300MPa. If it is too low, the carcass is easy to break.

3 The impact toughness of the drill bit body is generally above 4 J/cm2. That is, it can satisfy the bit body without collapse under the impact of the well.

4 The hardness of the bit body is also an important index. It is generally required to have a Rockwell hardness of 40HBC or more, so that the carcass can provide strong anchoring force and sufficient erosion resistance to the watch-set diamond.