Optimum Design And Fabrication Process Of Fibrous Monolithic Structure Layer Of Polycrystalline Diamond Compact

Polycrystalline Diamond Compact bits are the dominant bit-type account for 65% of footage having been drilled in oil and gas applications widely being used in oil and gas drilling today.PDC bits are widely used in soft to medium hard,non-abrasive formation drilling.However,in the non-homogeneous formation,such as hard,strong grinding and soft and hard interbeds,there are still problems like low drilling speed,short life.The main damage form of PDC bit is the fragmentation of the diamond layer.In order to solve this problem,the crack resistance of composite films should be improved.In this paper,the fiber monolithic structure was used on the diamond layer of polycrystalline diamond composite.The fiber monolithic structure is composed of continuous cell bodies and the separation layer between them(referred to the interface layer),in which the cell body mainly composed of more than 94% by volume of diamond and 6% by volume of cobalt is the matrix structure unit,is the main bearing part of the composite material.Interface layer mainly composed of 94% by volume of tungsten carbide and 6% by volume of cobalt is relatively weak,mainly acting as the role of crack deflection,the crack passivation,increase the crack surface,the consumption of fracture energy,in order to achieve the purpose of toughening.In this paper,natural bamboo fiber was studied to explore the geometric morphology of fiber monolith.Calculate the mechanical and thermal properties of the material being used in this paper by Material Studio.The representative units of fiber monolithic were taken out to optimize the mechanical properties and thermal properties.The effect of price factors were taken into account on the ratio of fiber body and interface layer of fiber monolithic structural material at the same time.One of the inner angle of the shape of the hexagonal fiber body was set as ?.In conclusion,fiber monolithic representative unit angle is between 60 ° <? <80 °,the interface layer ratio is between 0.3-0.35.The powder extrusion molding process was adopted in order to prepare the diamond composite sheet fiber monolithic structure layer.The polymer used was selected by the physical and mechanical properties of the polymer and determined the mixing method of the polymer and the powder.In order to accurately design the mold and determine the reasonable process parameters,a series of performance tests were carried out on the mixture of polymer and powder,including DSC,TG,rheological properties,heat transfer properties and tensile properties.DSC tests were carried out in order to select the kinds of polymers.TG tests were carried out in order to determine the process parameters of the discharge.Rheological properties and tensile properties of the tests were carried out in order to designing of the mold rationally.Heat conduction performance tests were carried out in order to choose a reasonable temperature control process.Five molds were designed to process the diamond composite sheet fiber monolithic structure layer.The design was mainly by the rheological performance test to optimize the use of the mold at the exit of the angle parameters.The mold rationality was analyzed which according to the actual operation process,the stress distribution along the path,the analysis of the Workbench safety tool and the assumption of the existence of the microcracks were analyzed according to the actual operation process of the die rod,which drew a conclusion that the design of the mold was reasonable.The process parameters of fiber monolithic structural layer extrusion process need to be controlled,mainly temperature of the process.So a kind of temperature control heating device was designed.The heating time was determined to be about 10 minutes to 15 minutes reaching about 130?-150?,and the heating time could be adjusted according to the extrusion pattern of each mold.In the process of making fiber monolithic structural materials,acetone,ethanol,water,and the introduction of a certain amount of organic impurities,were used for the cleaning of the mold degreasing,removal of organic matter,and cooling processes.At the same time in the EEA in the tungsten carbide powder and diamond powder mixed with the process of adding a lot of toluene,although as far as possible being removed,but there was a certain amount of residue.While the polymer contained not only EEA,but also contained a small amount of plasticizer MPEG-750.Therefore,the discharge process was controlled to six steps and the heating rate must be controlled,so that the structure did not apear dispersion.