Drilling Simulation Of Twist Drill Tip Of Long Spiral Drill And Structural Optimization

Long spiral drill, a mechanical product of pilling machinery, is widely used owing to its low cost, broad applicability, pile foundation of good quality, high allowable pile bearing load, less noise, no slurry pollution, and less consumption of steel, etc. However, there is still a problem of low drilling efficiency in the long spiral drill, which have a negative impact on the efficiency and the whole performance of the long spiral drill. In order to improve the drilling efficiency, this thesis conducts a simulation study on the drilling efficiency of the long spiral drill and designs a long spiral drill of twist drills.The main research and innovation of the thesis are:(1) Studying further on the long spiral drill, making a comparative analysis of the structure and use of the drill used both at home and abroad, providing a theoretical basis for the design of drill.(2) Analyzing theoretically the main factors affecting drilling efficiency, and designing the long spiral drill of twist drill, which is good for cutting the clay. The long spiral drill of twist drill enjoys advantages of accurate centering, no inclining drilling and having a second cutting in the clay with the cutter tooth of both ends, thus drilling capacity is improved. Establishing a mechanical model of the drilling process, and the analysis indicates that the long spiral drill of twist drills strengthens the abilities of cutting and of accurate centering.(3) Establishing a finite element model of the drilling process of the long spiral drill with twist drill and the traditional centering long spiral drill, and conducting a simulation, results of which shows that the former one increases drilling efficiency by16.60%.(4) Applying uniform test methods to optimize the set of variables, and on the bases of variable parameters establishing simulation model of simulations drilling to obtain the drilling depth values of different sets of variable parameters. After the optimization, the optimal parameters for peak drilling efficiency are:helix angle of35°, an apex angle of90°and an angle of10°.(5) Making an experimental frame set to have a spot test of the long spiral drill with twist drill and the traditional centering long spiral drill, the result of which shows that the former one has a higher efficiency of13.36%than the later, generally according with the conclusion of the simulation result.