The Research On Repairing Theory Of Drill Collar In Petroleum Field

Petroleum drill collar is used for oil-well drilling, which is installed at thebottom of the drill stem to combine drill pipe with drill bit. In order to make sure thenormal work of drilling platform under the rough working condition, the drill collarmust be maintained frequently. We often repair the damaged screw along the originalthread track to meet the screw machining precision. It is not only to improve thedrilling collar repeatedly utilization rate and prolong the drilling collar service life,but also play important part on economizing recourse. Now more and more factoriesuse the CNC lathe to repair screw instead of center lathe, for the higher efficiency andbetter machining precision. Cause the different principles between manufacturingscrews and repairing screws on the CNC lathe, it is difficult to set tool accurately.Therefore, we also cannot get higher machining efficiency through CNC lathe.Take the lathe machine motion principle and thread repairing as the researchobject. Analyze the basic structure of center lathe and the lathe feed motion tomanufacture the screw, through space analytic geometry theory to make the processunderstood. Learn the lathe feed motion principle of the two different thread methodsand how the lathe produce thread under the thread feed motion law. Analyze the basicstructure of CNC lathe and the lathe servo system feed motion to manufacture thescrew, through space analytic geometry t theory to make the process understood.Learn the CNC servo system feed motion principle and how the CNC lathe producethread under the thread feed motion law. Based on the understanding of threadrepairing principle and the lathe feeding principle of manufacturing screw, we bringup the “Null Signal Retrieval Method”. According to CNC lathe feeding principle inmanufacturing screw and original thread seeking site principle, testify the “NullSignal Retrieval Method”.Write the Null Signal retrieval Macro Program, which is used to seek the originalscrew track, of repairing thread in the FANUC CNC system. In the text we introduceinto a CAM soft named Mastercam, and we use it to create3D model and simulate thecutter track of screw repairing. And this process can testify feasibility of threadrepairing principle, spread the CAM soft usage in thread repairing field and improvethe produce efficiency.