A method for multi-cutter and multi-process numerical control turning and repairing threads

Abstract

A multi-tool split-process numerical control thread repairing method, comprising: using a tool starting point S on a reference workpiece with a tool K 0 , Spindle speed n 0 and tool K 2 , Spindle speed n 2 Separate turning helix T 0 , T 2 ;Set tool K 0 The tip of the tool is positioned at T 0 Point A in the middle 0 ;Turn the spindle to an angle to make K 0 The tip of the knife points to T 0 ;Tool change K 2 , moving K 2 Position the tool tip at point A 2 and point to the T 0 next to T 2 ;calculate the helix T 0 , T 2 The axial deviation or circumferential deviation between the two, eliminate the axial deviation or circumferential deviation; remove the reference workpiece; install the workpiece to be repaired and turn the main shaft to the angular position; change the tool K 0 and move K 0 Make the tool tip point to the bottom position B of the thread to be repaired; calculate BA 0 The axial offset distance between or calculate the circumferential deviation between the starting point of the tool required for turning repair and the starting point of the tool set by the turning repair program; eliminate the axial offset distance or circumferential deviation; execute the adjusted turning repair program. This method can distinguish between rough and finish turning processes.

Description

technical field [0001] The invention relates to a thread maintenance method, in particular to a multi-knife and multi-process numerical control thread repair method. Background technique [0002] A large number of threads are processed and repaired by oil drilling technology service companies every year. Oil pipe thread repair service itself is very necessary for the drilling industry to control equipment costs. Maintenance can prolong the service life of oil pipes and save equipment investment. The technical key point of oil pipe thread repair is to machine along the original helical line of the thread, not to completely remove and reprocess. [0003] For a long time, the industry has generally used special pipe lathes to process threads. Its advantages are simple structure and strong applicability. Its disadvantages are also obvious. The labor intensity of operators is high, the working environment is poor, and there are occupational risks such as accidental injury and dis...

AI Technical Summary

Problems solved by technology

[0004] 1. It is difficult to economically and conveniently obtain the installation position information of the existing helix of the thread to be repaired: the workpieces to be repaired in the petroleum technical service industry are very heavy, and the clamping position on the lathe can only be random, which is different from the successful completion of thread processing before. The program parameters of the

CNC lathes must associate the position information of the thread to be repaired with the processing program so that the tool can cut along the original thread trajectory, which is also a very inefficient repetitive labor

[0005] 2. There is a phenomenon of variable speed and chaotic teeth: when turning threads on a CNC lathe, the speed cannot be changed arbitrarily like an ordinary lathe, otherwise the threads will be randomly buckled

However, in actual operation, this method still has the following disadvantages: 1. It is difficult to ensure that the "flat plate" is perpendicular to the spindle in actual operation, which reduces the accuracy of subsequent tool setting; 2. The distance L1 cannot be obtained directly from the machine tool. Manual measurement is difficult to guarantee the measurement accuracy of L1. If instrument measurement is used, the equipment structure will be complicated; 3. This method also needs to detect and calculate "rotation angle difference", but most of the CNC lathe systems in the prior art do not have a spindle The phase angle display function, therefore, limits the scope of application of this method; to detect the "rotation angle difference", it is necessary to use a detection instrument, or to modify or modify the machine tool, which will complicate the repair operation of each thread, increase the cost input, and reduce the cost. Ergonomics; in addition, the introduction of "corner difference" complicates position calculation

Therefore, the existence of "flat plate" and "corner difference" in this method makes it cumbersome to operate, low in efficiency, and low in tool setting accuracy.

[0009] The Chinese invention patent application with the publication number CN109799783A discloses a method, a control device and a CNC machine tool for repairing a threaded pipe body by a CNC machine tool. The method obtains the thread track data of the threaded pipe and compares it with the program data of the CNC machine tool. Calculate the data difference between the program thread line and the thread line to be repaired. This method belongs to the "thread contour scanning detection technology". It is necessary to add other systems to obtain the information mentioned in the method and simulate turning the thread, which leads to the complexity of the equipment; at the same time , this method needs to obtain the angle of the CNC machine tool spindle encoder and the machine tool, which makes the whole tool setting process more complicated

In addition, it does not give a method on how to avoid thread disorder during thread maintenance

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