| Along with high technology and new technology products become moreprecision and integration, micro-hole application appears more and more in ourlives, so the processing technology of micro-hole is even more important. In themicro-hole processingmethods,thedrilling processcan obtainthegoodprocessingquality and the high production efficiency, But, there are fatal weaknesses in theprocess of drilling: Micro-drill has low intensity, wears out very easily and isextremely easy to break off when the scrap stops up;Also the Micro-drill's life istoo dispersive to estimate it . The drill once breaks off, then it's very difficult totakeit out from the work piece,we often do nothing but discard the work piece inthe end.Therefore there is a fatal question in theprocess of drilling that the drillsare easy to break off, it seriously affected the processing efficiency of themicro-holedrilling aswellastheautomaticityenhancement.The force increasing of micro-hole drilling is the basic reason which the drillbreaks off, but, the force signal of the micro-hole drilling are extremelydifficulttobe gained, and it needs to carry on the transformation to the existing processingequipment structure, this not only needs a not small expense and wastes much,moreover also possibly affects the Mechanics performance of the processingsystem. Therefore, this article proposed the plan that the micro-hole drilling basedon the on-line monitor of the main axle electrical machinery electric current, andhascarriedonthecorrelationtheoriesandthetechnicalresearch.This article developed a micro-hole drilling system based on the on-linemonitor of the main axle electrical machinery electric current. This system iscomposed by the hardware system and the software system. The hardware systemincludes the automatic drilling machine which arechanged from a manual systemby ourselves, the Hall electric current sensor, the data acquisition card NI 6,013,monolithic integrated circuit control system;The software system is the programsbased on the environment of the LabVIEW software, realizes to voltage signalgathering, the filter by wavelet, the memory, the displaying, the monitoring, thecontrolling and the serial communication to the monolithic integrated circuitsystem.This article has used the wavelet processing method todeal with the gatheredsignal in the analysis and processing. The wavelet transformation is one kind ofhaving the time and the frequency resolution analysis method to the signal at thesame time, thus can take the active component from the signal;Through theoperation of flexing and translating carries on the multi-criteria particularityanalysis tothesignal,has solvedmanydifficult problemsinsignal processing,so ithas the reputation of "mathematics microscope". the article has carried on theanalysis through the wavelet analysis method to the data signal each frequencyrange ingredient, it is advantageous to us further to each kind, the high andlow-frequency signal analysis, thus is advantageous to obtains the more reliablemonitorsignalthedatasampleintheexperiment.This article researched thedistributed rule ofthe the limit increment valueofthemainaxleelectrical machineryelectriccurrentwhenthemicro-hole drillbreaksoff in drilling, obtained the conclusion that the limit value obeys three parametersWeibull distribution. According to the reliability theory, established themathematical model of micro-hole drilling based on the on-line monitor of themain axle electrical machineryelectric current, obtained the reliable formulaof thevoltage difference monitor threshold valueunder the certain safety level, proposedone effective method of obtaining the monitor threshold value of the voltagedifference.After the above work, we carried on the experiment of micro-hole drillingbased on the on-line monitor ofthe main axle electrical machineryelectric current,the results indicated this method achieves the anticipated effect to avoid the drillsbreakingoff, andenhancethedrills useratebasically.
|
PDF Full Text Request