Machining Technology And Mechanism Of Abrasive Water Jet Deburring Deep Hole And Cross Hole

Burr and flash are inevitable in machining.With the improvement of machining precision and clean production demand,burr removal has become the key.Deep holes and cross holes are often used as lubricating oil transmission in engine and hydraulic parts.Burrs in deep hole and cross hole processing are difficult to be observed and removed.Burrs will accelerate the wear and damage of moving parts,when they enter into the moving parts driven by oil flow.The burr at the intersection line of cross hole is different from the general burr.Because of its complex shape,and the limited space in the deep hole,the existing methods can not effectively and efficiently deburr deep holes and cross holes.This paper presents a method to remove the burr in deep hole and cross hole of engine and hydraulic components using AWJ.The burr removal situation before and after erosion is analyzed,and the burr removal mechanism is analyzed combined with CFD simulation results.By optimizing the abrasive water jet erosion process,the burr at the intersection of the cross hole and the hole wall can be effectively removed without or less damage to the components.Fluent-Static structural one-way fluid solid coupling simulation technology is used to study the influence of burr shape parameters on the force of burr in the oil passage.Research shows that the change of burr height has the greatest influence on the force of burr in the oil passage.The research results provide a reference for the evaluation of burr removal effect.The abrasive water jet is a three-phase flow of gas,solid and liquid mixture.The impact simulation of abrasive water jet deburring in deep holes and cross holes is carried out by using VOF model and DPM model in fluent.The changes of axial and radial velocity,static and dynamic pressure in axial and radial direction are analyzed,and the movement path of abrasive particles in the flow field and erosion condition are analyzed.The erosion results show that the AWJ can remove the burr of deep hole and cross hole,and the simulation results of abrasive movement and flow field can provide reference for mechanism analysis.To facilitate the observation of burr before and after the experiment,a special design was made for the experimental workpiece.Two design schemes are put forward,which are splicing test piece and integral test piece.After comparison,the splicing test piece is used for erosion experiments.The cross hole burrs were classified.The morphology characteristics,generated region,formation mechanism and connection strength with the body were analyzed,so as to analyze the burr removal mechanism.The erosion experiments of pure water jet and abrasive water jet were carried out.According to the results,he pure water jet can remove the sticking burrs on the hole wall,but can not remove the intersection burr of the cross hole,and the abrasive water jet can availably remove the intersection burr of the cross hole.The influence of process parameters of abrasive water jet on the hole wall erosion,the hole bottom erosion and the residual height of burr are analyzed.The increase of jet pressure,erosion time and abrasive flow rate will aggravate the erosion of the hole bottom and the hole wall,and the increase of target distance will reduce the erosion of the hole bottom and enhance the erosion of the hole wall.When the jet pressure,target distance,erosion time and abrasive flow rate increased,the residual height of burr decreases,then the burr is removed more thoroughly.The jet structure model of abrasive water jet impacting cross hole is established.The jet structure is divided into external jet and in hole jet.The characteristics of each section of jet are analyzed.According to the characteristics of jet energy distribution,the model of jet impact distance selection is established.The removal mechanism of entrance burr,hole wall burr and cross hole burr is analyzed.The abrasive particles play a micro cutting role when they impact the hole wall.After the impact of water jet on the burr,the pressure difference resistance is produced,which makes the burr deform.Fatigue crack will occur in burr when burr impacted by abrasive particles,and then the burr will fall off under the action of water wedge.In addition,the edges of abrasive grains play a cutting role in burr removal.AHP method is used to establish the quality evaluation index system of deep hole and cross hole burr removal by abrasive water jet.Based on the processing standard of oil way cross hole,the weight analysis is carried out.The gray comprehensive analysis method was used to evaluate the results of orthogonal experiment.The effects of process parameters on the correlation degree of burr erosion results and the quality of burr removal were studied,which provided guidance for the selection of process parameters of abrasive water jet burr removal for deep holes and cross holes in oil pipeline.