| Generally it is called deep hole machining to L/D≥5. Deep processing techniquescommonly used by gun drilling，Gun drill in the drill bit diameter and guide sleeve, andwithin the drill pipe ventilation with high pressure liquid to the point, take chip and heatcutting. It cannot finish in one time to drilling the ejection hole and cooling hole with radialdrilling machine in the plastic mould hole machining practice, drilling must turn around.(usually aperture d=2~10mm, plate length L is generally more than100mm, the length todiameter ratio L/D≥10) And the stability of radial drill, positioning is not accurate, easyto cause the joint dislocation and axis deviation.Therefore, this subject mainly through experimental method to find the gun drilling processparameters influence the quality of deep hole processing, try to find the pattern and give thequalitative relation, reasonable selection of process parameters and processing. The mainsubject of experimental research the influence of cutting speed, feed rate, oil pressure, depthto diameter ratio and type of material on the import and export of machining hole diameterdifference, roundness, and the axis of the bias，to optimize the test by orthogonal experiment.A preliminary analysis of the factors in the theory from the tool structure, heat transfer,removal of these three aspects of influence of gun drill processing performance. The purposeis to provide some reference data selection of mold, automobile, petrochemical, and otherdeep hole processing machine tool.The results1. It is advantages Obviously of the gun drilling in deep hole processing,and the moreconvenient of the twist drill in the operation. whether it is the surface roughness, poresize precision axis deviation, etc., guns are better than the twist drill. The diameter ofentrance is larger than the exit diameter of gun drill，Entrance of roundness is betterthan the export of roundness.2. For different processing individual indicators of significant impact is different, byorthogonal relationship between the overall balance of the factors that can affect thequality of hole machining sequence is followed by a significant aspect ratio (L/D)>feed rate> cutting> hydraulic.3. Improve cutting speed can increase the effect of the roundness and axis deviation, theimpact is not so obvious of feeding speed on roundness and axis deviation effect.4. Because the increase of the hydraulic is conducive to heat transfer and chip removal, Oil pressure increases the drill pipe vibration enhancement. Oil pressure increases thehole of the inlet and outlet end diameter deviation and deviation of hole diameterincreased. The feed rate and cutting speed will influence the shape of chip, so the effectof roughness on its surface is more obvious,the surface roughness of their moreobvious in the case of low speed and small cutting feed aperture poor roundness andbetter performance.5. The cutting speed and feed rate have the greatest impact on the power of the gun drill,especially cutting speed, high power vibration generally make greater roundness andaxis deviation. |
