Lu: xingcai ovality defect causes and elimination methods
common single circle ( Shape) Aluminum alloy pipes of upper and lower deviation. The round ( Shape) Pipe ovality error reason is primarily on aluminum extrusion die manufacturing, has but little relations with aluminum extrusion die design. The reason: A) : artificial milling, dig, dig, cutting aluminum extrusion dies for feed cavity, welded chamber, such as mold core, the size of the asymmetric shape processing, aluminum finish is not consistent, this is the main reason, many mold factory imported machining center at all costs, lu: xingcai computer controlled automatic processing program for symmetric mould ( Including pipe) The size of the precision production is a major security. Eliminated artificial processing dimensional deviation is big, the uneven flow velocity factor! （ 2) : aluminum alloy round pipe wall with work zone length ratio is wrong, 2-1. Five or so) , aluminum than small proportion increase velocity and friction factor, influence the work flow of aluminium, aluminium extrusion die increased uncertainty, speed. （ 3) : strength of aluminum mold, mold core strength, upper die cutter size, empty belt orifice can affect the smooth degree. （ 4) : aluminum extrusion speed too fast or too much traction, large amount of stretch. Elimination method: ( A) : making qualified and quality of aluminum extrusion dies is essential! （ 2) : the production of aluminum extrusion speed control is a major, otherwise is also easy to rough surface, this is because the first level of circular tube air knife generally is not a great ( 0. 5毫米) , easy to stick Mg2Si particles. Aluminium profile surface quality work to beg with short, smooth but not withstand voltage, discharge the mold after nitriding 40 - general production - - After 50 stick nitride again. （ 3) : the production of double holes, more attention should be paid to the traction porous thin-walled aluminum alloy tubes is to profile the size of the diameter and the influence of aluminum ovality, due to the discharging speed relations, traction often focused on discharging the slowest one.