Metal stamping parts processing in the cause of the defective product
Metal stamping process for intermediate casing stent: blanking punching, punching incision - flanging forming - incision - flanging.
Tear in intermediate casing bracket forming, skewed in a variety of forms, the torn part mainly distributed in the pass of the parts, wall corner R arc and wall, such as the neck border because of difference of stamping and production process conditions, the proportion of the fractures are different.
Tear tear can be one-time forming, also can be caused by fatigue crack is invisible crack development according to the actual situation of the analysis of the causes of the tear, by examining the torn part of fabrication, fracture morphology and crowded degree of injury, thought to cause tearing parts, deflection behavior mainly embodied in the flange forming process, the causes of this process occurs as follows: 1.
Implementation does not reach the designated position forming process parameters in the process of stamping forming, technological requirements material core die, pressure and both parts must fit closely together, in the machine tool slide block slide compression forming sheet metal plastic deformation and implementation.
But now due to suppress the unsteady quality defects of parts, means that the pressure in the process of production machine tool in the beating pressure imbalance state.
Investigate its reason, mainly processing technical personnel not according to process requirements specified in this one phase in a timely manner to adjust machine pressure, every shift or in transition, no mutual communication machine pressure stability information, causes the product quality is not stable.
Flanging forming mould design defect of the mould for a double cavity left/right public, due to this process content in addition to the flanging, also have both shape forming content, combined with the special complex parts, curved surface is narrow, the forming requirements concave die core material consistent with the forming surface and so on, cause mould structure conditions for forming large travel, pressure area is small.
Designers in the original die design, only consider the pressure is small, this feature is neglected the material core forming defects following design guide slide stroke: (
Pressure material core design oriented length is 125 mm, the actual length is 115 mm, although within the scope of the design, but more than hold up part of the 115 mm motion effectively guide 10 mm long, there is pressure is the core in order is not stable, no the ills of product positioning.
Forming height 115 mm, it is necessary to design special guide board, not by the processing surface and die wall slip distribution gap direction, side friction increases, self lubricating effect is very poor, strong lateral force can not get effective eliminate, can cause caused by long-term wear after batch production guide clearance increases, loss of the mold in advance normal orientation effect, which will produce a vicious quality accident.
Mould processing parts and drawings design error such as marked clearly needs to work out of area.
But as a result of pressure core of modalities face again after the casting forming is adopted to guide surface machining, the machining surface and guide die surface match after clearance error exists, in the mold material emerged during the normal operation of the pressure core left/right.
Before forming parts, positioning by the pressure in the powder core plane positioning pin and hole, so it requires pressure core material in stamping forming must guarantee the stable, reliable, and correctly guide slide, otherwise will be instability in forming parts, so that the pressure is the core and the die wall extrusion, collision caused by stamping tensile stress, when more than ultimate strength of the material, causing a tear parts, deflection is not straight.
Plus, if consider other factors in the mould structure, and ignores the situation of using special guide slide guide, there are two parts in extrusion friction strongly, guide clearance was damaged and can't correct guidance to the dangerous moment.
Guide due to the structure of clearance for debugging with clearance, once the damage will be no more effective adjustment means, will influence the forming quality of parts, for a long time and bring security hidden danger.
And in guiding parts adopt special guide board, instead of using the processing surface orientation structure, after the clearance is too large, can't adjust the defects, which resulted in the tear, skew the parts is not straight.
On an essay: introduction on the development process of stainless steel