Precision aluminum alloy extrusion technology
naky
www.diecastingpartsupplier.com
2015-11-05 17:18:29
1 precision aluminum extrusions are some examples of small precision aluminum tolerance than the JIS standard special level of tolerance is smaller than half the size of the general requirements for precision aluminum tolerance of ± 0.04 ~ ± 0.07mm between. Precision aluminum sections with potentiometer for "︼" profiles weight 30 g / m, cross-sectional dimension tolerance range is ± 0 07 mm. Precision aluminum section looms as "■", section size tolerance of ± 0.04mm angle deviation is less than 0.5 °, curvature of 0.83 × L. A1050, A1100, A3003, A6061, A6063 (low, medium strength alloy) minimum wall thickness of small precision extrusion of 0.5mm, the smallest cross-sectional area 20mm2.A5083, A2024 , A7075, (middle, high-strength aluminum) minimum wall thickness of small precision extrusion of 0.9mm, the smallest cross-sectional area 110mm2. precise dimensional tolerances, for example aluminum Dimensions / mm size tolerances / mm JIS special class small, precision A 2.54 ± 0.15 ± 0.07 B 1.78 ± 0.15 ± 0.07 C 3.23 ± 0.19 ± 0.07 2 precision extrusion technology requires general, large deformation hot extrusion aluminum extrusion changes in temperature and speed extrusion equipment neutral, deformation tool and die and so easy to have an impact on the accuracy of the profile size, and they influence each other factors difficult to overcome. Figure 3 lists the factors affecting precision extrusion.
2.1 pairs of mold tooling requirements affecting the dimensional accuracy of the extruded product the most direct factor, to ensure that the extruded product in the production of zero or minimal cross-sectional dimensions, must make the mold rigidity, heat resistance, wear resistance reached certain requirements. First, to ensure the mold is not easy deformation at high temperature, a high heat resistance, for precision extrusion in terms of more stringent requirements in the operating temperature (about 500 ℃), the yield strength of the mold material is not less than 1200N / mm2 Secondly the need for high wear resistance, which depends mainly on the hardness and thickness of the nitride layer, the general requirements in the nitride layer hardness 1150HV above, nitriding depth between 0.25 mm ~ 0.45mm, and after nitriding mold changes in size should be within 0.02mm. For cantilever section has solid profiles and hollow sections, but also consider the elastic deformation of the mold, in order to ensure a certain rigidity mold may consider appropriate to increase the thickness or shape of the mold with a similar special pad. To control change size of the opening sections, you can open diversion channel to control the flow of metal in the mold.