What is the tolerance of aluminum profile extrusion?
The minimum wall thickness of the profile is only 0.4 mm, and the tolerance requirement is + 0.04mm.. The extrusion production process is very strict with the equipment, tooling and process requirements. This extrusion technique is often referred to as precision extrusion.1. Examples of precision aluminum extrusionThere are a number of small precision aluminum profile tolerances than JIS standards in the special class of less than half of the tolerance, general precision aluminum requirements of the dimensional tolerance between 0.04 to + 0.07mm.Potentiometer for precision aluminum section "]" profile weight 30 g / m, section size tolerances for precision aluminum profile + 007 mm. loom for "-", section size tolerance is + 0.04mm, the deviation angle less than 0.5 degrees, the bending degree is 0.83 * L.A1050, A1100, A3003, A6061, A6063 (low strength alloy) small precision extrusion the minimum wall thickness of 0.5mm, 20mm2.A5083, A2024, minimum basal area (A7075, medium and high strength Aluminum Alloy) small precision extrusion minimum wall thickness is 0.9mm, the minimum area of 110mm2.Examples of dimensional tolerances for precision aluminium profilesDimension /mm tolerance allowance /mmJIS special grade, small, preciseA 2.54 + 0.15 + 0.07B 1.78 + 0.15 + 0.07C 3.23 + 0.19 + 0.07
According to section calculation, the tube can be controlled in the positive and negative 0.05mm square tube, 100 think positive and negative 0.15mm, each mold factory technical process is different, the processing accuracy requirements are different, depending on the product!
2, precision extrusion technology requirementsIn general, the degree of Aluminum Alloy hot extrusion deformation, the influence of extrusion temperature and speed change, the extrusion equipment of neutral and die deformation are easy to profile precision, and their mutual influence factors is difficult to overcome. Figure 3 presents the factors affecting precision extrusion.3 、 requirements for toolingThe mold is the most direct factor to affect the product size precision extrusion, extrusion products to ensure that in the production section size or minor change, must make the mould rigidity, heat resistance, wear resistance can reach a certain requirement.First of all to ensure that the mold is not easy deformation under high temperature and high pressure, have very high heat resistance, the precision extrusion is more strict requirements in working temperature (500 degrees Celsius), the yield strength of the die material is not less than 1200N/mm2. then need to have high wear resistance, which mainly depends on the hardness and thickness of the nitrided layer. The general requirements of the hardness of the nitrided layer above 1150HV, depth of the nitrided layer between 0.25 mm and 0.45mm, and the changes after nitriding die size should be less than 0.02mm.For solid profile and hollow profile cantilever has cross section, but also consider the die elastic deformation, in order to make the mould to ensure certain rigidity, can be considered appropriate to increase the thickness of the mould with a special pad or similar shapes.Change control profile opening size, can be in the mold to control metal flow channel groove.
