12. Profile tolerances
The range of profiles that can be produced by extrusion is almost endless. For this reason, there are no general rules detailing potential solutions and applicable tolerances.
Profile design, wall thickness and alloy are critical factors that directly affect tolerances. In this connection, you should know that tighter tolerances can affect productivity and, consequently, price. Bear this in mind during the design stage.
Some profile manufacturers have standard tolerances of their own. Others use national standards for their production.
CEN, which is the European Committee for Standardization, has prepared European standards. These EN norms have gradually replaced the different national norms.
On the opposite page are extracts of the profile norms EN 755-9 and EN 12020-2. The content in the tables, including values, are collected directly from the complete norms.