BS EN 12020-2 pdf free download

BS EN 12020-2 pdf free download.Aluminium and aluminium alloys—Extruded precision profi] les in alloys EN AW-6060 and EN AW-6063—Part 2: Tolerances on dimensions and form.
2 Tolerances on dimensions 2.1 General If, for compelling reasons, tolerances closer than those specified in 2.2.1 and 2.2.2 are required, these shall only be specified for dimensions that are critical to the function, subject to particular agreement. Any such reduction shall not exceed two-thirds of the values specified in this standard and is subject to a minimum tolerance band of 0,3 mm. 2.2 Cross-sectional dimensions 2.2.1 General The tolerances of the following dimensions (see Figure 3) are specified in the relevant Tables 1 and 2. 一A: wall thicknesses except those enclosing the hollow spaces in hollow profiles; 一B: wall thicknesses enclosing the hollow spaces in hollow profiles, except those between two hollow spaces; -C: wall thicknesses between two hollow spaces in hollow profiles; -E: the length of the shorter leg of profiles with open ends; -H: all dimensions except wall thickness.When, for functional reasons, tolerances are specified for both the outside and inside dimensions of hollow sections, then the deviations given in Table 2 shall not apply as a wall thickness tolerance, but as a tolerance on the difference in wall thickness. This difference shall be determined by measuring the maximum and minimum wall thickness in the same plane. 2.3 Length If fixed lengths are to be supplied, this shall be stated on the order. The fixed length tolerances shall be as specified in Table 3.If no fixed or minimum length is specified in the order, profiles may be delivered in random lengths. The length range and the tolerances on the random lengths shall be subject to agreement between purchaser and supplier. 2.4 Squareness of cut ends The squareness of cut ends shall be within half of the fixed length tolerance range specified in Table 3 for both fixed and random lengths, e.g. for a fixed length tolerance of + 10 mm the squareness of cut ends shall be within 5 mm. 2.5 Length offset for profiles with a thermal barrier Length offset K, see Figure 4, for profiles with a thermal barrier shall be within the tolerance range for the fixed length specified in Table 3, e.g. for a fixed length tolerance of + 10 mm the length offset shall be within 10 mm. 3 Tolerance on form 3.1 Straightness Deviations from straightness, hs and ht, shall be measured as shown in Figure 5 with the profile placed on a horizontal baseplate so that its own mass decreases the deviation. The straightness tolerance h shall be as specified in Table 4. The local deviation from straightness hs shall not exceed 0,3 mm per 300 mm length. In the case of profiles with a width W of at least 200 mm, the local deviation F1 shall not exceed 0,5 mm for any 100 mm of width, W. 3.3 Contour For profiles with curved cross-sections, the deviation at any point of the curve, from the theoretically exact line as defined by the drawing, shall not be greater than the appropriate tolerance C specified in Table 6. Considering all points on the curve, a tolerance zone shall be defined as the zone between two envelopes running tangentially to all circles of diameter C which can be drawn with their centres lying along the theoretically exact line; this is shown in Figure 7 (a and b).BS EN 12020-2 pdf download.