Flatness Tolerance For Sheet Metal

Since rolled alloys also levels this product we work to the mill tolerances.

Flatness tolerance for sheet metal. Mm 48 1 219 in. The flatness tolerance references two parallel planes parallel to the surface that it is called out on that define a zone where the entire reference surface must lie. Flatness tolerance is the permissible distance between two parallel planes within which all irregularities of a given surface must lie. Linear tolerances should be held as loose as possible.

Parts may be measured in either unrestrained or restrained conditions. And for machined components iso 27 68 fh can be used. The flatness control c defines how much a surface on a real part may vary from the ideal flat plane. Sheet metal is often controlled with flatness tolerance.

This not only control the rock but also the allowable mechanical stress which deform the shape of the sheet metal like in case of parts that will be welded thermal stress bolted bending due to too much torque or screwed. Maximum difference between aa and bb up thru 12 over 12 3 32 x width ft 2 9 64 x width ft 2 5 64 x width ft 2 7 64 x width ft 2. General tolerance iso 2768 does not specify where to use these tolerances. Flatness tolerance is always less than the dimensional tolerance associated with it.

0 0129 0 33 aluminum sheet metal tolerances table chart. Up thru 3 over 3 allowable difference in length of diagonals inches. As per design requirements and manufacturing capability tolerance class is defined. Recommended limits are applicable to parts measured in the unrestrained condition flatness tolerances for metal stamping.

Tolerances of 010 should be considered minimum. Note any feature requirement comes with price tag on it. For material 10 or less in length variation should not exceed amount shown in table. Two sets of parallel planes where the entire referenced surface must lie.

Practical tolerances vary according to the design requirements. The flatness tolerance zone is the volume between two parallel planes. Tight tolerances raise the cost of manufacturing significantly. For sheet metal parts iso 27 68 mk is used.

For material longer than 10 the variation in flatness for any 10 feet of length should not exceed the amount shown. In the above example m and k has defined the tolerance class. The distance between the parallel planes is the stated flatness control tolerance value. Squareness tolerances flat sheet and plate.

Sheet metal tolerances should not be tighter than necessary to make the part functional. Flatness tolerances for sheet are published only for full size sheets. Plates can be out of flat for a number of reasons.