Flatness Tolerance For Sheet Metal

As per design requirements and manufacturing capability tolerance class is defined.

Flatness tolerance for sheet metal.

Up thru 3 over 3 allowable difference in length of diagonals inches. Since rolled alloys also levels this product we work to the mill tolerances. Specified width ft. For material 10 or less in length variation should not exceed amount shown in table.

In general sheets 60 wide and under are to be no more than out of flat when laid on a flat surface. Linear tolerances should be held as loose as possible. Practical tolerances vary according to the design requirements. 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.

The distance between the parallel planes is the stated flatness control tolerance value. 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. In the above example m and k has defined the tolerance class. 0 0129 0 33 aluminum sheet metal tolerances table chart.

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. Tight tolerances raise the cost of manufacturing significantly. Mm 48 1 219 in. Sheet metal is often controlled with flatness tolerance.

Squareness tolerances flat sheet and plate. For material longer than 10 the variation in flatness for any 10 feet of length should not exceed the amount shown. Plates can be out of flat for a number of reasons. For sheet metal parts iso 27 68 mk is used.

The flatness tolerance zone is the volume between two parallel planes. The flatness control c defines how much a surface on a real part may vary from the ideal flat plane. Flatness tolerances listed are of roller leveled sheets or plates with no or minimum margins. Flatness tolerance is always less than the dimensional tolerance associated with it.

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. Tolerances of 010 should be considered minimum. General tolerance iso 2768 does not specify where to use these tolerances.

Note any feature requirement comes with price tag on it. And for machined components iso 27 68 fh can be used. Two sets of parallel planes where the entire referenced surface must lie.