Flatness Tolerance For Sheet Metal

Linear tolerances should be held as loose as possible.

Flatness tolerance for sheet metal.

Flatness tolerance is the permissible distance between two parallel planes within which all irregularities of a given surface must lie. 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. Sheet metal tolerances should not be tighter than necessary to make the part functional. 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. For sheet metal parts iso 27 68 mk is used. Mm 48 1 219 in. For material 10 or less in length variation should not exceed amount shown in table.

Flatness tolerance is always less than the dimensional tolerance associated with it. Flatness tolerances for sheet are published only for full size sheets. Plates can be out of flat for a number of reasons. The distance between the parallel planes is the stated flatness control tolerance value.

General tolerance iso 2768 does not specify where to use these tolerances. Flatness tolerances listed are of roller leveled sheets or plates with no or minimum margins. Practical tolerances vary according to the design requirements. Sheet metal is often controlled with flatness tolerance.

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. Parts may be measured in either unrestrained or restrained conditions. The flatness tolerance zone is the volume between two parallel planes.

For material longer than 10 the variation in flatness for any 10 feet of length should not exceed the amount shown. Note any feature requirement comes with price tag on it. And for machined components iso 27 68 fh can be used. 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.

Tolerances of 010 should be considered minimum. Specified width ft. Tight tolerances raise the cost of manufacturing significantly. In general sheets 60 wide and under are to be no more than out of flat when laid on a flat surface.

Squareness tolerances flat sheet and plate. The flatness control c defines how much a surface on a real part may vary from the ideal flat plane. Up thru 3 over 3 allowable difference in length of diagonals inches.