Sheet Metal Tolerance Across Bends

Use the minimum bend dimension values in the charts below for your minimum closeness of cutout to a bend.

Sheet metal tolerance across bends.

Other standard bend radii available some of which will add additional cost to your part include. Material bend radii and minimum bend size charts please note. A 1 degree tolerance on all bend angles. Small change big difference.

As shown in the figure below the sheet metal bending height is too low and the sheet metal is easily deformed and twisted when bent which makes it difficult to obtain the ideal part shape and ideal dimensional accuracy. For bends over 165 there is no need to calculate bend allowances as the neutral axis stays pretty much in the middle of the detail. Controlled dimension bend tolerances are standalone and therefore do not need to be considered in relation to any other bend. Your manufacturer may not be able to match dimensions when creating the actual sheet metal part due to tooling and equipment limitations.

Sheet metal shops can bend to around 015 accuracy. Dimensional tolerances only apply to part in constrained state 3. Sms is not responsible for distortion of internal features inside bend areas. If you tell them to do 005 they are either going to ingore your tolerances or they are going to have to clean things up in the machine shop somehow.

Controlled vs uncontrolled dimensions. It is recommended to use the same radii across all bends and flange length must be at least 4 times the material thickness. Tolerances apply to any sheet metal product 0 024 to 0 194 thick 2. Bends in sheet metal are manufactured using sheet metal brakes.

Our bend radius option is 0 030 in 0 762mm. Applies to all internal features applies to flat part length up to 24 00. ß bending angle for bends between 90 and 165 degrees the formula is. The bend radius you select may not be available if the geometry of the part will not allow us to bend with the specific tooling required to achieve that radius.

Bends and their corresponding tolerances either pertain to a controlled dimension or an uncontrolled dimension. Thanks to material thickness variation the first bend elongated the material by a different amount which makes the second bend dimensionally inaccurate even before the punch tip contacts the sheet. The sheet metal bending height should be at least 2 times the thickness of the sheet metal plus the bending radius that is h 2t r. This is an industry standard and most cost effective.

By no means do bending tolerances need to be extraordinarily loose either. Controlled dimensions refer to the length of the flange of any bend. Since each metal fabricator has its own tooling bend factors and equipment to develop the flat blank it is better to fully dimension to formed views for that manufacturer.