Bent Sheet Metal Tolerances

Typically this information is located in the title block of a drawing.

Bent sheet metal tolerances.

L bracket with a single bend that s 0 009 in. In the above example m and k has defined the tolerance. Angle tolerances are typically denoted by x xx. For bends between 0 and 90 degrees the formula is as follows.

For bent part fabrication tolerances start with 0 006 in. Bend tolerances the tolerance specified by the engineer or designer tell the brake operator how much variation in the particular bend is allowable. 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. Geometry of tooling imposes a minimum bend dimension.

In the example of a 16 ga. Recommended inside bend radius for sheet metal parts should be equal to material thickness. Grain structure in the metal sheet is critical for avoiding cracks in sheet metal parts with lugs or tabs that are cut on. 1 all manufacturing tolerances used up to that point such as laser cutting tolerances welding tolerances and more 2 all bend tolerances for the entire part added together we call this an uncontrolled dimensions because there are additional tolerances to consider.

Uncontrolled dimensions contain two different categories of tolerances. To allow for accuracy of the fabrication equipment and add 5 percent of the thickness for each bend. ß bending angle for bends between 90 and 165 degrees the formula is. And for machined components iso 27 68 fh can be used.

As per design requirements and manufacturing capability tolerance class is defined. Both benson and boden emphasized that a precision bending operation can achieve some very tight tolerances but it takes time money and effort to achieve them. General tolerance iso 2768 does not specify where to use these tolerances. Refer to the chart for values for folder as well as various press brake tooling combinations.

The diagram shows one such mechanism. For sheet metal parts iso 27 68 mk is used. Bend relief and collars near pierced areas strengthen sheet metal parts. But for harder materials e g.

Sharp inside bend radius in sheetmetal parts can cause material flow problems in soft material and fracturing in hard material. As benson explained these would be the possible errors over the three flange dimensions and four bends involved in attaining the 6 110 in.