From the course: Engineering Drawings for Manufacturing

Dimensioning tips: Bent components

From the course: Engineering Drawings for Manufacturing

Start my 1-month free trial

Dimensioning tips: Bent components

“

- [Instructor] Manual and automated bending is a cost effective way to produce prototype and production parts, when tolerances permit. In this video, we will give you some specific tips for dimensioning bent sheet metal parts and tubing. Sheet metal parts should always be drawn in their as-bent condition. Don't dimension to a flat pattern, unless a manufacturer specifically requests it. Since it's impossible to form a perfectly sharp corner on a sheet metal part, each bend will be formed with a radius. The inside dimension of this radius should be specified on the drawing. The distance between bends should be dimensioned to the mold line. The mold line is the theoretical line formed at the intersection of the planar surfaces on either side of the bend. Just as you would with any other part, choose the dimensions that are most functionally significant. However, it is typically a bit easier on the manufacturer, if all dimensions are given to the same side of the material so that the tolerance of the material's thickness doesn't affect the measurement. Bent tubing is dimensioned to its center line. Just as with sheet metal parts, dimension the distance between bends to the theoretically sharp intersection of the central lines. The bend radius of tubing is dimensioned to the center line and the wall thickness and diameter of the tubing may be dimensioned either in a view or with a note. When designing and drawing bent parts, you will usually need to consider the manufacturing process in a bit more detail than you would with machine parts. For example, many manufacturers will have preferred bend radii that correspond to the standard tooling they have. Bent parts also require more generous tolerances than machine parts. To summarize, draw sheet metal parts and bent tubing in their as-bent geometry. Always dimension these parts to the theoretical intersection of the segments. Finally, remember that you may need to work more closely with the manufacturer when designing bent parts so that your design aligns with their standard tooling.

Contents