Web in CNC Machining

A web is a relatively thin section that connects and supports other parts of a structure. The central plate joining the upper and lower flanges of an I-shaped section is a familiar example. In a machined housing or bracket, a web may connect thicker walls, mounting areas, or bosses.

What Matters in Design and Machining

Consider the unsupported span, not just thickness. A broad web can flex even when its thickness seems reasonable. Loads and cutting forces must pass through its connections to the surrounding structure.

Preserve support during machining. Removing material from both sides can leave a flexible section before the final cuts. Plan the order of operations and local supporting stock so the tool does not push the web away.

Details Designers and Machinists Can Overlook

Pocket depths can determine the remaining web thickness. When opposite-side pockets leave a web between them, their combined depth variation affects the material left in the middle. Check the resulting thickness, not just each pocket separately.

A web can also change shape after unclamping as residual stresses redistribute. Do not use heavy clamping simply to force it flat for inspection. Define which surfaces matter and whether the drawing requires inspection in a free or restrained condition.