Injection Molding Draft and Texture Checker

Compare actual CAD draft with a supported feature-depth reference and a supplier-provided finish or texture minimum.

Formula and method

Depth reference = 1° for features up to 50 mm and 3° for features over 50 mm through 101 mm. Screening minimum = max(depth reference, entered texture/finish minimum). Margin = actual draft − screening minimum.

Inputs and units

Measure actual draft in the intended draw direction. Measure depth parallel to that direction. Obtain the minimum draft for the exact texture, polish, resin and steel from the texture supplier and moldmaker; enter zero only when no separate finish requirement applies.

Worked example

At 2° actual draft, 30 mm feature depth and a 1° supplier minimum, the screening minimum is 1° and the result is 1° draft margin.

When to use it

Use after defining core/cavity draw direction but before resolving shutoffs, slides, lifters or ejection details.

How to interpret the result

A positive margin meets only the entered depth-and-finish screen. It does not prove release, prevent drag or determine which mold half retains the part.

Assumptions and limitations

The hard-coded depth reference is limited to greater than 0 through 101 mm. Texture requirements are not universal presets. Undercuts, shutoffs, deep ribs, flexible materials, gloss and steel-safe changes require direct review.

Validation guidance

Run CAD draft analysis in each draw direction, identify zero/negative faces and parting-line changes, then confirm texture callout and ejection with the moldmaker and texture supplier.

FAQ

Does a passing screen approve the part for tooling?

No. It creates a traceable CAD review record. Formal DFM, material review, mold design, simulation where appropriate, and molded-part validation remain required.

Sources

Protolabs Designing for Mouldability · Protolabs wall-thickness guidance