How to Use Mold Tools in SOLIDWORKS

SOLIDWORKS Mold Tools help prepare plastic or cast parts for mold design. They can assist with draft analysis, parting lines, shut-off surfaces, parting surfaces, tooling splits, and core or cavity creation.

Start with a mold-ready part

Before using Mold Tools, inspect the part for draft, undercuts, small features, and manufacturing issues. A part that is not designed for molding can create difficult or impossible tooling geometry.

Check wall thickness, ribs, bosses, and sharp internal corners before focusing on the tool split. Good mold design starts with a part that can be molded reliably.

Also confirm the intended material and molding process. Shrinkage, draft, texture, and parting strategy can change depending on the material and production method.

Run draft analysis

Draft analysis helps show whether faces have enough draft relative to the pull direction. Select the pull direction and review the colored results. Faces with insufficient draft may stick in the mold or require design changes.

Use draft analysis early, not only at the end. It is much easier to fix draft problems before parting surfaces and tooling splits are created.

If a face fails draft analysis, decide whether the part design can change or whether tooling action such as a slide may be required. That decision affects cost and mold complexity.

Create parting lines

Parting lines define where the mold separates around the part. SOLIDWORKS can help detect parting lines based on the pull direction and draft conditions, but the result still needs engineering review.

Check that the parting line follows a manufacturable path and does not create unnecessary shutoffs, fragile steel, or difficult polishing areas.

The best parting line is not always the one SOLIDWORKS finds automatically. Review it with molding, appearance, and trimming requirements in mind.

Create shut-off and parting surfaces

Shut-off surfaces close openings that need to be sealed for core and cavity creation. Parting surfaces extend outward from the parting line to separate the mold halves.

These surfaces should be clean and continuous. Gaps, overlaps, or small sliver surfaces can cause tooling split failures or create mold geometry that is difficult to machine.

Spend time repairing parting surfaces before creating the tooling split. A cleaner surface model usually saves time compared with fixing a poor core or cavity afterward.

Create the tooling split

After parting lines, shut-offs, and parting surfaces are ready, use Tooling Split to create core and cavity bodies. Review the resulting bodies carefully and use section views to inspect critical areas.

The tooling split is not the end of mold design. Ejector pins, gates, runners, cooling, vents, inserts, slides, and machining details may still be needed depending on the part.

Use the split bodies as a starting point for mold layout. The final tool must still account for how plastic flows, how the part ejects, and how the mold will be built and maintained.

Troubleshooting

If Mold Tools fail, check the parting line, surface gaps, pull direction, and small model defects. Repair surfaces before trying to force the tooling split. Use section views and surface checks to find openings or overlaps.

For production molds, treat SOLIDWORKS Mold Tools as a modeling workflow, not a replacement for mold-design judgment. Confirm draft, shrinkage, parting strategy, material behavior, and manufacturing details before release.

Document assumptions such as pull direction, shrink factor, material, and revision. Those details help connect the mold model to the real tooling process.

For critical parts, review the Mold Tools output with an experienced mold designer before release. The software can help create geometry, but tooling decisions still require manufacturing judgment.