Can I upload STL if that is all I have today?

You can upload it as a visual aid. Ask for a solid export before tooling review. A planning estimate on a mesh is weaker. Mark the file type in notes so reviewers do not treat triangles as a released solid.

Do I need the native SolidWorks or Creo file?

STEP is enough for most quotes. A portal-supported native export can help some DFM checks when it matches the released revision. Do not send an outdated native file next to a newer STEP.

What if the STEP has more than one body?

Prefer one body per part number. If the file is an assembly, say which body is the molded part and which bodies are hardware or keep-out. Mixed bodies without a note are a common reason DFM looks confused.

My STEP has the molded part plus screws and inserts. Is that OK?

Prefer one body per part number. If the STEP is an assembly, name the molded body in notes and list screws and inserts as hardware or keep-outs. Mixed bodies without a note are a common reason DFM flags look confused. Reviewers cannot tell what the steel is supposed to form.

Why did my quote change after switching STL to STEP?

If the revision intent is the same, that row is a format fix, not a design change. True DFM flags come from the solid: walls, draft, shutoffs, bodies. Write STL to STEP, same revision in the comparison so sourcing does not treat a file-format correction as engineering scope. See why instant quote changes after CAD review.

Why did DFM look thin on my mesh upload?

A mesh approximates faces. Thin walls and draft need true surfaces. Re-export STEP from the solid and re-quote. Keep the same RFQ fields so the delta is the file format.

STEP vs STL for an Injection Molding Quote

Q: Is STEP better than STL for an injection molding quote?

Yes for DFM depth. STEP or STP keeps faces, edges, and volumes a molder can measure. STL is a triangle mesh. A mesh can show shape. It does not give the same check for walls, draft, and shutoffs.

What Is the Difference Between STEP and STL on a Quote?

Engineers search step vs stl for injection molding quote when a print mesh is the only file on the desk. STEP or STP is a solid exchange file that keeps faces, edges, and volumes a molder can measure. STL is a triangle mesh. A mesh can show shape. It does not give the same DFM depth.

For the full upload package, read what to upload for an injection molding quote. This page only compares the two formats.

Key Facts

Start the quote with a 3D solid in STEP or STP.
IGES or a portal-supported native export can work when it matches the released revision.
STL is a mesh. Use it as a visual aid, not as the only quote file.
Units and scale must be correct on the solid you upload.
Add a 2D when tolerances or inserts are not in the solid. See do I need a 2D drawing for molding quote.
File problems can look like DFM flags. Read what DFM flags mean on an instant quote.
Upload the released solid on the injection molding instant quote platform.

When STEP Is the Quote File

Watertight solid, one body per part number

Use a watertight solid, one body per part number when possible. The file must match the PLM revision you will buy. A STEP from last week's branch next to this week's drawing is two programs.

IGES or native export only when it matches the released revision

IGES can work. A native export can work. The test is the same: does the file match the released revision, and is it a solid. This page does not rank CAD brands. Do not send an outdated native file next to a newer STEP.

Units on the export dialog are part of the file, not a footnote

Units and scale live on the export, not in a later email. A millimeter part exported as inches will look like a different program. Check the dialog before you upload.

When STL Is Not Enough

Triangles approximate faces: thin walls and draft suffer

Thin walls and draft need true faces, not triangles. A mesh can show shape. It does not give the same DFM depth for walls, draft, and shutoffs.

Hollow bodies and wrong scale look like DFM flags

A print mesh often carries a different scale or a hollow body. Those errors look like DFM flags that are really file problems. See what DFM flags mean on an instant quote before you treat every note as steel scope.

STL is a teammate visual, not the quote solid

STL is still useful as a visual for a teammate who cannot open STEP. It is not the quote solid. Say so in notes if you attach both.

RFQ Checklist

Numbered steps:

Export STEP or STP from the released solid.
Check units on the export dialog.
If you only have STL, still request a solid export before tooling review.
Attach 2D notes for tolerances the solid cannot show.
Upload CAD through the injection molding instant quote platform.

If the first quote used STL and the second uses STEP, write that in the comparison. Otherwise sourcing will treat a format fix as a design change. That is why instant quote changes after CAD review.

A Worked Example

A designer has an STL from a print house and a STEP on the CAD server that is one revision behind. They upload the STL because it looks like the part. DFM flags thin walls that are really triangle noise. Two days later they upload the older STEP. Now there are two bad packages.

The right package is a new STEP from the current solid, units checked on export, one body per part number. Attach the STL only if a teammate needs a visual. Write STEP is the quote file in notes. Re-quote so the first DFM flags are about the part.

If the STEP has hardware bodies in it, name the molded body. A mixed file without a note looks like an assembly the molder is being asked to mold as one shot.

Common Mistakes

Uploading a hollow print mesh and asking why draft looks wrong.

Sending a native file from a different revision than the STEP. Pick one released solid.

Ignoring units on export. A millimeter part exported as inches will look like a different program.

Treating a format change as a design change in the sourcing table. STL to STEP on the same revision is a format fix, not a design change.

What to Tell Sourcing

The quote file is the solid. STEP or STP from the released revision, units checked. A mesh can ride along as a visual. It is not the file the number is supposed to describe.

If the first record used STL and the second uses STEP, label that row as a format fix. Do not ask finance to treat it as a design cost. Read why instant quote changes after CAD review.

If the STEP contains extra bodies, name the molded body in notes. An unnamed assembly looks like a different program.

If a print house only has mesh, still ask CAD for a solid export before tooling review. A planning number on a mesh is weaker than a planning number on a solid.