DFM · injection moulding
Injection moulding DFM check for STEP files
Pick a plastic and PartCheck checks your part against the rules a toolmaker applies before cutting steel — wall thickness, draft, undercuts, ribs, bosses and corners — and marks every problem on the part. Free, in your browser, nothing uploaded. (Injection molding, if you spell it the American way.)
What it does for you
- Fewer rounds with the toolmaker. Fix missing draft and thick bosses before the part goes out, and spend the DFM review on the questions that need a toolmaker.
- Cheaper tooling. Undercuts that need side actions are found while they are still cheap to design out.
- Better parts. Sinks, warpage and short shots start as geometry: wall thickness, ribs, bosses and corners.
- Decide before the plastic is chosen. Check against the common plastics at once, and see which one a problem applies to.
How to use it
- 1
Open your part
Drop a STEP file on the page and choose DFM.
- 2
Pick the process and the plastic
Choose injection moulding and a plastic — or Generic if it is not decided yet. Add glass fibre or talc where the plastic is sold filled, or enter a material of your own.
- 3
Run the checks
PartCheck measures the part and runs every check against your plastic.
- 4
Read the verdict
The answer first — 1 problem to fix · 3 to review — then the findings under Will cause defects, Will add cost and Worth knowing. Every finding is painted on the part; click one to zoom to it and step through each place it was found, with the measured value beside the limit.
- 5
Set your own limits
Every limit can be changed to match your shop or your moulder.
- 6
Send the report
The Manufacturability Report: the verdict, the part with every finding marked, pictures of the findings, the checks that passed, and the part's figures — ready to attach to a quote request.
The 11 checks
- Nominal wall in range
Whether the part's typical wall suits the plastic — too thin will not fill, too thick costs cycle time and sinks.
- Wall uniformity
Regions running much thicker or thinner than the rest of the part, which cool unevenly and warp it.
- Thin sections
Walls too thin to fill reliably, or thin enough to be weak.
- Thick sections
Heavy sections that sink, leave voids and slow the cycle.
- Wall transitions
Abrupt steps in wall thickness, where flow hesitates and stress builds — with how far to blend them.
- Draft angle
Walls that drag on the steel as the mould opens, because they have too little draft.
- Pull direction
Which way the mould should open — always reported, so you and your toolmaker start from the same direction.
- Undercuts
Features that will not come out of a simple two-part mould, and need a side action or a lifter — with the direction that would free them, where there is one.
- Internal corner radii
Sharp inside corners and tight fillets, where moulded parts crack and plastic flows badly.
- Boss wall thickness
Screw bosses with walls thick enough to leave a sink mark on the face opposite.
- Rib thickness
Ribs thick enough at the root to show as a sink line on the face behind them.
Recommended wall thickness by plastic
The range each plastic is checked against. Draft, ribs, bosses and corners are judged the same way for every plastic.
| Plastic | Thinnest wall | Thickest wall |
|---|---|---|
| ABS | 1.14 mm | 3.56 mm |
| PC | 1.02 mm | 3.81 mm |
| PA (nylon) | 0.76 mm | 2.92 mm |
| POM (acetal) | 0.76 mm | 3.05 mm |
| PP | 0.64 mm | 3.81 mm |
| PMMA (acrylic) | 0.64 mm | 12.70 mm |
| PS (polystyrene) | 0.89 mm | 3.81 mm |
| PE (polyethylene) | 0.76 mm | 5.08 mm |
| PBT (polyester) | 0.64 mm | 3.18 mm |
| PPS | 0.51 mm | 4.57 mm |
| LCP | 0.76 mm | 3.05 mm |
| TPE / rubber | 0.80 mm | 5.08 mm |
What it tells you about the part
- Measured
Weight, volume, size, typical and thickest wall, and the area the part covers in the mould.
- Estimated
The clamp force a press needs, and how long the part takes to cool — where the plastic's data is published. Estimates are kept apart from measurements, and labelled as such.
Good to know
The checks read the shape alone. They do not simulate flow, warpage or cycle time, and say nothing of gates, tooling or price — for gate positions, try the fill pattern. The checks are in beta: treat a finding as something to look at, and a clean result as not proof. Confirm with your toolmaker before committing to steel.
Questions
What draft angle does it check for?
1° by default, for every plastic. You can change it — textured faces usually need more.
What wall thickness is right for ABS?
PartCheck checks ABS against 1.14 mm to 3.56 mm. The table above has every plastic.
Does it replace a toolmaker’s DFM review?
No. It catches the geometric problems before you send the part, so the review can focus on the hard questions. The toolmaker's review is still the one that counts.
My plastic is not in the list.
Add it as your own material: a name and grade, the wall range and the density, plus thermal data if you have it for the estimates. It is kept in your browser and can be exported to share with your team.
Is my part uploaded?
No. The checks and the report run in your browser. It is free, with no account.
Try it on a real part
The demo is a moulded enclosure lid in two revisions, drawn in CAD. It opens in the tool with no files needed — or open your own STEP files. Nothing is uploaded: the analysis runs in your browser.