A solid plastic part DFM checklist reduces T1 failures, sink marks and tool ECOs. Run these checks before RFQ so China mold makers can quote realistic steel, gates and cycle times.
A solid plastic part DFM checklist reduces T1 failures, sink marks and tool ECOs. Run these checks before RFQ so China mold makers can quote realistic steel, gates and cycle times.
Walls, ribs and bosses
- Keep nominal walls as uniform as function allows.
- Rib thickness typically a fraction of wall to limit sink.
- Bosses with cores and gussets rather than solid masses.
- Avoid abrupt thickness jumps that trap heat.
Draft, parting and cosmetics
| Item | Guideline | Why |
|---|---|---|
| Draft | Add on shut faces & textures | Ejection & polish life |
| Parting line | Place off A-surfaces | Cosmetic control |
| Ejectors | Allow pads on B-side | Witness marks |
| Gates | Hide or tab where possible | Trim & appearance |
| Textures | Specify SPI / code early | Steel & draft impact |
Tolerances and assembly
Apply tight tolerances only to functional datums. Snap fits need material-specific deflection analysis. Living hinges require suitable resins (often PP). Insert molding needs insert material and knurl notes.
Pre-RFQ file readiness
- STEP with correct units.
- 2D critical dims and GD&T where needed.
- Resin grade and color.
- Annual volume for cavity proposal.
Free DFM with HC-Mold
HC-Mold provides free DFM review with complete project RFQs under ISO 9001:2015. Factory: Chang'an, Dongguan. Email contact@hc-mold.cn · Tel +86-769-85327002. Reply ≤12h; quote ≤24h when packages are complete.
Gate, knit line and warpage awareness for designers
Even before moldflow, designers can anticipate knit lines opposite gates on cosmetic faces and move logos or textures accordingly. Long thin U-channels warp; add ribs or adjust cooling expectations with the toolmaker. Large flat panels may need structural ribbing that industrial design must approve early.
Metal inserts change local shrink and can cause cracks if sharp corners meet boss roots. Specify insert material, knurl and preheat assumptions. For transparent parts, gate blush and venting discipline dominate—share optical requirements explicitly.
DFM is iterative. Expect a first factory response with marked screenshots, then a revised CAD drop. HC-Mold’s free DFM on complete RFQs is intended to catch these issues before steel purchase, saving weeks of T2 corrections.
Buyer checklist before you issue the PO
Confirm drawings are revision-controlled, materials are purchasable in China within your schedule, and inspection methods are agreed in writing. Ambiguity at PO stage becomes cost later. List secondary operations, packaging and labeling so they are not treated as free extras. If multiple factories are bidding, freeze the same specification package for all—do not let informal calls create hidden scope differences.
Align internal stakeholders: industrial design owns cosmetics, engineering owns function, procurement owns total cost and risk. A single RFQ owner should consolidate feedback so the manufacturer receives one voice. For export programs, involve logistics early on Incoterms preference and whether tools or finished goods will cross borders.
plastic part DFM checklist decisions improve when data is complete. HC-Mold International Co., Limited in Chang'an, Dongguan, Guangdong, China operates under ISO 9001:2015 with free DFM on complete packages, reply within 12 hours, and quote within 24 hours when files, material, volume and finish are clear. Email contact@hc-mold.cn or call +86-769-85327002. Prototype CNC frequently supports MOQ of one piece when geometry is defined.
Documentation to keep in your program folder
- Final quote with assumptions listed line by line.
- NDA and tooling ownership clauses if molds are involved.
- Approved DFM screenshots and CAD revision that matches the PO.
- Sample reports (dimensional and visual) with clear accept/reject notes.
- Packaging photos and carton specs for repeat orders.
FAQ
What draft for textured faces?
Textures generally need more draft than polished shut-offs. Confirm with texture depth and steel polish class.
Can DFM change my industrial design?
Slightly—engineers propose minimum changes that protect look while making the part moldable.
Should I moldflow every part?
Not always. Complex thin walls, large parts or cosmetic risk may justify flow analysis.
Is checklist enough without factory review?
Checklist reduces issues; factory DFM still catches process-specific risks.
Ready to source plastic parts after DFM review? Send your STEP/IGES drawings, material notes, volume band and finish requirements via our RFQ form. HC-Mold International Co., Limited is a direct OEM manufacturer in Chang'an, Dongguan, Guangdong, China (ISO 9001:2015). Contact: contact@hc-mold.cn · +86-769-85327002. Free DFM review; reply ≤12h and quote ≤24h on complete RFQ packages.
Talk to HC-Mold engineering
Free DFM · reply ≤12h · quote ≤24h on complete RFQ · ISO 9001:2015 · Dongguan, China