An injection molding DFM checklist should resolve geometry, material, tooling, process, quality, and production risks before mold steel is cut. The purpose is not to force every part into one design style; it is to expose decisions that affect function, cost, toolability, repeatability, and approval.
Part geometry checklist
- Wall thickness is practical for the resin, flow length, appearance, and cooling requirements.
- Draft, ribs, bosses, holes, corners, and texture allow release without damaging the part.
- Undercuts are identified, with slides, lifters, collapsible cores, or part redesign evaluated.
- Parting line, shutoffs, ejector marks, gates, weld lines, and cosmetic zones are agreed.
- Shrinkage, tolerances, datums, assembly fits, and critical-to-quality dimensions are defined.
Mold and process checklist
- Gate and runner layout supports balanced filling, packing, appearance, and manageable vestige.
- Cooling circuits reach thick sections and maintain practical temperature balance.
- Vents are placed at last-fill and gas-trap risks; ejection is adequate and safe for the part.
- Steel, inserts, standard components, mechanisms, surface finish, and maintenance access match volume and resin risk.
- Machine size, resin drying, process window, inspection method, and packaging are considered.
Release the design with evidence
Record open risks, owner, due date, and acceptance method. Use flow or cooling analysis where it can answer a real question, not as decoration. Before cutting steel, freeze the part revision, confirm tool ownership, approve the mold design, and define the trial and dimensional-report requirements.
Plan the next step
Share your part, resin, annual volume, critical dimensions, finish, and timing with the Cavity Mold team. We can review the manufacturing risks and recommend a practical next step through our contact page.
Related Cavity Mold resources
- Injection mold engineering services
- Injection mold making services
- Plastic injection molding services
- Contact Cavity Mold
Technical references
- Protolabs design-for-moldability toolkit
- Protolabs injection molding design, material, and process guide
Use DFM as a release gate: An injection molding DFM checklist is useful only when every item has an owner, a decision, and evidence. The goal is to identify geometry, material, appearance, tolerance, and tooling risks while the part can still be changed cheaply—not after steel has been released.
Checks before the CAD file is frozen
An injection molding DFM checklist is useful only when every item has an owner, a decision, and evidence. The goal is to identify geometry, material, appearance, tolerance, and tooling risks while the part can still be changed cheaply—not after steel has been released.
A DFM item-to-evidence map
| Decision area | What to examine | Evidence or output |
|---|---|---|
| Part geometry | Parting, draft, wall transitions, ribs, bosses, and undercuts | Section views and marked-up CAD |
| Material and shrinkage | Grade, fillers, environment, appearance, and data source | Resin datasheet and application assumptions |
| Tooling and process | Gate, vent, cooling, ejection, slides, and inspection access | Concept sketch and risk register |
| Quality and acceptance | Critical dimensions, datums, cosmetic zones, and test state | Drawing, acceptance standard, and measurement plan |
Release questions for the project team
- Mark every surface that must remain cosmetic or functional.
- Separate nominal geometry from dimensions that control assembly or performance.
- Identify assumptions that require Moldflow, trial parts, or application testing.
- Record the accepted risk, owner, and due date for every item not resolved before release.
What to send for a DFM review
A DFM request should include the STEP file, 2D drawing, resin and grade, expected volume, critical dimensions, cosmetic zones, mating parts, and target use environment. The engineering page is the natural next step before a tooling quote.