DFM Checklist for Medical Plastic Housings: Practical Points Before Tooling

Before committing to tooling for a medical plastic housing, a structured DFM review reduces iterations, cost, and regulatory risk. Below is a practical checklist used in Threegon projects.

1. Wall thickness: Target uniform walls (typically 1.5–3.0 mm for medical housings). Avoid abrupt changes; use gradual transitions. Confirm material-specific shrinkage and flow.

2. Draft angles: Minimum 0.5–1° on internal surfaces, 1–3° external. Increase for textured or deep cores. Medical-grade materials often need more draft than commodity resins.

3. Gate and runner: Prefer edge or tunnel gates that leave minimal vestige. Position to avoid weld lines in critical cosmetic or structural areas. Document gate location for process validation.

4. Undercuts and side actions: Minimize. If required, confirm tool complexity, cycle time, and cleanability. Side actions increase lead time and cost.

5. Material and regulatory: Select medical-grade or biocompatible resin early. Confirm documentation (USP Class VI, ISO 10993 if applicable). Align with intended sterilization method (EtO, gamma, autoclave).

6. Cleanroom and assembly: If the part will be assembled in ISO 7 cleanroom, design for easy handling, minimal particle generation, and clear inspection points. Consider overmold or insert requirements early.

Result: Addressing these points in the DFM stage typically shortens T0-to-qualification time and produces documentation that supports the client's regulatory pathway. Contact Threegon for a project-specific review.