An injection mold inspection checklist should verify that the tool is dimensionally correct, mechanically safe, thermally ready, documented, and capable of producing the approved part. A visual look at the mold exterior is not enough; critical systems should be checked before T1 and again after corrections or transfer.
1. Mold identity and documentation
- Tool number, customer, part number, revision, cavity count, and build status are correct.
- Steel specification, heat treatment, hardness, components, and certificates are recorded.
- 2D drawing, 3D mold design, electrode data, BOM, spare-parts list, and maintenance plan are available.
- Ownership, data transfer, sample approval, correction rounds, and shipping requirements are documented.
2. Mold appearance and dimensions
| Inspection area | Check |
|---|---|
| Base and plates | Dimensions, flatness, alignment, clamps, lifting points, markings, and damage |
| Cavity and core | Part geometry, parting line, shutoffs, polish, texture, steel-safe areas, and burrs |
| Inserts and mechanisms | Fit, orientation, replaceability, clearances, wear plates, and lubrication access |
| Parting line | Match, flash risk, vent locations, overflow, and cosmetic position |
3. Cooling system
- Water connectors are correctly identified, numbered, accessible, and free of burrs.
- Channels, plugs, baffles, bubblers, inserts, and flow paths match the design.
- Pressure and leak checks are complete, and the inlet/outlet arrangement is documented.
- Flow balance and temperature behavior are checked under realistic production conditions.
4. Ejection, return, and side actions
- Ejector pins, sleeves, blades, lifters, slides, return pins, springs, and hydraulic systems move smoothly.
- Ejectors return fully before mold close and cannot collide with cavity, core, or inserts.
- Part retention, ejection force, draft, and witness locations match the drawing and acceptance plan.
- Side actions have sufficient travel, locking, lubrication, cooling, and wear protection.
5. Runner, gate, and hot-runner checks
- Runner dimensions, balance, gates, cold-slug wells, and degating features are correct.
- Sprue bushing and nozzle fit are checked for alignment and thermal contact.
- Hot-runner manifolds, heaters, thermocouples, controllers, connectors, and leak checks are documented when applicable.
- Gate witness, fill pattern, venting, and cavity balance are confirmed during the trial.
6. T1 trial readiness
Prepare the machine, resin grade, color, drying record, mold-temperature plan, process sheet, inspection equipment, and approved drawing before T1. Capture short shots, first-off parts, dimensions, appearance, weight, cycle, pressure, and any correction list. A T1 is an engineering trial, not automatic proof that production requirements have been met.
7. Final release checklist
Before shipping or production release, confirm corrections are closed, spare parts are delivered, the mold is clean and protected, water lines are drained or preserved, the data package is complete, and the acceptance report is signed. The mold-making team can prepare the tool inspection, while the engineering team defines CTQs and T1 evidence. Contact Cavity Mold for a tool inspection plan matched to your part.
Technical reference
The Protolabs injection molding guide connects mold design, material, process control, inspection, first-article, and production documentation.