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Before Steel Release

Injection Mold Specification Sheet Template: What to Include Before Steel Release

Injection mold specification sheet review before steel release and tool approval

Freeze the mold specification before steel release so the buyer, toolmaker, and molder are aligned on resin grade, cavitation, steel callouts, SPI/VDI finish, cooling interfaces, press limits, and measurable run-off criteria, with approval evidence defined in advance for material certs, hardness reports, cooling leak test records, and FAI or CMM results.

  • Resin Grade & Shrink Basis
  • Gate Style & Vestige Limits
  • Steel Grade & Hardness Reports
  • SPI / VDI Finish Standards
  • Cooling Circuit Layout & Leak Test
  • FAI, CMM, and Run-Off Acceptance
Use this review when resin, steel, finish, or run-off requirements are still being frozen before steel cut.
Request a Mold Spec Review Download the Mold Spec Sheet PDF

What Is an Injection Mold Specification Sheet?

Definition

An injection mold specification sheet is the engineering control document that locks the key inputs for a new mold, including resin grade, cavitation, steel callouts, finish class, press interfaces, cooling requirements, and approval criteria. It defines what the toolmaker must build, what the molder must run, and what the buyer will use to approve the tool.

Typical approval items include resin grade confirmation, steel and hardness records, finish standard callouts, cooling leak test results, and FAI dimensional requirements for CTQ dimensions. For comprehensive project control, see our Injection Molding Tables & Checklists.

Why Buyers Use It Throughout the Lifecycle

1. Before RFQ Freeze

To ensure all suppliers quote against the same steel grade, cavitation plan, hot runner specification, and approval scope, ensuring a standardized commercial comparison.

2. Before Steel Release

To freeze approved part revision, shrink basis, gate locations, venting strategy, and cooling circuit layout, so machining starts against a locked specification rather than supplier assumptions.

3. Before Final Tool Approval

To verify that the physical tool and its evidence package match the agreed dry-cycle target, ejection layout, and FAI/CMM results before authorizing shipment.

What the Mold Specification Sheet Must Define Before Steel Release Approval

Program & Revision Control

Define the approved part drawing revision, CAD release package, and revision date before machining starts. This prevents tool build decisions from being made against outdated files.

Acceptance: Approved Drawing Revision + CAD Release Sign-off

Part, Resin & CTQ Basis

Lock the exact resin grade and shrink basis used for tool sizing. Define CTQ dimensions and the measurement plan for FAI/CMM verification.

Acceptance: Resin Data Sheet + CTQ Measurement Plan

Cavitation & Mold Base

Confirm cavity count, mold base standard, and cavity ID numbering so sampling, dimensional issues, and future maintenance can be traced back to the correct cavity.

Acceptance: Approved 2D Mold Layout with Cavity ID Scheme

Gate, Runner & Venting

Freeze gate type, location, vestige limit, and venting strategy before steel release. Approval is based on the mold layout review and Moldflow results where flow risk is high.

Acceptance: Approved Gate Layout + Moldflow Review (If Required)

Steel, Hardness & Finish

Specify steel grades and hardness targets based on resin wear. Define cosmetic zones using SPI or VDI standards.

Acceptance: Steel Certs + Hardness Verification Report

Press & Interface

Validate tie-bar spacing, daylight range, ejector pattern, and nozzle seat radius against the target press data before the mold interface is released for machining.

Acceptance: Target Press Compatibility Review Record

Ejection & Cooling

Lock cooling circuit layout, port identification, and leak test requirement. Define ejector pin locations, return function, and interference checks before the first trial.

Acceptance: Cooling Leak Test + Ejection Function Check

Tryout Plan & Sign-off

Establish the T1 and T2 trial plan and measurable run-off criteria including cycle time, cosmetic acceptance, and dimensional results for final sign-off.

Acceptance: Signed Run-Off Report + Trial Records
Preview of injection mold specification sheet PDF for steel release approval

Download the Injection Mold Specification Sheet PDF for Steel Release and Tool Approval

Use this 1-page engineering master sheet to freeze mold inputs, approval criteria, and sign-off responsibility before steel release, ensuring buyer, tooling, molding, and quality teams are working against the same controlled document.

The sheet is typically reviewed before RFQ freeze, steel release, T1 planning, and final tool approval, with sign-off fields for engineering, quality, and project ownership.

Approved Fields Included

  • Project Identification, Revision Status, and Approval History
  • Resin Grade, Shrink Basis, and CTQ Verification Items
  • Steel Grade, Hardness Requirement, and Surface Finish Class
  • Cooling Circuit Layout, Port ID, and Leak Test Requirement
  • Measurable Run-off Criteria for Functional and Cosmetic Approval

Engineering Review Use

  • Procurement Quote Review and RFQ Alignment
  • Engineering Design Freeze (T0 Review)
  • Supplier Review Meeting Before Steel Cut
  • Final Approval Package with FAI, CMM, and Supporting Records

PDF vs. Editable Version

Use the PDF Master as the frozen approval record for steel release, trial review, and final tool sign-off. The editable version should be requested during drafting, DFM review, and supplier-side updates before final revision lock.

Download PDF Master Request the Editable Spec Sheet

How to Define and Approve Each Critical Mold Specification Field Before T1

Misalignment during specification review is a common cause of steel release delays, T1 rework, and approval disputes. Use the same engineering logic for every critical field so the requirement, evidence, and approval method are defined before machining starts.

Resin Grade and Shrink Basis

What to define Define the exact resin supplier, commercial grade, and datasheet reference used for shrink assumptions and tool sizing. Refer to our Material Selection Guide.
Why it fails Using a generic resin family such as PC/ABS instead of a defined grade can drive the wrong shrink basis into steel dimensions and increase dimensional variation at T1.
What evidence to request Official Technical Data Sheet (TDS) and verified shrink test results where available.
Typical approval method Signed approval of the shrink factor and datasheet revision used in the CAD scaling package.

Cavitation and Interchangeability

What to define Final cavity count and specific interchangeability requirements for inserts and slides to ensure maintenance compatibility.
Why it fails Non-interchangeable cavities increase maintenance downtime and complicate spare part inventory management.
What evidence to request Approved cavity layout plus cavity-to-cavity dimensional comparison data from T1 or later trials.
Typical approval method Approved cavity-to-cavity dimensional report, with Cpk required only where the program or CTQ plan calls for capability evidence.

Gate Type and Vestige Limit

What to define Gate style (Sub, Valve, Edge), exact location, and the maximum allowable vestige height for assembly clearance.
Why it fails Gates in undefined cosmetic zones or high vestiges interfering with mating parts often lead to T1 welding or gate relocation.
What evidence to request Approved gate layout, and Moldflow analysis for pressure drop, freeze pattern, or fill balance where the part geometry carries flow risk.
Typical approval method Signed approval of the gate location, vestige limit, and cosmetic impact using a sample, mock-up, or approved review drawing.

Steel Callout and Hardness

What to define Define the steel grade, hardness target, and heat-treatment requirement based on resin wear, corrosion risk, and expected tool life. Consult our Mold Steel Guide.
Why it fails Inappropriate steel selection leads to premature tool wear, core collapse, or surface degradation when using glass-filled or corrosive resins.
What evidence to request Material mill certificate and heat-treatment hardness log for each critical insert or cavity component.
Typical approval method Supplier hardness verification report, with third-party confirmation where the program or customer requirement calls for it.

Finish and Cosmetic Zones

What to define Define each cosmetic zone and assign the required SPI or VDI finish callout to each visible surface or textured area.
Why it fails Subjective surface requirements create endless rework loops and approval disputes regarding texture depth or polish quality.
What evidence to request Plaque samples for texture verification and roughness (Ra) measurements for high-polish surfaces.
Typical approval method Signed cosmetic boundary sample or approved golden sample set for visual boundary approval.

Press Interface and Constraints

What to define Define tie-bar spacing, daylight range, locating ring size, nozzle seat, and ejector interface for the target molding press.
Why it fails Tools that physically cannot be mounted or lack the stroke to eject the part cause major logistic deadlocks at T1.
What evidence to request Machine interface layout and mold installation drawing confirming all mechanical clearances.
Typical approval method Press-to-mold interference check sign-off against the confirmed target press specification.

Cooling Ports and Leak Test

What to define Define cooling port size, circuit identification, connection direction, and leak test requirement for each loop.
Why it fails Inefficient cooling causes excessive cycle times and increases dimensional variation due to warping.
What evidence to request Pressure drop data and a documented 80 PSI air/water leak test report for all circuits.
Typical approval method Approved cooling circuit map, leak test record, and trial evidence showing the cooling system performs as specified.

Run-off Criteria: FAI and CMM

What to define Define the measurable run-off targets for CTQ dimensions, visual acceptance, cycle time, and sample quantity before the trial starts. Refer to our Validation Guide.
Why it fails Undefined quality targets create approval disputes and allow trial parts to pass informally even when functional dimensions are out of spec.
What evidence to request FAI or CMM results for defined CTQs, supported by cycle time logs and trial records. See our Quality Documents.
Typical approval method Signed tool run-off acceptance form based on the verified dimensional and performance data package.

What Evidence a Reliable Mold Supplier Should Attach to the Spec Sheet

A mold specification sheet is only useful when the attached evidence can support steel release, trial review, and final tool approval. These six deliverables should be attached or referenced before the tool is signed off.

Mold steel hardness verification report for H13 cavity insert approval
Material Integrity

Steel Certs & Hardness Record

Mill certificates and hardness records confirm that the mold steel used matches the specified grade and reaches the required HRC for wear resistance, corrosion control, and expected tool life.

Cooling pressure leak test setup for injection mold approval record
Mechanical Check

Cooling Pressure Leak Test

Documented air or water pressure tests verify that cooling circuits are open, correctly connected, and able to hold the specified test pressure without leakage before trial release.

Design Documentation

Approved Layout, BOM & Drawings

A complete 2D/3D drawing pack and BOM support tool approval, spare-part traceability, future maintenance, and internal engineering audit control throughout the tool's lifecycle.

FAI and CMM report evidence for CTQ dimensional approval
Quality Verification

FAI / CMM Report for CTQ

FAI and CMM reports verify whether the molded parts meet the defined CTQ dimensions and agreed tolerance targets specified in the initial sheet.

Process Control

PPAP / Validation Package

When required by the program, quality documents like PPAP document process readiness, capability evidence, and the records needed before final production approval.

Traceability

Revision & Change Log Control

A controlled engineering change log tracks approved revisions from T0 through final approval so tooling updates and maintenance decisions remain traceable. See our Injection Molding ECN Form.

Common Mold Specification Mistakes That Delay Tool Approval

These five specification mistakes commonly trigger steel release errors, T1 rework, mounting issues, and approval disputes before the tool can be signed off.

Undefined Cosmetic Zones

Failing to define cosmetic zones allows gates, ejectors, or parting lines to land in visible areas, which often leads to T1 welding, gate relocation, or cosmetic surface rework. Zones should be tied to an approved finish callout and golden sample reference.

Impact: Aesthetic Failure / Tool Welding rework

Unfrozen Resin Grade

Vague resin callouts such as generic ABS, without an exact grade and datasheet basis, can drive the wrong shrink value into steel dimensions, resulting in dimensional scrap at T1.

Impact: Dimensional Scrap & Shrink Error

Missing Press Constraints

Neglecting to verify tie-bar spacing, daylight range, locating ring size, nozzle seat, or ejector stroke against the target press data can result in a tool that physically cannot be mounted or run as planned.

Impact: Machine Compatibility Failure

Vague Hardness or Finish Callouts

Using subjective terms instead of defined SPI finish standards and steel grades with specific hardness ranges creates approval disputes and weakens tool-life control.

Impact: Tool Life Reduction / Approval Disputes

Subjective Run-off Criteria

Approving a tool without defined FAI/CMM data, cycle time targets, and signed trial records allows subjective decisions to pass into production, increasing long-term stability risk.

Impact: Production Stability Risk

Mold Run-Off Criteria for Tool Approval and Shipment Release

Before final tool shipment or production release, the mold should be reviewed against project-defined measurable criteria. Approval should be based on recorded engineering evidence rather than subjective trial judgment.

Spec Item Target Value Test Method Record Owner Approval Evidence
Cycle Time Within the approved target cycle or quoted window Stopwatch / Press Log Molder Production Log Report
Scrap Rate Within the program-defined limit during trial duration Continuous Audit Production Mgr Run Stability Sheet
CTQ Dimensions All defined CTQs meet tolerances on approved samples FAI / CMM QC Engineer FAI / CMM Report
Cooling Integrity No leakage at the specified cooling circuit test pressure Pressure Hold Test Tooling Engineer Leak Test Certificate
Process Capability Capability target as defined by program (where required) Statistical Analysis Quality Dept PPAP / Capability Study

Process & Mechanical Checks

  • Continuous Cycling: Stable continuous cycling over the agreed trial duration, with no abnormal interruptions or repeated defects that invalidate the run.
  • Mechanical Function: Verification of cooling and moving mechanisms through dry-cycle checks, leak test records, and thermal balance evidence where required.

Documentation Package

  • Quality Acceptance: Final Quality Documents including revision-controlled drawings, golden samples, and boundary limit plaques.
  • Engineering Pack: Final BOM, as-built 3D tool CAD, revision-controlled electrode drawings, and the maintenance schedule required for handover.

Run-Off Acceptance Clause

"The mold is approved for shipment or next-stage release based on successful completion of the agreed run-off criteria in the Master Specification Sheet, including dimensional results, cycle time review, mechanical function checks, and required document handover, as recorded on [Insert Date]."
Engineering Tip: Use this clause for run-off acceptance and a separate release note for final logistics authorization.

How the Spec Sheet Connects DFM, Validation, and Final Tool Handover

The spec sheet connects DFM review, trial validation, and final tool handover by keeping the same approved requirements in use from steel release through shipment approval. At each stage, the sheet points to a specific approval basis such as DFM decisions, trial records, dimensional reports, and final handover documents.

PHASE 01
Input Alignment

Before Steel Cut

During DFM review, critical mold inputs are aligned and frozen in the spec sheet, including shrink basis, gate location, and cosmetic boundaries. This phase ends with an approved DFM output and frozen revision basis ready for steel release.

Align Spec Sheet with DFM Review
PHASE 02
Verification Basis

During Mold Build & T1/T2

During T1 and T2, the spec sheet provides the run-off benchmark for cycle time, CTQ dimensions, and cosmetic acceptance. Trials generate measurable records and capability evidence recorded against the criteria defined before steel release.

Review Mold Validation Criteria

FAQ: Injection Mold Specification Sheets, Approval, and Shipment

Do prototype tools still need a mold spec sheet?

Yes. Prototype tools still need a mold spec sheet because resin grade, shrink basis, gate location, and press interface must be defined before trial parts are judged. The spec sheet allows prototype trial results to be compared against the later production mold instead of becoming isolated, non-transferable trial data.

What is the difference between SPI and VDI in a spec sheet?

SPI defines polished surface grades (such as A-1 or B-2), while VDI defines EDM texture grades (such as VDI 12 to VDI 45). In a mold spec sheet, SPI and VDI standards are used to assign requirements to cosmetic visual surfaces versus textured or non-cosmetic areas to remove aesthetic subjectivity during approval.

Can one spec sheet cover transfer molds and export molds?

Yes, if the spec sheet clearly defines the mechanical and regional interfaces. Export molds require standard system (DME/HASCO), thread type, and hot runner electrical requirements, while transfer molds must include the target press interface, ejector pattern, and daylight limits. If these interface fields are missing, the mold carries a high installation compatibility risk at the destination.

What documents should be signed before final mold shipment?

Before mold shipment, the signed release package should include the dimensional report for defined CTQs, steel and heat-treatment records, cooling leak test evidence, and the run-off acceptance record. These quality records provide the engineering evidence that the physical tool matches the frozen specification and is approved for handover.

Before Steel Release

Upload Your Drawing for Mold Specification Review Before Steel Release

Upload your part file, resin grade, target press data, and any critical tolerances or cosmetic requirements that must be frozen before steel release. We review the submitted inputs against mold specification risks such as shrink basis, gate concept, press compatibility, CTQ definition, and acceptance evidence.

3D CAD Data (STEP/IGS)
Resin Grade & Shrink Basis
Target Press Data
CTQ & Tolerance Targets
Upload Drawing for Mold Spec Review