Customer Requirements
What the customer needed
The customer is a precision mold manufacturer producing:Automotive interior componentsElectronic housingsMedical plastic partsHigh-precision industrial partsAnnual production:
Case Study
Mold & Die Case Study 04 / 15Mold Core Machining Case Study
The mold core is one of the most critical components in injection molds and die casting molds.
mold core machining case studymold die cnc machiningcnc machine for mold manufacturing
Project Overview
Standard case data fields.
Industry Mold & Die / Precision Tooling
Product Mold Core
Material P20 / H13 / NAK80 / S136 / 1.2344
Process CNC Milling + EDM + Grinding + Polishing
Machine Model HYR VMC850 / VMC1060
Tolerance +/-0.003-0.005 mm
Surface Finish Ra0.2-0.8
Application Automotive / Medical / Electronics / Optical Molds
Challenges
Machining difficulty
Mold core machining is not simple 3-axis cutting.It combines:Deep Cavities+Thin Structures+High Precision+Surface Requirements
HYR CNC Solution
Machine configuration
Machine: HYR VMC or gantry CNC system selected according to mold size, steel hardness and accuracy target
Process: Rough machining, stress relief, semi-finishing, EDM support, polishing preparation and inspection
Accuracy Control: Thermal stability, fixture rigidity, finishing allowance control and CMM inspection
Cost Method: Published with existing website assets first to keep implementation cost low
Machining Process
Timeline from raw material to inspection.
01 Material preparation
02 Rough machining
03 Stress relief
04 Finish machining
05 Inspection
Full Case Article
Machining background, difficulty and solution logic.
Quick Facts
Item
Details
Industry Mold & Die / Precision Tooling Product Mold Core Materials P20 / H13 / NAK80 / S136 / 1.2344 Process CNC Milling + EDM + Grinding + Polishing Machine HYR VMC850 / VMC1060 Tolerance +/-0.003-0.005 mm Surface Finish Ra0.2-0.8 Application Automotive / Medical / Electronics / Optical Molds
Introduction
The mold core is one of the most critical components in injection molds and die casting molds.
It directly determines: Internal GeometryFunctional AccuracyAssembly FitFinal Product Quality In most plastic and metal forming processes: Core + Cavity System=Final Product Shape
What Is A Mold Core?
A mold core is the internal forming component of a mold, responsible for shaping the inner geometry of the final product.
Typical structure relationship: Mold Core -> Internal ShapeMold Cavity -> External Shape During injection or casting: Material Fills Around CoreCoolingSolidificationProduct Formed
Customer Background
HYR CNC provided a dedicated mold core machining solution.
The customer is a precision mold manufacturer producing: Automotive interior components Electronic housings Medical plastic parts High-precision industrial parts Annual production: 1000+ mold cores per year Main challenges: High precision requirement Complex internal geometry Tight tolerance control Surface finish consistency Heat treatment deformation
Why Mold Core Machining Is Difficult
Mold core machining is not simple 3-axis cutting.
It combines: Deep Cavities+Thin Structures+High Precision+Surface Requirements
Challenge 1
Complex Internal Geometry Mold cores often include: Deep ribs Undercuts Multi-level surfaces Problem: Tool Access Limitation
Challenge 2
Heat Treatment Deformation After hardening: Internal Stress ReleaseDimensional Change This affects: Fit accuracy Assembly quality
Challenge 3
Surface Finish Requirements Depending on application: Functional parts -> Ra0.8 Cosmetic parts -> Ra0.4 Optical parts -> Ra0.2 Any machining marks may lead to: Product defects Mold failure in mass production
Challenge 4
Tool Wear Hard mold steels cause: High Cutting ResistanceRapid Tool Wear
Automotive Mold Core
Used for: Interior panels Dashboard structures Trim components Characteristics: Medium complexity High repeatability
Electronic Mold Core
Used for: Connector housings Device enclosures Characteristics: High precision Small features
Medical Mold Core
Used for: Syringes Diagnostic devices Characteristics: Ultra-precision Strict surface quality
Die Casting Core
Used for: EV housings Structural aluminum parts Characteristics: High thermal resistance Wear resistance
P20 Steel
Advantages: Good MachinabilityStable Performance Applications: General mold cores
H13 Steel
Advantages: Heat ResistanceHigh Strength Applications: Die casting cores High-load molds
NAK80
Advantages: Excellent PolishabilityStable Surface Finish Applications: Cosmetic mold cores
S136
Advantages: Corrosion ResistanceMirror Finish Capability Applications: Medical and optical molds
HYR VMC850
Best for: Small precision mold cores Electrodes High-detail parts
HYR VMC1060
Best for: Automotive mold cores Medium complexity parts
HYR VMC1165
Best for: Large mold cores Die casting core structures
Step 1
Material Preparation Forged steel blocks Pre-hardened material
Step 2
Rough Machining Remove: 70-85% Material
Step 3
Stress Relief Reduce: Internal StressDeformation Risk
Step 4
Semi-Finishing Shape core geometry Prepare critical surfaces
Step 5
Heat Treatment Increase: Hardness Wear resistance
Step 6
Finish Machining Requirement: +/-0.003-0.005 mmRa0.4
Step 7
EDM Machining Used for: Deep ribs Sharp corners Complex structures
Step 8
Polishing Depending on requirement: Functional finish Mirror finish Optical finish
CMM Inspection
Checks: Geometry accuracy Position tolerance Symmetry
Surface Roughness Test
Ensures: Ra compliance
Hardness Testing
Ensures: Heat treatment quality
Assembly Fit Test
Verifies: Core-cavity matching Mold functionality
Results
Item
After HYR CNC machining optimization: Before After Accuracy +/-0.012 mm +/-0.005 mm Surface Finish Ra1.6 Ra0.4 Tool Wear High Reduced 30% Scrap Rate 2.0% 0.2% Delivery Time 100% -25%
HYR VMC850
Precision cores, electrodes
HYR VMC1060
Automotive mold cores
HYR VMC1165
Large structural cores
Related Articles
Injection Mold Machining Case Study Automotive Mold Machining Case Study Die Casting Mold Machining Case Study Mold Cavity Machining Case Study Mold Insert Machining Case Study
What is a mold core?
A mold core is the internal shaping component that defines the inner geometry of a molded product.
Why is mold core machining difficult?
Because it requires high precision, deep cavity machining, and strict surface quality control.
What materials are used?
P20, H13, NAK80, and S136 are commonly used.
What tolerance is required?
Typically: +/-0.003-0.005 mm
Conclusion
Mold cores are one of the most critical components in mold manufacturing.
They require extreme precision, stable machining processes, and high-quality surface finishing.
With advanced CNC machining capability and mold engineering experience, HYR CNC delivers reliable mold core manufacturing solutions for global industries.
Results
Before and after machining improvement.
| Item | Before | After |
|---|---|---|
| Result 1 | Before optimization | After HYR CNC machining optimization: |
| Result 2 | Before optimization | Accuracy |
| Result 3 | Before optimization | +/-0.012 mm |
FAQ
Common buyer questions for this case.
What is this mold case about?
This page covers mold core requirements, machining difficulty, process planning and machine selection.
Which machines are recommended?
HYR VMC850, VMC1060, VMC1165 and gantry CNC systems are selected according to mold size and machining difficulty.
Can HYR-CNC support similar mold projects?
Yes. Send drawings, mold steel, tolerance, surface finish and mold size for a suitable machining proposal.
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