Problem
Machining problem to solve
Complex automotive part geometryTight tolerance controlStable batch production
Case Study
Automotive Case Study 12 / 20BDU Housing Machining Case Study
The Battery Disconnect Unit (BDU) is one of the most critical safety components inside an electric vehicle battery pack.
bdu housing machining case studyautomotive cnc machining case studycnc machine for automotive parts
Case Overview
Core project data for this machining case.
Industry Electric Vehicles
Product BDU Housing (Battery Disconnect Unit Housing)
Material Aluminum 6061-T6 / ADC12 / A380
Process Die Casting + CNC Machining + Surface Treatment
Machine Model HYR VMC850
Tolerance +/-0.01 mm
Surface Finish Ra0.8
Production Capacity Project based
Solution
HYR-CNC machining plan
The customer is an EV battery system supplier producing:BDU housingsBattery junction boxesHV distribution boxesElectrical protection unitsTheir products are supplied to:
Machine Used
Recommended machine configuration
Machine: HYR CNC machining center selected according to part size, material and tolerance
Process: Rough machining, semi-finishing, finish machining and inspection based on the document case
Accuracy Control: Fixture planning, deformation control, stable toolpath strategy and CMM inspection
Cost Method: Published with existing website assets first to keep implementation cost low
Process
Timeline from raw material to inspection.
01 Typical manufacturing process:
02 Die Casting
03 Shot Blasting
04 Leak Test
Full Case Article
Machining background, difficulty and solution logic.
Quick Facts
Item Details Industry Electric Vehicles Product BDU Housing (Battery Disconnect Unit Housing) Material Aluminum 6061-T6 / ADC12 / A380 Manufacturing Process Die Casting + CNC Machining + Surface Treatment Machine HYR VMC850 Tolerance +/-0.01 mm Sealing Surface Flatness ≤0.03 mm Surface Finish Ra0.8 Protection Level IP67 / IP68 Application EV Battery System
Introduction
The Battery Disconnect Unit (BDU) is one of the most critical safety components inside an electric vehicle battery pack.
Its primary function is to:
The BDU housing protects these internal components from:
Although the housing may appear simple, it is actually a precision aluminum component with:
Modern EVs require BDU housings with:
Therefore, CNC machining is essential.
Connect the battery pack to the vehicle Disconnect high voltage circuits during faults Protect battery systems from short circuits Monitor current and voltage Ensure passenger safety Water Dust Vibration Electromagnetic interference Thermal expansion Sealing surfaces Relay mounting faces Busbar interfaces Cable ports Thread holes EMC grounding features High sealing performance Excellent dimensional stability Lightweight structures Precise electrical interfaces
Customer Background
The customer is an EV battery system supplier producing:
Their products are supplied to:
The customer experienced:
HYR CNC developed a dedicated machining solution optimized for aluminum electrical housings.
BDU housings Battery junction boxes HV distribution boxes Electrical protection units Passenger EVs Electric SUVs Hybrid vehicles Commercial EVs Water leakage during testing Sealing surface deformation Poor thread accuracy Cable port misalignment Surface scratches after machining
Industry Background
The EV industry is rapidly evolving.
Higher Battery Voltage
Modern EVs are moving from:
Higher voltage requires:
As a result:
BDU housings must achieve higher machining precision.
400V ↓ 800V ↓ 1000V+ Better insulation Improved sealing More reliable electrical protection
Compact Electrical Systems
Modern battery packs integrate:
into smaller spaces.
This creates:
BDU PDU Fuses Current sensors HV relays More complex structures Smaller tolerances Higher machining difficulty
IP67 / IP68 Requirements
Most EV battery systems require:
Therefore:
Sealing surfaces become the most critical machining feature.
IP67 or IP68
Aluminum 6061-T6
Advantages:
Applications:
Excellent machinability Good corrosion resistance High dimensional stability Premium EV battery systems Prototypes Low-volume production
ADC12
Advantages:
Applications:
Excellent casting performance High productivity Stable dimensions Mass production Battery electrical housings Junction boxes
A380
Advantages:
Applications:
Good strength Excellent die casting properties Cost-effective EV battery systems Electrical enclosures High-volume production
Manufacturing Process
Typical manufacturing process:
CNC machining determines the sealing and assembly quality of the housing.
Die Casting ↓ Shot Blasting ↓ Leak Test ↓ Rough CNC Machining ↓ Semi Finishing ↓ Sealing Surface Machining ↓ Thread Hole Machining ↓ Cable Port Machining ↓ Deburring ↓ Surface Treatment ↓ Leak Testing ↓ Inspection ↓ Assembly
Why CNC Machining Is Necessary
Die casting alone cannot meet:
Sealing requirements Thread accuracy Flatness requirements Cable port precision
Sealing Surfaces
The housing cover seals against:
Requirements:
Poor machining may cause:
Rubber gaskets Silicone seals Flatness ≤0.03 mm Surface Finish Ra0.8 Water leakage Dust ingress Electrical failure
Relay Mounting Faces
High-voltage relays require:
Poor positioning may cause:
Position Accuracy +/-0.02 mm Installation issues Busbar misalignment Electrical failures
Cable Ports
Requirements:
Typical requirement:
Accurate dimensions Burr-free edges Reliable sealing Tolerance +/-0.01 mm
1. Thin-Wall Structures
Typical wall thickness:
Challenges:
2 mm ↓ 5 mm Vibration Deformation Surface waviness
2. Large Sealing Surfaces
Requirements:
Challenges:
Flatness ≤0.03 mm Thermal expansion Tool marks Surface distortion
3. Numerous Thread Holes
A BDU housing may contain:
Challenges:
M4 holes M5 holes M6 holes Grounding holes Tool breakage Thread burrs Position accuracy
HYR CNC Solution
HYR recommended the VMC850 Vertical Machining Center.
High-Speed Spindle
Spindle:
Advantages:
BT40 12000 rpm Excellent aluminum machining Smooth surface finish High productivity
High Rigidity Structure
Features:
Benefits:
Cast iron bed Reinforced column Wide guideway spacing Reduced vibration Stable flatness Better surface quality
Precision Guideways
Advantages:
Suitable for:
High positioning accuracy Excellent repeatability Sealing surfaces Thread holes Cable ports
Automatic Tool Changer
24-tool ATC.
Supports:
Improving production efficiency.
Face milling Drilling Tapping Chamfering
Step 1
Machine:
Remove casting allowance.
Rough Milling Reference surfaces Structural features
Step 2
Machine:
Prepare for finishing.
Semi Finishing Internal cavities Mounting faces
Step 3
Requirement:
Machine:
Sealing Surface Machining Flatness ≤0.03 mm Cover interfaces Gasket surfaces
Step 4
Machine:
Thread Hole Machining Relay holes Grounding holes Assembly holes
Step 5
Machine:
Cable Port Machining HV cable ports Connectors Sensor interfaces
Step 6
Remove:
Improve sealing reliability.
Deburring Burrs Sharp edges
Step 7
Processes:
Improve:
Surface Treatment Sandblasting Anodizing Chromate coating Corrosion resistance Appearance Durability
Step 8
Requirement:
Guarantee waterproof performance.
Leak Testing IP67 IP68
Cutting Parameters
Typical machining parameters:
Item Value Spindle Speed 10000 rpm Feed Rate 2500 mm/min Tool Material Carbide Coolant Emulsion Depth of Cut 0.4 mm Surface Finish Ra0.8
Quality Inspection
Every BDU housing undergoes strict inspection.
Flatness Inspection
Requirement:
Inspect:
≤0.03 mm Sealing surfaces Mounting interfaces
Hole Position Inspection
Requirement:
Inspect:
+/-0.02 mm Relay holes Cable ports Thread holes
Leak Testing
Requirement:
Inspect:
IP67 IP68 Water resistance Air tightness Sealing reliability
CMM Inspection
Verify:
Ensuring complete dimensional accuracy.
Hole positions Flatness Geometric tolerances
Results
After adopting HYR CNC machining solutions:
The customer achieved:
Item Before After Surface Finish Ra1.6 Ra0.8 Flatness 0.08 mm 0.03 mm Leak Failure Rate 2.1% 0.2% Cycle Time 22 min 15 min Scrap Rate 3.0% 0.4% Better waterproof performance Improved sealing reliability Higher production efficiency Reduced manufacturing costs Improved product quality
HYR VMC850
Recommended for:
BDU Housings PDU Housings Electrical Enclosures
HYR VMC1060
Suitable for:
Battery Module Frames Cooling Plates Structural Battery Parts
HYR VMC1165
Ideal for:
Battery Trays Battery Enclosures Large EV Structures
Related Articles
What Is Surface Finish?
What Is CNC Milling?
PDU Housing Machining Case Study EV Battery Tray Machining Case Study Cooling Plate Machining Case Study Aluminum Machining Guide
What is a BDU housing?
A BDU housing protects the Battery Disconnect Unit and its electrical components inside an EV battery pack.
Which materials are commonly used?
Aluminum 6061-T6, ADC12 and A380 are widely used.
Why is CNC machining necessary?
Critical sealing surfaces, cable ports and thread holes require precision machining beyond die casting capabilities.
What sealing performance is required?
Most BDU housings require IP67 or IP68 waterproof protection.
Which CNC machine is recommended?
The HYR VMC850 is an excellent solution for machining BDU housings and EV electrical enclosures.
Conclusion
BDU housings are critical safety components in electric vehicle battery systems.
From sealing surfaces and cable ports to thread holes and relay interfaces, every feature requires precision CNC machining.
With excellent aluminum machining capability, stable flatness control and high production efficiency, HYR CNC machining centers provide reliable and efficient solutions for BDU housing manufacturing.
HYR CNC continues to support global EV manufacturers with advanced machining technology and customized battery system production solutions.
Result
Before and after machining improvement.
| Item | Before | After |
|---|---|---|
| Result 1 | Before optimization | After adopting HYR CNC machining solutions: |
| Result 2 | Before optimization | Item |
| Result 3 | Before optimization | Before |
FAQ
Common buyer questions for this case.
What is this case about?
This article covers bdu housing (battery disconnect unit housing) machining requirements, challenges, process planning and CNC machine selection.
Which machine is recommended?
The final machine should be selected according to part size, material, tolerance, cycle time and fixture plan.
Can HYR-CNC support similar parts?
Yes. Send drawings, material, tolerance and volume so HYR-CNC can recommend a suitable machining proposal.
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