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Combining SLS Printing with CNC Machining for EV Coolant Flow Channel Housing
Learn how SLS 3D printing and CNC machining were combined to manufacture complex EV coolant flow channel housings with precise hole alignment, sealing surfaces, and internal channels for prototype validation.
At a Glance of the Project
| Information | |
|---|---|
| Product | Coolant Flow Channel Housing for EV Thermal Management System |
| Technology | CNC machining +SLS printing |
| Challenges | Complex enclosed channels, irregular geometry, high-precision multi-point assembly, difficult fixturing |
| Material | Black nylon + fiberglass |
| Surface Finish | As machined |
| Quantity | 16 pcs |
| Lead Time | 15 days |
Product Introduction
EV powertrains require precise thermal management. Batteries and motors under high power need stable, uniform cooling to maintain performance and lifespan. Coolant flow channel housings (upper and lower reservoirs) feature intricate, enclosed channels and precise multi-point assembly alignment. These complex structures pose a challenge for their prototyping: traditional CNC alone cannot machine all channels in one setup while maintaining the accuracy of critical holes and flat surfaces.
To balance internal channel complexity with the precision requirements of key assembly features, it will adopt a hybrid manufacturing approach. Complex coolant passages were produced using SLS 3D printing, followed by CNC finishing of critical mounting surfaces and holes. This combination enabled accurate internal geometries while ensuring dimensional consistency and assembly precision. Let’s take a closer look at how this project was completed.
Structural Analysis and Critical Hole CNC Fine Machining
The coolant flow channel housing is designed to balance sealing, flow optimization, and multi-point assembly. The housing must be machined as a single piece to ensure internal channels are leak-free. This complex internal structure and irregular geometry are better suited to 3D printing for prototype production.
In addition, there are several critical features that determine assembly precision:
- Top: three large threaded holes that interface with the lid’s O-ring for sealing.
- Bottom: two mounting holes that must align precisely with the flow channel plate.
- Side: two high-precision quick-connect ports.
To ensure assembly accuracy and functional reliability, these key features also require CNC secondary machining. This guarantees strict tolerances for hole positions, flatness, and thread precision. The unusual and complex shape makes fixturing the biggest challenge in CNC processing.
SLS Printing and CNC Machining Strategy for Coolant Flow Channel Housing
To meet the structural complexity and assembly accuracy requirements of the enclosed flow channel housing, a combined solution of SLS 3D printing and CNC secondary machining was adopted.
SLS Printing
The SLS stage was designed with downstream machining in mind. Machining allowances were intentionally reserved on critical holes and sealing surfaces, creating a controlled margin for precision CNC machining.
CNC Process and Fixturing Strategy
The irregular geometry of the part and strict assembly requirements pose challenges for machining accuracy. During CNC machining, WayKen implemented a systematic process plan combined with multi-point fixturing. Measures such as controlling clamping-induced deformation, optimizing datum surfaces, and pre-machining critical holes ensured overall part precision and assembly reliability.
The machining plan was arranged as follows:
CNC Process 1: Machining of the inner diameters of the three top threaded holes
Fixturing strategy: The bottom surface of the housing served as the primary datum and was secured with bolts. This setup stabilized the part, minimized deformation from clamping, and ensured the positional accuracy of the holes.
CNC Process 2: Machining of the two precision bottom mounting holes (for precise alignment with the flow channel plate)
Fixturing strategy: The part was secured using ABS contour-locking screws to ensure stability. This form-fitting clamping method allowed strict control of hole positions and flatness, guaranteeing reliable assembly.
CNC Process 3: Machining of the side quick-connect port
Fixturing strategy: The part was again secured with form-fitting locking screws, supplemented by L-shaped blocks supporting the side. This setup ensured stable clamping, prevented vibration from the part’s weight, and maintained both perpendicularity and positional accuracy of the machined surface.
Final Process: Machining of the opposite side special quick-connect port (angular and uniquely positioned)
Fixturing strategy: This feature presented the most complex geometry and required an upgraded clamping setup. The part was secured using form-fitting locking screws, supplemented with L-shaped blocks and a G-clamp.
After aligning the datum and verifying perpendicularity, the setup was further reinforced. Multi-point support and angle adjustments ensured both machining accuracy and part integrity.
Project Outcome
This project successfully realized the complex geometry and high-precision multi-point assembly requirements of an EV coolant flow channel housing through the seamless combination of SLS 3D printing and CNC machining. Internal flow channels were preserved intact, while critical hole positions and flatness were strictly controlled, providing the customer with a reliable foundation for prototype validation and functional testing.
Leveraging the combined expertise in CNC machining and SLS printing, WayKen demonstrated its capability to machine complex, irregular parts to tight tolerances, providing custom solutions that accurately match our customers’ design and functional requirements.
