Achieving High Machined Surface Finish for Custom Pump Parts

Project Background

Automotive prototyping involves several stages: from conceptual design to determine the overall direction, to design freeze for finalizing details, followed by prototyping to create physical models, multiple testing to ensure structural functionality, and low-volume trial production in preparation for mass manufacturing.

Quick turnaround is essential for design optimization during prototyping. Usually, for metal parts, the casting process is used in production, but this method has long lead times and high costs. In contrast, CNC prototype machining offers several advantages:

• High Precision: Controlled by computer programs, CNC machining ensures high manufacturing accuracy, meeting the precision fit required for custom automotive parts.
• Flexibility: It easily adjusts processing parameters to accommodate different designs and efficiently replicates complex internal structures and unique contours.
• Fast Turnaround: From receiving drawings to final products, CNC machining offers a shorter production cycle and lower costs. This allows clients to optimize designs based on sample feedback and rapidly iterate products.

Partnered with a Professional Manufacturer for Automotive CNC Machining

With over a decade of experience in CNC machining, WayKen specializes in customized automotive component manufacturing, meeting various machining requirements and ensuring smooth prototyping and part production.

In this case study, we will explore the production of aluminum electric coolant pump components. Let’s see how WayKen approaches this project with precision and efficiency!

Analyzing Parts Structure and Machining Solutions

In this project, WayKen mainly makes two housings and two covers for the coolant pumps. The two housings are cylindrical with 2-3mm wall thickness. They provide structural support for the impeller, bearings, motor shaft, etc., and ensure these key components installation to make the pump smooth operation and minimize vibration.

At the same time, the two covers are disk-shaped, and a spiral channel is distributed on each top to guide the coolant flow direction, enabling the coolant to pass through the pump more smoothly and improving cooling efficiency. In these engine coolant pumps, all components have round bodies with multiple lugs, side structures, and connecting arms.

Therefore, to ensure efficient machining, we first consider using CNC turning to precisely shape the cylindrical body, bore, and end faces. This is followed by CNC milling to machine the sides, lugs, holes, slots, and other structural features.

Processing Keypoints and Considerations

When machining engine coolant pump components, precise dimensions, smooth surfaces, and accurately formed flow channels contribute to overall performance. Here are the key areas WayKen focused on during production:

1. Achieving a High-Quality Surface Finish

A smooth surface finish is critical for these coolant pump components, as coolant flows through the pump. Rough surfaces can cause turbulence, reducing cooling efficiency and affecting engine heat dissipation.

We usually do fine machining and manual polish to realize. However, manual polishing makes it difficult to maintain uniform sanding strength and direction. Moreover, housing and covers require assembly accuracy, poor polishing may poor sealing. Also, it is not cost-effective for low-volume production because of extra time and cost.

To address this, WayKen implemented precise CNC machining techniques:

• Fine Machining: CNC turning was applied to key areas such as internal housing passages and cover fitting surfaces, followed by high-precision milling for areas inaccessible by turning.
• Optimized Tool Paths: Before machining, we programmed continuous, even tool paths to avoid joint marks, ensuring a uniform finish and proper sealing.
• Cutting Parameter Control: For complex internal runners, increased cutting speeds and reduced feed rates minimized material tearing and rough surfaces.
• Tool Selection: We used fine ceramic-coated or carbide tools with excellent wear resistance and sharp edges to minimize cutting marks and ensure consistent surface quality.

2. Machining of the Cover’s Spiral Flow Channel

The cover of the engine coolant pump part features a spiral flow channel with a gradually decreasing diameter, designed to enhance fluid dynamics. According to fluid mechanics principles, as the cross-sectional area decreases, pressure drops, and flow velocity increases. This prevents coolant backflow when the pump stops or operates unstably, avoiding potential engine issues.

Therefore, this structure requires the machining path to accurately match the helical trajectory, if it is unreasonable, overcutting or undercutting may occur. Moreover, the uneven force on the tool during machining will wear the tool and shorten the tool’s life.

WayKen addressed these questions through:

• Optimized Machining Strategies: We carefully planned tool paths, cutting parameters, and feed rates, conducting simulated trial machining before actual production.
• Real-Time Measurement & Adjustments: An online measurement system allowed for real-time monitoring, enabling immediate adjustments to tool paths and cutting parameters when deviations were detected.
• Efficient Chip Removal & Tool Cooling: High-pressure cutting fluid was applied to clear debris promptly, ensuring a smooth surface finish while minimizing the impact of heat on tool life and machining accuracy.

3. Ensuring High Precision in Critical Features

In this project, the internal surfaces of the pump require high precision, with tolerances such as:

• Coaxiality: 0.05mm
• Cylindricity: 0.02–0.05mm
• Perpendicularity: 0.05mm

These tolerances ensure proper assembly with the rotor, stator, and bearings. Additionally, the mounting holes on the ends and sides must be precisely positioned to achieve a secure fit with external components and prevent coolant leakage.

To achieve this level of precision, WayKen employed the following:

• High-Accuracy CNC Turning: The inner round surfaces were CNC turned to maintain dimensional accuracy.
• One-Setup Milling for Complex Features: High-precision milling was used for structures that turning could not achieve, and wherever possible, we completed machining in a single setup to minimize positioning errors.
• Advanced Quality Control: All final parts were inspected using Zeiss coordinate measuring equipment to verify dimensional accuracy before shipment.

By implementing these precision machining strategies, WayKen ensured the reliable performance and quality of the engine coolant pump components.

Future Plan

Nowadays, the automotive industry is increasingly looking for personalization, performance, and refinement. Custom CNC machining breaks traditional manufacturing limitations and offers flexibility, precision, and repeatability, which reinvigorates the metal parts for the automotive industry.

As a custom CNC machining supplier, WayKen has accumulated more than 10 years of manufacturing experience, which has been fully demonstrated in various automotive projects. We also continue to refine our manufacturing techniques and efficient management, to consistently meet customers’ precision, quality, and quick turnaround requirements. Contact us and start your project today!