Process Overview for Machining Impellers of A Special Equipment Booster Pump

Project Background

A leading fluid dynamics technology enterprise designed a special equipment booster pump impeller. This impeller features specific material composition, precise structural dimensions, and stringent performance requirements, necessitating a detailed processing plan to ensure product quality.

This equipment serves as a high-pressure booster pump for reverse osmosis (RO) systems. It must withstand high pressure and resist long-term corrosion from chloride ions in various water qualities, such as seawater.

Particularly critical is the nickel-based high-temperature alloy cladding applied to the blade edges. This material is indispensable in extreme environments, delivering long-term stability under high temperatures (typically exceeding 600°C), high pressure, severe mechanical stress, and harsh chemical corrosion. Its core value lies in maintaining strength, creep resistance, fatigue resistance, and corrosion resistance under these demanding conditions.

Key Parameters of the Impeller

(1) Material Properties

Main Material: 316 Stainless Steel，Edge Reinforcement Material: 1.5mm thick nickel-based high-temperature alloy welded to the blade edges via cladding process.

(2) Structural Dimensions

Number of Blades: 5, Impeller Diameter: 318mm, Impeller Height: 108mm.

(3) Performance Requirements

Dynamic Balance Grade: G1.0, Dynamic Balance Test Speed: 750 rpm.

Geometric Tolerance Requirements: - Symmetry: 0.01 mm, - Radial Runout: 0.01 mm, - Cylindricity: 0.006 mm

Surface Roughness: Ra 0.6.

Processing Steps and Processing Time Assessment- The processing diagram is shown at the bottom of the page

Quality Control and Acceptance Criteria

(1) Process Inspection

Non-destructive Testing: After the cladding process is completed, inspect the workpiece interior for Gas porosity, cracks, or other defects.

Cutting tools Management: Due to the hard surface of nickel-based high-temperature alloys, special alloy tools are used during finishing operations. Cutting tools must be replaced every half hour to ensure machining accuracy.

(2) Final Acceptance

Dynamic Balancing Test: Dynamic balancing measurement results must achieve G1.0 grade.

Dimensional Measurement: full-dimensional measurement report and 3D coordinate measurement results file.

Surface Quality: Test results certifying surface roughness Ra0.6.

Certification Materials: The following documents must be provided as acceptance basis:

• Material Composition Certificate

• Solution treatment and tempering heat treatment process certificates

• Workpiece non-destructive testing certificate

• Nickel-based high-temperature alloy remelting process specification.

Summary

This report clearly defines the material properties, key parameters, machining process steps, and quality control and acceptance standards for impellers of special equipment medium-pressure pumps. Each phase must be strictly executed according to the established plan to ensure the machining quality of impellers meets the company's stringent requirements. During subsequent production, close attention should be paid to the implementation of each process, with timely adjustments and optimizations to ensure the smooth progress of the project.

Processing flow diagram for reference

By Leo Liao

Hi everyone, I am one of the co-founders of Zhihui Precision. You can call me Leo.

I've been in the parts machining industry for 15 years, I'm 38 years old, and now I'm a senior engineer at Zhihui Precision.

In the past 15 years of career, from the very beginning of the mechanical design apprenticeship, to bench-worker, machining process engineers, project engineers, and then to the senior engineer, all the way, has been in the machining industry inside the deep cultivating, learning a amount of rich theoretical knowledge and practical experience.

What makes me persist in this seemingly boring industry? I think it should be the love, as well as watching part process start from scratch, from the beginning of a concept to design, and then step by step to make it into a physical process, so that I have a sense of fulfilment and achievement, love and enjoyment in it, the joy will come with it.

I have a dream, that is, in their own professional life while taking care of family life can always stick to the original intention, tireless in their favourite machining industry with the attitude of craftsmanship to do a good job of every part by my hands, so that looks very textured, it smell rust, plus gorgeous surface treatment to add, the appearance and dimensions are just prefect, so that every part like a work of art in the hands of the customer.

So, what can be done to give each part the appearance and dimensions that are just perfect and present it to the customer like a work of art?

I think we're on our way, because here's what we did.

1. Upgraded factory facilities and equipment, respectively:

1.1 With a 10,000 square metres factory workshop.

1.2 50+ CNC Machining Centres and Turn-Mill Machining Centres (Vertical and Horizontal) with 40 sets of 4 & 5 Axis CNC Machining Centres.

1.3 Complete production and machining auxiliary equipment, including a flexible line with automatic loading, a complete and leading cutting tools management warehouse, a separate parts polishing department, a warehouse centre, and a production management system scientifically managed by MES and ERP.

2. Enriched team, with 100 + people, 15 people more than 10 years of 5-axis CNC programming and machining experience in the core team, 5 people experienced in foreign trade project management team.

3. Equipped with an advanced inspection system and equipment, with multiple RENISHAW inspection systems, including CMMs of ZEISS and LK, hand-held material analysers, hand-held 3D part scanners, as well as providing CT scanning measurement.

4. Improving and perfecting our company through international certifications, we are ISO9001:2015 certificated, in the process of applying for ISO13485 certification, China High-Tech Enterprise certified, and have 20 company technology patents.

5. We are still moving forward to the goal, towards refinement, lean process, and through advanced digital, automation equipment and improve the company, so that the production process is more efficient, quality is more stable, through lean process and automation continuously optimise the cost, so that customers can rest assured and satisfied.