Case Study of Positioning 5-axis Machining of Medical Electronic Rotor Discs

1. Background Introduction

In the medical field, electronic rotor discs are important devices in extracorporeal membrane oxygenation systems and have strict material and processing requirements. This case study demonstrates the company's successful experience in using positioning 5-axis CNC to process electronic rotor discs. 1.4016 stainless steel has low cost, magnetism, and oxidation resistance as its core advantages.

2. Material and Technical Challenges

1. The main processing challenges of 4016 stainless steel include:

Poor corrosion resistance: The corrosion resistance is relatively poor compared to SUS304 stainless steel, and it is prone to corrosion in chloride ion (seawater), strong acid or high temperature and high humidity environment.

Poor strength and toughness: Under high and low temperature conditions, the strength and toughness are significantly reduced, and brittle fracture is prone to occur

Work hardening: Work hardening will occur during cold processing, increasing processing difficulty and tool wear.

Dimensional stability: This product has a small tolerance in the drawing, a complex structure, and requires secondary clamping, which may affect the stability of the dimensions and cause out-of-tolerance phenomena.

High appearance requirements: No defects such as burrs, vibration marks, hand steps, scratches, etc. are allowed at all positions of the product, and the root cleaning in the magnet slot may not be cleaned.

High salt spray requirements: This product has a high salt spray requirement level (GB/T 10125-2012 is implemented for 72 hours and should meet the 10th level requirements), and the salt spray may not meet the requirements.

Cost control: This product has a complex structure and high dimensional requirements, and the defective rate and scrap rate are high.

Therefore, processing such parts requires high-precision equipment and strict process control. Pseudo-5-axis CNC machine tools can provide advantages in these aspects, including reducing the errors caused by multiple clamping and being able to complete the processing of complex curved surfaces in one go.

3. Advantages of 5-axis CNC machining with positioning

Shiyuxiang Precision uses precise 5-axis CNC machining with positioning, and the main advantages include:

Improve machining efficiency: The 5-axis CNC with positioning can fix the workpiece angle by rotating the worktable, and can complete multi-face machining in one clamping, reduce repeated disassembly, and improve machining efficiency.

Simplify fixture design: Complex workpieces do not need to customize complex fixtures, and rely on the rotating axis to adjust the machining surface, which can reduce the cost and time of tooling.

Low programming and operation threshold: The programming method is close to 3-axis, and only needs to set the fixed angle of the rotating axis, without complex 5-axis linkage tool path calculation, which reduces the skill requirements of programming engineers; there is no need to master complex 5-axis linkage post-processing technology, and ordinary 3-axis operators can be competent after short-term training.

Wide application scenarios: Applicable to polyhedral parts processing, complex curved surface parts processing and diversified order requirements through angle positioning, with high flexibility.

High precision: Using the positioning 5-axis can complete the processing of complex geometric shapes without multiple repositioning of parts, which significantly improves the machining accuracy.

Cost-effective: The 5-axis positioning is achieved by adding a rotary table to the original 3-axis machine to achieve multi-angle positioning, reducing hardware costs by 30%-50%; the mechanical structure is simplified (no complex linkage control system), the failure rate is low, and the cost of repair and daily maintenance is more controllable.

4. Processing process

In order to ensure the accuracy and surface quality of the electronic rotor disk, Shiyuxiang Precision follows the following processing steps:

1. Design and programming: According to the 2D and 3D drawings provided by the customer, Shiyuxiang Precision's engineering team programs the processing path of the parts in detail, especially the magnet slots and curved surfaces, to ensure the consistency of the processing path with the design.

2. Roughing and finishing: Use CNC lathes for roughing to remove most of the material, and then use positioning 5-axis CNC for finishing to ensure the required dimensional accuracy and surface finish.

3. Surface treatment: In order to meet the strict requirements of medical devices, the electronic rotor disk is surface treated after processing, such as deburring and passivation, to ensure that its surface is smooth and defect-free.

5. Quality control

In the production of medical devices, quality inspection is crucial. In order to ensure the performance of the electronic rotor disc, Shiyuxiang Precision has implemented the following quality control measures: Dimension inspection: Use a high-precision coordinate measuring machine (CMM) to inspect the key dimensions of the electronic rotor disc to ensure that it meets the design tolerance requirements.

Surface quality inspection: Visually inspect the surface for burrs, cracks, hand-feel steps, three injuries, and whether the color is uniform or other defects that may affect product safety.

Salt spray performance test: Salt spray test the finished product to ensure its corrosion resistance in actual use.

6. Compliance requirements of the medical industry

As a medical device, the production of electronic rotor discs must meet strict industry standards. Shiyuxiang Precision also has the ISO 13485:2016 medical device quality management system certification. Shiyuxiang Precision strictly follows the ISO 13485:2016 medical device quality management system to ensure that every link from material procurement, processing to testing meets the standards. In addition, the electronic rotor disc must pass a series of performance tests to ensure its safety and stability in use.

7. Conclusion

Through this case study, it can be seen that Shiyuxiang Precision successfully used the positioning 5-axis CNC technology to solve the difficulties in the processing of electronic rotor discs, ensuring the high standards of stability, flexibility and surface quality of electronic rotor discs in processing. This case not only demonstrates Shiyuxiang Precision's technical strength in difficult processing, but also shows that it has excellent experience and capabilities in the field of medical device manufacturing, providing customers with products that meet the strict requirements of the medical industry. It also highlights Shiyuxiang Precision's innovative ability in the medical field and its advantages in providing customized high-precision component solutions.