Precision Machining PEI for Aerospace: How KGL Machinery Solved SAFRAN's Toughest Polymer Challenge

Company Profile: KGL Machinery (KINNEX PRECISION)

Founded in 2013 in Shenzhen, China, KGL Machinery has grown from a 2-CNC startup to a 100+ machine facility spanning 12,300 sqft. We serve 200+ global clients across aerospace, medical, robotics, semiconductor, and petroleum industries.

Leadership: Dr.Jason Hu

Our founder and General Manager, Dr. Jason Hu, is a mechanical engineer with 26 years of industry experience and a PhD from NLBA Business University, Netherlands. His doctoral research on lean manufacturing has been directly implemented at KGL, achieving ±0.003mm precision on Mazak 5-axis equipment and a 30% production cycle reduction.

Quality Infrastructure

• Hexagon GLOBAL S 07.10.07 + Zeiss CAPTUM 7/10/6 Verity CMMs (0.0015mm precision)
• Olympus DPO6500 alloy spectrometer
• Keyence IM-8010 image dimension measurement (0.003mm)
• IQC-IPQC-FQC three-tier quality control system

The Challenge: SAFRAN PEI Wastewater Treatment Components

Client & Application

SAFRAN, a Tier-1 French aerospace OEM, required a series of PEI (Polyetherimide/Ultem) components for an aircraft wastewater treatment system. The parts needed to withstand internal pressure to 3 bar, thermal cycling from -40C to +80C, and chemical exposure to aerospace fluids—all while maintaining ±0.01mm geometric tolerance.

Material: German Röchling PEI

PEI was sourced directly from Röchling Engineering Plastics GmbH in Germany under aerospace-grade protocols. Key properties:

Four Critical Challenges

1. Extreme Deformation & Burring: PEI's toughness causes elastic recovery and ragged edges during machining.

2. ±0.01mm Tolerance with Thermal Sensitivity: Machining heat causes dimensional drift; CTE of 56 ppm/C makes temperature control essential.

3. Poor Weldability: PEI's high Tg resists thermal softening; conventional welding methods failed.

4. 3D Printing & Injection Molding Rejected: Additive manufacturing produced ±0.1-0.3mm tolerances and anisotropic properties; injection molding required  $50K+ tooling and 12-16 week lead time for only 200-500 units/year.

Our Solution: Mazak 5-Axis + 9-Axis CNC + Proprietary Welding

Equipment: Mazak 5-Axis Cluster

Five Mazak 5-Axis VARIAXIS C-600 / J-500 centers provided the geometric flexibility to machine complex internal channels, asymmetric ports, and thin-wall sections in a single setup—eliminating rechucking errors that would destroy the ±0.01mm tolerance.

• Positioning Accuracy: ±0.003mm
• Control: Mazak SMOOTHX CNC with thermal compensation
• Work Envelope: Ø500-600mm

Equipment: Mazak 9-Axis Mill-Turn

For components combining cylindrical and prismatic features, we deployed two Mazak INTEGREX i-250H/HS 9-axis mill-turn composite centers:

• Positioning Accuracy: ±0.003mm
• Turning Diameter: Ø670mm
• Turning Length: 1,011mm / 1,519mm
• Key Advantage: Single chucking for turning + milling + drilling + side-milling—critical for thermally sensitive PEI

The INTEGREX's single-chucking capability was decisive: each rechucking introduces thermal disturbance and mechanical stress. By completing all operations in one setup, we maintained thermal equilibrium and achieved Cpk > 1.67.

Machining Strategy: Multi-Parameter Optimization (MPO)

We developed a proprietary MPO strategy optimizing seven interdependent variables simultaneously on our Mazak platforms:

Result: 72% reduction in burr formation, 85% improvement in dimensional stability.

Thermal Management: TDMS

Our proprietary Thermal Dynamics Management System (TDMS) integrates FEA predictive modeling, infrared thermography, and real-time CNC compensation through the Mazak SMOOTHX macro programming interface. The closed-loop system achieves ±2 micron thermal compensation accuracy—well within our ±10 micron tolerance budget.

Ultrasonic Welding Breakthrough

After 8 months of R&D, we developed a proprietary 35 kHz Ultrasonic Welding process with a micro-serrated energy director (0.1mm pitch) that increases effective weld area by 40%:

Results & Quality Verification

Dimensional Inspection (Sample)

All measurements conducted on Hexagon/Zeiss CMMs (0.0015mm resolution) after 24-hour thermal stabilization:

Process Control Metrics

Why Mazak CNC Beat 3D Printing & Injection Molding

When deciding how to manufacture aerospace PEI components, engineers typically evaluate 3D printing, injection molding, and CNC machining. Here is why CNC is superior for low-volume, high-precision needs:

For SAFRAN's 200-500 units/year with complex internal channels and no draft angles, Mazak 5-axis + 9-axis CNC machining was the only viable method.

Component Gallery

Figure 1: PEI Component Assembly

Figure 1: Primary PEI component assembly--complex multi-port geometry machined on Mazak VARIAXIS J-500 5-axis center.

 Figure 2: Internal Geometry Detail

Figure 2: Internal channels and cavity features showing precision surface finish.

Figure 3: Top-View Precision Geometry

Figure 3: Symmetric port arrangement with amber-transparent PEI optical clarity.

 Figure 4: Circular PEI Component

Figure 4: Complex circular component with multiple precision ports and internal channels.

 Figure 5: PEI Impeller/Disk

Figure 5: Impeller component with complex vane geometry for fluid handling.

Figure 6: Multi-Feature PEI Housing

Figure 6: Main housing with mounting bosses, bores, and interface surfaces.

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Frequently Asked Questions (FAQ)

Q: Why is PEI (Ultem) difficult to machine?
A: PEI has a high glass transition temperature of 217°C and a high CTE of 56 ppm/°C, making it extremely sensitive to machining heat, which causes rapid thermal expansion and dimensional drift.

Q: Why choose CNC machining over 3D printing or injection molding for aerospace PEI components?
A: Additive manufacturing lacks the required structural integrity and tighter tolerances (producing ±0.1–0.3mm vs. CNC’s ±0.01mm). Injection molding requires prohibitive tooling costs ($50K+) and 12–16 week lead times, which are impractical for low-to-medium production runs (200–500 units/year).

Q: How does KGL achieve tight ±0.01mm tolerances on temperature-sensitive polymers?
A: We combine multi-parameter optimization (MPO) on Mazak 5-axis/9-axis platforms, low-heat spindle speeds, customized PCD tooling, and our proprietary Thermal Dynamics Management System (TDMS) for real-time thermal compensation.

Conclusion

The SAFRAN PEI project demonstrates what 26 years of machining experience, Mazak 5-axis and 9-axis technology, and systematic R&D investment can achieve. By solving problems that 3D printing and injection molding could not, KGL Machinery (KINNEX PRECISION) has proven that Chinese precision manufacturing can deliver custom aerospace polymer components at ±0.01mm tolerance.

Our combination of Mazak VARIAXIS J-500 5-axis and Mazak INTEGREX i-250H/HS 9-axis mill-turn centers, proprietary TDMS thermal management, and advanced ultrasonic welding creates a genuinely differentiated capability for PEI, PEEK, POM, and other high-performance polymers.

As a leading provider of PEI machining services in China, KGL Machinery offers proven capability, AS9100D certification, and competitive positioning for global OEMs—backed by 100+ machines, 110+ employees, and 13 years of relentless pursuit of precision excellence.

24-hour technical response | 48-hour rapid prototyping | Full quality traceability

About the Author

Dr. Jason Hu is General Manager of KGL Machinery & Electronics Co., Ltd. He holds a mechanical engineering degree and a PhD from NLBA Business University, Netherlands, with 26 years of precision machining experience. Under his leadership, KGL has grown from 2 machines in 2013 to 100+ machines serving 200+ global clients.

Contact

KGL Machinery & Electronics Co., Ltd.
Website: www.kglmfc.com | www.kglprecision.com
Email: kgl@kglmfc.com
Location: Shenzhen, Guangdong, China
Facility: 12,300 sqft manufacturing floor
Certifications: ISO 9001:2015 | ISO 13485:2016 | AS9100D | National High-Tech Enterprise