To achieve a strong and durable bond between metal surfaces and PTFE, proper surface preparation is crucial. The recommended methods involve mechanical roughening of the metal surface to an optimal roughness level, followed by thorough cleaning to remove contaminants. Adhesive selection and application techniques also play a vital role, with specific epoxy adhesives like Araldite HV 953U and AW106 being recommended. The bonding process requires precise clamping pressure and controlled curing temperatures to account for differences in thermal expansion between materials. These steps ensure maximum adhesion strength while preventing premature failure of the bonded assembly, especially important when creating custom PTFE parts that require precise metal-PTFE interfaces.
Key Points Explained:
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Mechanical Surface Preparation
- Machining methods: Grinding, milling, shaping, or planning create the necessary surface texture
- Optimal roughness: Ra = 1.6-3 µm (never exceeding Ra = 6 µm)
- Purpose: Creates microscopic anchoring points for the adhesive to grip
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Surface Cleaning Process
- Recommended solvents: Trichloroethylene, perchloroethylene, or acetone
- Critical step: Removes all machining debris, oils, and surface contaminants
- Ensures: Clean surface for maximum adhesive wetting and bonding
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Adhesive Selection & Application
- Preferred adhesives: Araldite HV 953U hardener with Araldite AW106
- Application method:
- Use serrated spatula for uniform distribution
- Apply ~200 g/m² total quantity
- Brush direction: Longitudinal on PTFE, transverse on metal
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Bonding Process Parameters
- Clamping pressure: Maintain 10-15 Kg/cm² during curing
- Temperature control: Never exceed 40°C to prevent thermal stress
- Curing times:
- 15 hours at 20°C
- 12 hours at 25°C
- 5 hours at 40°C
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Special Considerations for PTFE
- Account for PTFE's low surface energy and thermal expansion
- Proper preparation compensates for PTFE's inherent non-stick properties
- Critical for custom PTFE parts requiring metal bonding
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Quality Control Measures
- Verify surface roughness meets specifications
- Ensure complete solvent evaporation before adhesive application
- Monitor curing conditions precisely for optimal bond strength
Summary Table:
| Step | Key Parameters | Purpose |
|---|---|---|
| Mechanical Preparation | Ra = 1.6-3 µm (max 6 µm) via grinding/milling | Creates anchoring points for adhesive |
| Surface Cleaning | Trichloroethylene, perchloroethylene, or acetone | Removes contaminants for better adhesive wetting |
| Adhesive Application | Araldite HV 953U + AW106 (200 g/m²); longitudinal on PTFE, transverse on metal | Ensures uniform adhesive distribution |
| Curing Process | 10-15 Kg/cm² pressure; 15h@20°C, 12h@25°C, or 5h@40°C (never >40°C) | Achieves optimal bond strength while preventing thermal stress |
Need precision-bonded PTFE components for your application?
KINTEK specializes in custom PTFE-metal assemblies for semiconductor, medical, and industrial applications. Our expertise in surface preparation and bonding techniques ensures durable, high-performance components tailored to your exact requirements.
Contact our engineers today to discuss your project needs – from prototypes to high-volume production of critical PTFE-metal interfaces.