CNC Machining
PEEK
PEEK (Polyether Ether Ketone) is an ultra-high-performance semi-crystalline engineering thermoplastic. Capable of continuous operation at 250°C (482°F), inherently flame retardant, and 100% biocompatible, PEEK is the ultimate lightweight metal-replacement material for aerospace, medical implants, and deep-sea oil exploration.
Core Mechanical Properties
PEEK bridges the gap between plastics and metals. Below are the typical mechanical and thermal properties for standard unfilled PEEK billets used in precision CNC machining.
| Property | Typical Value (Unfilled) | Key Benefit |
|---|---|---|
| Continuous Use Temp. | 250°C (482°F) | Survives extreme heat environments that would melt standard engineering plastics like Delrin or Nylon. |
| Tensile Strength | 90 - 100 MPa | Exceptional load-bearing capabilities. Can exceed 150 MPa in Carbon-Filled (CF30) variants. |
| Chemical Resistance | Outstanding | Insoluble in all common solvents; resists steam, boiling water, and harsh chemicals without degrading. |
| Flammability Rating | UL94 V-0 | Inherently flame retardant without toxic additives. Emits ultra-low smoke and toxic gas when exposed to fire. |
Material Comparison: PEEK Grades
Depending on your structural or tribological requirements, PEEK can be compounded with various fillers to drastically alter its performance characteristics.
| Material Grade | Visual Identifier | Key Characteristics & Use Case |
|---|---|---|
| Unfilled PEEK | Natural (Tan/Brown) | The purest form. Offers the highest elongation and toughness. FDA-compliant and biocompatible, making it the absolute standard for medical instruments and food-contact parts. |
| PEEK GF30 | Opaque (Grey/Tan) | Contains 30% glass fibers. Dramatically increases rigidity, compressive strength, and creep resistance at high temperatures. Ideal for structural aerospace components. |
| PEEK CF30 | Black | Contains 30% carbon fibers. Provides the highest strength, stiffness, and thermal conductivity. Frequently used to replace aluminum parts to reduce weight without sacrificing load capacity. |
| Bearing Grade PEEK | Dark Grey / Black | Typically filled with PTFE, graphite, and carbon fibers. Engineered for the lowest possible friction and highest wear resistance. Perfect for high-speed, unlubricated bearings and seals. |
Hardcore Industrial Applications
Because PEEK raw material is exceptionally expensive, it is reserved exclusively for mission-critical applications where failure is not an option.
Medical Implants & Tools
Medical grade PEEK is highly radiolucent (invisible on X-rays) and biocompatible. We 5-axis mill spinal cages, dental healing caps, and surgical instruments that endure repeated autoclave sterilization.
Downhole Oil & Gas Connectors
In deep-sea drilling, components face extreme pressures, temperatures exceeding 200°C, and sour gas (H2S). PEEK seals, back-up rings, and electrical connectors survive where other plastics instantly degrade.
Aerospace Gears & Valve Seats
Replacing aluminum in aircraft systems, PEEK gears and valve seats reduce weight, resist aviation fuels, and maintain critical tolerances across severe thermal fluctuations.
Expert Machining Tips
Machining PEEK is challenging due to its high cost and tendency to warp if internal stresses are not managed. Huade engineers apply stringent protocols to guarantee perfection:
- 1
Critical Annealing Cycles
PEEK billets hold immense internal stress. To prevent the part from warping or cracking during or after machining, we often perform multiple thermal annealing cycles (heating and slowly cooling the part) between heavy roughing and final finishing passes.
- 2
Liquid Coolant is Mandatory
Unlike standard plastics where air blasts suffice, PEEK must be kept cool to maintain its tight tolerances and prevent localized melting. We use copious amounts of water-soluble coolants, especially when drilling deep holes.
- 3
PCD Tooling for Filled Grades
While unfilled PEEK can be machined with sharp carbide, Carbon-Filled (CF30) and Glass-Filled (GF30) PEEK are violently abrasive. We strictly use Polycrystalline Diamond (PCD) tooling to prevent rapid tool wear and ensure dimensional consistency.
Post-Processing & Assembly
PEEK’s inherent chemical resistance means it cannot be solvent-welded or easily glued. Post-processing focuses on thermal stability, cleanliness, and mechanical fastening.
1. Post-Machining Annealing
While not a cosmetic surface finish, a final annealing cycle is often the most important post-process. It relieves any remaining surface stresses induced by the cutting tool, ensuring the part maintains its exact shape in service.
2. Ultrasonic Cleaning
For medical and aerospace components, PEEK parts are run through industrial ultrasonic cleaning baths to remove all traces of cutting fluids, dust, and handling contaminants before clean-room packaging.
3. Laser Marking & Engraving
Medical implants and high-value aerospace components require strict traceability. PEEK reacts exceptionally well to laser marking, allowing us to permanently etch part numbers, lot codes, or QR matrices directly onto the surface.
Start Your Manufacturing RFQ
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