ピーク (Polyether ether ketone) is a standout high-performance thermoplastic prized for its chemical resistance, 高温安定性, and mechanical strength. But these very attributes make it challenging to machine. Skip the proper steps, and you risk cracked parts, ruined tools, or wasted material—an expensive mistake when PEEK bar stock costs upwards of $100 キログラムあたり. This guide dives deep into nine critical tips to ensure your PEEK machining runs smoothly, delivers tight tolerances, and protects your bottom line.
Anneal Before Machining
なぜそれが重要なのか:
Raw PEEK often carries residual stresses from extrusion or molding. Under the heat and forces of cutting, these stresses can manifest as cracking or warping.
それをする方法:
Preheat Oven: Ramp to 200–220 °C.
Soak: Maintain the PEEK bars or plates at that temperature for 1–2 hours (time scales with thickness: ~30 minutes per 10 mm of material).
Slow Cool: Turn off the oven and allow to cool down to room temperature over several hours—avoid removing parts while still hot.
ボーナス: For long machining runs, perform an intermediate anneal (例えば, midway through a large batch) to keep stress buildup at bay.
Maintain Tool Condition
なぜそれが重要なのか:
PEEK is abrasive—especially filled grades—and will dull standard carbide cutters rapidly, leading to poor surface finish and increased cutting forces.
Recommendations:
Unfilled PEEK: 使用 炭化ケイ素 (sic) または fine-grain carbide エンドミル.
PEEK-GF30/CA30: 選択してください polycrystalline diamond (PCD) または diamond-coated tools to resist abrasion.
Tool Rotation: 使用 highest spindle speed your machine and tool allow (まで 6,000 回転数) to minimize tool-workpiece contact time.
ヒント: Routinely inspect your cutter edges under a stereo microscope—minor wear can double cutting forces and spoil finish quality.
Manage Heat with Proper Cooling
なぜそれが重要なのか:
PEEK’s low thermal conductivity traps heat at the cutting interface. Excessive heat softens the polymer, causes smearing, and can deform tolerances.
Cooling Strategies:
Industrial Grades: Flood with a water-soluble coolant or light oil-based coolant. Ensure high-pressure nozzles target the tool-workpiece zone.
Medical-Grade PEEK: Avoid oil or solvent coolants to maintain biocompatibility. その代わり, 使用 クリーン, 圧縮空気 (5–7 bar) または deionized water.
Air Blast Note: Keep the nozzle moving to avoid local chilling, which can induce brittleness.
Handle Gently to Minimize Stress
なぜそれが重要なのか:
High cutting forces and deep cuts generate mechanical stresses, leading to edge chipping or internal cracks.
ベストプラクティス:
Light Depths of Cut: Start with 0.5–1 mm axial depth for roughing; finish at 0.1–0.3 mm.
Moderate Feed Rates: 使用 0.05–0.15 mm/rev in milling, 0.1–0.3 mm/rev in drilling.
Avoid Dwell: Keep the tool moving—pauses can burnish the material and raise local temperatures.
ヒント: Climb milling often reduces thrust forces and improves chip evacuation compared to conventional milling.
Optimize CNC Parameters
なぜそれが重要なのか:
PEEK responds best to specific speed and feed combinations; stray too far, and you’ll see smearing, poor finishes, or surface cracking.
| 手術 | 切断速度 (メートル/分) | 送り速度 |
| フライス加工 | 50–200 (産業) | 0.05–0.2 mm/rev |
| 200–300 (医学) | 0.05–0.2 mm/rev | |
| 旋回 | 250–500 | 0.1–0.5 mm/rev |
| 掘削 | 50–200 (産業) | 0.1–0.3 mm/rev |
| 80–100 (医学) | 0.1–0.3 mm/rev |
プロのヒント: Always run a test cut on scrap PEEK to dial in the sweet spot for your specific machine, tool, and material grade.
Special Drilling Techniques
なぜそれが重要なのか:
PEEK’s low elongation means deep holes can crack or “snag” the workpiece.
How to succeed:
Peck Drilling: Retract every 3–5 mm to break chips and clear debris.
Point Angle: 使用 130–140° split point bits to reduce thrust.
Chip Evacuation: Continuously blow chips away with air or vacuum—accumulations can wedge the bit and cause cracks.
ヒント: あ bracelet-style backup under thin sections prevents blowout on the exit side.
Prevent Contamination
なぜそれが重要なのか:
Medical implants and food-contact parts demand absolute purity. Even trace oils or metal particles can compromise biocompatibility.
Clean Protocols:
Gloves & Clean Tools: 着る nitrile gloves and dedicate a set of tools to PEEK.
Work Area: 使用 HEPA-filtered air or laminar flow above the machining station.
Part Storage: Place finished components in sealed, ラベルが貼られた containers until inspection.
ヒント: For ultra-clean blanks, rinse in an ultrasonic bath with deionized water and food-grade detergent after machining.
利点 & Limitations of Machining PEEK
| 利点 | 制限事項 |
| Outstanding biocompatibility | Abrasive to cutting tools |
| High chemical & temperature resistance | Low elongation means brittle under load |
| 優れた耐摩耗性 & 低摩擦 | Requires special tooling & 備品 |
| 厳しい許容範囲 (±0.05mm) achievable | Sensitive to heat; needs cooling |
| Low moisture absorption | Higher material cost (対. commodity plastics) |
| Excellent surface finish (ラ < 0.4 μm) | Slow feed speeds increase cycle time |
結論 & Next Steps
Machining PEEK demands respect for its thermal and mechanical quirks—but with the right annealing, ツーリング, cooling, and process parameters, you can achieve precision parts that excel under extremes. By following these nine tips, you’ll minimize scrap, lengthen tool life, and deliver components that meet the strictest industry standards.
If you lack in-house expertise, partner with a specialist—reach out to Tops Precision or your trusted CNC service provider for fully supported PEEK machining, from material sourcing through final inspection. With expert guidance, you’ll unlock PEEK’s full potential and avoid costly missteps on your next high-performance project.
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