PEEK is a high-performance engineering thermoplastic, renowned for its outstanding mechanical properties, high-temperature resistance, chemical resistance, and excellent dimensional stability. It is widely applied in the Automation industry, Medical industry, Automotive industry, Semi-conductor industry and Food & Packing Industry. PEEK has the following obvious advantages:
High-temperature resistance: The continuous operating temperature can reach 260°C, and it can withstand even higher temperatures for a short period of time.
Strong mechanical properties: High tensile strength, good fatigue resistance, suitable for high-load environments.
Excellent chemical resistance: Resistant to most acids, alkalis, oils and organic solvents.
High insulation and low dielectric constant: Suitable for precision electronics and semiconductor applications.
Available for medical implantation (some grades) : such as PEeK-Optima, medical-grade PEEK.
The main processing methods of PEEK
CNC milling, CNC turning, milling and drilling are the most commonly used processing methods for PEEK, especially suitable for the manufacturing of high-precision hardware components, precision automation components and precision mechanical components.
The processing method of CNC milling
Tool material and geometric design
Tool material:
Hard alloy cutting tools (tungsten steel) : They have strong wear resistance and are suitable for high-precision processing.
Diamond-coated tools: Reduce frictional heat, extend tool life, and are especially suitable for deep cavity processing or long-term continuous operation.
Avoid high-speed steel (HSS) : The high wear resistance of PEEK can cause rapid wear of HSS.
Tool geometric parameters:
Number of cutting edges: It is recommended to have 2 to 4 cutting edges to reduce cutting resistance (too many cutting edges may lead to poor chip removal and heat generation).
Rake Angle: 10° to 15°, reducing cutting force and minimizing material adhesion to the tool.
Helix Angle: 30° to 45°, optimizing chip removal and heat dissipation.
Edge sharpness: Prioritize sharp edges to reduce cutting heat and burrs.
Processing parameter setting
Spindle Speed:
Recommended range: 200-800 m/min (Adjust according to the tool diameter, for example, for a Φ6 tool, approximately 8000-12000 RPM).
Principle: Avoid overheating of the material caused by excessively high rotational speed (the glass transition temperature of PEEK is approximately 143℃, and the decomposition temperature is above 400℃).
Feed Rate:
Rough machining: 0.1-0.3mm per tooth (for example, for a 4-edge tool: feed rate = 0.2mm/tooth × 4 edges × rotational speed).
Finishing: 0.05-0.15 mm per tooth, ensuring surface finish (Ra≤3.2 μm).
Depth of Cut:
Axial depth of cut (Ap) : ≤ 0.5 times the tool diameter (for example, for a Φ6 tool, Ap≤3 mm).
Radial depth of cut (Ae) : ≤ 0.3 times the tool diameter (for example, for a Φ6 tool, Ae≤ 1.8mm), to prevent tool wobbling and vibration.
Processing strategy and process design
Clamping and fixing
Fixture selection:
Use soft claws, nylon gaskets or vacuum adsorption tables to avoid scratching the PEEK surface.
Thin-walled parts need to be subjected to uniform pressure to prevent deformation (profiling fixtures can be designed).
Staged processing
Rough machining: Quickly remove the allowance, leaving 0.2 to 0.5 mm of finish machining allowance.
Semi-finishing: Further homogenize the allowance and reduce the finishing load.
Finishing: Small cutting depth, high rotational speed and low feed rate are adopted to ensure dimensional accuracy and surface quality.
Cooling and heat dissipation
Dry cutting: Prioritize the use of compressed air or cold air for cooling to prevent PEEK from absorbing water (caution is required for wet cutting).
Minimal Lubrication (MQL) : Use a small amount of specialized cutting fluid (such as polyolefin type) to reduce frictional heat, but ensure subsequent cleaning.
Tool path optimization
Climb Milling: Reduces burrs and cutting forces and improves surface quality.
Layered milling: Complex structures are processed in multiple layers to avoid overheating caused by excessive cutting depth in a single cut.
Avoid excessive overhang of the tool: Prevent tool vibration from affecting accuracy.
Summary: In the CNC milling process of PEEK, special attention should be paid to tool sharpness, heat dissipation control, and matching of cutting parameters. Through staged processing and post-annealing treatment, the quality of the finished product can be significantly improved.
Tool selection
Tool material:
Hard alloy tools (such as tungsten steel tools) : They have strong wear resistance and are suitable for high-precision processing.
Diamond-coated cutting tools: Reduce frictional heat, extend tool life, and are suitable for long-term processing.
Avoid HSS (high-speed steel) tools: The high wear resistance of PEEK can cause rapid wear of HSS.
Tool geometric parameters:
Number of cutting edges: It is recommended to have 2 to 4 edges to reduce cutting resistance and prevent the material from overheating.
Rake Angle: Select a larger rake Angle (such as 10° to 15°) to reduce the cutting force.
Helix Angle: 30° to 45°, which is conducive to chip removal and heat dissipation.
Processing parameter optimization
Spindle Speed:
Recommended range: 200-800 m/min (adjust specifically according to the dimensions of the tool and part).
Principle: High rotational speed may cause local overheating of the material, and it is necessary to balance efficiency and temperature control.
Feed Rate:
Rough machining: 0.1-0.3mm per tooth, quickly remove the allowance.
Finishing: 0.05-0.15 mm per tooth to ensure surface finish.
Depth of Cut:
Axial cutting depth: It is recommended to be ≤ 0.5 times the tool diameter (for example, the cutting depth of a Φ6 tool is ≤3 mm).
Radial cutting depth: ≤ 0.3 times the tool diameter to prevent tool wobbling and vibration.
Clamping and fixing
Tooling design:
Use soft claws or non-metallic clamps (such as nylon gaskets) to avoid scratching the PEEK surface.
Thin-walled parts need to be subjected to uniform pressure to prevent deformation.
Vacuum adsorption: Suitable for processing flat plate parts, reducing clamping stress.
Cooling and Lubrication
Dry cutting: Compressed air or cold air cooling is preferred to avoid PEEK absorbing water (caution is needed for wet cutting).
Minimal Lubrication (MQL) : Use a small amount of specialized cutting fluid (such as polyolefin type) to reduce frictional heat, but ensure subsequent cleaning.
Summary: In PEEK milling, key attention should be paid to tool selection, temperature control, and optimization of cutting parameters. Through reasonable process design, high-precision and low-stress parts can be efficiently obtained. For complex structures, it is recommended to adopt a layered milling strategy and supplement it with annealing post-treatment to ensure that the final performance meets the engineering requirements.
CNC turning processing method
Tool material
Hard alloy cutting tools (tungsten steel) : They have strong wear resistance and are suitable for high-precision turning. They are recommended for rough and finish machining.
Diamond-coated tools: Reduce frictional heat, extend tool life, and are especially suitable for long-term continuous processing or high surface finish requirements.
Ceramic cutting tools (optional) : Good high-temperature resistance, but relatively brittle, and should be used with caution for intermittent cutting.
Tool geometry design
Rake Angle:
Rough machining: 6° to 10° to enhance the strength of the cutting edge.
Finishing: 10° to 15°, reducing cutting force and minimizing material sticking to the tool.
Clearance Angle: 8° to 12° to prevent friction between the tool and the workpiece.
Nose Radius:
Rough machining: 0.4-0.8mm to enhance tool strength.
Fine processing: 0.2-0.4mm, to improve surface finish.
Blade type
C-type or D-type inserts: Suitable for cylindrical turning and end face processing.
V-shaped blade: used for slotting or cutting.
Threaded blade: When processing PEEK threads, a sharp cutting edge is required to prevent material tearing.
Processing parameter optimization
Spindle Speed
Recommended range: 150-600 m/min (Adjust according to the workpiece diameter. For example, for a Φ50 mm workpiece, the rotational speed is approximately 1000-2000 RPM).
Principle: Avoid overheating of the material caused by excessively high rotational speed (the glass transition temperature of PEEK is approximately 143℃, and the decomposition temperature is above 400℃).
Feed Rate
Rough machining: 0.1-0.3mm /rev, quickly remove the allowance.
Finishing: 0.05-0.15 mm/rev, ensuring surface finish (Ra≤3.2 μm).
Depth of Cut
Rough machining: 1 to 3 mm (axial cutting depth), maximizing material removal rate.
Fine machining: 0.1-0.5mm, ensuring dimensional accuracy and surface quality.
Processing strategy and process design
Clamping and fixing
Fixture selection:
Use elastic sleeves or soft claw chucks to avoid scratching the PEEK surface.
Thin-walled parts should be supported in both axial and radial directions (such as tailstock ejector pins) to prevent deformation.
Centrifugal force control: At high rotational speeds, the workpiece needs to be balanced to avoid dimensional deviations caused by vibration.
Cooling and lubrication
Dry cutting: Compressed air or cold air is preferred for cooling to prevent the material from absorbing water.
Minimal Lubrication (MQL) : Use polyolefin cutting fluids to reduce frictional heat (ensure subsequent cleaning).
Classification of turning operations
Outer circle turning
Rough turning: Large cutting depth, medium feed rate, and quick removal of allowance.
Precision turning: Small cutting depth and low feed rate to ensure dimensional tolerances (IT7 to IT8).
Inner hole machining
Use rigid boring bars to avoid rough hole walls caused by tool vibration.
After pre-drilling and fine boring, the hole diameter tolerance can be controlled within ± 0.02mm.
Slotting and cutting
Sharp V-shaped blades are adopted, and the feed rate is reduced to 0.05mm /rev to prevent material from sticking to the blade.
Thread processing
Use sharp threaded blades with low speed and high feed (for example, a pitch of 1 mm and a rotational speed of 500 to 800 RPM).
Summary: The CNC turning process of PEEK should focus on tool sharpness, heat dissipation control, and parameter matching. By optimizing clamping and staged processing (rough turning → semi-finish turning → finish turning), the target size can be gradually achieved and the quality of the parts can be improved.
The processing method of drilling
Drill bit material
Hard alloy drill bits (tungsten steel) : They have strong wear resistance and are suitable for medium and small batch processing.
Diamond-coated drill bits: Reduce frictional heat, extend service life, and are suitable for deep holes or high-precision requirements.
High-speed steel (HSS) drill bits: Only suitable for a small number of boreholes and need to be replaced frequently (prone to wear).
Geometric design of drill bits
Helix Angle: 30° to 45°, optimizing chip removal efficiency and preventing chip blockage.
Number of cutting edges: Double-edge or triple-edge drill bits are recommended to balance the cutting force and chip removal capacity.
Point Angle: 118° to 135°, to reduce the axial force and prevent the hole opening from cracking.
Edge band design: Narrow edge band (to reduce friction) + polished edge (to reduce burrs).
Processing parameter optimization
Spindle Speed
Recommended scope:
Drill bits with a diameter of less than 3mm: 2000-5000 RPM
Φ3-6 mm drill bit: 1000-3000 RPM
Drill bits with a diameter of Φ 6mm or more: 500-1500 RPM
Principle: Avoid overheating caused by excessive rotational speed (PEEK decomposition temperature > 400℃).
Feed Rate
Recommended value:
Rough drill: 0.05-0.15 mm/rev
Fine drill: 0.02-0.08 mm/rev
Key point: If the feed is too low, it is prone to friction and heat generation; if it is too high, it may cause burrs or make it difficult to break chips.
Depth of Cut
Through hole: Step-by-step drilling (such as drilling a pre-hole first and then reaming the hole) to reduce the heat generated by a single cut.
Blind holes: Control the frequency of tool withdrawal to prevent chip accumulation and friction against the hole wall.
Processing strategy and process design
Cooling and Lubrication
Dry drilling: Compressed air or cold air is preferred for cooling to prevent PEEK from absorbing water and expanding.
Minimal Lubrication (MQL) : Use polyolefin cutting fluid (residues need to be cleaned to prevent contamination).
Chip removal control
Chip-breaking design: Select a drill bit with a chip-breaking groove or periodically withdraw the tool (withdraw chips 2 to 3 times the hole diameter per drill depth).
Chip removal path: Tilt the workpiece or use the Peck Drilling strategy to force chip removal.
Drilling steps
Pre-drill positioning holes: Use a center drill or a short drill bit (such as Φ 1mm) to pre-drill positioning points.
Step drilling: Reaming the hole in stages (such as Φ3→Φ5→Φ 8mm), gradually releasing the cutting stress.
Fine-tuning the hole wall: Use a reamer or diamond-coated drill bit for the final hole diameter calibration.
Summary: The core of PEEK drilling processing lies in temperature control, chip removal, and tool matching.
Common Problems and Solutions in processing PEEK
During the CNC milling process
Overheating deformation of the material
Cause analysis: The cutting speed is too high, the tool becomes blunt, and the heat dissipation is poor
Solution: Reduce the spindle speed, increase the feed rate, use diamond-coated tools, perform multiple cuts, and reduce the depth of each cut
Burrs and surface roughness
Cause analysis: The tool is blunting and the feed rate is too fast.
Solution: Replace the tools for fine machining, adopt Climb Milling, and reduce the feed rate to 0.05mm per tooth.
Dimensional rebound deviation
Cause analysis: The material has a high elastic modulus, and the cutting stress is released
Solution: Reserve machining allowance, secondary fine finishing, annealing treatment (hold at 200-250℃ for 2-4 hours)
During the CNC turning process
Chip entanglement and sticking to the tool
Cause analysis: The chip was not broken and the rake Angle of the tool was too large
Solution: Adjust the design of the chip-breaking groove, increase the feed rate or reduce the rake Angle
The inner hole is rough or has taper deviation
Cause analysis: Tool vibration and insufficient cooling
Solution: Use rigid boring bars, increase the frequency of tool withdrawal, process in stages, and adopt Minimal Lubrication (MQL)
Thread processing tearing
Cause analysis: The cutting edge of the tool is not sharp and the cutting parameters are inappropriate
Solution: Use sharp threaded blades and low speed high feed (such as 500 to 800 RPM)
Clamping deformation
Cause analysis: Uneven fixture pressure and insufficient rigidity of thin-walled parts
Solution: Use soft claws or vacuum adsorption fixtures, and add auxiliary supports (such as tailstock center pins)
Choose a high-quality PEEK parts processing manufacturer
As a professional precision machinery factory, Dahong Precision Machinery Company is well aware of the significance of PEEK(Polyetheretherketone) material in high-end industrial applications. Choosing the right PEEK parts processing manufacturer is crucial to the quality and performance of the product. Here are our professional suggestions that can help you find your ideal partner.
PEEK is a high-performance thermoplastic with excellent mechanical properties, chemical resistance and thermal stability (it can be used continuously at temperatures up to 250°C). However, these characteristics also make its processing more difficult than that of ordinary plastics: the high melting point (343°C) requires precise temperature control, the low thermal conductivity easily leads to processing stress, there are unique requirements for cutting tools, and strict tolerance control needs
The key criteria for choosing a high-quality PEEK processing manufacturer
Materials expertise and certification
We hold the certification of PEEK raw material manufacturers to ensure the use of genuine raw materials
We understand the characteristic differences of different PEEK grades (such as PEEK-1000, PEeK-HPV, PEeK-OptimA)
Precision processing capability
Our expertise: Equipped with precision CNC machines (accuracy ±0.005mm) and a constant-temperature processing environment
The tolerance that can meet your requirements (usually PEEK parts need ±0.02mm or stricter)
Special processing experience
We have been dedicated to PEEK components for the medical, automotive and semiconductor industries for over 9 years
Processing samples of similar complex parts can be provided
Technical consultation and design optimization
Our service: We offer free design optimization suggestions to reduce your processing costs
Have a team of engineers to assist in design optimization
Production flexibility and delivery time
Our flexibility: Offering flexible services ranging from OEM to mass production
Be capable of handling urgent orders
The production capacity and supply chain stability are good.
We offer:
1. Full-process quality control: From raw material inspection to full inspection of finished products, the defect rate is less than 0.1%
2. Rapid response service: Professional project team, providing technical solutions within 48 hours
3. Cost optimization plan: Through process innovation, help customers reduce processing costs by 15-30%
Frequently Asked Questions
Q: How to determine whether PEEK material is genuine from the original factory?
A: We provide the original factory quality guarantee certificates of raw materials and traceable batch reports, and can arrange for third-party testing.
Q: What is the minimum machinable tolerance?
A: Depending on the complexity of the parts, we can usually achieve ±0.01mm. For special requirements, please consult our engineers.
Q: Can PEEK parts with fine features be processed?
A: Sure. We have a special machine for fine processing, which can process fine features as small as 0.1mm.
Conclusion: PEEK plastic plays a significant role in global high-end manufacturing due to its outstanding performance. Whether you are a medical equipment manufacturer, a purchaser of auto parts, or a design engineer looking to expand lightweight material solutions, mastering PEEK processing technology is a crucial step towards the high-end market.
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