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PEEK Injection Molding
PEEK Products with high temperature resistance, chemical resistance, and high strength and stiffness.
Resources for The Complete Guide to PEEK Injection Molding
What is PEEK?
PEEK is a semi-crystalline, high-performance, rigid engineering thermoplastic material with a variety of properties and excellent resistance to harsh chemicals. The first synthesis of PEEK occurred in 1977, and industrial production was achieved in 1981.
Although PEEK is often grouped with fluoropolymers such as PFA or PTFE, it does not contain fluorine. PEEK has excellent mechanical and electrical properties, with a maximum continuous operating temperature of 250°C, and excellent mechanical performance in steam or high-pressure water environments up to 300°C.
PEEK (Polyether ether ketone) is a high-performance engineering thermoplastic polymer known for its exceptional mechanical, thermal, and chemical properties. Its molecular chain contains ether bonds and ketone bonds. These special chemical bonds allow PEEK to maintain good performance at high temperatures. performance.
Can PEEK materials be injection molded?
Yes, you can injection mold PEEK (Polyether Ether Ketone). PEEK has a high melting point (around 343°C/649°F), so you need specialized equipment and processing conditions. Also, PEEK has a high viscosity and a relatively low flow rate, so it’s hard to fill complex geometries and cavities. But, with the right equipment, know-how, and processing conditions, you can injection mold PEEK.
Here are some key considerations:
1. Injection Machine Equipment:
You need high-temperature injection molding machines with a high clamping force and precise temperature control.The screw of the injection molding machine needs a high temperature resistant screw that can handle temperatures above 350 degrees.
2. Design Considerations:
You have to be careful when you design PEEK parts so you don’t get defects like warping, cracking, and sink marks. This means you have to think about runner design, gate size, and draft angles. You should make the runner, gate, and draft angle as big as you can.
3. Injection Mold Tooling:
You have to make the mold with high-temperature-resistant steel materials like H13 or S136. Because of PEEK processing needs high temperatures and pressures.
4. PEEK Material selection:
You have to pick the right PEEK grade. Some PEEK grades are better for injection molding than others. Look for grades that flow better and have lower viscosity.
5. Material Preparation:
PEEK must be thoroughly dried before molding to remove residual moisture, typically by drying for 2 to 4 hours at temperatures around 150°C to 160°C.
6. Processing conditions:
You have to be careful with the processing conditions, like temperature, pressure, and injection speed, so you can fill and cool the mold right. Its processing conditions: barrel temperature 370~390℃, injection pressure 120MPa. The mold temperature is 170℃.
7. Cooling:
PEEK parts require slow and controlled cooling to prevent warping or distortion. This may involve using cooling systems or delaying the ejection of the part from the mold.
8. Post-processing:
Since the Injection Gate is pretty big, or some structural molds can't be made, you need to do post-processing. PEEK parts might need extra steps, like cutting, grinding, or treating the surface, to get the surface you want and the size you want.
What are the characteristics of PEEK injection molding material?
PEEK combines high temperature and chemical resistance, excellent mechanical properties, biocompatibility and electrical insulation. It is a multi-purpose material. Some of the key properties of PEEK materials include:
High temperature resistance: PEEK can withstand high temperatures up to 250°C (482°F) without losing its strength or dimensional stability.
Chemical resistance: PEEK has strong resistance to various chemicals, including acids, alkalis, and organic solvents, making it suitable for use in harsh chemical environments.
Excellent mechanical properties: PEEK has a high strength-to-weight ratio, excellent fatigue and wear resistance, and good dimensional stability, making it ideal for applications requiring high strength and durability.
Biocompatibility: PEEK is biocompatible and has been approved for use in medical implants and devices.
Hydrolysis resistance: PEEK has good hydrolysis resistance and is suitable for water and steam environments.
Electrical Insulation: PEEK has excellent electrical insulation properties and is suitable for electrical and electronic applications.
Low Flammability: PEEK has low flammability, which makes it suitable for use in applications requiring fire resistance.
Creep resistance: PEEK keeps its properties under long-term stress, especially at high temperatures.
Radiation resistance: The ability to withstand gamma radiation is very strong, exceeding that of polystyrene, which has the best radiation resistance among general-purpose resins. Can be made into a γ-irradiation dose up to 1100 Mrad and still be safe High-performance wires with good insulation capabilities.
Low moisture absorption: PEEK has outstanding thermal hydrolysis resistance and has very low water absorption in high temperature and high humidity environments. It will not cause significant changes in size due to water absorption like general plastics such as nylon.
What are the properties of PEEK injection molding?
PEEK (polyetheretherketone) plastic raw material is an aromatic crystalline thermoplastic polymer material with high mechanical strength, high temperature resistance, impact resistance, flame retardant, acid and alkali resistance, hydrolysis resistance, wear resistance, fatigue resistance, radiation resistance and Good electrical properties.
| Property | Characteristic |
|---|---|
| High temperature resistance | It has a high glass transition temperature (Tg=143℃) and melting point (Tm=343℃), its load thermal deformation temperature is as high as 316℃, and its instantaneous use temperature can reach 300℃. |
| Mechanical properties | It has rigidity and flexibility, especially its outstanding fatigue resistance under alternating stress, which is comparable to alloy materials. |
| Self-lubricating | It has excellent sliding characteristics and is suitable for applications that strictly require low friction coefficient and wear resistance. In particular, PEEK modified with a certain proportion of carbon fiber and graphite has better self-lubricating properties. |
| Corrosion resistance | Except for concentrated sulfuric acid, PEEK is insoluble in any solvent, strong acid, and strong alkali, and is resistant to hydrolysis and has high chemical stability. |
| Flame retardancy | It is self-extinguishing and can reach UL standard 94V-0 even without adding any flame retardant. |
| Ease of processing | It has the characteristics of good high-temperature fluidity and high thermal decomposition temperature, and can be processed in a variety of ways: injection molding, extrusion molding, compression molding, melt spinning, etc. |
| Peel resistance | It has good peeling resistance, so it can be made into thinly coated wires or magnet wires and can be used under harsh conditions. |
| Fatigue resistance | Best fatigue resistance of all resins. |
| Radiation resistance | It has strong resistance to high radiation, surpassing polystyrene, which has the best radiation resistance among general-purpose resins. It can be made with high performance that can still maintain good insulation ability when the gamma irradiation dose reaches 1100 Mrad. |
| Hydrolysis resistance | PEEK and its composite materials are not chemically affected by water and high-pressure water vapor. Products made of this material can still maintain excellent properties when used continuously in high-temperature and high-pressure water. |
| Smoky | PEEK has the lowest smoke generation among plastics. |
| Toxic gas dissipation | PEEK is the same as many organic materials. When decomposed at high temperature, PEEK mainly produces carbon dioxide and carbon monoxide. Using the British aircraft testing standard BSS 7239, extremely low concentrations of poisonous gas escape can be detected. This detection process requires a space of 1 cubic meter. Completely burn 100 grams of sample, and then analyze the poison gas produced. The toxicity index is defined as the ratio of the concentration of poison gas produced under normal circumstances to the dose that can be fatal in 30 minutes. The index of PEEK450G is 0.22, and no acidity is detected. gas. |
| Insulation stability | Has good electrical insulation properties and maintains to a very high temperature range. Its dielectric loss is also very small at high frequencies. |
| Stability | It has excellent dimensional stability properties, which is important for some applications. Changes in environmental conditions such as temperature and humidity have little effect on the size of PEEK parts, and can meet the requirements for use under conditions with relatively high dimensional accuracy requirements. |
| PEEK plastic raw material injection molding has a small shrinkage rate, which is very beneficial to controlling the dimensional tolerance range of PEEK injection molded parts, making the dimensional accuracy of PEEK parts much higher than that of general plastics. | |
| The coefficient of thermal expansion is small. As the temperature changes (which can be caused by changes in ambient temperature or frictional heat during operation), the size of PEEK parts changes very little. | |
| Good dimensional stability. The dimensional stability of plastics refers to the dimensional stability of engineering plastic products during use or storage. This change in size is mainly due to the increase in the activation energy of the polymer molecules, which causes the chain segments to have a certain degree of stability. Caused by curling. | |
| PEEK has outstanding thermal hydrolysis resistance and has very low water absorption in high temperature and high humidity environments. It will not cause significant changes in size due to water absorption like general plastics such as nylon. |
Why is PEEK injection molding so expensive?
PEEK (Polyetheretherketone) is a high-performance polymer known for its exceptional mechanical, thermal, and chemical properties. Its high cost can be attributed to several factors, including:
① Making PEEK is complicated: it’s made by mixing special chemicals together. This takes a lot of time and money because you need special machines and people who know what they’re doing.
② Top-notch raw materials: PEEK production needs high-purity raw materials, like aromatic diamines and aromatic dicarboxylic acids, which are expensive to produce and buy.
③ The reaction conditions are harsh and the cost is high: The PEEK polymerization process must ensure reaction in an oxygen-free state, and the reaction temperature is as high as 310-340°C. In order to obtain PEEK resin with higher purity, the crude product needs to be subjected to dozens of alcohol refinement processes and water washing processes.
④ High technical requirements: PEEK has good processing performance, but because PEEK melts at 343°C, and PEEK sticks to stuff, you need special barrels, screws, and molds for your machines, and you have to be good at controlling the temperature.
⑤ There are a lot of products and high initial research and development costs: In order to meet the various working conditions of customers, not only the commonly used basic grades such as carbon fiber reinforcement and glass fiber reinforcement are needed, but also the development of anti-static grades, conductive grades, wear-resistant grades, high-strength grades, etc. ;At the same time, it also requires a lot of R&D work such as structural design, mold design, process design, and mold trial in the early stage.
⑥ The product batch is small and the non-standard specifications are many: Because PEEK has excellent comprehensive performance, it can be used in a wide range of industries. However, most of them are used in special occasions on equipment. Therefore, the overall dimensions, structural features, specifications and models are different. Currently, we are exposed to more than 1,500 products using PEEK.
⑦ Most of them are in the trial stage, and the promotion cost is high: PEEK synthesis has been monopolized by Victrex in the UK. PEEK has been promoted and used abroad for 30 years. However, the understanding and application of PEEK materials in the domestic market have just begun, and many customers are in the trial stage. , the promotion cost is relatively high.
⑧ The requirements for the product are high and the processing steps are many: Because the PEEK material is expensive, the customer’s requirements for the finished product are relatively high. The appearance quality, tolerances, surface finish, etc. need to be strictly controlled. Some products have complex structures, resulting in too many processing steps and too many people participating, resulting in increased costs.
What are the application of PEEK injection molding?
PEEK is a material with excellent comprehensive properties. It can replace traditional materials such as metals and ceramics in many special fields. Its high temperature resistance, self-lubrication, wear resistance, and fatigue resistance make it one of the most popular high-performance engineering plastics today. It is mainly used in aerospace, automotive, electronics and electrical, medical equipment, and other fields.
| Application areas | Specific application situations |
|---|---|
| Aerospace Field | It can be processed into various high-precision aircraft parts. Due to its good hydrolysis resistance, corrosion resistance and flame retardant properties, it can be processed into internal/external parts of aircraft and many parts of rocket engines. |
| Automotive Industry | Polyetheretherketone PEEK has been successfully used in the automotive manufacturing industry. Due to its good friction resistance, it can replace metals (including stainless steel and titanium) to manufacture engine inner covers, automotive bearings, seals, brake pads, etc. |
| Industrial Field | Due to its good mechanical properties, high temperature resistance, wear resistance, and high pressure resistance, it is often used to manufacture compressor valve plates, piston rings, seals, etc. |
| Medical Instruments | It can withstand 3,000 cycles of autoclave sterilization at 134°C. This feature can meet the manufacturing requirements of surgical and dental equipment that require high sterilization requirements and needs to be used repeatedly. Coupled with its creep resistance and hydrolysis resistance, it can be used to manufacture Various medical devices that require high-temperature steam sterilization. What is particularly important is that PEEK is non-toxic, lightweight, and corrosion-resistant. It is the material closest to human bones. Therefore, PEEK can be used to replace metal to make human bones. |
| Insulation Materials | Due to its excellent electrical properties, PEEK can still maintain its insulation properties under harsh conditions such as high temperature and high humidity. It is an ideal electrical insulation material and is widely used in the semiconductor industry. |
| It is a new type of engineering plastic that can be used as high-temperature resistant structural materials and electrical insulation materials. It can be combined with glass fiber or carbon fiber to prepare reinforced materials. | |
| Modified polyetheretherketone includes black carbon fiber reinforced conductive polyetheretherketone, red carbon fiber reinforced conductive polyetheretherketone, mineral reinforced polyetheretherketone, glass fiber reinforced polyetheretherketone and PEEK resin. Although polyetheretherketone has many excellent properties, it is expensive, which limits its application in some fields. In addition, its impact strength is poor. In order to further improve its performance to meet the comprehensive performance and diversified needs of various fields, it can be modified by filling, blending, cross-linking, grafting and other methods to obtain better performance. More excellent PEEK plastic alloy or PEEK composite material. For example: blending PEEK with polyether can obtain better mechanical properties and flame retardancy; blending PEEK with PTFE to form composite materials has outstanding wear resistance and can be used to manufacture sliding bearings, dynamic sealing rings and other parts; PEEK is modified with carbon fiber and other fillings to make reinforced PEEK composite materials, which can greatly improve the hardness, rigidity and dimensional stability of the material. | |
| IT Manufacturing Field | Semiconductor manufacturing and electronic and electrical industries are expected to become another growth point for PEEK resin applications. In the semiconductor industry, in order to achieve high functionality and low cost, silicon wafers are required to be larger in size and more advanced in manufacturing technology. Low dust, low gas release, low ion dissolution, and low water absorption are the requirements for various equipment materials in the semiconductor manufacturing process. For special requirements, this will be where PEEK resin comes into play. |
| Office Machinery Parts Field | For copier separation claws, special heat-resistant bearings, chains, gears, etc., using PEEK resin instead of metal as their material can make the parts lightweight, fatigue-resistant, and oil-free lubrication. |
| Wire Covering Field | The PEEK coating has good flame retardancy. Without adding any flame retardant, its flame retardant level can reach UL94 V-0 level. PEEK resin also has the advantages of peeling resistance and radiation resistance (109 rad), so it is used in special wires in military industry, nuclear energy and other related fields. |
What is Mold Flow Analysis?
Mold flow analysis simulates the injection molding process to predict potential defects and optimize part design, enhancing efficiency and quality in production. Mold flow analysis aids engineers in detecting issues
How to Improve the Precision of Injection Molds?
Achieving high precision in injection molding is key to ensuring product quality. Fine-tuning mold design, material choice, and processing parameters can all enhance mold accuracy. Improving precision in injection molds
What are the Requirements for Standardized Mold Making for Injection Molds?
Standardized mold making in injection molds is vital for ensuring consistency, efficiency, and cost-effectiveness in production processes across various industries. Standardized mold making requires precise engineering, material quality selection, adherence
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