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PEEK (polyether ether ketone) is an aromatic crystalline thermoplastic special polymer material with excellent physical and chemical properties such as high mechanical strength, high temperature resistance, impact resistance, corrosion resistance, hydrolysis resistance, and wear resistance. PEEK is widely used in aviation industry, machinery industry, electronic and electrical fields due to its excellent comprehensive performance.

 

Large Size, Thin Wall PEEK Long Bushing

In practical applications, the most common product forms of PEEK are sealing rings, insulating rings, shaft sleeves, etc. However, the large-size, thin-walled, and high-length PEEK shaft sleeves are prone to problems such as clamping deformation and knife vibration during processing, making their processing difficult.

 

Solution to clamping deformation problem

1. When machining PEEK pipes, if the size requirements are very high, try to grind the outer circle of the PEEK pipes on both sides to ensure that the roundness of the PEEK pipes can be well maintained no matter what clamping method is used.

2. For the clamping method of PEEK pipe processing, try to use manual three-jaw chuck and spring collet for clamping, and try to avoid using pneumatic-hydraulic three-jaw chuck. Control is easy to cause loss of roundness to the pipe, and the size is not guaranteed).

The spring collet can wrap the PEEK tube as a whole (it is better to use the PEEK tube that has been ground through the outer circle), and there are more stress points, which is conducive to maintaining the stability of the processing size. The clamping force of the manual chuck can be controlled manually, which is also conducive to the control of the size.

Vibration knife problem solution

Taking the actual processing example as a reference, the shaft sleeve with an outer diameter of 137mm and an inner hole of 127mm and a length of 342mm. The inner hole knife uses a Φ60*400mm anti-vibration tool holder made of special steel. The excellent material properties can effectively control the vibration of the tool holder and better control the tolerance and smoothness of the inner hole of the product.

Use the center bracket to support the front end of the outer circle of the product. The adjustment and support strength of the center clamp must be moderate, otherwise it will affect the roundness of the inner hole of the processed product or the displacement of the workpiece. The cover is supported at the step of the inner hole at the rear end to prevent the three claws from affecting the roundness of the product. The machining of the outer circle will be completed after the watch is made with a metal mandrel.

ARKPEEK CNC workshop has nearly 15 kinds of processing equipment such as CNC lathe, manual instrument car, drilling machine, centerless grinder, double-sided grinding, single-sided grinding, etc. In order to improve processing efficiency, various parts are automatically clamped by automatic equipment to achieve 24-hour uninterrupted production and ensure high-quality and high-efficiency production of product parts.

We research and improve existing equipment and processes all the time, introduce international advanced technology, and carry out innovative improvements to meet the market’s requirements for functionality, reliability and safety. At present, we have completed the application research and development of more than 20,000 kinds of PEEK parts and production.

Cranioplasty refers to the operation of filling and repairing the defective skull with various repair materials. It is currently one of the most routine neurosurgery operations and can be carried out in many primary hospitals. Studies have proved that cranioplasty not only restores the shape of the cranial cavity, but also achieves the effect of restoring aesthetics, and also plays an important role in the recovery of the patient’s neurological function.

Cranioplasty is a medical technique with a long history. Our ancestors had already carried out such medical attempts thousands of years ago. The Museum of Osteology in Oklahoma, USA has a collection of a warrior in Peru 2,000 years ago The warrior’s skull was injured in battle, and a metal plate was implanted in the wound to repair the fracture.

With the rapid development of industrial level, science and technology, and diagnosis and treatment methods, cranioplasty has become a relatively common and routine operation in neurosurgery. During this process, cranioplasty materials also go through the following stages:

Xenograft bone material

In 1668, doctor van Meekeren used canine bone tissue to repair a human skull defect, which was the first documented xenograft in the world. Subsequently, the use of bone tissues such as apes, rabbits, and cattle to be transplanted to humans appeared one after another. In addition to common complications such as post-transplant infection and bone resorption, xenograft bone transplantation often causes secondary damage to patients due to the great immune rejection of xenograft materials by the human body.

Autologous bone graft

In 1821, doctor Vonwalther performed the world’s first autologous bone graft to repair skull defects. In 1867, doctor Lollier proposed the important role of periosteum in bone regeneration. Subsequently, there have been a large number of reports in the literature on the repair of skull defects with autologous skull flaps, mandibular outer plates, ribs, iliac crests, and fibula flaps. Autologous ribs made into strips or powder are suitable for repairing small skull defects. At present, autologous bone repair is still the gold standard for skull reconstruction. Autologous bone tissue has good osteoconductivity and histocompatibility, no rejection, and a low rate of postoperative bone exposure. Increased secondary trauma, high bone resorption rate of grafted bone and other problems, the clinical application is limited.

Allograft bone

The large numbers of soldiers in World War I and World War II who suffered skull defects from gunshots and explosions led to significant advances in methods of repairing skull defects. At the beginning of the 20th century, there were reports of using human cadaver skull transplantation to repair skull defects. Allograft materials are often obtained from other people’s bone flaps, which can solve the problem of insufficient autologous bone in patients with large skull defects to a certain extent, and meet clinical needs. In order to reduce the rejection reaction, methods such as radiation method and high-pressure steam sterilization are commonly used to treat allograft bone. Because the acquisition of allogeneic materials will cause great trauma to the donor and involve many ethical issues, it has been rarely used at present.

Polymer Materials

Polymethylmethacrylate

This material is strong, stable, heat-resistant, and can be penetrated by X-rays. It is also called bone cement because its strength is similar to that of human bones. However, it is brittle and prone to cracking when impacted by external forces, so it is rarely used alone in cranial repair. Compared with autologous bone, polymethyl methacrylate lacks porosity and cannot be infiltrated and wrapped by new tissue after being implanted in the cranium. It is prone to infection after operation, and it is less used at present. In addition, because it is difficult to be compatible with the surrounding tissue and cannot grow with the skull, it is forbidden to be used as a repair material for children’s skull defects.

Hydroxyapatite

Its molecular structure and calcium-phosphorus ratio are very similar to the inorganic components in normal bones, and it belongs to calcium-phosphorus ceramics. Hydroxyapatite has good biocompatibility, osteoconductivity and osteoinductivity. After implanted in the body, calcium and phosphorus will be released from the surface of the material to be absorbed by body tissues and induce new bone tissue growth. Through CAD/CAM technology, hydroxyapatite can be prefabricated into personalized implants according to the size and shape of the defect before operation, but the main problem is that intraoperative screw fixation and postoperative external force are easy to break it , a higher rate of postoperative infection. Moreover, hydroxyapatite degrades too quickly in the body, so it is usually used to repair small bone defects left by skull drilling, and large skull defects need to be fixed with titanium mesh.

Silicone Rubber

A non-metallic material widely used in cranioplasty at the end of the last century. It has the advantages of easy cutting and fixing, good tissue compatibility, and low price. But its disadvantages are that the material is thicker, the texture is softer, the strength is poor, and the edges are not easy to adhere to and easily warped. The unstable material can easily cause subcutaneous fluid or infection, displacement, upturning and exposure. The use of silica gel for repair is difficult to achieve timely stability and long-term support effects, so silicone rubber is gradually eliminated.

Metal grafting material

Metals that can be used for cranioplasty mainly include gold, silver, aluminum, titanium, etc. Aluminum is no longer used as a metal material for bone grafts, which dissolves over time and can irritate nerve tissue in the brain and induce epilepsy. Gold, while effective as a restorative material, is not widely used because of its soft texture and not being cost-effective. The skull repaired with silver plates is prone to oxidative reactions with the surrounding skin tissue, causing the skin flap to change color. Moreover, pure silver is soft and has poor resistance to external forces. It deforms after being stressed, thereby damaging intracranial tissues and nerves. Titanium began to be used in cranioplasty in the 1950s. The material made of titanium is safe, high in strength, and strong in acid and alkali resistance, and rarely produces rejection in the human body, so it is currently widely used in clinical practice. However, titanium metal has high brightness in postoperative CT or MRI imaging. If hematoma or tumor occurs near the intracranial implant after surgery, it is difficult to judge on the image. In addition, because titanium is a metal material with good heat transfer properties, it may cause damage to intracranial brain tissue and nerves in an outdoor high-temperature environment. Therefore, titanium metal is still not the most ideal material for cranioplasty.

PEEK

Polyetheretherketone (PEEK), as a semi-crystalline linear polycyclic aromatic linear polymer, was first used in clinical implants in 1998, mainly in spinal and hip replacements, due to its strength, durability Due to the excellent properties exhibited in the combination of toughness, stiffness and resistance, the use in clinical medicine continues to expand. In 2007, the experience of using PEEK material in the reconstruction of fronto-orbital defects in maxillofacial surgery was reported for the first time, making PEEK material gradually recognized by neurosurgeons.

The main advantage of PEEK material is that the elasticity and strength thresholds are very close to those of cortical bone, making it a valuable option for reconstruction of cranial defects. PEEK has the strength and hardness similar to cortical bone, and is highly inert, which basically excludes the release of cytotoxic substances caused by mechanical or chemical decomposition factors. In addition, due to the structural stability of the PEEK material at high temperatures, it can be sterilized by wet or dry heat without deformation. Its extremely low thermal conductivity reduces the possibility of damage to intracranial brain tissue and nerve tissue caused by changes in external temperature, and will not affect the results of imaging examinations of patients. In addition, polyether ether ketone material can also be made into a molding material that is almost identical to the biological curvature of the patient’s skull through the combination of CT thin-layer scanning and computer 3D printing technology, making the skull more beautiful after repair. However, the price of polyetheretherketone materials is relatively high, which is difficult for some patients to accept. Therefore, under the premise of not considering the price factor, polyetheretherketone material is considered to be the most ideal material for cranioplasty.

ARKMED ARK-BioPEEK’s self-developed and produced medical implant grade polyetheretherketone (PEEK) material has excellent performance and low price, and is suitable for the repair and implantation of skull defects.

THE BASIS OF PEEK PLASTICS

 

Plastic has evolved tremendously since its first uses in society, and every day, new uses and modifications are discovered. In today’s advanced world, engineered plastics such as PEEK are sought after to replace metals and increase the performance of certain parts.

PEEK plastic, also known as polyether ether ketone is a high-performance thermoplastic polymer. PEEK plastic is available in blocks, rods, sheets, pipes, powders, or pellets. Many parts made from PEEK are found in environments where temperature or chemical exposure poses a problem. PEEK plastics are not designed for every day or generic use. They are specially engineered plastics that are designed for very specific applications.

PEEK plastics can be manufactured in two different ways: PEEK injection molding or PEEK machining. Read on to learn about the two different types of PEEK processing.

MATERIAL SPECIFICATIONS & MECHANICAL PROPERTIES OF PEEK

Easy to fabricate and machine

Dimensionally stable

Lox toxic gas and smoke emissions

Stable at elevated temperatures up to 170°C/338°F

Low moisture absorption

Tension resistant

Boiling water and hot steam resistant

Radiation resistant

Chemical resistant

 

PEEK INJECTION MOLDING 

PEEK plastic is processed through an injection molding machine and unique molds to form raw plastic materials into the parts you need. The plastic is melted into the injection molding machine and then into your customized mold. Once the plastic cools and hardens, it’s transformed into a strong and durable plastic part for your project or industry.

For PEEK injection molding, processing temperatures ideally need to be somewhere between 662°F-752°F. For the best PEEK injection molding process, it is crucial to keep the PEEK plastic clean and dry. If your PEEK plastic is in pellet form, you can dry them on trays that circulate in an oven for 2-3 hours. To keep your PEEK plastic clean, keep any contaminants away during PEEK processing. For the best PEEK injection moulding performance, additives found in PEI plastic can be pre-compounded into PEEK plastic to make it ideal for injection molding.

PEEK CNC PLASTIC MACHINING

A PEEK plastic CNC machine is the second most common type of PEEK processing. CNC, or computer numerical control, is the automated control of machining tools by a computer. CNC machines process materials by following a coded programmed instruction instead of a manual operator.  CNC machined plastic is made by machining in the mass of a plastic block by milling machines with 3 axes with digital control.

PEEK CNC machining is popular because it is the most efficient and economical option for the rapid production of prototypes and plastic models. The automated CNC machine is controlled by a computer that determines the path of the machine cutter according to the 3D file created. No molds are needed in CNC machining, therefore reducing startup time and costs. CNC plastic machining is ideal for parts larger than 600mm.

MOVING FORWARD

If you know that you are in need of processed PEEK plastic, consider reaching out to PEEK plastic manufacturers. ARKPEEK will know exactly how to transform your exact PEEK material into the durable part that you need. Companies that specialize in CNC machined plastic can produce PEEK plastics of larger sizes and in more quantities. No matter what process you decide to choose, contact a custom plastic manufacturer today.