PEEK Plastic Machining for Medical, Life Science, and Aerospace OEMs

Belonging to the family of materials known as polyaryletherketones (PAEK), PEEK itself carries many of the family's prime properties. Known for its several types of resistance to certain elements, teams commonly choose PEEK plastic because of its tolerance for intense and harsh operating environments. Regarding its high temperature resistance, the material can withstand continuous exposure to temperatures as high as 250°C (482°F) without harming the material's structure. It can also handle limited exposure up to 300°C (572°F) without seriously compromising its mechanical properties. Constant exposure to hot liquid or steam usually does not affect the plastic's integrity, making some PEEK grades sterilizable in autoclaves and other steam sterilization methods. However, it does have a lower heat deflection temperature of around 152°C (~306°F). A PEEK machined part still retains its function in that range, but will likely lose some of its strength due to softening.

Delving more into its mechanical properties, the material exhibits excellent strength, stiffness, and dimensional stability. Due to these qualities, engineers have marked its high tensile strength and modulus with a low friction coefficient that make it a preferred material for structural applications. It can take abrasive and extended use in this regard. That combined with its low moisture absorption makes this material's performance consistent even in wet or humid environments.

Considering its many chemical resistances, PEEK stands out. Its high resistance to most organic and inorganic chemicals (except for concentrated nitric and sulfuric acids) make it particularly attractive to those in medical and life science. For a comprehensive list of how it performs against certain chemical types, visit our chart. If interested in seeing the resin's performance against those chemicals used in life science,  we have a chart for that as well.

When working with PEEK, we have some design suggestions:

• Manufacturers cannot bond this plastic and will instead create manifolds through drilling only.
• Pay attention to intersecting holes for burrs. Proper tooling is critical for the component to serve its purpose.
• Stress-relieved parts are only necessary for exacting applications, but the plastic is not stress-sensitive.
• The material (once finished) can have a mottled look, especially in the non-450g version.
• Sheet material comes + .030. Design parts to avoid the next size up as that increases cost.

Some varieties of PEEK are made with pre-qualified biocompatible materials and are FDA approved, making them ideal options for life science applications. It is one of the few biologically safe materials for continuous use in the human body. Due to this, we find it often used in products like implants and dental applications to enhance product longevity and effectiveness.

Although the life sciences and medical find this resub a choice material, other industries find uses for it as well. For example, industries serving aerospace and defense recognize its durable nature and create products that need to withstand harsher environments. With PEEK's high continuous use temperature, this quality makes it stand out from other options fairly often. The same goes for industries in oil/gas, automotive, and several others.

We need to make a note here about cost when it comes to PEEK plastic. While the plastic is usually a more expensive material than others we use, engineers need to weigh the benefits to the cost. If there is a more cost effective material that will suit with maybe fewer features, we suggest that route if cost is of great concern. However, if it's not as largely influential, its many benefits will pay for itself long term.

You may be wondering if its price will fall and to wait. To give some background, we can only guess where its prices will fall when you get a quote for your project. This is because initially, it was only available from Victrex with their unfilled resin number known as 450g. Though lately additional manufacturers are competing in the marketplace, which helps to improve the price point. Rest assured that we are always on the lookout for the best prices that don’t sacrifice any quality. And here's our secret on how we do that: through our esteemed partners at Quantum Plastics. Our special partnership grants us access to more direct pricing that we pass on to you, but this is for Controlled Fluidics clients and customers only.

Aside from cost considerations, PEEK does have some disadvantages. Its low resistance to UV light and the need to process it at high temperatures could cause some reservations in choosing this material. Also, in medical applications, the material's hydrophobic, nonpolar nature means it has rudimentary cell adhesion. If any of these cause pause, we encourage your exploration of other materials.

Plastic Machining with PEEK Plastic transcript