The Best CNC Materials for the Medical Device Industry

The medical device industry covers an enormous line of products, but even so, there are often overlapping material requirements between applications. Learn about medical industry materials that offer low moisture, high heat-resistance, low corrosion, high hardness, and more.

By Greg Paulsen · October 21, 2019

The medical device industry covers an enormous line of products ranging from artificial joints to diagnostic equipment to therapeutic devices. Even so, across varying applications are often overlapping requirements that help narrow the list of material choices. For example, most devices need surfaces that do not absorb moisture and can be sterilized easily.

Medical device components are often manufactured through injection molding, additive manufacturing (3D printing), and CNC machining. CNC machining has the advantage of high customization, tight tolerances, great surfaces finishes, and certified material selection. When using CNC machining, parts are typically milled using 3 to 5 axes or turned using a live-tooling CNC lathe. Below are the top metal and plastic materials machined for medical device products.

Plastics and Composites for Medical Devices

The most common plastics for medical devices boast low water absorption (moisture resistance) as well as decent thermal properties. Most of the following materials can be sterilized using an autoclave, gamma, or EtO (ethylene oxide) method. Low surface friction, as well as better temperature resistance, is also preferred for the medical industry. Beyond direct or indirect contact housings, fixtures, and guides, plastics can act as a substitute for metals where magnetism or RF (radio frequency) signature may interfere with diagnostic results.

Name Description
Delrin (Acetal) Resin with good moisture-resistance, high wear-resistance, and low friction.
Polycarbonate (PC) With almost twice the tensile strength of ABS, polycarbonate has superior mechanical and structural properties. Used widely in automotive, aerospace, medical, and other applications that require durability and stability. Solid infill parts are fully dense.
PEEK Offering excellent tensile strength, PEEK is often used as a lightweight substitute for metal parts in high-temperature, high-stress applications. PEEK resists chemicals, wear, and moisture.
UHMW PE UHMWPE is a general-purpose material. It offers a unique combination of wear and corrosion resistance, low surface friction, high impact strength, high chemical resistance, and does not absorb moisture.
PTFE (Teflon) Teflon surpasses most plastics when it comes to chemical resistance and performance in extreme temperatures. It resists most solvents and is an excellent electrical insulator.
Polypropylene (PP)PP has excellent electrical properties and little or no moisture absorption. It carries light loads for a long period in widely varying temperatures. It can be machined into parts requiring chemical or corrosion resistance.
Garolite G-10Garolite G-10 is constructed from an epoxy resin with fiberglass fabric reinforcement and is also called epoxy-grade industrial laminate and phenolic. This material offers high strength and low moisture absorption. CNC machined Garolite is often used as a substitute for metal components when structural features cannot be magnetic.

Metals for Medical Devices

The best machinable metals for the medical device industry boast inherent corrosion resistance, the ability to be sterilized, and are easily cleaned. Stainless steels are very common because they do not rust, have low or no magnetic properties, and are machinable. Some grades of stainless can be further heat treated to enhance hardness. Materials like titanium offer high strength-to-weight ratios that benefit handheld, wearables, and implantable medical devices.

NameDescription
Stainless Steel 316/L Stainless Steel 316/L is a highly corrosion-resistant steel popular for medical devices.
Stainless Steel 304 Although one of the most widely used stainless steel alloys due to a great balance of corrosion resistance and machinability, stainless steel 304 cannot be heat treated for hardening. 18-8 stainless steel is recommended if hardening is required.
Stainless Steel 15-5 15-5 stainless steel offers corrosion resistance similar to Stainless 304. Improved workability, hardness, and high corrosion resistance.
Stainless Steel 17-4 Stainless steel 17-4 is a high strength, corrosion-resistant stainless alloy that easily heat treatable. This material is typically used in medical equipment.
Titanium Grade 2 Titanium grade 2 is a high strength, low weight, and high thermal conductivity metal. It is is a high purity, non-alloy material.
Titanium Grade 5 Excellent strength-to-weight ratio and the high aluminum content in Ti-6Al-4V increases its strength. This is the most commonly used titanium, offering good corrosion resistance, weldability, and formability.

CNC Machining Medical Parts

Whether a medical or dental project requires machined titanium or slippery PTFE, manufacturing platforms like Xometry can instantly price, provide lead times, and allow for custom certifications and inspection all in one interface. Xometry takes the guesswork out of choosing the best material with its knowledgable engineers and extensive design-for-manufacturing resources. The platform also helps you choose the best machine shop by pairing the work ordered through its AI-driven quoting platform with the best manufacturing partner for that project.

Posted in Machining Manufacturability Tips