1. Machined polymers are the most cost-effective solution when compared to metal.
Machined plastic parts are significantly less expensive than many raw metal materials; since plastics are produced in faster cycles than metals, manufacturing costs are often very low. In bearing and wear applications, polymers also allow for lower frictional properties in moving parts compared to metals. This means less wear, less maintenance-related downtime, and products that can be used for longer periods of time.
2. Machined polymers allow for radiolucency, unlike metallic parts.
Radiolucency is the quality of permitting the passage of radiant energy, such as x-rays, while still offering some resistance to it. Surgical instruments and components manufactured from polymer materials allow the surgeon a clear, unobstructed view under fluoroscopy. This allows for safer, more precise surgical outcomes in the operating room. Metal instruments impede the surgeon’s view.
3. Plastics are more resistant to chemicals than their metal counterparts.
Without extensive and costly secondary finishes and coatings, metals are easily attacked by many common chemicals. Corrosion due to moisture or even dissimilar metals in close contact is also a major concern with metal components. Polymer and composite materials such as PEEK, Kynar, Teflon, and polyethylene are impervious to some of the harshest chemicals. This allows for the manufacture and use of precision fluid handling components in the chemical and processing industries which would otherwise dissolve if manufactured from metallic materials. Some polymer materials available for machining can withstand temperatures over 700 degrees F (370 degrees C).
4. Plastic composites are lighter than metal materials.
Instead of using metal, plastic and composite surgical components allow orthopedic OEMs to meet ergonomic weight limits for items like surgical trays. Metallic instruments and products, on the other hand, add weight and strain to the surgical team and/or patients carrying and using those items.
5. Polymer parts do not require post-treatment finishing efforts, unlike metal.
Polymers and composites are both thermally and electrically insulating. Metallic components require special secondary processing and coating in order to achieve any sort of insulating properties. These secondary processes add cost to metallic components without offering the level of insulation offered by polymer materials. Plastic and composite components are also naturally corrosion resistant and experience no galvanic effects in a disimilar metal scenario that require sheathing. Unlike metals, plastic materials can be compounded with color before machining, eliminating the need for post-treatment finishing efforts such as painting.
6. Sterility is much easier to achieve in plastics, compared to metals.
In the medical industry, cleanliness is vital when it comes to equipment. Infection is the greatest threat facing hospital patients. Compared to metal, polymer and composite materials are much easier to clean and sterilize.
As has been explained with these six statements, plastics have a variety of unique attributes that often place them above metals in terms of utility, cost-effectiveness, and flexibility for precision-machined components.
John MacDonald is president at AIP Precision Machining in Daytona Beach, Fla. He has extensive technical experience in machined polymer and composite materials, but first and foremost, he is a customer-centric executive. MacDonald has held various manufacturing, quality, engineering, sales, and executive roles in the plastic manufacturing industry, which allows him to provide leadership and solutions from a broad background.