Choosing the Proper Electrical Insulating Material


There are hundreds of decisions required when flexible […]

There are hundreds of decisions required when flexible duct tape designing mission critical electro-mechanical components.   In every one of these decisions, choosing the right material combinations for a specific application can mean the difference between success and failure.   Most of these design decisions are made utilizing the same material choices design after design, sometimes compromising the true intent of the project simply because the designer is unaware of the many other material choices available.  With this in mind, a primer in common and not-so-common electrical insulating materials may be helpful.For simple electrical insulating applications where a thin film is required, polyester films are probably the most common type of electrical insulator material used. 

Polyester films are commonly characterized as either  polyethylene terephthalate or  the differences lying in their chemical composition and their resulting physical and electrical insulating properties.  PET films, such as  offer good dielectric withstanding resistance within a relative temperature range films are more expensive than films; however for mission critical applications this cost difference may be negligible.  These thin films are found in thousands of applications including flexible electronics, battery and motor insulations, and electronic component manufacturing.Polyether materials  Where higher temperature environments prevent the use of PEN films, often times the mechanical design engineer will consider the use of poly ether ether ketone peek or polyetherimide .  PEI materials have a significantly higher glass transition temperature than  material is its availability in film, sheet, or extruded rod forms, allowing the design engineer greater flexibility in designing critical mechanical components depending on the specifics of the application. 

Again, just as PEN films are typically more expensive than PET films, the greater performance attributes of the PEI materials lends itself to a higher price point than the   The specific requirements of the electro-mechanical component, as well as the requirements of the specific application must be weighed when determining what material to choose.  Because of the different material forms available, PEI materials are often used in aircraft components, microwave applications, and electric/electrical components.Where even greater temperature resistance is required while maintaining excellent electrical insulating performance, polyimide materials are often called upon.  Polyimide films such as have been used for years as an outstanding electrical insulating material, and thicker polyimide materials such as continue to be utilized as alternatives to PEI materials where mission critical applications require precision engineered materials.  polyimide film, has a glass transition temperature of , far exceeding that of PEI materials, providing exceptional stability at demanding temperatures. 

Its very low Coefficient of Thermal Expansion  along with its high tensile strength  makesan exceptionally strong and stable material across its operating temperature  This allows a tremendous amount of design flexibility for the mechanical engineer, as the engineer can enter the design phase without thinking of material thickness limitations, but rather design specifically for their application knowing the right thickness material is available to them.  The availability of in 0.001” increments also greatly reduces the amount of machining time required to get to final thickness tolerances, which must be considered when designing for manufacturability. Cirlex’s® physical and mechanical stability are also evident during and after the machining process, as there are no residual stresses built up in the material leaving the final design in its dead-flat form.  In applications where extreme temperature or environmental requirements are needed.