Sheet in PAI C GF30 254x254 mm green

PAI C GF30 is a compression molded polyamide-imide reinforced with 30 percent glass fiber. The glass fiber content takes the material from the already high base figures of PAI one step further in stiffness and dimensional stability. The sheet is electrically insulating, has low thermal expansion and keeps most of its mechanical properties also at very high temperature. That is unusual among thermoplastics and makes the material relevant in applications where metals are too heavy or cannot be used for electrical reasons.

The heat resistance sits at the top of the thermoplastic layer. Continuous operation well above the PEEK range is possible, and short exposure to even higher temperature does not damage the material if the load is moderate. The glass fiber contributes dimensional stability rather than better tribology. It lowers the creep at elevated temperature and keeps the geometry of the component stable also in temperature cycles where the surrounding metal expands more. For components that are to sit fixed in a metal chassis and hold their position through the whole operating temperature, this is decisive.

The sheet is used in designs where stiffness, insulation and heat resistance matter more than perfect sliding properties. Common applications are insulated washers and holders in high voltage environments, electrical cams and slots in motors that run hot, fixtures for soldering and wave soldering, holders in semiconductor production and structural parts in pumps and compressors that are not sliding surfaces. The material is also a well proven alternative in valve structures where thermal stability is decisive. In the transformer industry PAI GF30 is used as a holder for coils and as structural insulators where neither epoxy nor ceramic fits.

The chemical resistance is broad. PAI handles most organic solvents, oils, fuels, hydraulic fluids and refrigerants. The material takes weak acids and alkalis but should not be exposed to concentrated lyes or strong oxidizing acids. The ester bond in PAI is sensitive to hydrolysis in a hot, alkaline environment, which is wise to allow for if the component is to be CIP cleaned or live in steam. The moisture uptake is low and stable, which means the dimensions hold even in a temperature cycling environment with changing humidity.

Tribologically, GF30 works in lightly loaded sliding contacts but is not the right choice for heavy bearing applications. The glass fiber is abrasive against softer mating surfaces and builds up the wear as the running hours add up. If you need a plain bearing you pick the CF30 variant or a bearing grade with PTFE and graphite added. GF30 suits very well where the material is to carry load, hold its shape and stand up to temperature, rather than slide against steel. Picture a washer that sits still and a bushing that turns: GF30 belongs in the first, not in the second.

Machining calls for carbide inserts or PCD. The glass fiber wears on the tools and quickly builds up a damaged cutting edge if feed and cutting speed are wrongly set. Moderate feed, sharp inserts, good chip clearance and compressed air as cooling work well. The sheet is dimensionally stable during machining, but it is wise to let parts acclimatize in a temperature chamber before finish machining if the tolerances are tight. Post-curing can lift the figures further, which some designs require in order to use PAI to the full. Expect the tool life to be shorter than when machining POM and PA, and budget accordingly.

When choosing the thickness it is practical to start somewhat thicker than the finished dimension, partly for machining allowance, partly to handle the small amount of internal stress that can be released during machining. The sheet comes in a limited range of sizes; if you face large cross sections it is often cheaper to weld several smaller parts into an aluminum chassis than to machine one large PAI sheet from scratch. Do you want to compare GF30 against CF30 for a specific component? Get in touch, and we will go through load, operating temperature and mating surface together. This product, PAI C GF30 254x254 mm green, has the format 254x254 mm, which makes it easy to place in an existing design.