Sheet in PEI GF30 3000x500 mm green

PEI GF30 is PEI reinforced with 30 percent glass fiber. The addition lifts stiffness, dimensional stability and tensile strength considerably compared to an unfilled grade, while the material keeps the high service temperature and V0 fire rating of the PEI family. The sheet is therefore a common choice when a part has to hold its shape and carry load under heat, not just withstand it. The difference shows clearly in creep under long term load.

Density is around 1.27 g per cubic centimeter. Continuous service temperature is 170 degrees, and the material works down to minus 50 degrees without turning brittle to any dangerous degree. UL 94 V0 keeps it inside most of the fire requirements that the rail vehicle and aircraft industries place on interiors and enclosures. The glass fiber content also gives lower thermal expansion than unfilled PEI, which is valuable when tolerances have to hold across a wide temperature range. Water absorption is low, around 0.5 percent, which keeps dimensions stable even in a humid environment.

The natural color is green, which is typical for PEI GF30. The tone comes from the glass fiber together with the base resin and is not added for looks. It is also an easy way to tell the grade apart from unfilled PEI on the workbench. The surface turns matte after milling and carries detailed engraving well without clogging up.

As a sheet, PEI GF30 goes into load bearing and dimensionally stable parts. Typical applications are insulators and support plates in switchgear cabinets that run hot, fixtures and jigs in soldering and wave soldering ovens, wear strips in conveyor systems running close to the temperature limit of ordinary engineering plastics, and housings or base plates in medical equipment that has to take repeated steam sterilization. The material is also interesting in test equipment where metal parts need to be swapped for something lighter without losing stiffness in heat. In aircraft and rail vehicles the sheet is used for interior parts where the fire requirement is high and weight has to come down.

The sheet machines in most ordinary machine shops. Use sharp carbide or diamond tipped tools, since the glass fiber wears hard on a plain steel edge. Moderate cutting speeds and good chip evacuation matter more than aggressive feed pressure. Drill larger holes in two steps, and cool with compressed air or a clean emulsion. PEI is stress sensitive to certain aromatic solvents under load, so avoid acetone and methylene chloride in machining and in cleaning of loaded parts. Count on shorter tool life than with unfilled plastic and plan for tool changes in longer runs.

Delivery comes as fixed sheet sizes in several thicknesses. Pick a thickness close to the finished dimension to save milling, and leave margin for face milling of the surface if the part calls for it. On larger runs it is often worth thinking through the cutting pattern before ordering, since the starting format largely decides the material waste. For single parts it is simpler to start from the next larger stocked thickness. Sheets of PEI GF30 should be stored flat and dry, preferably with cardboard between them if they are stacked, so you avoid pressure marks and scratches on the surfaces before machining.

If the choice stands between PEI Eco and PEI GF30, it usually comes down to stiffness in heat: where maximum dimensional and shape stability and higher load capacity are needed, GF30 is right. If the part instead needs easier machining, a smoother surface and a more transparent tone, unfilled material is preferable. Where an even higher service temperature is required, PEEK or PEKEKK is the choice. If more stiffness is the most important criterion, you step up to GF50.

PEI GF30 is also a common choice in hybrid designs where the sheet works together with metal. Thermal expansion sits closer to aluminum than with unfilled plastic, which keeps fits and hole patterns stable through temperature cycles. In joints with screws and insert bushings the material behaves predictably, as long as tightening torque and hole clearance are matched to the thickness. Bonding works with polar epoxy systems after a light surface activation. That is why the sheet often ends up in designs where some metal parts need to be swapped for something lighter without affecting the rest of the interfaces.

Would you like help choosing between unfilled PEI and a glass fiber reinforced grade? Write or call, and we will check it against your drawing and load case.

Green and 3000x500 mm, glass fiber reinforced PEI for larger dimensionally stable parts in heat. A longer format with plenty of material.