Sheet in PEI GF30 2400x610x46 mm green

PEI GF30 is PEI reinforced with 30 percent glass fiber. The addition lifts stiffness, dimensional stability and tensile strength considerably compared with an unfilled grade, while the material keeps the high service temperature and the 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 in heat, not just survive it. The difference shows clearly in creep under long-term load.

The density is around 1.27 g per cubic centimeter. Continuous service temperature is 170 degrees, and the material goes 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 aerospace industries put 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 damp surroundings.

The natural color is green, which is typical of PEI GF30. The tone comes from the glass fiber in combination with the base resin and is not added for cosmetics. It is at the same time 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 is used for load-bearing and dimensionally stable parts. Typical applications are insulators and support plates in electrical panels that run hot, fixtures and jigs in soldering and wave soldering ovens, wear strips in conveyor systems that run 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 aerospace and rail vehicles the sheet is used in interior parts where the fire requirement is high and the weight has to come down.

The sheet is machined in most ordinary machine shops. Use sharp carbide or diamond tipped tools, since the glass fiber wears hard on a normal steel edge. Moderate cutting speeds and good chip evacuation matter more than aggressive feed pressure. Drill in two steps for larger holes, 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 when machining and cleaning loaded parts. Count on shorter tool life than for unfilled plastic and plan for tool changes in longer runs.

Delivery forms are fixed sheet sizes in several thicknesses. Pick a thickness close to the finished dimension to save milling, and leave margin for face milling 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 governs the material waste to a large degree. For single parts it is simpler to start from the nearest larger stock thickness. Sheets in PEI GF30 should be stored flat and dry, preferably with cardboard between them if they are stacked, which avoids pressure marks and scratches on the surfaces before machining.

When the choice stands between PEI Eco and PEI GF30, it usually comes down to stiffness in heat: if maximum dimensional and shape stability and higher load capacity are needed, GF30 is right. If the part instead needs easier machining, a more even surface and a more transparent tone, unfilled material is preferable. If an even higher service temperature is required, PEEK or PEKEKK is the choice. If more stiffness on top of that 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 is closer to aluminum than for unfilled plastic, which keeps fits and hole patterns stable across temperature cycles. When joined 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 other interfaces.

Do you want help choosing between unfilled PEI and a glass fiber reinforced version? Write or call, and we will help you check it against the drawing and the load.

46 mm thick material in format 2400x610 mm and green, a heavily glass fiber filled PEI blank for milled high temperature parts. The thickness makes it a block to machine.