Sheet in PEEK SX 1000x620x120 mm beige

PEEK SX is a slide optimized PEEK grade where lubricating additives are baked into the base material during manufacturing. Friction is low. That means bearings and sliding surfaces can be run completely dry, with no external lubrication, even when the temperature creeps up and ordinary oil would have charred. The sheet takes 260 degrees continuously and short peaks toward 300 degrees. That is where most simpler sliding plastics run out.

Mechanically the material delivers a tensile strength around 110 MPa and a ball indentation hardness around 240 N/mm², which goes a long way for loaded sliding surfaces that have to hold their shape under pressure. The density is around 1.31 g/cm³. Water absorption is negligible, about 0.03 percent, so the dimensions of a bearing part stand still even in damp and hot operation and the fit does not change over time. The fire rating is V0. Thermal conductivity around 0.27 W/mK is typical for unreinforced PEEK, which means friction heat is led away relatively slowly. That is something to allow for at high sliding speeds, since the heat gathers in the contact surface. Chemically the material handles most oils, fuels, hot water and process liquids, so the part is not affected by the medium it works in.

As a sheet, SX is meant to become components you mill out of a block. Dry plain bearings in kiln cars and hot conveyors where lubricant would burn away. Wear rails and guides where oil must not be present, for example in equipment near food or pharmaceutical production with clean surface requirements. Bottom bearings and thrust bearings in pumps that run intermittently and have to start without binding. Contact surfaces against metal where you want minimal stick-slip at start-up, so the movement is smooth from the first millimeter. The point through all of these cases is that the material slides quietly against steel and bronze without you adding a single drop of lubricant.

Machining goes smoothly with sharp carbide tools and good cooling of the cut. The material mills, turns and drills cleanly and holds fine tolerances without chipping at the edges. Keep in mind that the sliding additives make the surface somewhat softer than pure PEEK, which both makes it easy to machine and means the finishing cut has to go lightly toward final size. Clamp the blank firmly and let roughing and finishing differ in cutting data if you are chasing tight dimensions. Stress relieving before finishing helps on thick parts that can otherwise move as the material is opened up. Drill through holes in stages and clear the chips in between.

One property that often decides the choice is how the material behaves at start and stop. Many plain bearings wear most in the moment movement begins, since static friction is higher than friction during movement. With built-in sliding additives the difference gets smaller, so the bearing does not jerk into motion but slides softly from the first movement. That is kind to both the bearing and whatever moves against it. Over time it means smoother running and less wear on the mating surface of steel or bronze, which in turn keeps the whole machine in trim longer.

Think about the mating surface when you design the bearing. A smooth, hardened steel surface gives the lowest wear and the longest service life, while a rough or soft mating surface wears the sliding plastic faster. The clearance in the fit should allow for the material expanding more than steel when it gets hot, so the bushing or the plate does not seize at full operating temperature. The SX grade is typically brown to black in color from the sliding additives. At really high surface loads or where static has to be dissipated, a fiber reinforced low friction grade can be a better choice, something we are happy to help you judge from your load case.

The thick 120 mm block in the 1000 x 620 mm format gives depth enough for turned and milled parts in one piece, and the SX quality with ultra-high purity belongs in semiconductor manufacturing.

The sheet comes in different thicknesses and is cut into blanks to drawing, so material waste is kept down. Do not hesitate if you are unsure whether a sliding grade or a fiber reinforced PEEK suits your application best. Describe the load, the sliding speed and the temperature and we will point you right and help you avoid a part that is either over or under dimensioned.