Round Rod in POM H+PTFE 3000 mm brown

Round rod in POM H+PTFE is an acetal plastic in homopolymer form with PTFE particles spread evenly through the structure. The additive lowers friction against the mating surface and improves wear resistance in dry running, while the stiffness and dimensional stability of the POM base are kept. The material is made for turned sliding and rotating parts where running lubrication is impractical or unwanted, for example in cleanrooms, food environments or spots that are hard to reach.

The density is around 1.41 g/cm³ and the continuous service temperature reaches up to 105 degrees. The lowest working temperature is about -40 degrees. Water absorption is low, around 0.8 percent, so tolerances on turned parts hold in damp environments and through temperature swings. The fire rating is HB to UL 94. The high dimensional stability means bushings and sleeves keep their fit dimensions even when humidity and temperature vary over a year of operation.

The PTFE filling gives two clear effects. The dynamic coefficient of friction drops sharply against steel, brass and other plastics. And the stick-slip behavior that can turn up in unlubricated plain bearings is damped or disappears completely. You notice it as quieter running, less heat in the bearing and longer service life on both the plastic and the mating surface. The hardness comes out slightly lower than plain POM H, which is a deliberate trade for the sliding properties. The PV value in dry running is higher than for standard POM, which widens the range of applications.

The rod is used mainly where a piece of material is to be turned, milled or drilled into a finished sliding component. Typical parts are plain bushings, shims, slide rings, pivot sleeves, cams and shaft ends in pumps, valves and small gearboxes. In conveyor technology, packaging machines and food equipment the material is common in roller bearings, guide wheels and sleeves that have to survive dry periods without seizing. In assembly equipment the material is used in pivot sleeves and small bearings where an oil would contaminate the product.

Machining follows the same rhythm as ordinary POM. The material is turned at high cutting speeds, leaves short chips and gives a glossy, dimensionally accurate surface without extra finishing. The thermal expansion is around 0.11 mm per meter and degree, which is worth counting on in a press fit against metal. With large temperature swings the running clearance should be increased somewhat compared with a metal bearing. Use sharp tools with a positive rake angle; dull inserts create heat and ruin the sliding surface in bushing parts.

Bonding works poorly and welding is not practical, since the PTFE filling disturbs the melt. Parts are assembled with screws, snap fits or mechanical mounting. To make use of the friction improvement in a bushing a thin wall of the material is enough; it is the surface that slides, not the whole cross section, that decides the friction. That opens up designs where a thin POM H+PTFE sleeve is pressed into a load carrying metal housing and combines the strength of the metal with the sliding property of the plastic.

Chemically the material handles most organic solvents, mineral oils, fuels, weak acids and alcohol. Strong acids, concentrated bases and strong oxidizers should be avoided in longer contact. The natural color is faintly brownish from the PTFE additive, and the material is not UV stable in longer outdoor use. When you choose the mating surface, hardened or ground steel works best; soft, roughly machined metal wears the plastic down faster.

Choosing between POM H+PTFE and an oil filled POM variant, it is usually the load case that decides. PTFE grades are the first choice for low friction at a moderate PV value and in dry running, while oil filled POM often gives longer service life at higher load. For parts working in cleanrooms or food environments, where oil must not reach the product, the PTFE filling is especially valuable, since the lubrication is locked into the material and cannot migrate out.

The rod is supplied in natural color as standard, in a wide selection of diameters from small bushing sizes up to heavier dimensions for shaft and cam gear blanks. Lengths are cut at delivery as needed. The standard length is around one meter, and longer rods can be cut to order to make handling easier in automatic lathes and sliding head lathes. For larger production runs it is also possible to order pre-cut blanks with chamfered ends, which saves both setup time and material waste. If you are unsure which grade suits your application, get in touch with a drawing or a description of the function, and we will help you choose the right grade and dimension based on load, mating surface and operating environment.