Round Rod in POM GF25 3000 mm natural

Round rod in POM GF25 is extruded acetal with 25 percent short glass fibers. The filler lifts stiffness and dimensional stability considerably compared with unreinforced POM C or POM H, while the material is still turned, milled and drilled without complications in an ordinary workshop. For designers who often work between acetal and the heavier engineering plastics, GF25 is a useful middle station where the machining cost stays low.

The density is around 1.5 g/cm³. The material is approved for continuous service around 100 degrees and works down to about minus 40. Water absorption is low, which is one of the most important traits of acetal; a turned part keeps its dimensions even when humidity changes sharply over the year. The fire rating is HB. The material is not hygroscopic the way the nylons are, which is worth keeping in mind when choosing between POM-based and PA-based options. A PA6 part can swell a full percent on moisture; a POM part moves considerably less.

The glass fibers give two things above all. The modulus of elasticity rises markedly, so a loaded shaft, cone or sleeve bends less under the same force. Shrinkage after machining is lower, so tolerances can be held even on somewhat larger parts. In return, wear resistance against other surfaces gets worse and the material is no longer a good choice as a plain bearing. For sliding functions you pick unreinforced POM or a modified grade with blended lubricants such as graphite or PTFE. Impact strength drops as well, so parts that take direct blows are better designed in unreinforced POM C.

Thermal expansion is lower with glass fiber. That shows when the part is bolted to metal, where a wider temperature span would otherwise risk either loosening or cracking the part. For designers who have tried unreinforced POM outdoors before and run into trouble with thermal movement, the difference is noticeable.

The round rod format is used above all for turned machine parts: load-transmitting sleeves, spacers, threaded end pieces, insulators, adjusting sockets, wheels with no sliding requirement and stiff mechanical parts. In pump and valve engineering GF25 turns up in the stiffer detail components, in automation as holders and adapters. The material turns nicely with sharp carbide inserts and gives a clean surface finish without stringing. The glass fibers wear on the tools, so count on shorter tool life in large runs and pick coatings accordingly. Thread cutting works without trouble, but a clean surface finish in the thread requires a sharp tool.

POM GF25 stands up well to mineral oils, fuels, greases, aliphatic solvents and weak acids. It reacts badly, on the other hand, to strong acids, powerful oxidizers and long-term UV radiation outdoors without a stabilizer. For outdoor applications or heavy UV load, pick a grade pigmented with carbon black. Against heavily chlorinated hot water over a long time the material should be avoided; POM C is a better choice there.

Standard diameters are stocked across a wide range, from small pin shaft blanks up to heavier turning blanks. The round rod is extruded with a slight skin effect on the surface; with tight tolerances you count on turning away a few tenths at the outside. In deeper turning of heavy dimensions internal stresses can be present, which can give a slight change of shape once a surface has been exposed. For really tight precision parts an intermediate step in the machining is often reassuring, and for the most demanding parts a stress relieving before final machining can be valuable.

If you want to discuss whether GF25 is enough or whether you need to go up to GF30, or whether a carbon fiber reinforced grade suits better for conductivity and stiffness, just get in touch. We also have creep and tensile test data for most grades and can send over datasheets for the design documentation. On larger runs we can also advise on machining strategy, since the right cutting geometry and feed give noticeably longer tool life on glass fiber reinforced plastics. Where tolerance demands are extreme, stress relieving before final machining can settle even the most sensitive parts. In the choice between GF25 and a carbon fiber reinforced grade you weigh stiffness and conductivity against price; for purely mechanical designs with no electrical requirement GF25 goes a long way, while conductive applications such as ESD-safe parts need a carbon fiber bearing grade or a special filler.

In natural and 3000 mm long, the glass fiber reinforced rod gives full length for stiff, dimensionally stable turned parts.