Round Rod in POM LF Nano 3000 mm black

Round rod in POM LF Nano is a glide optimized acetal blank for turned wear parts. LF stands for low friction; the grade is friction modified compared with standard acetal and developed for bearings and sliding surfaces that run dry, meaning entirely without lubrication. The base is polyoxymethylene (POM), the material that has made acetal the workshop's first choice for turned bushings.

Why a friction modified grade, when ordinary POM already slides well? Because dry running bearings with long duty cycles sooner or later suffer from jerky motion and friction heat, what is usually called stick-slip. A friction modified acetal evens out the movement, lowers the friction and extends the service life of both the bearing and the shaft; extra valuable in machines where grease is forbidden, or where it is forgotten in practice during maintenance. The additive is also mixed into the whole body of the material, so the sliding property does not wear away with the surface.

At bottom the material behaves the way acetal should. High stiffness, low moisture absorption and a dimensional stability that holds the tolerances even when the air humidity swings between winter and summer. The creep under constant load is low, which decides how long a preloaded bushing stays on size. Exact values for coefficient of friction, density and temperature range for this particular grade are in the manufacturer's TDS.

The applications are the same as for acetal in general, but with the weight on the sliding function: dry running plain bearings in packaging machines, guide sleeves and slide pieces in automatic lines, chain guides, running rollers, gears with a small module and positioning parts where even, quiet motion is asked for. In Swedish engineering industry the grade often ends up in machines that run three shifts; there every percent of lower friction pays for itself in reduced wear and fewer unplanned stops. Think packaging lines, the wood industry and paper mills.

A design tip along the way: plastic bearings need more bearing clearance than metal bearings, because plastic expands more with the heat. Calculate on the operating temperature instead of room temperature when you set the tolerances, and let the bearing be a hundredth too loose rather than too tight. A binding plastic bearing builds heat quickly and wears out early. The same reasoning applies to guides and slides; give the movement a little air, and it lasts longer.

The machining is as rewarding as for standard POM. Turning gives a bright surface straight away without polishing, the chip is dry and easy to clear, and both HSS and carbide work well at high cutting speeds. Drilling and tapping are clean and predictable. Gluing, on the other hand, works poorly on acetal; choose a mechanical fastener, threaded brass inserts or ultrasonic welding when parts are to be joined.

The rods are supplied in the length 3000 mm and in eight diameters from 10 to 100 mm, so the same grade follows along from small guide pins to heavy bearing blanks. If you want to avoid cutting them yourself, we do it for you with CTS, our cut to size service; practical when the lathe has limited distance between centers or when the material is to be spread over several jobs.

The choice between this grade and standard POM C is easy to reason your way to. If the part has no sliding function the standard grade is plenty, and it costs less. If the part runs dry against steel or another plastic, with demands on even motion and long service life, a friction modified grade is the right way. And for really heavily loaded sliding cases there are also oil filled acetal grades to put alongside in the comparison.

Do you have a specific bearing application in mind? We will help you choose the right grade.