For everything that moves.
{{SALTI}}Materials › Polyacetal (POM)
Low friction, dimensional stability and excellent fatigue resistance: gears, guides, cams, hinges. POM, though, is not chosen on a single axis: how well it flows — the melt index varies sixfold from grade to grade — and whether it is homopolymer or copolymer. The homopolymer is stiffer and stronger; the copolymer stands up better to hot water, alkalis and prolonged heat.
Only two of the four levels below carry figures, and the reason is flow: the row states 190 °C and 2.16 kg, and among the datasheets in the archive barely more than a third of the POM grades state the test conditions. Without them a grade is not assigned to a viscosity level, and the two intermediate levels stay under the threshold: we prefer to leave them empty rather than fill them with a figure that does not hold. Flow is an important criterion for filling the mould properly, but it is not the only one: the grade must also be chosen according to fatigue, impact, friction and wear resistance and to the service environment, distinguishing homopolymer POM, copolymer POM and modified formulations. And POM cannot be bonded or painted without pre-treatment: above 230 °C in the barrel it degrades, releasing formaldehyde.
MFR ≈ 2.5 — The toughest
Thick walls, parts working in fatigue, where the resin must give its most.
General purpose
Gears, guides, valve bodies: the starting choice.
Grade-dependent figure: check the datasheet of the selected material.
Easy moulding
Complex geometries, multi-cavity moulds, short cycles.
Grade-dependent figure: check the datasheet of the selected material.
MFR ≈ 15 — Thin and stiff
Long flow paths, thin walls, fine detail that still has to stay stiff.
Each row is the median of a selection of manufacturers’ datasheets held in our archive, with the property, the standard and the number of grades stated next to the value. These figures describe the sample: they serve to compare the levels with one another, not to size a part, and they are not a guaranteed material specification. For that you need the datasheet of the chosen grade, which we supply on request.
Where a level shows no value, the documented sample was not sufficient: we prefer to remove the figure rather than publish one that does not hold. HDT and impact strength are deliberately absent, because datasheets often do not state the test condition — whether HDT is at 1.8 or 0.45 MPa, whether the impact specimen is notched — and values collected under different conditions cannot be compared.
Parts that came out of our own machines: geometries that elsewhere would need moulds, finishes obtained in house.
Not sure which one to choose? You do not have to decide on your own. Upload the model: in a few minutes you have the price, the delivery times and an automatic check that warns you if something cannot be produced — before you order, not after.