Round Rod in PET ZX 1000 mm gray

Round rod in PET ZX is one of the more faithful workhorses at the lathe. The material is stress relieved already in production, which shows when long shafts or deep holes have to be made: the parts do not bow and the dimensions do not move when the stresses are released.

The density is 1.45 g/cm³ and the rod takes continuous service up to 115 degrees. Under shorter loads the material handles somewhat more. The lowest service temperature is minus 20. The water absorption is low, around 0.47 percent, which means turned parts keep their diameter across seasons and humidity levels. The fire rating is UL 94 HB.

Mechanically PET ZX is hard, stiff and has low sliding friction against steel. The material is wear resistant and dimensionally stable, which are two properties that rarely go together in the world of plastics. That is why the rod is often brought out when PA moves too much with the moisture and POM C moves too much thermally.

In practice the rod is used for plain bearings, guide bushings, spacers, cams, gears, valve components and wear parts in food machinery. In packaging machines and filling lines you find PET ZX as dosing pistons and rolling parts that stand up to cleaning with hot water and alkaline agents. For precision parts that have to sit in tight fits, this is a natural choice.

The chemical resistance is good against weak acids, bases, alcohols, oils and greases. Strong acids, chlorinated solvents, phenol and long exposure to hot water should be avoided because of hydrolysis. For service in hot steam or continuously in water above 80 degrees, PEEK or PVDF is the better choice.

Machining is straightforward. The rod is turned with sharp inserts and good chip clearance; moderate cutting speeds and generous feeds give the cleanest surface. Drilling deep holes works well if you back the chip out often. Threading works in coarse metric threads; finer threads hold better with thread inserts. Bonding does not lie in the nature of the material, mechanical fastening is what is recommended.

The rods come in diameters from a couple of millimeters and up. The color is naturally bone white, slightly translucent in thinner diameters. For turned series it is recommended to allow for 0.1 to 0.2 percent dimensional movement depending on the temperature range and humidity level, which is clearly less than for the corresponding PA rod.

When it is the dimensional stability that governs the choice, PET ZX is often right. When it is low friction under dry conditions that governs, POM C is there as an alternative; when it is high temperature, other grades should be considered. The range is large and the right grade for the right part usually makes a bigger difference than people think.

The gray rod at 1000 mm with added dry lubricant is turned into slide bushings and rollers that have to run dry.

Do you need help comparing PET ZX with other engineering plastics or settling on the right diameter? Get in touch and we will go through it.