Round Rod in PPSU MG XR 76x1219 mm yellow

Round rod in PPSU is a semi-finished product for turned and milled structural parts in sulfone plastic. The material is amorphous, yellowish translucent and designed for components that are repeatedly exposed to steam, hot water and autoclaving without losing strength or dimensions. The rods are used for turned fluid couplings, sleeves, spring and locking parts in washer disinfectors, holders in medical clean rooms, insulators in electrical cabinets and structural parts in aircraft and vehicles where fire and smoke ratings have to be documented. The material is well established at workshops that make instrument accessories, and it is supplied at a quality that answers the requirements of validated processes.

The core quality of PPSU is hydrolysis resistance combined with toughness across a wide temperature range. The density is about 1.29 g/cm³ and the design temperature is around 180 °C continuously. The material is impact resistant down to about -50 °C and does not change its geometry from repeated steam sterilization the way many other engineering plastics do. The fire rating is V0 to UL94 and smoke density in a fire is low, which opens up use in cabin and passenger areas. Water absorption lands around 0.6 percent at equilibrium, which calls for dry material before thermoforming but rarely affects finished parts in service. The material also takes repeated contact with enzymatic cleaning agents and alkaline disinfectants, which is central in medical technology.

In turning and milling, PPSU is kind to tools as long as you keep the rake angles positive, the feed even and the cooling generous. Use sharp carbide, avoid rubbing with a worn edge and keep the depth of cut steady. The material is tough rather than brittle, so long grooves give soft, continuous chips instead of short breaks. Drilling works well with a twist drill for plastics, threading with a die gives clean threads, and chamfers polish up to an almost optical surface. Before heavy machining in a thick rod, stress relieving in a dry oven is recommended, since amorphous materials in extruded rods can otherwise release stresses during turning and change dimensions a couple of days later. Joining is done with adhesive (epoxy, cyanoacrylate) or with ultrasonic welding for thin sections.

Typical uses are turned couplings in steam and hot water circuits, spring washers and axial stops in automation that gets steam sterilized, holders in medical technology, insulators that take steam condensate, plus components in aircraft cabins and in clean room equipment. The material combines enough transparency for simple crack inspection with good toughness, so a part under impact load does not crack but deforms visibly; that is a valuable property in safety critical applications where a cracked plastic part is otherwise hard to spot. For gears and precision parts that need low friction, POM or PEEK is often chosen instead, but for structural and holder parts in steam and autoclave environments PPSU is hard to beat.

PPSU is chosen over PEI when autoclaving is involved, or when the part meets aggressive alkaline cleaning; PEI is stiffer and cheaper but breaks down faster in that environment. Against PEEK, PPSU holds its own on cost and at temperatures up toward 180 °C; above that, PEEK is still the better choice. Against PSU, PPSU wins on toughness and hydrolysis resistance, and against PC it simply lasts far longer under thermal and chemical loads. That makes it a regular choice in designs where a combination of requirements is otherwise hard to meet in a single material.

When choosing a diameter, a good rule of thumb is to leave at least three to four millimeters of total machining allowance all round, so that any stresses in the surface layer can be taken away and the final dimension comes out clean. For critical parts that have to survive validated autoclave programs, stress relieving in an oven before finishing is also recommended, so the material sits stable in its dimensions when it leaves the workshop. Parts like that are best checked both straight after machining and after a first trial autoclave run, so that any micro shrinkage is caught before the part goes into production.

The rods are stocked in standard diameters that cover both small turned parts and larger machine components. Lengths are cut to order. Do you need help picking the right diameter with stress relieving and machining allowance in mind, or do you want advice on turning parameters for a specific part? Get in touch, and we will go through the drawing together and put together a proposal on material, dimensions and cutting data.

Yellow round rod, 76 mm in diameter and 1219 mm long. The heavy rod is radiopaque, so a part that gets cut off can be found on an X-ray image.

XR stands for radiopaque, so a broken off piece can be found on an X-ray.