In total joint arthroplasty manufacturing, GUR 2122 M powder is consolidated by direct compression moulding or ram extrusion into bar and sheet stock, then machined into bearing geometries. The critical processing constraint is the narrow oxidative degradation window: prolonged residence above 220 °C accelerates chain scission, while consolidation pressure below 10 MPa leaves fusion defects detectable by transmitted-light microscopy. Production-scale direct compression moulding presses with platen parallelism better than 0.05 mm/m are required; mismatch above that value produces non-uniform density and delamination after machining. The material is charged at 100 wt% virgin GUR 2122 M. When oxidation-resistant bearing stock is specified, alpha-tocopherol is added at 0.05–0.10 wt% prior to consolidation; no other stabilizers or processing aids are used because they alter wear behaviour measured under ISO 14242-1:2014 and tensile properties under ISO 527-2:2012. Powder is pre-dried at 80 °C for 2 h when ambient relative humidity exceeds 60 %. Direct compression moulding uses platen temperatures of 200–220 °C, consolidation pressure of 10–20 MPa, dwell time scaled at 15–20 min per 10 mm section thickness, and cooling under pressure at 5–10 °C/h. Ram-extruded preforms are annealed at 120–130 °C for 2–4 h before CNC machining, because residual orientation in UHMWPE causes dimensional drift after final shaping. Finished components are cleaned, packaged under nitrogen, and terminally sterilized by gamma irradiation at 25–40 kGy; if radiation crosslinking is required for wear reduction, doses of 50–100 kGy are applied prior to machining. Compliance is assessed against ISO 5834-1:2019, ISO 5834-2:2019, ASTM F648-21, ISO 10993-1:2018, and quality systems under ISO 13485:2016. Terminal product types include acetabular liners for total hip arthroplasty, tibial inserts and patellar components for total knee arthroplasty, and glenoid components for shoulder arthroplasty.

What Restricts Screw Plastication of Neat GUR 2122 M in Conveyor Wear-Profile Production?

GUR 2122 M possesses a melt viscosity above 10^8 Pa·s at 190 °C; under ISO 1133-1:2022 standard conditions, no measurable melt flow rate is obtained. Consequently, screw injection and conventional single-screw extrusion are not viable, and ram extrusion is the standard conversion route for beverage packaging wear profiles. The formulation is undiluted resin at 100 wt%; no plasticizer, heat stabilizer, or mould-release agent is compounded into the polymer. If clean in-house re-grind is used, the maximum loading is 10 wt% because higher levels reduce notched impact strength measured by ISO 179-1:2010. Ram extruders operate with barrel zones at 180–220 °C and die temperatures at 150–180 °C. Powder is compacted in discrete strokes under 30–70 MPa; the absence of screw shear prevents chain scission, but batch-to-batch variation in powder bulk density measured by ASTM D1895-17 can shift stroke weight and requires closed-loop feeder adjustment. Profiles are cut, post-annealed at 120 °C for 2 h to reduce thermal memory, and calibrated for straightness. Finished wear strips and guide rails are certified for direct food contact under FDA 21 CFR 177.1520, EU 10/2011, and EC 1935/2004. Terminal product types include bottle conveyor guide rails, neck guide profiles, star wheel pads, and chain guide strips on bottling and canning lines.

Sintered porous sheets and plugs are produced from GUR 2122 M powder without a melt-compounding step. The powder is screened into controlled particle-size fractions and lightly compacted in a mould, then heated to achieve partial particle coalescence while retaining interconnected voids. This route avoids the high-shear mixing and molecular orientation that would collapse the pore network. The sinter body is 100 wt% GUR 2122 M; no binder or sintering aid is used. Pore size is controlled by powder sieve cut rather than chemical blowing agents. Typical sieve cuts below 200 µm produce mean flow pore diameters below 50 µm, but the exact combination is set by target air permeability measured by ISO 4022:2018 and bubble-point values measured by ASTM F316-03.

Mould filling uses controlled powder deposition; compaction pressure remains below 5 MPa to prevent pore collapse. Sintering is carried out at 170–200 °C in forced-air ovens with dwell times of 20–60 min per 10 mm section thickness. Because UHMWPE has low thermal conductivity, thick sections require staged heating to avoid surface skinning and core porosity loss. Post-sintering cooling is conducted below 2 °C/min to limit pore anisotropy. For pharmaceutical, food-contact, and bioreactor applications, finished parts are specified against FDA 21 CFR 177.1520, EU 10/2011, USP <88> Class VI, and ISO 10993-1:2018. Terminal components include porous filter sheets, spargers for bioreactors, vent plugs, and pneumatic silencers.

When Compression Moulding Is Selected for Bulk-Handling Liners Thicker Than 40 mm

For chute liners, silo discharge cones, and chain guide blocks with section thickness above 40 mm, compression moulding from GUR 2122 M powder provides a void-free cross-section that ram extrusion cannot deliver at equivalent wall uniformity. The material is used undiluted at 100 wt%. In-plant machining regrind is capped at 15 wt% when tensile yield stress measured by ASTM D638-14 must remain above 90 % of virgin control. Carbon black, graphite, and glass fiber fillers are omitted because they reduce Charpy impact toughness measured by ISO 179-1:2010 without providing a meaningful gain in sliding abrasion resistance. Compression moulding presses with platen dimensions above 2.5 m are typical. Powder is heated to 200–220 °C under 10–20 MPa, held for 20 min per 10 mm thickness, and cooled under the same pressure at 5–10 °C/h to reduce residual stress. Post-machining annealing at 120 °C for 2–4 h is required before final CNC finishing because UHMWPE releases frozen-in stress slowly. Hardness of finished liners is typically 62–68 Shore D under ASTM D2240-15, and water absorption remains below 0.01 % under ISO 62:2008. Material specification is anchored to ASTM D4020-18, ISO 11542-2:1998, and ISO 1183-1:2019. Terminal product types include silo and hopper liners, chain conveyor wear blocks, screw conveyor bushings, and impact pads for railcar unloading.

Wet-process microporous separator manufacture converts GUR 2122 M into a gel film by mixing the powder with paraffin oil and a minor antioxidant package, followed by extrusion, biaxial stretching, solvent extraction, and thermal setting. Industrial formulations typically use 25–35 wt% GUR 2122 M and 65–75 wt% paraffin oil; antioxidant loading remains below 0.5 wt% to avoid interference with lithium-ion transport. The exact polymer-to-oil ratio is adjusted to target melt strength, final Gurley permeability, and shutdown temperature. Compounding occurs in a co-rotating twin-screw extruder with L/D 40–52, barrel zones 180–230 °C, and screw speeds 200–600 rpm. The elevated screw speed is required to disperse the ultra-high-viscosity polymer into the plasticizer without entering a screw-constrained melt state.

The gel is cast through a slit die, quenched to form a gel sheet, biaxially stretched in a temperature window of 100–130 °C, and then extracted with methylene chloride or n-hexane to remove paraffin oil. Residual oil is typically controlled below 0.1 wt% because higher residues impair electrolyte wettability and thermal shutdown consistency. Exact extraction and stretching temperature profiles are proprietary; published data for this specific configuration is limited. Battery separator lines are qualified under ISO 9001:2015 and IATF 16949:2016; separator tensile properties are tested under ASTM D882-18. Terminal product types include microporous separator films for lithium-ion cylindrical, prismatic, and pouch cells.