For unpainted cowl vent grilles, B-pillar appliqués, and mirror shell bases, LG Chem ASA LI968W is processed at melt temperatures in the range of 240–260 °C on a reciprocating screw with L/D 20:1–24:1 and compression ratio 2.1:1–2.4:1. The desiccant hopper should maintain a closed-loop dew point below -30 °C, with the resin predried at 80 °C for 3–4 h and residual moisture held below 0.02 wt%. Mould temperature is maintained at 50–70 °C for grained surfaces and 55–70 °C for high-gloss B-pillar covers, because lower mould temperatures produce visible flow-hesitation lines and uneven grain replication in a 2.0–2.5 mm nominal wall. Injection speed is profiled, starting at 25–40 mm/s and ramping to 80–120 mm/s before screw-position switch-over at 6–8 mm from zero. Hold pressure between 45 MPa and 65 MPa hydraulic is applied until gate freeze, which occurs in roughly 4–7 s for a 2.0 mm side wall. Because the unfilled grade is high-flow, pack pressure must be limited below the point that produces sink opposite rib roots; rib thickness should not exceed 60% of adjacent wall, and rib root radius should not fall below 0.5 mm. On a production-scale line with a 50 mm screw and 2.2:1 compression ratio, the most common defect is not short shot but splay from a melt cushion below 3 mm. The injection-unit temperature profile should run flat: rear zone 220–230 °C, middle zone 230–240 °C, front zone 240–250 °C, and nozzle 245–255 °C. Lot-to-lot viscosity differences are absorbed by injection-velocity adjustment rather than by raising melt temperature; changing melt temperature more than ±5 °C from the validated window alters surface gloss and reduces weather resistance. Weathering qualification for these parts is driven by OEM schedules, commonly 1500–2500 kJ/m² under ISO 4892-2:2013 or SAE J2527, with a moulded-in-colour black part expected to remain below ΔE 2.5 after the specified exposure. Unpainted ASA has lower scratch resistance than coated ABS/PC, so these parts are restricted to close-out components that are not subject to fingernail or car-wash brush contact unless a clear hard-coat is approved. Terminal parts include cowl vent grilles, B-pillar covers, and non-Class-A mirror housings.

How Does a Multi-Port Telecom Enclosure Shift the Processing Window?

The primary constraint in moulding a multi-port telecom enclosure from LI968W is not flow length but boss cooling and weather-seal flatness. Mould temperature should be raised to 60–80 °C for parts with 2.5–3.5 mm nominal walls, because the high-flow grade tends to swell at the gate and requires extended holding time to condense melt in thick bosses adjacent to cable entry ports. Screw plasticising capacity, rather than clamp force, determines the cycle on a 300–450 t press when shot volume exceeds 900 cm³. Venting depth at end of fill must be controlled between 0.015 mm and 0.025 mm to prevent burn streaks on ribs, while a draft allowance of 0.5–1.0° is specified on split-line bosses to maintain seal gland flatness after ejection. Gate placement should be off-centre on an internal wall, with fan gate thickness 0.8–1.2 mm, to avoid visible gate blush on the exterior surface. Outdoor exposure compliance is assessed through UL 746C UV resistance and UL 94 HB flammability; telecom installers may additionally require glow-wire ignition resistance according to IEC 60695-2-11 at 650 °C. Post-moulding shrinkage is measured per ISO 294-4 after 48 h at 23 ± 2 °C, with a target of 0.4–0.7 % in flow direction. Ejection difficulties occur because seal gland ribs with 0.5° draft create vacuum drag on the moving half; delayed ejection start of 0.2–0.5 s and low-friction core coating reduce the need for mould release. This grade is unsuitable for load-bearing underground vaults or structural brackets because it is unfilled; glass-filled ASA is specified where flexural modulus above 4500 MPa is required. Terminal parts include outdoor DSL/fiber distribution enclosure bodies, splice trays, and non-pressure-rated terminal covers.

Roof Vent Base and Flashing Collar Moulding in Weatherable ASA

Injection moulding of a dark grey roof vent base and companion flashing collar from LI968W is selected when the component must survive roof-level UV exposure without painting. The vent base is a thin-plate component with multiple angled ribs and a raised collar, so a hot runner valve gate system is preferred over conventional edge gates to prevent weld lines at the collar base. Melt temperature is held between 235 °C and 255 °C; for dark grey natural compounds the lower half of this range is preferred because residence-time yellowing becomes visible after 8–10 min at 260 °C. Mould temperature is controlled at 45–60 °C to keep the textured roof-facing surface dull enough to hide minor sink marks. The drying hopper must be dedicated or purged to avoid contamination from PA or POM pellets, which form visible black specks in light grey flashing collars. Weathering acceptance for roof accessories is based on ISO 4892-2:2013 with xenon-arc radiation filtered at 340 nm; the material must exhibit no chalking before 3000 h of artificial weathering and no cracking after 1000 h of xenon exposure. Flashing collars are checked for impact after ageing by ISO 179-1/1eA, with a practical minimum of 10 kJ/m² after 2000 h of accelerated weathering. The unfilled flexural modulus measured per ISO 178 is below 2500 MPa, so the grade is limited to non-structural roof trim, vent bases, flashing collars, and pipe flashing covers; it is not suited for load-bearing roof staddle blocks or structural glazing profiles. Published data for LI968W in dark grey roof vent geometries are limited, so the first tool trial should include a full dimensional recheck after 24 h at 55 °C.

When a moulded-in-colour garden vacuum blower housing is converted from painted HIPS to ASA LI968W, the critical change is gate-freeze control in deep-draw areas around the motor mount bosses. The housing is normally moulded in a two-plate tool with a hot runner and valve gates; processing temperatures must stay within 240–260 °C, but the nozzle temperature should not exceed 260 °C to avoid splay from overheated regrind. Mould temperature of 50–70 °C improves impact strength at the boss holes where self-tapping screws are inserted without brass fittings. Thread-forming torque from PA or PC/ABS housings is not directly transferable; ASA LI968W requires lower peak installation torque of 1.2–1.8 N·m for M3 thread-forming screws to avoid radial cracking. The moulded parts are assessed for double-insulated creepage distances under IEC 60335-1 and external impact per IEC 60068-2-75 at 0.5 J. Colour retention is tested using ASTM G154 cycle 1 for 500 h, after which the orange housing must show ΔE not greater than 3.0. Practical regrind level is limited to 20 wt% because virgin-plus-regrind mixtures produce measurable reduction in notched impact after three heat histories. The terminal part is an outdoor garden vacuum/blower housing, where moulded-in-colour ASA eliminates the paint adhesion failure seen on HIPS at the seam lines and screw bosses.

Dimensional Stability Window in RV Exterior Trim Components

Long-term edgewise expansion in a black ASA RV window bezel is controlled by the interaction of orientation, tool shrinkage, and post-moulding moisture regain. LI968W is moulded at 240–260 °C with a mould temperature of 50–70 °C for a grained bezel wall of 2.5 mm; flow-direction orientation is minimised by lowering injection speed to 25–50 mm/s and extending hold time until gate freeze. Shrinkage after 48 h at 23 °C under ISO 294-4 typically falls between 0.4 % and 0.7 %; post-moulding dimensional change across a 600 mm bezel should be limited to 1.5 mm for fit onto the aluminium frame. Accelerated weathering to trigger chalking and gloss loss is run under ISO 4892-3 with wet/dry cycles for 2000 h; the black bezel must retain at least 70 % of original 60° gloss. For cold impact performance, notched Izod at -30 °C per ISO 180/1A should be above 8 kJ/m²; published data for LI968W at this exact temperature may be limited, so end-use testing is required before specifying in unheated Northern European winters. The unfilled grade is not recommended for parts with continuous tensile stress from metal fastening clips because creep at 60 °C exceeds that of glass-filled ASA. Terminal parts include exterior window bezels, luggage compartment door surrounds, and air-conditioner shroud panels.