Sinopec Shanghai Gaoqiao ABS 345 is specified for instrument panel trim, centre console side panels, door handle bezels and steering column covers where thin-wall sections meet snap-fit retention requirements. The resin is processed on toggle-clamp injection moulding machines in the 1,200–3,000 kN range with screw diameters of 30–50 mm and an L/D ratio of 20:1. A shut-off nozzle is mandatory because the melt has low viscosity and can drool during carriage retraction. The melt temperature is held at 230–250°C; the mould temperature is held at 40–70°C. When the melt temperature falls below 230°C, visible flow lines appear on grained surfaces. When the melt temperature exceeds 250°C, the gate area shifts toward a yellow-white blush and residual monomer odour increases. This is the primary thermal processing window for unpainted cabin trim.

Desiccated drying is conducted at 80–90°C for 2–4 h in a bed with a dew point of −40°C or lower. Final moisture content above 0.02 wt% results in silver streaking at the flow front and a dull cloud on the textured surface. The same moisture level produces intermittent blistering behind the gate after painting. Dryer outlet moisture is interlocked with the machine control. If the dryer reaches 0.03 wt%, the hopper loader stops and the screw is pulled back automatically. In high-humidity plants where ambient relative humidity exceeds 60%, open conveyors are not permitted between the dryer and the feed throat.

Gloss variation is controlled by turbulent water cooling through the cavity plates. At a mould temperature above 70°C, sink marks deepen around the base of snap-fit ribs and the surface becomes too glossy for OEM grain specifications. At a mould temperature below 40°C, the grained surface loses texture transfer and the gate region can delaminate during demoulding. Closed-loop mould-temperature control within ±5°C is used for production. Cooling time is set so that the part ejects below its Vicat softening point by at least 20°C. Ejection above that limit causes ejector pin push-outs and post-mould warpage.

For cabin interior emission compliance, parts are annealed at 70–80°C for 2 h before VDA 278 testing. Annealing strips residual process volatiles and reduces total VOC output under OEM limits that commonly fall in the 50–150 µg/g band, depending on the vehicle platform. Published data for this exact grade under VDA 278 is limited; therefore each OEM program validates lot-to-lot variability on a quarterly basis. Unpainted ABS 345 is not used for high-wear visible surfaces without a grain depth of at least 0.05 mm, because smooth surfaces show whitening under a 10 N scratch stylus within the first cycle.

Does ABS 345 Survive the Glow-Wire Agenda in White Goods?

In white goods enclosure programs, ABS 345 is released for washing machine control panel frames, detergent drawer fronts, vacuum cleaner bodies and small appliance enclosure cladding that do not demand inherent flame retardancy. The base resin is not a brominated or halogen-free FR grade. Under UL 94, unfilled mouldings are evaluated as HB at a section thickness of 3.0 mm. A V-0 classification should not be inferred from the grade name; any V-0 listing belongs to a separately compounded formulation and requires revalidation on the injection line because flame-retardant packages shift melt viscosity and screw torque.

Filling analysis for a washing machine detergent drawer front with a flow path of 300–350 mm at 2.5 mm wall shows stable cavity filling at a melt temperature of 240°C and a mould temperature of 50°C. Packing pressure is maintained at 35–55 MPa hydraulic for 3–5 s to reduce sink over internal ribs. The rib height is limited to 3×nominal wall for structural bosses, and the rib root radius is kept above 0.8 mm to avoid stress concentration at the base.

Chemical contact is limited to short-term spills from detergent, bleach and fabric softener solutions. ABS is attacked by ketones, esters, aromatic hydrocarbons and some chlorinated solvents. Methyl ethyl ketone, a common solvent cement component, causes surface crazing and stress cracking if contact occurs on a stressed snap-fit hook. Therefore the gate location is moved away from snap-fit terminals, and the snap-fit deflection is designed below 2% outer fibre strain. For appliance housings that face repeated cleaning with isopropanol, validation includes a 30-minute surface wipe test with IPA under no external load. Visible whitening constitutes a reject.

Large flat panels in white goods are sensitive to flow-front speed. The recommended melt front velocity is 80–120 mm/s. Below 80 mm/s the grained surface shows hesitation lines around the edge vents. Above 120 mm/s the end of fill traps air and produces gas burn marks. In production, the converter uses a sequentially opened valve-gated hot runner to keep the melt front speed within this band. The hot runner manifold temperature is set at 230–245°C. If the manifold goes above 250°C, the material yellows at the valve gate and creates visible streaks.

Low-Smoke Pathway for Telecom Housings Without Halogen Synergists

Router lower shells, set-top box covers, power strip bases and patch panel frames are moulded from ABS 345 in ambient indoor service. The grade is not specified for outdoor radome or antenna skins, because unreinforced ABS lacks sufficient ultraviolet stability for long-term weathering. In IEC 62368-1 evaluations, the unfilled moulding is treated as a decorative or mechanical enclosure, not as a fire enclosure, unless the power source is limited by the end-product standard.

Mechanical release is checked with ASTM D638-14 for tensile yield and ASTM D256-23 for notched Izod. Typical values for unreinforced ABS fall in the 40–50 MPa tensile-yield band and 200–300 J/m notched-Izod band at 23°C. These ranges are used for initial snap-fit spring-rate calculations only. Lot-specific certificates from the supplier carry the actual values. At a wall thickness of 2.0 mm, the draft angle on bosses is kept at 1.0° minimum to reduce ejection drag and avoid stress whitening around the boss.

The moulding window is tighter than standard packaging containers because the housing must pass a drop test with the installed printed circuit board. Ribs under the board mount use a rib thickness of 0.5–0.7×wall to avoid sink marks on the outer cover. The gate is placed away from sidewall screw bosses. If a weld line crosses an impact-absorbing snap-fit, notched impact retention at the weld line can fall by 30–40% relative to un-welded material. For that reason the tool design uses multiple sub-gates with a runner balancing tolerance of ±2%.

Flammability is a threshold issue. The base ABS 345 is not a low-smoke formulation. Smoke density under ISO 5659-2 is not claimed from the base resin. If the product specification requires a halogen-free FR package with a smoke density below a given DM value, the compound is manufactured separately, and the injection moulder must requalify flow length, mould deposit and gas venting. Handlers should avoid blending with halogen-containing regrind from unknown sources, because a mixed stream can compromise the halogen-free declaration under RoHS 2011/65/EU.

In toy brick, board-game frame, storage case and child-resistant closure applications, ABS 345 is processed in multi-cavity tools with edge sub-gates and ejector sleeves. The melt temperature is 230–250°C; the mould temperature is 40–60°C. The material is dried at 80°C for 2–4 h to below 0.02 wt% moisture. Masterbatches are pre-blended at 2–4 wt%. The blend is dried again because some masterbatch carriers are hygroscopic and can raise moisture above the base resin limit.

Filling balance is critical because toy tools often use 16–64 cavities. The runner system is balanced to within ±1.5% volumetric fill using pressure drop software or short-shot study. If one cavity fills early, that cavity overpacks and the remaining cavities show sink marks. Holding pressure is set at 25–45 MPa and held for 2–4 s. A screw back pressure of 0.5–1.0 MPa is applied to improve masterbatch dispersion without overheating the melt.

Regulatory release for toy applications requires compliance with EN 71-3 for migration of certain elements and REACH Annex XVII entries covering phthalates in toys and childcare articles. ABS 345 is supplied under a declaration that the polymerization and finishing system does not contain the restricted phthalates covered by entries 51 and 52 of Annex XVII. Incoming lot certification is required because additive packages can change without notice. Published data for this specific grade’s migration output is limited; brand owners routinely run independent extraction on first production shots.

Snap-fit design uses a tensile modulus of 2.0–2.4 GPa from ASTM D638-14 for hinge spring-rate calculations. Unreinforced ABS shows ductile behaviour at room temperature. At 0°C, notched impact falls, so products rated for outdoor winter use are either impact-modified or thickness-restricted above 2.5 mm. No low-temperature impact claim is made for the base grade under ISO 180 without validation on the actual part.

When Solvent Weld Fittings Require Low Molded-In Stress

When solvent-welded ABS fittings are produced from ABS 345, moulded-in stress is the principal process risk. The part is used for injection-moulded socket fittings, adapters and small-bore fittings in drain-waste-vent systems. Dimensional requirements follow ISO 15493 or ASTM D3965, depending on the regional market. The socket taper is formed by a collapsible core or an unscrewing core. The solvent cement used on site contains methyl ethyl ketone and acetone. The ester and ketone components attack stressed areas and can produce environmental stress cracking in the socket heel.

The melt temperature is kept at 235–250°C and the mould temperature is held at 50–70°C to reduce frozen-in orientation. Packing pressure is limited to 30–45 MPa. High packing pressure creates dimensional compliance during ejection but leaves stress near the gate. When the socket is later exposed to solvent cement, the stress releases as cracks at the base of the socket. A low and controlled packing profile is preferred over high pressure, even if the mould must use a longer holding time of 5–8 s to control sink.

The gate location is placed on the spigot end, not on the socket throat, so that the melt front reaches the socket heel last. The optimal melt-front speed in the socket wall is 40–120 mm/s. Below 40 mm/s the heel freezes and creates a weak weld line at the socket bottom. Above 120 mm/s the gate area overpacks and the fitting shrinks away from the plug gauge after 24 h. Ovality on a 32 mm socket is held below 0.15 mm by cooling the core to 40°C below the cavity temperature and delaying ejection until the part reaches 80°C or lower measured at the core.

Long-term hydrostatic design is not inferred from injection moulding alone. The fitting lot is released through notched Izod, Vicat softening and solvent-cement compatibility testing. Published data for this specific grade under ISO 15493 long-term hydrostatic evaluation is limited; therefore pipeline certification is based on the fitting manufacturer’s own type tests. Regrind is restricted to 15 wt% or less in pressure-bearing fittings to preserve stress-crack resistance.

Drop-Impact Mapping Across Ribbed Luggage Shells at −20°C

For injection-moulded luggage wheel housings, telescopic handle frames, corner guards and internal stiffener frames, ABS 345 is processed with conventional water-cooled tools. Full shell thermoforming uses an extrusion-grade ABS of different molecular weight. The injection grade is selected for ribs, bosses and latch attachment points that require accurate dimensions and repetitive impact resistance. The grade is dried to 0.02 wt% moisture or lower before processing. Melt temperature is 235–250°C and mould temperature is 45–65°C.

Drop-impact mapping is performed on complete luggage after conditioning at −20°C for 4 h. The test focuses on wheel housing bosses, corner guards and the telescopic handle guide. Unreinforced ABS shows a drop in notched impact at low temperature. The transition from ductile tearing to brittle cleavage is influenced by part thickness and weld-line location. A gate weld line crossing the axle boss can reduce impact resistance by 30–40% relative to un-welded material, so the axle boss is gated separately or the weld line is shifted to the inner side of the boss.

Rib design follows a rib thickness of 0.5–0.7×wall for acceptable surface quality. The base wall is 2.2–2.5 mm in wheel housings. Gas-assisted moulding is not used with ABS 345 in these ribbed parts because surface haze appears near the gas channels and the melt viscosity is not high enough for stable gas penetration in thin sections. Sequential valve gating is preferred for long handle guides with a flow path of 400 mm or more.

The material is not weatherable. Long-term outdoor exposure causes colour shift and loss of gloss. Exposed luggage shells are therefore painted, hard-coated or covered with fabric overlays. Internal frames and wheel housings are shielded from direct sunlight and operate within the material’s service window. If the luggage specification requires impact at −30°C or lower, a separate low-temperature impact-modified grade should be evaluated, because published data for this grade under those conditions is limited.