Dongguan Hailong Plastic supplies a pre-compounded acrylonitrile-butadiene-styrene compound containing 30% by mass short-glass fibre. The material is typically designated ABS-GF30; sales documentation may append a plant-specific product code. The product is pelletised for injection moulding and extrusion. Because the glass-fibre mass fraction is fixed at 30%, the compound sits between lower-glass ABS grades and higher-modulus engineering polymers in rigid housings, brackets, and supports. No public grade code is specified here; lot-specific certificates of analysis should be requested for exact melt-flow and mechanical values. Density measured according to ISO 1183-1 is typically reported in the range 1.27–1.30 g/cm³ for conditioned samples at 23 °C and 50% relative humidity, which is materially higher than unfilled ABS at 1.04–1.06 g/cm³. This density increase is the first design consequence: wall sections designed for unfilled ABS become heavier. The glass phase also changes mould filling behaviour, weld-line strength, and warpage, each of which is addressed in the following sections.

Which property shifts occur at 30% glass fibre loading compared with unreinforced ABS?

Mechanical data reported for comparable 30% glass fibre–reinforced ABS compounds under ISO 527-1/2 indicate tensile stress at break in the range 70–85 MPa, compared with 35–45 MPa for unfilled ABS. Flexural modulus determined under ISO 178 is commonly 5,800–6,800 MPa, roughly 2.3–3.0 times the unfilled value. Heat deflection temperature under ISO 75-2/A at 1.8 MPa rises to approximately 95–105 °C, while unfilled ABS typically remains near 85–95 °C. Notched Charpy impact strength under ISO 179-1/1eA typically declines to 7–12 kJ/m², confirming that fibres increase stiffness at the expense of crack-initiation resistance. Published data for the Dongguan Hailong specific formulation is limited; these numeric ranges should be verified against the supplier certificate before load-bearing design.

The property shift is not isotropic. Fibre alignment in the moulding direction raises tensile modulus along flow while transverse tensile values remain lower. Designers must therefore request mechanical data from plaques with a defined gate location, not isotropic test coupons. In a side-gated plaque, the ratio of flow-direction to transverse-direction tensile modulus can exceed 1.3, depending on part thickness, filling speed, and packing pressure. This anisotropy is a critical difference from unfilled ABS and from mineral-filled ABS, where particle aspect ratios are lower and shrinkage is more uniform.

Pre-drying is mandatory prior to injection moulding. The glass sizing and the styrene-acrylonitrile matrix absorb atmospheric moisture; processing at residual moisture above approximately 0.05% produces splay, surface streaks, and reduced impact. Desiccant drying at 80 °C for 3–4 h with a dew point of −40 °C to −20 °C is the standard vendor recommendation for glass-filled ABS. If material has been stored in open containers at relative humidity above 60%, drying time should be extended to 4–6 h and residual moisture checked by Karl Fischer titration in accordance with ISO 15512. Hopper capacity should not exceed 2 h of machine throughput when ambient humidity is high, because re-moistening of dried granules occurs rapidly.

Melt temperature settings for unfilled ABS are typically 220–250 °C. For 30% glass fibre ABS, the higher viscosity and lower thermal conductivity of the melt require a flatter or slightly ascending barrel profile in which the rear zone remains at 220–230 °C, the centre zone at 230–240 °C, the front zone at 240–250 °C, and the nozzle at 250–260 °C. Mould surface temperature should be maintained at 60–90 °C. Injection pressures of 80–120 MPa and moderate screw speeds of 50–100 rpm preserve fibre length. Residence time above 260 °C should be held below 5 min; the polybutadiene phase degrades through crosslinking and oxidation under prolonged thermal exposure, with visible darkening and odour generation.

When GF30 ABS replaces unreinforced ABS in load-bearing enclosures, what processing constraints appear?

Injection moulding of 30% glass-filled ABS in high-cavitation tools forces attention to gate geometry and pressure drop. The compound exhibits shear-thinning behaviour, but its viscosity remains higher than unfilled ABS; spiral-flow lengths at a nominal 2 mm wall thickness are reduced by approximately 20–35% relative to unfilled ABS at the same barrel temperature. Gates below 1.5 mm diameter or edge gates below 1.0 mm thickness can fracture fibres and increase pressure drop beyond 30% of the machine injection-pressure limit. When thin-wall sections below 2 mm are required, a sequential valve-gated hot runner or multiple direct gates are generally necessary to avoid short shots.

Hot-runner processing introduces additional thermal exposure. Manifold temperatures should not exceed 260 °C, and the hot-runner channels should be sized for shear rates below approximately 30,000 s⁻¹ to limit fibre attrition and frictional heating. In production-scale tools, check-ring wear accelerates because glass fibres become trapped in the non-return valve during screw recovery. Standard nitrided screws show measurable wear after several thousand cycles; bimetallic barrels, hardened screw tips, and ceramic or hardened check rings are recommended. The exact wear interval is application-specific, but published data for this glass-fibre grade in the same equipment configuration is limited; moulders should trend cushion position and back-pressure stability to detect valve leakage.

Shrinkage anisotropy is more pronounced in 30% glass fibre ABS than in unfilled ABS and is a primary cause of warpage in flat rectangular parts. Mould shrinkage measured after 48 h at 23 °C and 50% relative humidity on 60 mm × 60 mm × 2 mm plaques according to ISO 294-4 is typically reported in the range 0.10–0.25% in the flow direction and 0.30–0.55% transverse to flow. Because the semi-major axis of glass fibres aligns with the filling direction, the polymer matrix is mechanically constrained along flow; transverse contraction is less constrained and produces greater shrinkage. In a centre-gated rectangular enclosure, this mismatch creates concave or convex distortion depending on fibre orientation gradients through the cross-section.

The distortion is not correctable by packing pressure alone when the gate freezes before the cavity is fully packed. Packing pressure should be raised to 60–80% of injection pressure for the first 2–4 s after fill, with pack time set by gate freeze-off determined using short-shot and weight-stability trials. Fibre orientation can be altered by increasing mould temperature toward 90 °C, reducing fill velocity, or moving the gate to change the flow pattern. Compared with 20% glass fibre ABS, the 30% grade provides a higher modulus but often shows greater differential shrinkage and lower weld-line strength; this trade-off should guide material substitution decisions.

Fibre length distribution is a second composition variable that separates high-performance GF30 compounds from lower-cost variants. In a properly compounded short-glass ABS, the number-average fibre length in the pellet is commonly 250–450 µm after twin-screw extrusion; aggressive screw speeds, high back pressure, or narrow gates push the moulded-part fibre length below 150 µm, at which point tensile modulus and heat deflection fall measurably. Users should request a fibre length distribution from the compounder if the part is load-bearing at elevated temperature. Published data for the Dongguan Hailong grade in this specific configuration is limited.

Comparative mechanical ranges across unfilled ABS, ABS GF20, and ABS GF30

Indicative ranges are compiled from public technical literature for general-purpose injection-moulding grades; Dongguan Hailong lot-specific values may differ and must be confirmed before design freeze. Test specimens are conditioned at 23 °C and 50% relative humidity.

The table isolates the property cliff-edge between 20% and 30% glass loading: modulus rises by roughly 1,500–2,000 MPa, while notched impact drops by approximately 3–6 kJ/m². This trade-off is a principal differentiator from ABS-GF20 and from talc-filled ABS. Compared with a 30% mineral-filled ABS, the glass-fibre version shows higher tensile strength but greater anisotropy; compared with PC/ABS GF30, the ABS matrix offers lower heat resistance and lower multi-axial impact but is generally easier to mould at barrel temperatures 30–50 °C lower.

Chemical resistance boundaries are set by the styrene-acrylonitrile matrix, not by the glass fibre. The compound tolerates dilute aqueous acids, many aliphatic hydrocarbons, and some vegetable oils at room temperature, but it is not suitable for continuous contact with ketones, esters, aromatic hydrocarbons, or concentrated oxidising acids. Stress-crack resistance under load is lower than unfilled ABS because the fibre ends act as local stress concentrators in the presence of solvents. For applications requiring repeated exposure to brake fluid, chlorinated solvents, or fuel blends, published data for this specific configuration is limited, and immersion testing under ISO 22088-2 or ASTM D543-21 is required. Regulatory compliance for general-purpose glass-filled ABS typically rests on REACH Regulation (EC) No 1907/2006 and RoHS Directive 2011/65/EU Annex II; flame-retardant variants, if any, require additional screening for restricted substances. Users should request a supplier declaration for each production lot because glass sizing chemistry is often proprietary and may contain silane coupling agents not visible on a generic safety data sheet.

Rigid load-bearing parts with moderately elevated continuous service temperatures are the primary use window for this compound. In practice, the material is specified for electrical enclosures, appliance support frames, pump bases, HVAC brackets, and industrial housings where deflection under load must stay below approximately 0.5% strain at service temperatures up to 80–90 °C. The product is less suitable for aesthetic exterior surfaces because glass fibres produce visible surface bloom and lower gloss; texturing or post-mould painting is usually required. These application boundaries are based on typical 30% glass-filled ABS performance and should not replace part-specific validation under ISO 16750 or end-use mechanical test protocols.