CHIMEI (Chi Mei) ABS D-1000 is an acrylonitrile–butadiene–styrene injection-moulding grade supplied by Chi Mei Corporation. The formulation is positioned as a general-purpose ABS with a melt flow balance between high-flow grades and high-impact grades. It is specified for injection-moulded enclosures, appliance components, electrical accessories, and automotive interior parts where the service temperature remains below the upper deflection boundary of the unreinforced ABS matrix. The grade is not a flame-retardant compound, not a plating-grade ABS, and not an extrusion-grade material.

Product documentation for D-1000 refers to the material under the commercial designation “ABS D-1000.” Typical mechanical, thermal, and rheological data are reported according to ISO and ASTM methods. Because ABS is a two-phase polymer system, the values measured on dry-as-moulded specimens reflect a combination of the styrene-acrylonitrile matrix and the dispersed polybutadiene rubber phase. Changes in rubber particle size distribution, SAN molecular weight, and additive package shift the balance between melt flow and notched impact.

What limits the processing window for CHIMEI ABS D-1000?

Moisture removal is the first processing limitation. Virgin D-1000 pellets are supplied in sealed bags, but the resin undergoes atmospheric moisture uptake when hopper systems are left open. At ambient relative humidity above 60%, the material is pre-dried in a desiccant dryer with a dew point of -30°C or lower. A drying temperature of 80°C for 2 h to 4 h is specified for virgin material. The target residual moisture before plastication is below 0.1% by weight. Personnel monitoring moisture by Karl Fischer titration according to ISO 15512:2019 or ASTM D6869 can use this threshold as the lot-acceptance limit. Moisture above the threshold produces silver streaks, splay at the gate, and occasional surface voids in hot-runner drops operating above 240°C.

The second limitation is thermal history. Melt temperature measured at the nozzle is maintained between 220°C and 250°C. A reverse barrel profile is commonly set with the rear zone at 200°C to 230°C, the centre zone at 210°C to 240°C, and the front zone at 220°C to 250°C. Sustained melt temperatures above 260°C degrade the polybutadiene rubber phase. The visible result in natural-colour parts is yellowing; the mechanical result is a measurable reduction in notched Izod impact, frequently before tensile strength change is observed. Maximum residence time at melt temperatures above 240°C is held to 6 min in hot-runner systems. Dead spots in the manifold, poorly matched nozzle tips, and undersized sprue channels increase local hold-up and should be eliminated.

Screw recovery and injection velocity are adjusted to avoid excessive shear heating. A general-purpose screw with an L/D ratio of 20:1 to 24:1 and a compression ratio of 2.0:1 to 2.5:1 is suitable. Peripheral screw speed is kept between 0.2 m/s and 0.5 m/s. Back pressure is limited to 0.5 MPa to 1.5 MPa. For wall sections of 1.0 mm to 2.0 mm, fill times between 0.5 s and 1.5 s are typical. Gate shear rates above 50,000 s⁻¹ can cause surface blush, flow lines, and rubber particle orientation that reduces impact at weld lines. If a mould includes hot-runner needle shut-offs, valve-gate opening should be staged to avoid abrupt pressure spikes.

Mould temperature is set between 40°C and 80°C. The lower portion of this range is used when cycle-time reduction is critical; the upper portion is used for high-gloss surfaces, weld-line strength, and dimensions requiring lower moulded-in stress. The temperature difference across the cavity set should not exceed ±5°C. Variation beyond this limit generates differential shrinkage, uneven packing, and part warpage in flat panels. Clamping force is calculated from the projected area of the part and runner using a factor of 0.35 ton/cm² to 0.50 ton/cm² for this viscosity class.

The following representative values are extracted from supplier technical literature for CHIMEI ABS D-1000. They are not minimum lot specifications and are reproduced here for material selection and tool design. Values obtained under ISO and ASTM methods may differ because of specimen geometry and conditioning. Direct substitution of one standard’s result for another is not valid.

Mould shrinkage values are practical tool-design guidance and are not absolute material constants. Shrinkage is affected by wall thickness, gate freezing, pack pressure, mould temperature, and colourant loading. For unreinforced ABS of this class, shrinkage in the flow direction is generally higher than in the transverse direction. A uniform nominal wall thickness of ±0.1 mm is recommended for flat housing panels to minimise sink marks and differential cooling.

Because ABS is hygroscopic only to a limited extent, the drying thresholds above are not governed by hydrolytic decomposition in the same manner as polyamide or polyester; the issue is expansion of absorbed moisture into steam during plastication. Processors who operate hoppers in high-humidity environments above 80% relative humidity should extend drying time to 4 h and verify moisture content rather than relying on fixed dryer settings.

Tool steel selection follows standard ABS practice. P20 or high-hardness mould steels are used for high-volume tools; cavity surfaces are polished to SPI-A2 or SPI-B1 for appearance parts. A polished cavity surface improves part release and reduces micro-roughness that can act as stress concentrators. Draft angles of 0.5° to 1.0° on side walls and 2° on textured surfaces are specified. Ejector pins are positioned over large flat areas to avoid localised stress whitening; ejector area should be sufficient to keep ejection stress below the tensile yield of the material.

Gates should be located at the thickest section and sized so that gate freeze occurs after packing is complete. For 2.0 mm wall sections, a subsprue gate diameter of 0.8 mm to 1.2 mm and a land length of 0.5 mm to 1.0 mm are typical for direct gates. Tunnel gates and submarine gates require a minimum angle to avoid material hang-up. The high-viscosity tail of ABS means that insufficient gate size leads to premature gate freeze, short shots, sink marks, and high residual stress near the gate.

Vents are placed along the last area to fill and at weld-line locations. Vent depth for ABS is typically 0.02 mm to 0.04 mm, and width is increased rather than depth beyond this range. Insufficient venting causes gas burn marks at the end of fill and deposits on the cavity surface. In multi-cavity tools, the runner system is balanced; artificial runner balancing with different gate sizes changes shear heating and pack behaviour. A naturally balanced or rheologically balanced runner layout is used to hold fill imbalance below 2% across cavities.

When ABS D-1000 is Specified Instead of High-Impact or Flame-Retardant ABS Grades

Selection between D-1000 and CHIMEI PA-757 or PA-747 requires a comparison of service load, wall thickness, and tool flow length. Publicly available comparison data for the specific grade pair D-1000 and PA-757 is limited; however, the supplier’s product positioning places D-1000 as a general-purpose injection-moulding grade with medium flow and medium impact, while PA-757 is positioned as a higher-impact grade for durable components. In multi-cavity trials, D-1000 generally permits shorter filling of ribs and bosses than extrusion-oriented ABS, but the room-temperature notched Izod value is lower than that of a high-impact ABS. Components with snap-fit arms, screw bosses, or constrained metal inserts may require the higher impact grade if the design contains high moulded-in stress.

D-1000 is not a flame-retardant compound. It is rated HB under UL 94 and must not be substituted for CHIMEI PA-765 or PA-764 where a V-0 classification at 1.5 mm or 3.0 mm is required. Flame-retardant ABS grades use halogenated or phosphorus-based systems that alter melt stability, density, and heat deflection behaviour; their processing windows and mould plate corrosion characteristics differ from non-flame-retardant D-1000. Substitution without requalification would invalidate the UL yellow-card listing for the finished device.

The grade is also not formulated for electrolytic plating. Dedicated plating ABS such as CHIMEI PA-726M has a controlled rubber morphology and particle size distribution that allows acid etching of the butadiene domains and palladium-tin activation. D-1000 is not represented for this process. If electroplated parts are produced from D-1000, the peel adhesion of the metal layer is generally lower, and the reject rate from skip plating and blistering increases. Adhesion tests such as ASTM B571-18 on plated plastics are used to quantify the difference; sample plaques should be plated in the same production line before changing from a plating grade to D-1000.

For transparent ABS applications, D-1000 is not a substitute for methyl methacrylate-modified transparent ABS grades. The product is an opaque natural resin. For high-gloss appearance parts, D-1000 can be processed at the upper mould temperature range, but surface gloss is influenced by cavity polish, packing, and colour masterbatch; it is not positioned as a high-gloss grade.

Application areas reported for D-1000 include small household appliance housings, electrical enclosures, switch panels, business machine chassis, consumer electronics frames, and automotive interior trim that does not require continuous service above 85°C. In these parts, the material is processed with a melt cushion of 2 mm to 4 mm to maintain consistent pack pressure. Cavity pressure sensors are recommended for switchover; typical switchover pressure at the cavity is between 35 MPa and 50 MPa. Hold time is set until gate freeze. Premature release of hold pressure before gate freeze creates sink marks, gate blush, and higher part-to-part mass variation. On multi-cavity tools with 8 to 16 cavities, shot-to-shot cushion variation should be kept below 2 mm; larger variation shifts pack pressure and part mass.

Colour-matched variants are compounded with masterbatch addition. Loading is typically limited to 2 wt% to 3 wt% for organic pigments and can be higher for inorganic pigments if impact and flow are rechecked. High pigment loadings can act as nucleating agents, alter shrinkage, and increase the melt viscosity. The use of regrind is acceptable in many non-appearance applications at addition levels up to 20 wt%. For appearance housings, regrind is usually limited to 10 wt% because repeated heat history reduces impact and yellows the natural resin. The regrind fraction should be blended gravimetrically with virgin pellets rather than manually layered in the hopper.

Post-industrial regrind should be ground in a low-dust granulator with screen size of 6 mm to 8 mm. Fines content above 1% is removed by screening because fines melt early and degrade during plastication. Regrind use changes the bulk density of the feed and may require adjustments in screw speed and barrel zone set points. The melt flow rate of a regrind blend is measured after every 50 production hours in some high-volume operations to detect cumulative thermal degradation.

Thermal Ageing, Chemical Resistance, and Regulatory Boundaries

The long-term thermal boundary for unreinforced ABS of this class is below the heat deflection temperature measured at 1.82 MPa. Continuous air exposure above 85°C accelerates oxidative degradation of the polybutadiene phase. Impact ductility declines before tensile strength; embrittlement may occur after several hundred hours depending on part geometry and stress. For short-term excursions only, the heat deflection temperature of 88°C under 1.82 MPa and the Vicat softening temperature of 96°C under 5 kg provide reference limits for dimensional stability, not continuous service limits.

Chemical contact with ketones, esters, chlorinated hydrocarbons, and aromatic hydrocarbons is not recommended. These solvents attack the SAN matrix or cause stress cracking at moulded-in stress concentrations. Contact with plasticiser-containing PVC gaskets can also produce environmental stress cracking over time. Dilute aqueous acids and alkalis are generally tolerated at room temperature, but validation under service stress and temperature is required. Because ABS absorbs some mineral oils and vegetable oils, gasket materials that exude plasticiser should be avoided in bearing surfaces.

Regulatory documentation for D-1000 should be obtained from the supplier for each shipment. The product is represented in supplier approvals as compliant with EU RoHS 2011/65/EU as amended by (EU) 2015/863 for lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls, polybrominated diphenyl ethers, and the four specified phthalates. REACH compliance under EC 1907/2006 is subject to the current candidate list of substances of very high concern. Food-contact use under FDA 21 CFR 177.1020 and medical use under ISO 10993-5 are not automatic for this grade. A specific regulatory certificate is required before use in food-contact or body-contact applications.

The following compliance checklist matrix summarises common regulatory certifications and their typical status for non-customised CHIMEI ABS D-1000. The status column is a starting point for technical review, not a substitute for shipment-specific supplier declarations.

For moulders servicing electrical equipment, the UL 94 HB classification is a material rating only. Finished device testing according to IEC 60695-11-10 may be required to establish end-product flammability. The material rating does not transfer to a finished part if wall thickness, colourants, or regrind content differ from the rated configuration.