3D Systems Fused Deposition Modeling Material ABSi is an impact-modified acrylonitrile-butadiene-styrene feedstock formulated for extrusion-based fused deposition modeling. The model designation ABSi distinguishes this grade from general-purpose ABS, flame-retardant ABS, and electrostatic-dissipative ABS compounds. The polymer backbone includes a methyl methacrylate component, producing a translucent ivory appearance and a more ductile mechanical signature than many heavily pigmented or mineral-filled ABS grades. The product is supplied as spooled cylindrical filament with machine-specific diameter and ovality tolerances; certificates of analysis normally report filament diameter, ovality, and moisture content. Dimensional mismatch between the spooled filament and the machine feed path produces feed-roller slip, a documented cause of under-extrusion and random layer void formation in production builds.

The designation “ABSi” does not correspond to a filled or flame-retardant system. The methyl methacrylate segment increases translucency and broadens the post-yield plateau in tensile response compared with standard opaque FDM ABS. Because the butadiene phase remains present, the material has an upper processing temperature limit above which surface oxidation and discoloration occur. Users should verify the exact thermal limit from the current supplier datasheet; published data for this specific configuration is limited.

Fused deposition modeling creates a layered structure, so ABSi mechanical performance is not equivalent to injection-molded ABS of the same molecular architecture. The tabulated data are orientation-specific. Coupon values are generated in the XY plane with solid raster fill; Z-direction properties are governed by interlayer diffusion and are routinely lower. Design calculations for loaded structures should therefore use characterized Z-direction data rather than the XY values reported below.

Mechanical and thermal property set for ABSi FDM extrusions

Representative values for ABSi FDM feedstock, as reported in supplier documentation, are summarized in the following table. Values are normalized to conditioned test coupons; test method designations are included for traceability.

In ABSi processing, the principal process conflict is between maintaining a chamber temperature high enough to minimize residual stress and keeping the melt temperature low enough to avoid butadiene degradation. Drying before extrusion is required when spool storage has exceeded 24 h at relative humidity above 60%. A forced-air oven set point of 80 °C for 4 h to 6 h is normally sufficient; desiccant dryers with supply dew point of −40 °C or lower are preferred for production rates. The extrusion nozzle is typically operated between 230 °C and 270 °C, and the heated build chamber is maintained at 90 °C to 110 °C. On build platforms larger than 300 mm in the shortest planar axis, a thermal soak of 30 min to 45 min after reaching chamber set point reduces edge-lift defects. If chamber temperature falls below 90 °C, differential shrinkage between solid contour perimeters and sparse interior raster produces tensile stress at the part base; this is the dominant cause of late-build corner delamination for wall sections thinner than 3 mm. Extruder current draw should be monitored as an indirect indication of melt viscosity; upward drift in current draw at constant speed often indicates moisture-induced voiding or filament diameter variation. Published data for this specific configuration is limited, but the mechanism is consistent with documented behavior of ABS-based FDM feedstocks.

How does ABSi alter failure mode under notched impact compared with ABS-M30?

The practical distinction between ABSi and ABS-M30 is not a simple strength ranking. Under ASTM D638-14, ABSi is generally reported at 6.0% elongation at break, whereas ABS-M30 is generally reported near 3%. This difference allows thin snap-fit arms and compliant tabs to deflect further before crack initiation. Notched Izod values under ASTM D256-10 are strongly influenced by raster angle, notch orientation, and feedstock lot. Supplier literature commonly reports 106 J/m for ABSi, while some ABS-M30 datasheets report up to 139 J/m. Consequently, ABSi is not automatically the higher-impact material in every orientation; its failure-mode advantage appears as ductile drawing at the crack tip rather than abrupt crack propagation. Compared with PC-ABS, ABSi has lower heat deflection temperature and lower tensile modulus, but it avoids the higher extrusion temperature and drying burden associated with polycarbonate-containing feedstocks.

When residual moisture and chamber humidity control interlayer fusion

Moisture in ABSi does more than create cosmetic surface splay. At melt temperature, absorbed water vaporizes and forms microvoids in the extruded road. These voids reduce the contact area available for molecular diffusion across adjacent roads, lowering Z-direction tensile strength below the already reduced anisotropic value. For well-dried material, Z-direction tensile strength can be 40% to 60% lower than the XY value; with residual moisture above 0.15 wt%, the loss is compounded by void coalescence. Chamber relative humidity above 50% increases cooling rate at the road surface and shortens the interdiffusion time available for interface healing. Control measures include maintaining the build chamber dew point below 10 °C, minimizing door opening sequences during long builds, and returning spools to sealed desiccant storage within 30 min after removal from the dryer. Mixing dried and undried spools on the same machine produces measurable batch-to-batch variation in interlayer adhesion; this is a frequent failure mode in multi-spool production cells.

For functional prototypes that require snap-fit closures, compliant tabs, and low-load living hinges, ABSi is specified when operating temperature remains below the heat deflection temperature at 0.455 MPa. Low-volume production of interior brackets, sensor housings, and air-duct segments has been reported on enclosed production-scale FDM equipment. The material is not recommended for continuous load-bearing service above 85 °C because the heat deflection temperature at 1.82 MPa is close to that limit and creep accelerates in amorphous ABS. Primary tensile loads should be oriented in the XY build plane. Cantilevered features built vertically exhibit lower fracture resistance and should be reinforced with gussets or repositioned. Sharp internal corners should receive a minimum radius of 0.5 mm to reduce stress concentration at the raster boundary. Validation on the target printer remains necessary because published data for this specific configuration is limited.

Support removal fluids, chemical exposure limits, and secondary finishing

ABSi is typically paired with soluble support or breakaway support depending on the machine platform. When water-soluble support is removed in an alkaline bath, the bath temperature, pH, and immersion time must remain within the support material supplier’s stated limits; prolonged immersion can soften the ABSi surface and alter surface gloss. The material is susceptible to environmental stress cracking in the presence of ketones, esters, and some aromatic hydrocarbons. Alcohol-based surface wiping should be limited to short exposure; immersion in isopropanol is not recommended for parts containing residual internal stress. Mechanical finishing by sanding, epoxy coating, or priming is feasible, but solvent vapor smoothing with aggressive solvents can remove the ductile surface layer and reduce notched impact performance. Regulatory documentation should be obtained for each lot; ABSi is generally expected to conform to RoHS Directive 2011/65/EU, and a REACH declaration under EC 1907/2006 should be retained in the technical file.

Unopened spool storage conditions follow the supplier’s shelf-life statement. Polyethylene packaging with desiccant sachets is not a substitute for active dry storage once the bag is opened. The operational boundary for indoor service is set by the combination of 85 °C heat deflection at 1.82 MPa, moisture sensitivity above 60% relative humidity, and sensitivity to polar solvent stress cracking. The product should not be specified for potable-water contact or food-contact use unless a specific regulatory grade and migration test data are available for the intended condition.