On a gantry-based fused granular fabrication cell fitted with a heated build chamber at 70 °C and a single-screw extruder with a hardened barrel and screw, Mitsubishi FGF CARBON-P PET-G is deposited at bead widths from 1.0 mm to 5.0 mm onto a glass-fiber-reinforced polymer build sheet for vacuum forming and pressure forming tooling. The carbon fiber loading modifies tool substrate response under clamping and plug-assist loads: dimensional movement is lower than unfilled PET-G when measured by ASTM E831-19, although the exact coefficient of thermal expansion for this specific filled grade must be taken from lot-level data rather than transferred from filament-grade carbon PET-G publications. Pre-drying in a desiccant dryer at 65 °C for 4 h to 6 h at a dew point no higher than -40 °C is required before processing; residual moisture below 0.03 % by Karl Fischer titration is a typical PET-G processing criterion, and pellets exposed to ambient air above 60 % RH for more than 30 min should be re-dried because hydrolytic degradation of the PET-G ester linkages produces splay and loss of interlayer fusion. The printed near-net blank is machined with carbide or polycrystalline diamond tooling and sealed with a two-part epoxy or polyurethane coating to close inter-bead porosity before vacuum drilling. Bead widths below 1.0 mm increase shear heating and fiber attrition, while bead widths above 5.0 mm can trap voids at undercut transitions. Toolpath strategy uses contour-first perimeters with alternating 45° raster fill to reduce curl at the tool perimeter. Post-print annealing at 65 °C for 2 h in a convection oven can reduce residual stress in thick beads, but the part must be supported because the PET-G matrix softens near its glass transition. Operational boundary: continuous tool surface temperature must remain below 60 °C; autoclave or oven cure above 65 °C causes creep and loss of pattern accuracy. Cleaning with concentrated amines or strong alkaline degreasers is incompatible with the PET-G matrix and should be avoided.

Robotic End-of-Arm Tooling Subject to High-Cycle Pick-and-Place Loads

Low part mass and moderate flexural stiffness are primary design requirements for robotic end-of-arm components operating on six-axis arms with payload classes from 7 kg to 25 kg. A single-piece gripper frame printed from Mitsubishi FGF CARBON-P PET-G at a wall count of 5 to 7 perimeters consolidates vacuum channel routing, locating dowels, and bolted interface pads into one structure, eliminating multiple aluminium plate and linear shaft components. The filled polymer exhibits a density range of 1.30 g/cm³ to 1.40 g/cm³ under ISO 1183-1:2019, relative to 2.70 g/cm³ for 6061-T6 aluminium, but flexural modulus measured by ISO 178:2019 is not equivalent to aluminium; carbon-fiber-filled PET-G grades with preserved fiber length typically fall between 3 500 MPa and 5 500 MPa, so section depth must increase where metal-equivalent stiffness is required. The extruder screw and barrel should be hardened or coated because the carbon fiber phase accelerates metal wear; screw speed and throughput are normally run at 60 % to 80 % of unfilled PET-G settings to limit melt-pressure spikes and fiber length reduction. Machining and assembly require brass heat-set threaded inserts; hole undersizing due to fiber-filled melt elasticity can be controlled by using 0.2 mm to 0.5 mm larger pilot bores after measuring the thermal insertion bore collapse on the specific FGF cell. The limiting mechanical property is interlayer tensile strength: Z-orientation ultimate tensile strength for FGF-processed carbon PET-G has been observed at 40 % to 60 % of XY ultimate tensile strength when assessed by ISO 527-2:2012 Type 1B specimens, requiring compressive fastening paths and avoiding direct out-of-plane pull at gripper jaws. Surface resistivity must be characterised by ASTM D257-14 before use around unshielded electronics because carbon fiber orientation creates non-uniform dissipative paths along the print direction, and grounding continuity cannot be assumed from bulk resistivity alone.

The following characterisation envelope is collected from publicly reported 15 wt% carbon-fiber-filled PET-G FGF materials and is provided for preliminary design comparison only; lot-level values for Mitsubishi FGF CARBON-P PET-G must be taken from the supplier technical datasheet.

What Happens When Carbon-Filled PET-G Replaces Aluminium in Foundry Pattern Construction?

Foundry pattern shops using sand casting and no-bake core processing can use FGF-printed carbon-filled PET-G for split patterns, core boxes, and match plates when machining stock is added at 2 mm to 4 mm per surface and finishing is carried out with carbide or diamond-coated tooling under local exhaust ventilation because carbon fiber machining dust is conductive and abrasive. Moisture absorption is lower than wood and unfilled PET-G; 24 h water immersion by ASTM D570-98 generally remains below 0.50 %, which reduces hygroscopic dimensional movement in shops without full humidity control. Surface hardness measured by ISO 868:2003 is higher than unfilled PET-G, but the carbon fiber phase is abrasive to sand and core binders; high-wear edges should be fitted with replaceable steel wear strips rather than relying on the polymer surface alone. The main process conflict is chemical: cold-box sand binders contain tertiary amines such as dimethylethylamine and triethylamine, and concentrated amine exposure can cause environmental stress cracking in PET-G; compatibility tests with production binder formulations are required before pattern shop deployment. Heat exposure must remain below 60 °C because hot-box pattern surfaces that retain sand core heat above this threshold soften the amorphous matrix and create dimensional drift. Dimensional control should follow ISO 8062:2013 for casting tolerances, with the printed tooling itself inspected after machining at 20 °C to 23 °C on a coordinate measuring machine to separate thermal growth from machining error.

Short-run automotive prototype programs require bracket geometries that are machined, inspected, and fitted within 48 h, eliminating the lead time for injection moulded ABS or glass-filled PP tools. Pellet-fed FGF cells loaded with carbon-filled PET-G produce cabin and chassis-adjacent brackets at wall thicknesses from 3 mm to 8 mm, with integrated clip bosses and threaded brass or steel inserts. The printed material must not be used for continuous service above 60 °C or short-term exposure above 75 °C; solar-soaked interior surfaces can approach this threshold, so parts should be located away from windshield and rear package tray dead zones unless the specific HDT is verified by ASTM D648-18. Fiber orientation along the bead path means tensile modulus is anisotropic; finite-element material cards should use orthotropic properties derived from XY and Z specimens rather than a single datasheet modulus. Surface finishing requires sanding from 180 to 320 grit before primer because the carbon fiber raises surface roughness and interrupts paint film adhesion; low-bake primers below 60 °C are preferred. Insert pull-out validation should be conducted with the actual fastener torque sequence, and the interlayer shear plane must not be loaded in tension; clamped joints should orient the bolt axis along the printed Z direction only when a through-bolt and metal backing washer are used. Vibration resistance and creep under clamp load can be monitored by ISO 527-2:2012 tensile creep tests at the expected cabin temperature, but published data for this specific configuration is limited and should be supplemented with prototype-level validation.

When Industrial Machine Guards Require Integrated Cable Routing and Impact Resistance

Single-piece machine guarding panels produced by FGF from carbon-filled PET-G can replace segmented polycarbonate or sheet-metal assemblies where the panel span exceeds what unfilled PET-G can hold flat within a 5 mm flatness tolerance per metre, as verified on a granite-bed coordinate measuring machine. The carbon fiber raises flexural modulus and reduces creep, but the Charpy unnotched impact energy measured by ISO 179-1/1eU is lower than unfilled PET-G, meaning that high-speed chip impact from machining centres must be validated with production tooling geometry and not inferred from slow flexural data. Flammability classification of this grade is not automatically equivalent to a V-0 or 5VA enclosure material; unfilled PET-G typically carries UL 94 HB, and carbon-filled variants must be tested before use as electrical guard panels. Cutting fluid and light mineral oil resistance is acceptable for limit-switch enclosures and splash shields, while chlorinated solvents, esters, and ketones cause stress cracking in the PET-G matrix. FGF inter-bead porosity must be sealed with a solvent-borne two-part polyurethane topcoat if the guard is exposed to flood coolant, because capillary wicking into the carbon-filled beads can carry oil into unsealed pockets. Grounding and surface-resistance measurements should follow IEC 60093 and ASTM D257-14 before installation around live busbar; carbon fiber can create conductive paths along the print direction even when the surface appears polymer-rich. Impact loading should be assessed under ANSI B11.19-2019 safeguarding performance criteria when the guard is located within the designated danger zone. EU RoHS Directive 2011/65/EU and REACH Regulation (EC) No 1907/2006 declarations should be requested from the supplier for electrical/electronic guard applications because carbon-filled PET-G is not automatically exempt from restricted substance limits.

When qualifying FGF-printed carbon-filled PET-G components against industrial or electrical safety requirements, the following verification matrix should replace generic datasheet comparisons.

Where Interlayer Adhesion Limits Thin-Walled UAV Arm Performance

Non-certified UAV prototype frames, arm tubes, sensor mounts, and launch fixtures printed from carbon-filled PET-G are processed with wall thicknesses from 2 mm to 4 mm and print direction aligned along the primary bending span. The bending modulus in the XY plane is higher than unfilled PET-G, but the interlayer tensile strength remains the critical design value; Z-direction tensile strength by ISO 527-2:2012 Type 1B specimens should be assumed no higher than 65 % of the XY value unless milled from a solid printed block and tested. Thin walls below 2 mm reduce fiber alignment consistency at the bead boundary and increase the probability of inter-bead voids under bending; a minimum safety factor of 3.0 on Z ultimate tensile strength is applied when the load path crosses layer boundaries. For rotor-induced vibration, dynamic mechanical analysis by ISO 6721-1:2019 is required to characterise the storage modulus and loss factor; carbon fiber raises modulus but can reduce damping relative to unfilled PET-G, altering resonance behaviour near motor harmonics. Extended outdoor UV exposure embrittles the PET-G matrix even with carbon black present; UV protective coatings should be qualified by ISO 4892-2:2013 accelerated weathering rather than assumed from fiber loading alone. Launch fixtures subject to sliding wear can exploit the carbon fiber phase for improved abrasion resistance, but dry sliding without replaceable inserts eventually produces fiber pull-out and rough surfaces that increase friction and dimensional variability. The material is not qualified as a primary airframe material under FAA or EASA airworthiness requirements and should not be substituted into type-certified structure without a full qualification programme.