How to Print PAHT-CF (PPA-CF) Filament: Settings, Drying and Annealing

To print QIDI PAHT-CF, dry the spool at 80–100 °C for 4–6 hours, print at a 300–320 °C nozzle and a glued 70–90 °C bed with the part cooling fan off, use a hardened steel or tungsten carbide nozzle of 0.4 mm or larger, and feed it from a sealed dry box rather than the QIDI Box. Anneal parts that need heat resistance: QIDI's data sheet shows heat deflection rising from 84.8 °C to 190.7 °C at 0.45 MPa after annealing.

What Is PAHT-CF Filament?

PAHT-CF is a high-temperature polyamide (nylon) filament reinforced with chopped carbon fiber; QIDI's version uses a semi-aromatic polyamide base with 15% chopped carbon fiber. The name reads as "polyamide, high temperature", which matches how QIDI's technical data sheet (TDS, revised 02.2025) describes it. Ordinary polyamides such as PA6 are aliphatic. A semi-aromatic polyamide puts rigid aromatic rings into the chain, which raises heat resistance and lowers water uptake. QIDI states that the base absorbs about one tenth of the moisture that ordinary PA6 does at saturation.

QIDI PAHT-CF ($62.99 per spool) is aimed at functional parts: gears, jigs, brackets and anything that rubs. QIDI's TDS highlights a low coefficient of friction and self-lubricating behaviour for wear parts, and the product page adds chemical and heat resistance. It is a stiff, low-elongation material: 1.92% elongation at break in the X-Y plane before annealing.

Is PAHT-CF the Same as PPA-CF?

At QIDI, yes: "PAHT-CF" and "PPA-CF" are two names for one product. QIDI sells it as "PAHT-CF (PPA-CF) Filament", files it under the PPA family on its filament comparison page, and the product page describes the base as "QIDI UltraPA (PPA), high-temperature nylon". Polyphthalamide (PPA) is a family of semi-aromatic polyamides, which is consistent with the TDS wording. Other brands may use either label for different formulations, so compare data sheets rather than names.

Do not confuse it with UltraPA-CF25. That is a separate QIDI product with 25% carbon fibre, a 300–340 °C nozzle range and its own settings; see how to print UltraPA-CF25.

PAHT-CF Properties: Unannealed vs Annealed

Annealing is what moves PAHT-CF from an 84.8 °C material to a 190.7 °C material at 0.45 MPa, so any heat figure you quote must say whether the part was annealed. QIDI's TDS tests three conditions: as printed, annealed (100 °C for 8 hours), and annealed then saturated with moisture. Specimens were printed at 320 °C nozzle, 80 °C bed, 45 mm/s, 100% infill at ±45°.

Other TDS values: density 1.20 g/cm³, saturated water absorption 1.37% (ISO 62 Method 1), melting point 237 °C (ISO 11357), melt index 3.4 g/10 min at 300 °C / 2.16 kg.

Three conditions follow from that table. First, the often-quoted "194 °C" is the annealed, moisture-saturated value at the light 0.45 MPa load. At 1.80 MPa, the annealed figure is 117.5 °C. Heat deflection temperature is always tied to a load. Second, annealing is a trade: stiffness and heat resistance go up, but notched Charpy impact strength drops from 10.37 to 5.62 kJ/m². For a part that takes shocks, you may be better off not annealing. Third, Z-axis tensile strength is 51.03 MPa, about 55% of the X-Y value, so orient load paths along the layers.

What Print Settings Does PAHT-CF Need?

Print PAHT-CF at 300–320 °C with a 70–90 °C bed, the cooling fan off and 30–120 mm/s. The TDS and product page agree on the core numbers; the TDS adds retraction and raft values.

QIDI's engineering materials guide adds three habits. Clean the nozzle at 280 °C before loading a fibre-filled material. Keep speed to roughly 100 mm/s on 0.4–0.6 mm nozzles if clogging appears. When printing many small parts, print them one object at a time so each layer does not over-cool before the next one arrives.

What Hardware Does PAHT-CF Need, and Which QIDI Printer Fits?

PAHT-CF needs a hotend that holds 320 °C, a nozzle of hardened steel or harder, an enclosure, and a feed path that does not run through PTFE tubes from a multi-colour unit.

• Nozzle: QIDI recommends hardened steel, bimetal or tungsten carbide bimetal, 0.4 / 0.6 / 0.8 mm. Brass, copper-plated and 0.2 mm bimetal nozzles are listed as not recommended.
• Build plate: QIDI Cool Plate Pro, PEI, HF or Smooth PEI plate, with glue stick or 3D LAC spray. The PC plate is not recommended.
• Feeding: QIDI lists the QIDI Box, AMS and other multi-colour systems that feed through PTFE tubes as not recommended for PAHT-CF. Feed it from an external spool holder or a sealed dry box instead.

Every current QIDI printer covers the nozzle side: the Q2C, Q2 and Max4 product pages each list a bimetal hardened steel nozzle and a 370 °C hotend, and the Plus 5 also has a 370 °C bimetal nozzle. All four beds reach 120 °C. The difference is the chamber, and here QIDI's guidance is narrower than many people assume. The comparison chart marks PAHT-CF as needing a closed chamber, and QIDI publishes no chamber temperature for it.

• Q2C ($349, 270 × 270 × 256 mm): enclosed and flame-retardant, with no chamber heater. It meets every requirement QIDI lists for PAHT-CF and is the lowest-cost way in for small and medium parts.
• Q2 ($499), Plus 5 ($749, 320 × 320 × 300 mm), Max4 ($1,049, 390 × 390 × 340 mm): add 65 °C active chamber heating. QIDI does not require it for PAHT-CF, but it is the next lever if large flat parts lift or tall walls crack on an unheated machine. Polyamides shrink as they cool, which is why chamber heating helps prevent cracks in nylon parts.

How Do You Dry and Store PAHT-CF?

Dry PAHT-CF at 80–100 °C for 4–6 hours in a blast drying oven, then keep it sealed below 15% RH while printing. QIDI's TDS is blunt: nylon absorbs moisture easily, and damp PAHT-CF strings, extrudes with bubbles and prints a rough surface. The same 80–100 °C, 4–6 hour cycle is how the TDS says to recover a spool that has already absorbed moisture.

• QIDI's wiki gives a slower alternative for engineering materials including PAHT-CF: 80 °C for at least 8 hours in an oven. If you use the printer's heated bed as a dryer, allow at least 10 hours at 90 °C.
• Because PAHT-CF should not go through the QIDI Box, the QIDI filament dryer box ($39) is the practical feed option. It is a sealed box used with desiccant, so it keeps a dried spool dry during the print but does not heat it.
• Return unused filament to its vacuum aluminium foil bag. QIDI measured 0.014% water vapour transmission for that packaging, against 4.76% for ordinary sealed packaging.

Moisture also matters after printing. QIDI's wiki notes that PA parts used in humid air or water gradually lose some strength and stiffness and become tougher, especially thin, slender parts. The TDS numbers for annealed-then-saturated specimens show PAHT-CF holding 94.51 MPa tensile strength. For the underlying method, see how to dry filament for 3D printing.

How Do You Anneal PAHT-CF?

Anneal PAHT-CF at 80–100 °C for 4–8 hours (TDS; the product page says 4–6 hours), then let it cool to room temperature naturally. The TDS property data uses 100 °C for 8 hours, the top of that window. QIDI's wiki estimates that annealing reinforced engineering filaments at about 80 °C for 8 hours improves overall mechanical properties by 10–20%, depending on part size, infill and wall count.

• Use an oven with uniform temperature. QIDI's wiki advises against microwave ovens and household ovens for drying or annealing.
• Leave supports on during annealing, and consider a sand bath for thin features, as QIDI's annealing guide suggests.
• Switch the oven off at the end and let parts cool inside it.
• Measure a test piece before and after; annealing shrinks parts slightly.

Separately, QIDI's wiki advises removing supports from PA parts within 2 hours of printing, before they absorb moisture and soften.

Common PAHT-CF Failures and Fixes

For warping in general, see how to fix warping in 3D printing.

PAHT-CF vs PET-CF, PETG-CF and PPS-CF

PAHT-CF has the strongest layer bonding of the four at 51.03 MPa Z-axis tensile, and its heat resistance after annealing is second only to PPS-CF. Figures are from QIDI's filament comparison chart; its heat column uses 0.45 MPa and shows PAHT-CF's annealed value.

• Choose PAHT-CF for gears, bushings, clips and brackets where layer strength and wear resistance decide, and where you can anneal for heat.
• Choose PET-CF if the part must hold shape in warm, humid conditions without annealing: 105.2 °C HDT at 1.8 MPa, 0.53% water absorption, QIDI Box compatible. See the PET-CF printing guide.
• Choose PETG-CF for stiff parts that stay well below 77 °C.
• Choose PPS-CF for sustained heat above 200 °C or chemical exposure; see how to print PPS-CF.

For the wider picture, read the carbon fiber filament guide and the nylon 3D printing guide, or browse QIDI's high-performance filaments.

PAHT-CF Frequently Asked Questions

What temperature should I print PAHT-CF at?

300–320 °C on the nozzle and 70–90 °C on a glued bed, per QIDI's TDS and product page. QIDI's own test specimens were printed at 320 °C nozzle and 80 °C bed.

What is the heat deflection temperature of PAHT-CF?

It depends on annealing and load. Unannealed, it is 84.8 °C at 0.45 MPa and 82.0 °C at 1.80 MPa. Annealed at 100 °C for 8 hours, it is 190.7 °C at 0.45 MPa and 117.5 °C at 1.80 MPa.

Does PAHT-CF need a heated chamber?

QIDI lists an enclosure as required but publishes no chamber temperature. An enclosed printer such as the Q2C meets that. A 65 °C heated chamber on the Q2, Plus 5 or Max4 is an extra margin for large or tall parts.

Can I use PAHT-CF in the QIDI Box?

No. QIDI lists the QIDI Box, AMS and other PTFE-tube multi-colour systems as not recommended for PAHT-CF. Feed it directly from a sealed dry box.

Is PAHT-CF the same as PPA-CF?

At QIDI, yes. The product is sold as "PAHT-CF (PPA-CF)". It is not the same as UltraPA-CF25, which has 25% carbon fibre and different settings.

Should I anneal every PAHT-CF part?

Not always. Annealing lifts heat resistance and stiffness but cuts notched impact strength from 10.37 to 5.62 kJ/m². Anneal parts that see heat or constant load; think twice for parts that take shocks.