PLA-CF and HT-PLA-GF: reading carbon and glass data

Two products, two PLA bases: this is not carbon versus glass in general

Polymaker describes PolyLite PLA-CF as carbon-reinforced PLA for functional applications and a matte finish. HT-PLA-GF's V1.1 PDF declares 12% glass fiber and improved heat resistance after annealing. Those descriptions identify two products, not an experiment changing only fiber type. Keep the full name and document version with each figure instead of assigning it to every PLA-CF or PLA-GF.

That difference in base material changes how you should read every number. When a value differs between the two sheets, it may come from the fiber, from the base polymer, or from both. Nothing in the documents lets you split those contributions. You are comparing two specific products, not carbon against glass as a category. None of this data transfers to a PLA-GF or PLA-CF from another brand.

Density already shows the formulation gap: 1.29 g/cm³ for PLA-CF and 1.337 g/cm³ for HT-PLA-GF, both measured per ISO 1183. Melt index differs as well, 9.2 g/10 min versus 22.9 g/10 min under identical test conditions. For a wider look at carbon fiber filaments on nylon or PETG bases, the dedicated guide takes over. This page stays with the PLA matrix.

Stiffness and strength: read the values with matching methods

The documents cite ISO 527 for tensile, ISO 178 for flexural and ISO 179 for notched impact. Listed preparation settings are shared: 230 °C, 50 °C bed, two shells, three top/bottom layers, 100% infill, ambient conditions and cooling on. That alone does not establish exhaustive identity of every test or conditioning step. Values are described as typical and for reference/comparison rather than design or quality-control specifications.

For XY, PLA-CF lists Young's modulus 3280.7 ±79.6 MPa, tensile strength 31.2 ±0.7 MPa and elongation 13.2 ±1.7%. Printed HT-PLA-GF lists 3793.85 ±129.17 MPa, 50.09 ±0.73 MPa and 2.77 ±0.45%. These are the formulations' figures with the ± terms as published; they isolate no superiority of glass fiber and guarantee no personal part properties.

Along Z, both materials drop sharply: 15.1 MPa for PLA-CF and 23.68 MPa for HT-PLA-GF, with under 1 percent elongation in both cases. Notched Charpy impact in X-Y is close, 5.5 kJ/m² against 5.31 kJ/m². A part loaded across its layers deserves careful orientation in the slicer no matter which filler you pick.

Heat resistance: as printed, then after annealing

For PLA-CF, the TDS lists Tg 62 °C, Vicat 64 °C and HDT 50 °C at 1.8 MPa or 54 °C at 0.45 MPa. Methods and loads belong with those numbers. This comparison supplies no unfilled PLA sheet for an identical base, so it cannot measure the carbon effect on that base or turn any figure into a service ceiling for every PLA part.

Printed HT-PLA-GF lists Tg 59.76 °C, HDT 59.7 °C at 1.8 MPa and 75.5 °C at 0.45 MPa, plus Vicat 148.9 °C. After annealing, the sheet gives HDT 84 °C and 114.7 °C at those loads and Vicat 148.3 °C. Separate these tests from the introduction: the wiki states up to 130 °C, while its linked V1.1 PDF says up to 100 °C. Choosing the larger figure does not resolve that discrepancy or establish your assembly's permissible temperature.

The HT-PLA-GF sheet lists a crystallization temperature of 81.56 °C, but these two sheets do not show that this value alone explains the other results. Read each measurement with its method, load and state (as printed or annealed); HDT, Vicat and Tg are not universal service temperatures.

Annealing and shrinkage: what the HT-PLA-GF sheet documents

HT-PLA-GF's sheet lists shrinkage of 0.05% XY, 0.05% Z and 0.10% diagonal without that table alone describing every condition of your annealing process. It also lists annealed properties including XY modulus 4206.91 MPa and XY tensile strength 50.2 MPa. For annealed impact, the PDF prints MPa while the printed-state table uses kJ/m². This inconsistency is visible in the original document, so the affected values are not compared here.

For Z tensile strength, the sheet gives 23.68 ±1.28 MPa before annealing and 22.46 ±1.54 MPa afterward. Those numbers establish neither a universal bonding improvement nor a remedy for layer defects. Keep them attached to their specimens and states instead of converting a material property into a guaranteed result on another geometry or orientation.

The V1.1 PDF lists annealing at 80–100 °C for 20–30 minutes, recommending 100 °C and 30 minutes. It notes that thin parts may need the lower temperature to limit warping. Those are this grade's settings, not a procedure for every filled PLA. For your design, record before/after state and the intended measurement method; a personal trial does not replace required mechanical or dimensional acceptance criteria.

Nozzle diameter and wear: assume nothing the sheet does not say

The 0.4 mm nozzle note accompanies printing recommendations and says they may vary with other diameters. It does not turn every property, including density, into a nozzle measurement. When changing diameter, identify the product and printer conditions rather than promising that a 0.6 mm nozzle automatically supplies higher flow.

HT-PLA-GF's V1.1 PDF does include Hardened nozzle & print annealing under additional requirements. That is absent from the web summary, showing why the linked document matters. The reviewed PLA-CF V5.4 TDS does not publish the same line; infer neither absence of wear nor compatibility with every nozzle. Follow the exact product guidance and your printer's installation instructions.

The nozzle guide helps identify your setup's components. These documents supply no temperature correction for switching nozzle materials. Keep the actual reference, diameter and settings rather than transferring a correction found for another nozzle or filament.

Print settings and drying from the PLA-CF datasheet

The PolyLite PLA-CF sheet recommends a nozzle temperature of 190 to 230 °C, a bed of 25 to 60 °C, a PC or textured PEI surface with glue when needed, cooling fan on and a speed of 50 to 300 mm/s. Retraction is listed at 1 to 3 mm and 20 to 40 mm/s. No enclosure is deemed necessary. Recommended supports are PolySupport and PolyDissolve S1.

PLA-CF drying is listed at 55 °C for six hours. The V5.4 PDF's curve uses 70% RH and 23 °C; it does not measure your spool's condition. The drying guide helps examine the setup. Do not copy that temperature to HT-PLA-GF: its V1.1 PDF gives 60 °C for six hours for that product.

HT-PLA-GF's PDF also gives 210–230 °C nozzle, 25–60 °C bed, cooling on, speed up to 350 mm/s and retraction of 1–3 mm at 20–40 mm/s. These remain that sheet's recommendations, not guaranteed print time or quality. Both documents give chemical-resistance descriptions at ambient temperature; they qualify neither a critical application, food contact nor every chemical concentration.

Sources and limits

• Polymaker Wiki — PolyLite PLA-CF technical data
• Polymaker Wiki — HT-PLA-GF technical data
• Polymaker — PolyLite PLA-CF TDS V5.4, original PDF
• Polymaker — HT-PLA-GF TDS V1.1, original PDF

We organize manufacturer and community documentation; we have not measured these products ourselves. The manual for your exact model takes precedence over general guidance.