| Spec Or Behavior | PC Filament Example Values | What That Usually Means On A Printer |
|---|---|---|
| Density | 1.19 g/cm³ (23°C)[d] | Parts feel “solid” for their size; slicer weight estimates are typically close when your extrusion is calibrated. |
| Glass Transition Temperature (Tg) | 113°C (DSC, 10°C/min)[d] | Above Tg, stiffness drops fast. For heat-loaded parts, Tg matters more than “it printed at high nozzle temps.” |
| Heat Deflection Temperature | 99°C @ 1.8 MPa; 114°C @ 0.45 MPa[d] | HDT tells you how a loaded part behaves near heat. Lower load = higher apparent heat tolerance. |
| Vicat Softening | 117°C[d] | Good clue for “softening point” feel, but it’s not a direct “max service temperature.” |
| Tensile Strength (Printed) | 53.44 ± 0.60 MPa (X–Y); 41.43 ± 1.50 MPa (Z)[d] | PC can be impressively strong, but Z strength still depends on heat, dryness, and layer bonding. |
| Young’s Modulus (Printed) | 2435 ± 63 MPa (X–Y)[d] | Stiff enough for brackets, housings, mounts—without feeling brittle like some “hard” plastics. |
| Nozzle / Bed | 250–270°C nozzle; 90–105°C bed[d] | High temp flow + hot bed reduce cracking. If your hotend can’t hold stable temps, PC becomes frustrating fast. |
| Enclosure / Chamber | Closed chamber needed; ~70–100°C noted as target range[d] | PC hates cold drafts. A warm, stable “microclimate” is the difference between success and stress cracks. |
| Cooling Fan | OFF[d] | Cooling makes layers shrink unevenly, pushing warp and layer-splitting. PC usually prefers calm, warm air. |
| Drying / Annealing (Example) | 75°C for 6h drying; 90°C for 2h annealing[d] | Dry filament = smoother surface, fewer bubbles, stronger layers. Annealing can calm internal stress in some setups. |
Numbers above are from one published PC-filament datasheet and are meant for reference, not as a universal guarantee. Different “PC” spools can behave very differently depending on additives, blends, and how they’re tested.
Polycarbonate (PC) filament is where FFF printing starts feeling like real engineering plastic. Not because it’s mysterious—because it’s picky. When PC is dry, warm, and printed with steady heat, you get parts that feel dense, tough, and reliable. When the environment is cold or the filament is damp, PC can respond with warp, stress whitening, and cracks that show up like they were waiting for the worst moment.
- High Heat Use
- Toughness
- Layer Bond Potential
- Moisture Sensitive
- Enclosure Friendly
PC Performance Feel Typical
Table of Contents
🧩 What Polycarbonate Filament Is
Polycarbonate is a family of thermoplastics known for impact resistance, solid stiffness, and strong performance in warm environments. Industrial polycarbonate resins can have a glass transition temperature (Tg) up to 148°C[a], which is one reason PC is used in demanding applications beyond 3D printing.
In filament form, “PC” is not always a single, pure formulation. Many spools are engineered polycarbonate blends designed to reduce warping and improve adhesion, and that can shift Tg, HDT, and the exact feel of the final part. One published PC-filament spec shows Tg around 113°C[d], which is still high for many functional parts, but clearly different from “maximum resin Tg” claims.
PC on a label often means “polycarbonate-based,” not “laboratory-grade pure PC.” That’s usually a good thing for printing consistency—just treat each brand like its own material family.
🧠 Why PC Parts Can Feel Extremely Strong
PC’s “strength vibe” comes from how it combines stiffness and toughness. A well-printed PC part can resist bending while still handling impacts without shattering. In printed test specimens, published PC-filament data shows tensile strength around 53 MPa (X–Y) with a modulus around 2.4 GPa[d]. That combo is why PC is popular for brackets, mounts, and covers that get bumped, flexed, or warmed.
- Layer bonding potential: PC can fuse layers strongly when temperature, chamber warmth, and dryness are stable.
- Ductile behavior: instead of snapping, PC often yields and absorbs energy, especially compared to more brittle plastics.
- Stress visibility: PC can show whitening or micro-cracks when stressed; that’s a useful “feedback signal” to improve design or print conditions.
Where Strength Gets Lost
- Moisture in filament (bubbles, rough walls, weak interlayer bonds).
- Cold airflow near the print (uneven shrink, stress cracking).
- Too much part cooling (layers contract before they can fully knit).
- Thin, sharp internal corners (stress concentrators).
🔥 Heat Behavior and Dimensional Stability
For PC, “heat resistance” isn’t just surviving a hot car interior. It’s also about creep (slow deformation under load) and how much stiffness remains as temperatures rise. A PC filament example datasheet lists HDT at 99°C under 1.8 MPa load and 114°C under 0.45 MPa[d]. That gap matters: lighter loads can tolerate higher temperatures before noticeable bending.
Service temperature depends on load. If a part must hold a bolt-tightened clamp force near heat, design for a bigger cross-section and use inserts or washers to spread stress.
Thermal Expansion and Stress
PC expands and contracts noticeably with temperature swings. In printing, that shows up as warping, edge lift, and sometimes layer-splitting. In real use, it can show up as fit changes. When a PC part must interface with metal or another plastic, build in a bit of tolerance and avoid ultra-tight press fits unless you can control temperatures.
🛠️ Printer Setup That Makes PC Practical
PC printing is mostly about stable heat. A published PC-filament guide explicitly calls out a closed chamber and even suggests a heated chamber for large parts, with chamber targets in the ~70–100°C range[d]. That should immediately tell you what PC wants: no drafts, no sudden cooling, no temperature surprises.
- All-Metal Hotend
- PC commonly runs 250–270°C (and some blends run hotter), so reliable high-temp hardware matters.[d]
- Heated Bed That Holds Temperature
- Published settings show 90–105°C beds for PC filament; blends can be higher.[d]
- Enclosure
- Not optional for many setups. Even a simple enclosure can reduce cracking and warping.
- Consistent Build Surface Strategy
- PC can bond aggressively to some sheets. A controlled “bond and release” plan is safer than guessing.
🎛️ Settings That Usually Feel Stable With PC
Start with a known-good set of numbers, then adjust one thing at a time. A PC-filament datasheet example lists 250–270°C nozzle, 90–105°C bed, and cooling fan OFF[d]. That trio is a solid baseline because it prioritizes bonding and reduces sudden shrink.
| Knob | Practical Target For Many PC Filaments | What You’ll Notice |
|---|---|---|
| Nozzle Temperature | Start inside the manufacturer range (example: 250–270°C)[d] | Too low: weak layers, matte and “dry” walls. Too high: stringing, glossy sag, overheated bridging. |
| Bed Temperature | Hot and steady (example: 90–105°C)[d] | Too cool: corner lift. Too hot: elephant foot, overly soft first layers. |
| Part Cooling | Usually OFF or extremely low[d] | Cooling can “freeze” shrink stress into the part. PC prefers warm air. |
| Chamber Temperature | Warm enclosure; heated chamber helps large prints (example target noted: 70–100°C)[d] | Warps less, cracks less, walls look more uniform. |
| Surface Treatment | Texture PEI with glue when needed (example recommendation)[d] | Adhesion becomes predictable and safer to remove. |
Some “PC blend” materials are tuned to be easier while still keeping high performance. One PC material guide lists a recommended nozzle temperature of 275°C and bed around 110–115°C for a PC blend, and it also notes that pure PC can have bad adhesion and significant thermal expansion that leads to deformation and cracking[e]. If your printer isn’t built for a hot chamber, PC blends are often the more enjoyable path.
Airflow and Filtration
PC printing is high temperature printing, so it’s smart to treat airflow seriously. A NIOSH guide summarizes concerns around exposures to ultrafine particles and chemicals, and discusses controls like adequate room ventilation, portable HEPA filtration, and using ventilated enclosures or local exhaust for better source control[f]. The goal is simple: keep the air clean while you keep the part warm.
💧 Drying and Storage Without Guesswork
PC is known for absorbing moisture. In practice, damp PC often looks like tiny bubbles, rough “popping” walls, and weaker bonding. Published PC-filament guidance includes a drying setting example of 75°C for 6 hours[d], which is realistic for many filament dryers and helps avoid deforming spools.
What “Dry Enough” Looks Like
- Smoother extrusion: less fizzing, fewer micro-voids.
- More consistent lines: corners stop looking sandy or pitted.
- Stronger layers: parts feel less “crumbly” when flexed.
Industrial resin processing references can be even stricter. One polycarbonate processing guide describes drying at 120°C for 2–4 hours and aiming for residual moisture below 0.02% before processing[b]. Filament spools often can’t safely handle those pellet-processing temperatures, but the message is still valuable: PC really does prefer extremely low moisture.
🧱 Warping, Stress Cracks, and Annealing
Warping is not “bad luck.” It’s stored thermal stress leaving the part. A PC material guide notes that pure polycarbonate tends to deform and crack due to adhesion challenges and significant thermal expansion, and that additives are commonly used to improve printability[e]. That’s the most honest summary of PC printing you’ll ever read.
Design Choices That Calm PC Down
- Round internal corners instead of sharp corners (stress loves sharp geometry).
- Even wall thickness to reduce uneven shrink.
- Ribs over bulk for stiffness; solid infill can increase warping on larger parts.
- Use mechanical fasteners with washers or inserts to spread load and avoid point stresses.
🧪 Annealing is sometimes used to relax stress. One published PC-filament spec suggests annealing (example: 90°C for 2 hours) to release internal stress[d]. Annealing can change dimensions, so it’s best treated like a controlled process: test with a small calibration part before committing a large functional print.
🧰 Applications Where PC Usually Shines
If you have the printer setup for it, PC is great when you need strength plus heat tolerance and you don’t want a part that feels fragile. Think “functional and warm,” not “decorative.”
- Functional brackets near warm motors, electronics, or light enclosures.
- Protective covers and housings that get bumped and flexed.
- Jigs and fixtures that must hold alignment while staying stable around heat.
- Fan shrouds and ducting when higher temperature resistance is needed.
❓ FAQ
Is “PC filament” always pure polycarbonate?
No. Many products are polycarbonate-based blends designed to reduce warping and improve bed adhesion. Expect real variation in Tg, HDT, and print behavior between brands and “PC” subtypes.
Do I really need an enclosure for PC?
In most setups, yes. PC benefits from a warm, stable air environment. A published PC-filament guide even states a closed chamber is needed and gives a warm chamber target range in the 70–100°C area for certain use cases.[d]
Why does PC warp more than easier filaments?
PC tends to build up thermal stress as it cools. Drafts and uneven cooling make that stress release as lifting corners or cracks. Additives and blends can reduce the effect, but stable heat is still the main tool.
What’s the biggest sign my PC filament is wet?
Rough walls, tiny bubbles, popping sounds, and weaker layer bonding. Drying (example guidance: 75°C for 6 hours) is commonly recommended for PC filaments.[d]
Is PC a good choice for parts exposed to heat?
Often, yes—especially compared to many general-purpose filaments. Look at Tg and HDT numbers from the specific product you’re using, because “PC” can range from engineered blends to higher-heat formulations.
What safety approach makes sense for high-temp printing?
Keep the part warm, keep the air clean. A NIOSH guide discusses controlling exposures from 3D printing with approaches like adequate room ventilation, portable HEPA filtration, and ventilated enclosures or local exhaust for source control.[f]
📚 Sources
[a] Covestro — Makrolon® Polycarbonates (Tg Up To 148°C Stated)
[b] Covestro — Makrolon® Product Range: Typical Values For Properties (Drying Guidance Included)
[d] Polymaker — PolyMax™ PC Technical Data (Properties, Print, Drying, Annealing)
[e] Prusa Knowledge Base — Polycarbonate (PC) (Blend Notes, Temperatures, Hygroscopic Behavior)
[f] CDC/NIOSH — Approaches To Safe 3D Printing (Ventilation, Filtration, Enclosures, Local Exhaust)