When it comes to cutting-edge additive manufacturing, few know the landscape better than Micah Chaban. As Founder and Vice President of Sales at RapidMade, a full-service 3D printing service and digital manufacturing firm, Micah has helped companies across industries—from aerospace to medical—engineer parts that don’t just meet specifications, but excel under pressure. Founded with a mission to combine deep technical expertise with production-grade quality, RapidMade stands out for its focus on functional, manufacturable solutions.

Today, Micah shares his insights on one of the most critical, yet often misunderstood aspects of 3D printing: how 3D printing thermal properties shape the success or failure of printed parts.

Why does heat deflection temperature (HDT) matter in 3D printed parts?

HDT is fundamental because it tells you at what point your part will start to deform under load when heated. It’s not just about when a material melts; it’s about when it begins to lose its structural integrity in real-world conditions. In many functional parts—things like enclosures, jigs, and mechanical components—you can’t afford deformation. You need a clear understanding of how your material will behave at elevated temperatures under service loads, not just in idealized lab conditions.

What’s the difference between glass transition temperature and melting point?

Glass transition is where things get interesting for polymers. It’s the range where an amorphous thermoplastic changes from rigid to rubbery without actually melting. It’s gradual, and it’s where mechanical properties begin to slip. Melting point, on the other hand, is much more binary—particularly for crystalline materials and metals. It’s when the material goes from solid to liquid. Knowing which behavior your material exhibits is critical for selecting the right material for thermal or mechanical loads.

How do thermoplastics and thermosets differ in thermal behavior?

Thermoplastics can be reprocessed because they soften with heat. That’s great for certain applications but comes with limitations in high-temperature environments unless you’re using engineered grades like Ultem 9085. Thermosets cure permanently; once they set, they don’t melt again. That makes them dimensionally stable at higher temperatures, but it also means they can be more brittle, especially after prolonged exposure to mechanical stress.

Why is sustained use temperature essential for functional parts?

Short-term peaks are one thing. Most materials can survive a thermal spike. But what matters for a real-world part is the sustained operating temperature—what it can tolerate day-in, day-out without deforming, creeping, or breaking down. If you ignore that, you’re designing failure into your system. Sustained use temperature is the true metric of long-term reliability.

Can 3D printed metals withstand high thermal cycling without failure?

Yes, absolutely. Metals like 316L and 17-4 PH stainless steel, when printed correctly and post-processed properly, perform very similarly to their forged counterparts. They handle repeated thermal cycling extremely well, making them ideal for applications in aerospace, medical devices, and heavy industry where parts are exposed to fluctuating or extreme temperatures.

Does adding carbon fiber to polymers improve thermal stability?

It’s a common misconception, but the answer is usually no. Carbon fiber increases stiffness and dimensional stability, yes, but it often reduces the base polymer’s thermal resistance. For example, Nylon 12 CF is stiffer than standard Nylon 12, but it has a much lower heat deflection temperature. It’s great for lightweight frames and drones, but not for parts exposed to high thermal loads

Which materials are best suited for high-heat, load-bearing parts?

Ultem 9085 is a standout among polymers. It’s flame-retardant, it has an HDT around 177°C, and it’s tough enough for aerospace interiors and structural components. If you need even higher performance, you move into metals like 17-4 PH stainless steel, which combines thermal resistance, high strength, and excellent mechanical fatigue properties.

How does humidity affect thermal performance in 3D printed polymers?

Moisture absorption can wreak havoc on polymers, especially nylons. Nylon 12, for instance, is hygroscopic—it absorbs moisture from the air. That moisture can lower the glass transition temperature and weaken the material’s structural performance. In thermal cycling environments, absorbed moisture can even cause micro-cracking or delamination over time.

How significant is anisotropy when considering thermal deformation in printed parts?

It’s a major factor. In 3D printing, parts are inherently anisotropic—meaning they are weaker along the Z-axis, or the layer lines. Under thermal stress, those weaker planes can expand or creep differently than the rest of the part. Orientation during printing and smart design decisions are critical to minimizing this risk.

Is thermal conductivity important in 3D printed parts?

It depends on the application. If you’re designing a part that needs to dissipate heat—like a heat sink or a thermal interface—you want higher thermal conductivity, which metals excel at. If you’re designing an insulating part, you want low conductivity, which many plastics naturally offer.

Can SLA resins be used for high-temperature applications?

Only selectively. Some SLA resins like X Pro 9400 B FR are designed for better thermal resistance and flame retardance. But most standard SLA materials are not built to survive sustained high temperatures. They are best suited for prototyping and low-heat applications where surface quality matters more than thermal endurance.

How do short-term peak temperatures affect material selection?

Materials like Estane TPU can survive short-term heat spikes to 200°C without catastrophic failure. But sustained exposure even at lower temperatures—say, 120°C—can cause permanent deformation or mechanical degradation. Always differentiate between peak survival temperatures and sustained use ratings when selecting a material.

Are flame-retardant properties correlated with higher thermal resistance?

Not automatically. A material can self-extinguish in flame exposure without necessarily surviving prolonged high-heat service. Ultem 9085 manages both—flame retardance and high thermal resistance—which is why it’s so highly valued in transportation and aerospace. But flame retardance alone isn’t a free pass for high-temperature stability.

Why do printed metal parts sometimes require post-processing for optimal thermal performance?

Additive metals can have porosity, residual stresses, or microstructural inconsistencies right out of the printer. Post-processing techniques like hot isostatic pressing (HIP) or heat treatment eliminate these issues, closing pores and relieving stresses. This ensures the part performs consistently under mechanical and thermal loads, just like a traditionally manufactured component would.

What failure modes are common when a 3D printed part exceeds its thermal limits?

You’ll typically see creep deformation, surface warping, dimensional loss, cracking, and eventually structural failure. Polymers might soften and lose shape long before they visibly fail. Metals can experience thermal fatigue cracking over many cycles. Understanding these modes is key to designing parts that survive real-world operating environments.

For expert consultation on material selection, thermal performance, and manufacturing solutions that meet your toughest challenges, reach out to RapidMade at rapidmade.com or contact the team directly at info@rapidmade.com.