Save money on prototypes without compromising quality – but know the material’s limits
PLA (Polylactic Acid) constitutes the industrial standard within modern 3D print. The material solves the task in the vast majority of cases, ranging from the first visual prototypes to simple holders on the production floor. For the professional buyer or engineer, however, choosing PLA for the wrong task poses a risk. If you expose a PLA part to high heat, aggressive chemicals, or constant mechanical pressure, it fails.
This guide establishes exactly when PLA works as the most cost-effective solution and when your project requires more specialized materials like PETG or Nylon.
What is PLA and what properties does the material have?
PLA is a bio-based plastic manufactured from renewable resources such as corn starch. The material differs from oil-based types like ABS because it does not emit toxic fumes during production. This makes PLA safe to use directly in open office environments without requirements for special ventilation.
More than just starch
Many overlook the material’s most important mechanical property, which is its stiffness. PLA is actually stiffer than many other plastic types, including the otherwise robust Polycarbonate. This means that a part printed in PLA holds its shape precisely under load until it reaches its breaking point. Here, the material behaves like carbon fiber. It does not bend under pressure but snaps without warning when the limit is exceeded.
This stiffness, combined with very low deformation during cooling, ensures extremely sharp visual results. We run our cooling fans at 100% immediately after the first layer, providing sharp corners and precise tolerances that other materials rarely match.
Variants for specific needs
The market offers several variants of PLA, each of which adjusts the material’s basic properties. Standard PLA is the economical choice for visual verification, but the industry often utilizes “Tough PLA” or “PLA+”. These variants are typically added with PBT (Polybutylene Terephthalate), which changes the material’s structure. The addition significantly increases impact resistance so the part can withstand shocks without shattering, making it more suitable for production jigs.
For tasks requiring high speed, there is “High-speed PLA”. This type contains additives that lower viscosity, allowing the material to flow faster through the nozzle at speeds above 300 mm/s. Finally, there is Carbon Fiber PLA (CF-PLA), where the plastic is added with carbon fiber dust. This does not necessarily increase tensile strength, but it maximizes stiffness and provides a matte surface that hides layer lines effectively. Be aware, however, that “Silk PLA”, which gives a shiny surface, often has weaker layer bonding and should be avoided for functional parts.
What advantages does PLA provide in your 3D print project?
When you need to validate a design, PLA is most often the best starting point, primarily due to economy and finish.
Nylon and carbon-fiber reinforced materials often cost two to three times more than PLA. It therefore makes sense to print your first iterations in the cheaper material. Use PLA to check form and fit before ordering the final product in a more expensive polymer. This saves the budget from unnecessary expenses for expensive materials in the development phase.
At the same time, PLA delivers the best surface finish for architectural models and exhibition items. The rapid cooling during the 3D print process means that details remain sharp. If you choose a matte variant, you hide the layer lines further, saving time on post-processing. Furthermore, you avoid the occupational health challenges that follow materials like ABS, which can leave a greasy film on the printer’s enclosure and require extraction.
When should you avoid using PLA?
Although PLA covers the majority of needs, it consistently fails in specific industrial scenarios. You should choose another material if your part is exposed to heat or constant pressure.
The temperature limit is critical
Heat constitutes the greatest risk for PLA. If you leave a part in a car window on a summer day or place it near warm electronics, it becomes soft and deforms. Already at temperatures above 50°C, PLA loses its structural integrity. For applications in engine bays or near heat sources, you must always upgrade to materials with higher heat tolerance.
Mechanical pressure and “creep”
PLA suffers from the phenomenon engineers call “creep”. This means the material deforms slowly under constant pressure over time. If you tighten a screw hard in a PLA part, the plastic gradually gives way, and the screw loosens. This makes PLA unsuitable for assemblies that must maintain a constant tension, or for click-locks and snap mechanisms that must be opened and closed often. Here, the material’s stiffness will cause the mechanism to break.
Environmental impact and hygiene
For outdoor use, PLA falls short against UV radiation. Sunlight bleaches the color and makes the plastic brittle over time. For an outdoor bracket, ASA is a far better choice. Also, be aware of hygiene regarding food contact. Although the raw material corn starch is food-safe, the 3D print itself rarely is. The microscopic layer lines collect bacteria that regular washing does not remove. Only use PLA for food if the part is subsequently coated with an approved epoxy.
Can you process and finish PLA parts?
Many engineers want to drill holes or sand the surfaces after printing. Here, PLA requires careful handling. The material has a low melting point, and the friction from a fast-rotating drill creates enough heat to melt the plastic around the drill bit. This creates a lump that can destroy the part and get stuck on the tool. The solution is to drill slowly and take breaks so the material can cool down.
The same issue applies to sanding. Mechanical sanding quickly develops heat that causes the surface to “gum up” instead of becoming smooth. We recommend wet sanding by hand, which cools the part and provides a better result. When mounting screws, you should use washers to distribute the pressure and counteract the material’s tendency to deform under the screw head.
How does PLA compare to other materials?
It can be difficult to determine when to upgrade from the standard material. The table below provides an overview of the most important parameters.
| Property | PLA (Standard) | PETG (All-round) | Nylon (Performance) |
| Primary strength | High stiffness, great finish | Impact resistant, chemical resistant | Extreme wear resistance, flexible |
| Temperature (max) | approx. 50°C | approx. 75°C | approx. 80-100°C |
| Impact resistance | Low (Brittle) | High (Tough) | Very high |
| Outdoor use | No (UV degrades) | Yes (OK) / ASA is best | Yes (But absorbs moisture) |
| Price index | Low | Medium | High (2-3x PLA) |
To put it in perspective, you can consider PETG as a robust “SUV” and PLA as a “city car”. PETG withstands temperatures up to approx. 75°C, making it possible to wash the parts in a dishwasher, and it resists chemicals better than PLA.
Nylon belongs in a completely different category and is often used for “under-the-hood” applications, as it withstands oil, petrol, and brake fluid. The challenge with Nylon is that it is hygroscopic and absorbs moisture from the air, requiring correct drying and storage.
For gaskets and shock absorption, TPU is the right choice. Where PLA breaks upon impact, TPU absorbs the energy like rubber. At the very heavy end is PEEK, which can cost up to 5,000 DKK per kg and requires extreme 3D print temperatures. This emphasizes the value of using standard materials like PLA where possible and only upgrading when the specification requires it.
What is the difference between PLA and PETG filament?
The primary difference lies in temperature resistance and toughness in the finished part. While PLA is stiff but brittle and only withstands 50°C, PETG is more flexible, impact-resistant, and withstands up to 75°C. Consider PLA as the economical choice for prototypes and PETG as the functional choice for usable parts.
Can you use PLA for outdoor parts?
No, PLA is not recommended for permanent outdoor use as the material is not UV-resistant. Over time, the sun’s rays will bleach the color and make the plastic brittle, causing the part to break. For outdoor applications like brackets or signs, you should instead choose ASA, which resists both UV light and changing weather conditions.
How much heat can a PLA print withstand?
PLA begins to soften and lose its shape already at temperatures around 50°C. This means that parts printed in PLA will deform if left in a warm car during summer or placed close to electronics that develop heat. For warm environments, other materials are required.
Is 3D printed PLA food-safe?
Although the raw material is often approved, the 3D print itself rarely is without correct post-processing. The microscopic layer lines in the print act as bacteria traps that cannot be cleaned effectively. Only use PLA for food if the part is subsequently sealed with a food-grade epoxy coating to ensure the necessary hygiene.
Is PLA strong enough for functional parts?
PLA is very stiff but also brittle, making it vulnerable to sudden shocks and impacts. It also suffers from “creep”, where it deforms under constant pressure from screws. For functional parts with mechanical load, materials like Nylon or PETG are far better and more durable alternatives.
Can you drill and sand a PLA part?
Yes, but it requires great caution as frictional heat quickly causes the plastic to melt. When drilling, you must run slowly to avoid melting around the drill bit. When sanding, wet sanding by hand is recommended, as mechanical sanding develops too much heat, which destroys the surface instead of smoothing it.
Secure delivery with the right material choice
The choice of material does not have to be a guessing game. PLA is the correct choice for your project if the temperature around the part stays below 50°C and the purpose is primarily visual verification, fit-checking, or non-load-bearing function. Here, you get the sharpest possible surface finish at the lowest price.
Are you in doubt about whether PLA can handle your specific task? At 3D actions, we advise engineers and designers daily on material choices. We help you evaluate whether you can settle for the economical solution or if your project requires the strength of Nylon or PETG to ensure a successful delivery.
