PLA and PETG are material families, not single guaranteed property sets. Filament formulation, moisture, print orientation and process settings can change the finished part substantially.
| Decision | PLA, typical tendency | PETG, typical tendency |
|---|---|---|
| Printing behavior | Often convenient for detailed prototypes | Often needs attention to stringing and surface adhesion |
| Mechanical feel | Often relatively stiff, potentially brittle | Often more ductile or impact-tolerant |
| Heat exposure | Can soften in relatively warm service | Often more heat-tolerant than ordinary PLA, but still limited |
| Best evidence | Actual filament data and printed tests | Actual filament data and printed tests |
Choose around the service condition
For a room-temperature visual prototype, dimensional appearance and ease of printing may dominate. For a clip, impact and repeated flexing may matter more. For an enclosure near a heat source, evaluate temperature, load and long-term creep rather than only a material name. Neither material should be assumed suitable for a safety-critical load without qualification.
A manufacturer’s heat-deflection or tensile value comes from a specified test. It is not automatically an allowable continuous-use temperature or a design strength for every printed orientation. Filled and modified grades may behave differently from ordinary PLA or PETG.
Fit must be tested after the material change
Print the same small hole-and-pin or tab-and-slot coupon in the intended orientation. Measure after the part has cooled under consistent conditions. Compare external dimensions, internal holes, first-layer effects and assembly behavior. Do not keep a clearance rule simply because it worked with the previous spool.
PETG bed adhesion can be strong on some surfaces, while PLA has its own bed and cooling requirements. Follow the printer and build-surface instructions rather than improvising removal force or adhesive choices.
Compare total job cost
Use actual slicer mass, print time, failure rate and finishing labor. A cheaper spool can cost more per accepted part if it requires repeated reprints. Store and dry filament according to its manufacturer’s guidance, and use appropriate ventilation. The cost calculator handles the accounting; a representative trial establishes whether the material meets the function.
A named-product comparison, not a universal material ranking
The following values are from Prusament technical datasheets, version 1.1, last updated 16 February 2022. They describe those products and test methods, not every PLA or PETG filament.
| Reported property | Prusament PLA | Prusament PETG |
|---|---|---|
| Density, ISO 1183 | 1.24 g/cm³ | 1.27 g/cm³ |
| Heat deflection at 0.45 MPa, ISO 75 | 55°C | 68°C |
| Heat deflection at 1.80 MPa, ISO 75 | 55°C | 68°C |
Sources: PLA datasheet, page 2 and PETG datasheet, page 2. Heat-deflection temperature is a specified test result, not an allowable continuous service temperature. A loaded part can creep or distort under a different temperature, time, orientation or stress.
Apply the comparison to the job
- Display prototype: prioritize detail, appearance and easy finishing; verify that storage and transport temperatures are acceptable.
- Repeated-flex clip: compare the actual clip geometry and layer direction. Count cycles to your acceptance criterion instead of choosing from a tensile number alone.
- Warm enclosure: measure the expected temperature and evaluate a representative loaded assembly. Neither 55°C nor 68°C should become an automatic pass/fail design limit.
For an identical hypothetical net volume of 20 cm³, these densities imply 24.8 g of PLA versus 25.4 g of PETG before support, purge or infill differences. This modest mass difference is usually less useful than the slicer’s actual material usage and the number of accepted prints. Record material brand and profile when comparing results; changing from ordinary PLA to a modified or filled grade changes the comparison.
Content updated October 8, 2026. Sources and numerical examples are explained above; examples are not production test results. Editorial method · Report a correction.
References and verification
Original explanations and worked examples by MfgWorkbench. Sources below support the stated concepts or selected reference data; they do not certify every example or a production application.
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