FDM 3D Printing: How Much Does PLA Brand Affect Strength?

When selecting PLA filament for FDM 3D printing, price and a manufacturer’s data sheet may seem like enough to guide the decision. But products sold as the same material can behave differently when a printed part is pulled under load. A 2020 study compared five PLA filaments from different manufacturers, printing and testing specimens under the same conditions to measure how their tensile properties varied.

Key findings

• The study examined five PLA filaments, with five specimens per manufacturer and 25 specimens in total.
• Every specimen was printed on the same Ultimaker S5, with the same settings, in white and in a flat orientation.
• PM Filament had the highest tensile strength, 62.7 MPa; 3D Republika had the lowest, 52.9 MPa. The difference reached 17%.
• Ultimaker had the highest yield strength, 36.3 MPa. PM Filament had the lowest, 26.0 MPa, which was 33% below the highest value.
• Young’s modulus was 2.9 GPa for Ultimaker, Devil Design and PM Filament, and 2.7 GPa for 3D Republika and Prima Select.
• Strain results stood out: the reported values for 3D Republika ranged from 40% to 90%.

Why compare PLA filament brands?

Fused Deposition Modelling, or FDM, makes a part by depositing thermoplastic material layer by layer. PLA is a widely used filament, but the material name alone does not mean that products from different manufacturers will have identical mechanical properties. The paper notes that the prices of filaments for the same material can differ by as much as 50%. The study therefore measured whether the tensile strength of printed PLA differed by manufacturer and considered whether price differences were supported by test results.

For engineers, product designers and students, it is useful to distinguish a material’s properties from the performance of a finished FDM part. Printing settings can also affect a part, so this study kept production conditions consistent while changing the filament manufacturer. That makes it possible to examine brand-to-brand variation within this experiment. It does not, however, establish a universal ranking of every PLA product or every FDM setup.

Materials and testing method

The five PLA filaments came from 3D Republika, Ultimaker, DevilDesign, PrimaSelect and PM Filament. All were white. The study used dogbone-shaped tensile specimens prepared according to ISO 527-2. A dogbone specimen has a narrower central section where deformation and failure can be measured. Its CAD model was designed in SolidWorks and prepared for printing in CURA slicer version 4.5.

All specimens were printed on an Ultimaker S5. The settings included a 0.40 mm nozzle, 0.15 mm layer height, 1.00 mm wall thickness, 100% infill density and a print speed of 70.00 mm/s. Infill density describes how much of the model’s interior is filled with material; these specimens used full infill. They were placed on the build plate in the same flat orientation. Although manufacturer specifications listed different recommended filament diameters and printing temperatures, the study printed the specimens using the same settings.

The study prepared five specimens from each manufacturer. After printing, the specimens were tested on a Shimadzu AGS-X Std tensile machine according to ISO 527-2, at a strain rate of 5 mm/min. A tensile test pulls a specimen until it deforms and breaks. The paper reports force and mechanical-property data; the reported results are mean values from the five tested specimens for each PLA manufacturer.

Tensile strength and other results

PM Filament’s PLA withstood the highest maximum force before breaking, 2511.3 N. The lowest maximum force was 2115.9 N for 3D Republika. Force and tensile strength are related but are not interchangeable: tensile strength describes the material’s resistance to pulling and is reported in MPa in this study. PM Filament had the highest tensile strength at 62.7 MPa, while 3D Republika had the lowest at 52.9 MPa. Across the five materials, the difference in tensile strength reached 17%.

The ranking differed for yield strength, the stress at which a material begins to deform permanently. Ultimaker recorded the highest value, 36.3 MPa. PM Filament recorded the lowest, 26.0 MPa, or 33% below the highest result. This difference in ranking matters: the filament with the highest tensile strength in this experiment did not also have the highest yield strength. A single measurement cannot stand in for every mechanical property that may matter in a design.

Young’s modulus describes stiffness, or a material’s resistance to elastic deformation. Ultimaker, Devil Design and PM Filament each had a modulus of 2.9 GPa, while 3D Republika and Prima Select each had 2.7 GPa. The paper reports a variation of 7% for this property. Strain results showed a much more unusual pattern. The reported strain for 3D Republika ranged from 40% to 90%; compared with the other manufacturers, the difference in strain reached 170%.

The paper also considered repeatability, or how much individual measurements varied among specimens of the same brand. For tensile strength, 3D Republika showed slightly greater scattering, with differences of up to 12%. Scattering in strain results was more pronounced: it reached 68% for 3D Republika and 56% for Ultimaker. These figures describe the set of five specimens tested per manufacturer; they should not be read as a guarantee for every spool or future print.

What the results mean for practice

The findings do not identify one filament as best for every application. PM Filament produced the highest tensile strength and maximum force in this test, whereas Ultimaker produced the highest yield strength. If a design depends on deformation before failure, the unusual and scattered 3D Republika results suggest that further testing would be useful. Material selection should therefore reflect the type of load and the property that matters for the specific part.

For engineers and product developers, the study is a reminder to check which mechanical property a specification actually reports and how it was measured. For students and researchers, it demonstrates the value of controlled comparison: printer, specimen geometry, settings, color, orientation and test procedure were held constant to examine differences among filaments. At the same time, the results apply to the PLA products and printing conditions included in the experiment. They should not automatically be extended to other colors, printers, geometries, orientations or process settings.

Scope and possible next steps

The paper points to the lack of standards for FDM-printed materials as a barrier to comparing mechanical properties and checking manufacturer specifications. It also notes that Ultimaker included the testing rate among its specifications, an important detail when a common rate is not prescribed. The experiment used five specimens per manufacturer, one printer, one color, one orientation and a defined set of printing parameters, so its conclusions should be understood within that scope.

The paper identifies tensile test rate and its relationship to material strength as a topic for future research. It also recommends similar studies of other additive-manufacturing materials. For anyone comparing PLA filaments, the results support looking beyond a data-sheet value and checking the conditions under which that value was obtained.

Conclusion

In a study by Adi Pandžić, PhD, measurable differences were found among five PLA filaments printed under the same FDM conditions. Tensile strength varied by up to 17%, yield strength by up to 33% and Young’s modulus by up to 7%, while strain results showed substantially greater variation. The practical lesson is to choose a filament using the mechanical properties relevant to the intended part and to consider the test conditions behind published specifications, rather than relying on the material name or price alone.

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Author: Adi Pandžić, PhD in Mechanical Engineering

This article summarises a published research paper; please refer to and cite the original paper. About the author

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