The popularity of PLA stems from the fact that it is easy to print, doesn’t cause bad odours and is environmentally friendly. However, generic PLA compositions have their cons: in broad terms, PLA compositions we most frequently find on today’s market exhibit low distortion temperatures, high friction coefficients and a low melt flow index.
These attributes translate into a more rigid and delicate 3D print which is harder to extrude and easier to fracture. To overcome some of PLA’s issues and with the objective of improving 3D printing results, NatureWorks, backed by years of experience in the polymer industry, created the PLA Ingeo 3D850 resin.
PLA 850. First and foremost, the melt flow index is higher than ABS plastic. A high melt flow index often means a lower friction coefficient. This high melt flow index thus yields an advantage because extruder motors have to do less work to extrude the same length of filament (print faster). Also, a higher melt flow index leads to a cooler extruder operating temperatures and less wear on parts. Another advantage is a lowered probability of extruder gear slippage or stripping of the filament when back pressure occurs in the hot end.
When looking at a broader range of 3D printer filaments, it’s typical to see that materials with high impact resistances have conversely low tensile strengths (or vice-versa). The chart shown below (my3dmatter) illustrates how different filaments compare when looking at their tensile strength and impact resistance. We can see that a trade-off between tensile strength and impact resistance is apparent, and it’s rare to see filaments that exhibit both properties at the same time.
Next, let’s take a closer look at 850’s flexural modulus (i.e. the materials tendency to bend under stress).
So what does having a high flexural modulus mean for 3D printing?
Printing structures that are long and thin will have less deflection or bend under pressure, thus eliminating the need for supports or thick rafts.
One of the most significant issue of PLA is its low overhang temperature. The HDT (heat distortion temperature) is the temperature at which a polymeric material deforms under pressure. Historically, when prints required high thermal resistance, ABS was the best plastic material available. Unlike other PLA, the PLA 3D 850 material has an HDT between 80-90 ° C (100% filled piece, crystallized at 110 ° C / 15 min), which means that it will undergo minimal (or zero) deformation below that temperature . When compared with the ABS or PLA standard, with their values of 85 ° C and 50 ° C respectively, it must be recognized that thermal resistance is a property that has greatly improved.
From a usage perspective, filaments made with 3D850 resin feature other enhancements such as excellent bonding with print surfaces, a feature that is significantly improving first layer quality and minimizing the risk of warping. Next, shrinkage of parts during and after printing is also non-existent and virtually no odour is present during extrusion.
In conclusion, 850 shows that the trade-off between tensile and impact strengths can be avoided, allowing very resistant PLA prints. Our PLA Super Premium Series is designed to offer tough and thermally resistant prints, analogous to ABS but without its disadvantages.