As you may already be aware, additive manufacturing comprises several novel technologies that allow components to be created more rapidly and with fewer materials than subtractive manufacturing techniques. Nonetheless, it isn’t perfect. Indeed, countless factors must be accounted for each component printed to prevent printing mistakes. One common issue in 3D printing is curling. Despite being similar to another familiar occurrence, warping, the two are not exactly identical. However, what is the meaning of these two closely related yet different concepts?
Curling, also termed as rough corners or corner overextension, is a distortion in the top layers of the 3D printed object, particularly noticeable at the edges, which could render the component defective. Warping is a similar occurrence, but it impacts the lower layers of the component, causing it to detach from the printing plate. Furthermore, delamination, distinguished by the splitting of distinctive printed layers, is essentially the same occurrence but more extreme. Let’s further investigate the causes of these anomalies and the feasible solutions to avoid them.
In essence, curling in 3D printing (as well as the other phenomena) is prompted by an excessive temperature difference between the extrusion material and the surrounding air (as the filament vacates the nozzle, it quickly cools down to ambient temperature). This explains why this issue frequently arises in FDM 3D printing.
The process of melting 3D filament involves high temperatures – approximately 200°C for PLA, hence creating a stark contrast with the ambient air temperature. Curling is also a common issue with DED technology, in which the metal needs to be heated to extremely high temperatures creating an even more significant temperature difference with the part.
How to Avoid Curling in 3D Printing
It is evident that to prevent curling in 3D printing, temperature regulation is crucial. If you are using plastic like ABS, the suggested extrusion temperature ranges between 230 and 260°C. Ideally, you should set your 3D printer within these temperatures. It helps avoid extrusion troubles on the one hand, and irregularities such as stringing, curling, warping, or delamination on the other.
Remember, ABS can easily deform if printed under subpar conditions.
Moreover, employing a 3D printer that has a heated or shut enclosure reduces curling by decreasing the temperature disparity between the component and the surrounding atmosphere. This enclosed enclosure also guards the component currently being printed against air movements and their instantaneous temperature fall. If your 3D printer is lacking a close enclosure, it can be put in a print cabinet.
In order to prevent curling in 3D printing, the printing plate is warmed to keep the layers from cooling and expanding too quickly. For ABS, it needs to be heated to a range between 80 and 130°C. Without these conditions, the plastic can possibly contract about 1.5%, or more, depending on the part’s size.
If we draw a comparison to PLA, this has a melting point between 170 and 180°C, which is lower, and doesn’t always need a heated printing plate. This thermoplastic has less tendency towards curling. PETG, however, has nearly the same attributes as ABS, and needs to be situated in the right circumstances to avoid distortion.
Furthermore, most 3D printers come with fans designed to solidify molten filament. This system is crucial, but the settings must be correct to avert yet again too much of a temperature difference with the outside, resulting in the component’s warping. An additional measure to avoid curling or other deformation in 3D printing is to minimize layer height to help them stick together.
The 3D printer can be covered with a printing box to protect it from drafts (photo credits: Alveo3D)
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“Why did the 3D printer go to therapy? Because it had too many layers of unresolved issues!”
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