All You Need to Know About PVA for 3D Printing
PVA, or polyvinyl alcohol, is a material widely used in the 3D printing industry due to its ability to dissolve in water. In particular, it is used for the creation of print supports when using FDM dual extruder machines. This offers users greater design freedom for parts with complex geometries, without affecting print quality. The more details and cantilevered parts the design has, the more supports the part will require in order to be manufactured. This guide will help you better understand the properties of this material, as well as its role in 3D printing in obtaining the best results in each manufacturing process.
Characteristics of PVA in 3D Printing
On a technical level, PVA is part of the synthetic polymer family, with the particularity that it is biodegradable. It is created by polymerizing vinyl acetate, which is then hydrolyzed to obtain the material in filament form for 3D printing. It has a transparent to off-white appearance and is highly resistant to oil and grease. In addition to having very good adhesive properties similar to other thermoplastics such as PLA, CPE or Nylon, this material has a high tensile strength and flexibility. In order to obtain good substrate results, PVA requires preheating the printing tray to between 45 – 60ºC and bringing the extruder to a temperature of between 180 – 200ºC. It is also odorless, non-toxic and, as mentioned, biodegradable, making it safe for humans, animals and the environment.
Among its main advantages is, as mentioned, its ability to dissolve. Linked to this, the most remarkable thing is that it only needs water to remove the support material, i.e., it does not require solvents with more complex components. Furthermore, it does not require any additional hardware. However, it is also worth mentioning some of the disadvantages of PVA, though they are generally applicable to other soluble materials. One of these is the high sensitivity to moisture, which can directly affect the material. In order for its properties not to be altered, it will be necessary to keep it in areas where the air is highly controlled. PVA is also more likely to generate clogging if the nozzle is left hot when not extruding. To this can be added that many users consider it to be an expensive filament for what it is, as it ultimately is not used in the final parts being printed, but rather dissolves in post-processing.
Use and Applications
As a soluble material, PVA is ideal as a complement in the manufacture of parts with complex geometries, as well as internal cavities, conceptual models and molds. 3D printed supports offer improved surface quality and also allow the part to be oriented to optimize its mechanical properties. An important point to consider when working with this material is the configuration of the extruders. Cooling the PVA hotend while idle will prevent the oozing and clogging mentioned above. In addition, it is recommended to set the top support clearance distance to 0 layers for a more optimal surface finish. Since the supports will dissolve, it does not matter if they adhere to the final part during the fabrication process.
By allowing 3D printing of all types of parts, no matter how complex the design, PVA is a material widely used in the art world to create decorative models. However, it is not the only sector that is taking advantage of this filament. Even the most advanced industries that work with FDM technology to create tooling or prototypes are also increasingly integrating the soluble materials to create supports. Among the companies offering PVA filaments we can find Ultimaker, eSun, MatterHackers or Polymaker, among many others. If you want to learn more about other 3D printing filaments, you can consult our guide HERE.
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*Cover Photo Credits: Zortrax