3D PRINTING WITH PVA makenica.com/3d-printing-with-pva September 26, 2020
As the 3D printing technology is developing, so is the market for various materials to print with. There are many 3D printing materials available to choose from but each one of them has some specific quality. In this article, we will be talking about one such material - PVA. You will learn all you need to know about it and how it is different from all other materials.
WHAT IS PVA? PVA, or Polyvinyl Alcohol, is a synthetic, soft and biodegradable polymer formed by polymerizing vinyl acetate, which is then hydrolyzed to create PVA filament for 3D printing services. It is commonly known for its water-solubility and excellent adhesive properties. It is translucent white in appearance and resistant to oil, grease and other solvents. It has high tensile strength and flexibility. Due to its water-soluble nature, it is often used as a support structure to achieve complex geometries in intricate 3D prints.
WHAT ARE THE PROS AND CONS OF PVA? 1/4
Pros of PVA : 1. 2. 3. 4. 5.
Great water-solubility High tensile strength Easy to print Odorless, non-toxic & biodegradable Good for supporting complex prints
Cons of PVA : 1. 2. 3. 4. 5.
Hygroscopic (absorbs moisture from the air) Storage in air-tight containers required Prone to clogging while extrusion Expensive Requires adequate disposal
HOW TO 3D PRINT WITH PVA? Like every other material, certain conditions need to be kept in mind while 3D printing with PVA. Due to its usage as a support material, it is usually developed for dualextrusion prints. TEMPERATURE: Depending on the brand of PVA filament that you are using, the extruder temperature varies between 200- 250°C. A build plate temperature of 60°C is required if you're using PVA as a single material. However, if it is printed as a support material, simply use the build plate temperature required for the accompanying material. ADHESION: PVA can adhere well to the heated glass plate by itself depending upon the brand but sometimes a thin layer of glue might be required. For dual-extrusion prints, the adhesion method might differ based on the accompanying build material. PRINT ENVIRONMENT: No additional hardware is required to create a stable printing environment while printing only with PVA. However, while using another build material with it, an enclosure might be required depending on the material. It is also important to remember that PVA is a hygroscopic material. This means that it absorbs moisture from the environment. Therefore, it should be kept dry at all costs for the best printing results. For this, you should store your PVA filament in a sealed container with silica beads to reduce moisture. Also, PVA printed parts need to be kept in water for a few hours (depending on the brand) until there's no undissolved material left.
WHAT ARE THE TIPS AND TRICKS FOR SUCCESSFUL PVA 3D PRINTING? 2/4
Always keep the filament dry It is PVA's job to dissolve in water. Unfortunately, it doesn't know the difference between water that we need it to dissolve in and moisture in the air. That is why it's important to store it correctly. PVA should be stored in a dry and cool place, away from moisture as well as sunlight. An easy option is storing it in an airtight container with a desiccant. Brims should be made of PVA PVA is good adhesive but only when it is allowed to stick to itself. That is why you should make the brims used to support your model while printing from PVA and not the model material. Regularly cleaning the nozzle or hot end PVA tends to ooze and carbonize easily than other filaments. It can clog or jam the nozzle more frequently. Therefore it is important to clean your 3D printer's nozzle/print core when using PVA. Another hack is to use an ooze shield while using PVA as a support material for PLA prints. This will prime the PVA extruder after every tool change and it will be ready to print at the start of the layer. Moreover, the shield will prevent the plastic deposits from reaching your part by catching any oozing from both nozzles. You can remove and discard the ooze shield after the printing process is done. Speed up dissolving time The time required for PVA to dissolve completely is typically between 12-18 hours but this varies depending on the brand of PVA you're using. However, if patience is not your strong suit, you can reduce this time by several ways. Removing the extra material manually before placing it in water. This includes the large pieces that can be broken off using pliers. But be very careful while doing this and don't damage your precious model! Using hot water - If the temperature of the water is higher than the room temperature, PVA will dissolve faster. But be careful not to heat it to a very high temperature if you've used materials like PLA in your model. You can use a heater for this or change the cool water again with warm water. Stirring the water: PVA will dissolve faster if you keep the water moving. This can be done by using a pump or an ultrasonic tank. In multi - extruder setups, you can cool down the PVA hot end when it is not in use. This will prevent oozing and clogging.
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For a better finish, set the support upper separation distance to zero layers. It doesn't matter if PVA adheres to the part while printing because it will be dissolved away.
HOW IS PVA USED IN 3D PRINTING? PVA is commonly used to make : Decorative parts Quick prototypes Removable supports or rafts Support material for complex prints
CONCLUSION If you have access to a dual- or multi-extruder FDM 3D printer, PVA is a great solution for you to substitute difficult support removal. It is the best filament if you want to make detailed, clean and high-quality models. If you decide to work with PVA, be sure to use it in the right way keeping all the tips explained earlier in mind. You're sure to succeed and come up with the best 3D print.
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