PVA Support Printing: An Introductory Guide
Making parts with complex geometries and intricate designs has never been so easy since the appearance of 3D printing technologies. However, there’re some limitations, especially for FDM systems. For some prints, there’s the need for supports. But if you have …
Making parts with complex geometries and intricate designs has never been so easy since the appearance of 3D printing technologies. However, there’re some limitations, especially for FDM systems.
For some prints, there’s the need for supports. But if you have experience with it, we can probably agree that having to print supports is something that must be avoided if possible. Having to remove these structures can sometimes be very hard and even leave undesirable scrapes in the surface. But here’s a great solution: PVA.
What is PVA?
Polyvinyl alcohol (PVA, PVOH, PVAI) is an odourless and non-toxic material that dissolves when submerged into water. Thanks to its biocompatibility, this material is often used in medical applications like capsule coating, contact lenses and eye drops. Other common uses are for laundry pods coatings and as a strengthening agent for textiles and paper. It is often mistaken with PVAc (Polyvinyl acetate or plain white glue).
But what interests us the most is: What’s the deal with this material in 3D printing? Well, you can buy it in filament spool formats, with the sole purpose of serving as water-soluble supports in dual extrusion printings. The main reasons you might want to get PVA for your prints are the following:
- Your print has a very intricate geometry, and there’s the need to apply supports all over it.
- Large overhangs and bridges.
- Deep cavities
- You want to get clean surface finishes while avoiding support scars.
- Mechanisms. PVA can work as an interface between parts, allowing you to print assembled moving parts with no problem and smoothly!
PVA has a promising future for dual extrusion 3D printing as a contribution for empowering freedom in design. Furthermore, there can be more uses for PVA than just as a support material. For instance, pharmacists might be able to print PVA pills with personalised drug release times in the near future; research is still in progress.
Some PVA Facts and Tips
Let’s have a glimpse of PVA’s core aspects, best practices, and some tips.
Keeping It Dry
The main concern regarding polyvinyl alcohol might be its tendency to absorb moisture, heavily affecting the print quality. As a matter of fact, it becomes soft and sticky when moist, and then it can bubble and crack when printed. To avoid these issues, it’s better to store the spool in airtight containers or bags with desiccant. Additionally try to have a conditioned, fresh environment with ventilation and low humidity when printing. If the spool gets too wet, there are many things you can do to dry it:
- Use a specialised filament dryer
- Use a food dehydrator
- Put it in a convection oven (Never a household oven!)
- Or, with the printing bed itself! Place the spool at 40 to 45°C. In also, close the filament inside its original cardboard box for better results.
Dissolving in Water
Simple, submerge it in a container with tap water and wait some hours. To speed up the process, let’s see some techniques:
- Use warm water (Not higher than 50°C)
- Water in movement works better. As the water gets saturated with PVA, the process becomes slower. For this matter, you can apply an agitator, any system with flowing water or just add new freshwater periodically.
- After the PVA begins to soften, use pliers to remove what can be removed without damaging the part.
Disposing of the resulting PVA water is easy. Since it is biodegradable, you can drain it with no worries. But still, PVA manufacturers always recommend consulting your local disposal regulations for reassurance.
Compared to other materials, PVA printing temperatures are relatively low. Temperatures can range from 190 to 230 °C, depending on the brand. Beware of the fact that PVA can easily carbonise and cause clogging if you’re not careful enough. For the hotbed, it’s better to adapt to the primary printing material’s settings, but some manufactures provide their recommendations for this.
Which Materials Are Compatible
PLA is the ideal material to support with PVA for the following reasons:
- Similar printing temperatures
- Good adherence among their surfaces.
- PLA is also very resistant to water
Other materials that don’t meet these requirements can be harder to work with or even impossible. For instance, ABS and TPU won’t stick well to PVA. Thankfully there are other supporting materials like HIPS, which is ideal to support ABS.
Beware of Oozing PVA
One big issue with this material is its tendency to ooze a lot during extrusion, and thus contaminating the other material’s layers in the process. Thankfully there are many solutions you can apply in this case:
- Set prime towers or ooze shields with your slicer software. Both Cura and Ideamaker have great settings.
- Optimise cooling settings for each nozzle.
- Machines with an Independent Dual Extrusion (IDEX) system like the Raise3D E2 or the Sindoh 3DWOX 2X can provide significant advantages.
PVA is expensive, and you should use it wisely. One of the best practices for printing with PVA is to just apply it in the contact interface between the supports and the part (The external layers of the support structures), leaving the rest of the structure with the primary material. Make sure you use a slicer that enables you to control the support interface layers needed for this purpose.
PVA Brand Overview
SolidPrint3D offers a unique catalogue of PVA filaments, each with their own unique traits. Let’s briefly check them individually.
Ultimaker PVA Natural
- Spool Formats: 350/750 g
- Diameter: 2.85 ± 0.10 mm
- Nozzle Temperature: 215 – 225°C
- Bed Temperature: 60°C
- Price: Around 111.80 £/kg
Ultimaker’s version of PVA is one leading option in the market thanks to its dedicated formula. This brand focuses on enhancing thermal stability properties more than the average PVA brands, therefore increasing its resistance to moisture and higher temperatures. This improved thermal stability makes Ultimaker’s PVA ideal for high-performance printing materials like Nylon and CPE.
- Spool Formats: 2.3/4.5/8 kg
- Diameter: 2.85 mm
- Nozzle Temperature: 190 °C
- Bed Temperature: 60 °C
- Price: Around 105.30 £/kg
BigRep PVA spools are massive! But you won’t regret getting one of these if you want to make the large prints that make their printers widely known. BigRep filament is specially designed not to overheat, optimising melt flow characteristics to avoid typical PVA clogging issues.
Raise3D Premium PVA Pure
- Spool Formats: 1kg
- Diameter: 1.75 mm
- Nozzle Temperature: 210 – 230 °C
- Price: 96 £/kg
Raise3D’s PVA formula focuses on thermal stability in a similar way as Ultimaker. Despite the similarity, Raise3D Premium PVA Pure offers a unique approach to support printing (Just as shown in the features above).
Choosing to work with support materials like PVA is a wonderful step for those who want to engage further into a more comprehensive set of alternatives in freedom of design. But investing in this material can become costly if not handled efficiently.
I hope this guide was of help to get a practical idea of what to expect when handling this material. If you want to get further information and personalised support about PVA, Solid Print3D is here to help. For more information, please call Solid Print3D at 01926 333 777 or email at email@example.com