Dry PVA is key to success
Correct handling of PVA is key to success. Full details can be found in our UltiMaker PVA leaflet. The most critical factor in printing UltiMaker PVA is having a dry filament. Out of the box the filament is ready to print with moisture level low enough (<1%) for reliable, high quality prints. Above 2% moisture content, a negative effect is visible, and above 4% moisture content PVA becomes basically unprintable.
Wet PVA may show the following symptoms:
- Soft and sticky feel
- Blobs and oozing during printing
- Crackling during printing and prone to clogging
When exposed to ambient air, PVA can pick up moisture rapidly. In our tests at room temperature, 20°C and 55% RH PVA moisture level increased from 1% to 3% in 4 weeks.
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<1% H2O
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Best print quality
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>2% H2O
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Negative effects expected
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>4% H2O
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Do not use; significant negative impact
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Moisture determined using Precisa moisture analyzer XM50
To keep moisture level of PVA as low as possible, please observe the following:
- Don’t let it sit on back of printer when the print has finished
- Preferably store after use in a closed bag with desiccant
- In the UltiMaker Material Station PVA can be stored for up to 2 months without decrease in print quality
Drying wet PVA
The best way to dry PVA is by using a dedicated drying apparatus (oven or dry box) with precise temperature control, such as a PrintDry. Dry at 50 °C for 16 hours; several days if the filament is very wet.
An alternative way is by placing the spool on the heated bed at 55 °C for min. 24 hours. Use the original cardboard box, without plastic bag and including multiple bags of desiccant for optimal result.
Make sure that the filament has cooled to room temperature before loading the material in the printer.
Caution: Do not use a household oven and do not use temperatures above 55 °C because this can soften or crystallize the filament, resulting in brittle filament.
Tip: This procedure of drying filaments can be applied to other moisture-sensitive materials, such as UltiMaker Nylon, TPU 95A, and PC. The exact duration of drying is dependent on the material type, the amount of moisture in the filament, and the amount of filament that needs to be dried.
Store PVA in bag with desiccant
When storing the PVA in a sealed bag or box, add a few bags of fresh desiccant (silica gel). These will absorb the moisture and ensure that the PVA maintains its dryness level.
