3D Printing Tech Tips: Soluble Support Structures

Support structures printed with soluble materials like PVA, HIPS, BVOH, etc. are considered to be an effective replacement for breakaway supports. But these materials do not come without problems of their own. The following are some common issues faced while printing with soluble materials and one or more possible solutions for each problem.

Adhesion

Description: Soluble materials may not stick very well to the print bed. Some materials also do not adhere well to themselves or to other materials like PLA. ABS, etc.

Solution:

  1. Print with materials recommended by the manufacturer – No single soluble material works with all primary materials. Make sure you are printing with a soluble material that is compatible with your primary material.
  2. Use bed adhesion agents like hairspray, beer. Check the manufacturer’s specifications – not all bed adhesion agents are compatible with all materials.
  3. Reduce the print speeds. Soluble materials may print faster or slower than the build material.
  4. You generally want soluble materials to stick well to the primary material – so be sure to set the separation distance to zero.

Standby Temperature

Description: Soluble material crystallizes when allowed to sit in the nozzle at print temperatures for longer times. This causes nozzle jams and print failures.

Solution:

  1. Set a standby temperature that is lower than the print temperature.
  2. Use an ooze shield or priming tower to help prime the extruder on each level.

Support Removal

Description: Different soluble materials require different solvents and take different times to dissolve. For example, PVA dissolves in water but HIPS dissolves in D-limonene.

Solution:

  1. Check the manufacturer’s recommended support removal process.
  2. Warm water or stirring the solvent may speed up the support dissolution process.

Storage/Print Environment

Description: Soluble support absorbs moisture from the air causing the filament to pop, ooze out during printing due to evaporation of the water. It can also lead to nozzle jams.

Solution:

  1. Follow the manufacturer’s storage instructions.
  2. Keep in a dry area in a sealed bag.
  3. Do not leave the filament on the machine when not printing.
  4. Special storage boxes like ‘Polymaker’s PolyBox’ can be used to increase the shelf life of the filament.

Material Is Too Wet

Description: Material has already absorbed too much moisture to successfully print.

Solution:

  1. Purchase a vacuum drying machine.
  2. Build your own vacuum drying machine.

Strength

Description: Soluble material support columns are generally weaker compared to other materials and buckle easily under load.

Solution:

  1. Increase support density (> 75%).
  2. Add additional supports.

Material Prints Differently at Start of Job vs. End of Job

Description: The print job starts off okay, but adhesion worsens or the material makes noise (hissing/popping) during printing.

Solution:

  1. Material has absorbed moisture during job. Store material in a dry box during printing.
  2. Material is from a low-quality supplier without process controls. Purchase better material.