Shrinkage, drying, deformation and cracking

CRACKS

  • DIFFERENT SHELL THICKNESSES: Printing with different shell thicknesses can cause internal stresses in the ceramic material, leading to cracks forming during drying and firing.
  • UNEVEN OR TOO FAST DRYING: Rapid drying or uneven drying can cause stress and warping in the ceramic material, resulting in cracks.
  • MATERIAL THAT IS TOO HARD: Using a ceramic material that is too hard can increase the likelihood of cracks during drying and firing.
  • PRINT BED THAT DOES NOT ABSORB MOISTURE: If the build bed is unable to absorb moisture evenly, the bottom of the part can remain damp, while the top dries faster, causing cracks.

UNDERSTANDING RETREATS:

  • It is important to consult the technical table of the ceramic material used to understand the specific shrinkage rate. Ceramic materials can shrink from 5% to 25% of the volume during the drying and firing process due to the evaporation of water.
  • Shrinkages are an intrinsic phenomenon in ceramic 3D printing and cannot be completely avoided. It is essential to take this into account when designing and planning the manufacturing process.

DRYING:

  • Drying should take place in a temperature- and humidity-controlled environment. This will help minimize internal stresses in the material.
  • Again, please refer to the technical table of the ceramic material for specific drying instructions.
  • In some cases, turning the workpiece upside down during drying or partially covering it with a thin plastic film can help maintain a more even drying and prevent warping.