Mold Removal

cda-fab-mold-1.png

Once we have the mold with fully casted and cured silicone, we need to remove the mold. Unfortunately, because of the monoblock structure of the actuator, we cannot simply open the mold and release the actuator. We must destroy the mold and the most effective method is to choose a mold material that is strong enough to hold up to the molding process, but is also soluble in certain liquids. We have chosen ABS because it is soluble in acetone, so we can simply dissolve it away.

  • Put the molds containing cured silicone into a bath of acetone.
  • After a while, the dissolving process has advanced in such a way that one can peel off the outer shell. The inner ABS structures will need more time.
  • One can accelerate the dissolving by slightly pulling away the silicone wall from the structure, with a spatula for example. Then, the gap created between the ABS and silicone can be filled with acetone. Another possibility is to inject acetone directly into the inner mold.
  • Due to the low density printing, there should be enough voids to fill. If enough acetone has entered the mold material, the dissolving will take much less time.

Bibliography

Loepfe et al. (2015) Contrast Agent Incorporation into Silicone Enables Real‐Time Flow‐Structure Analysis of Mammalian Vein‐Inspired Soft Pumps.

Loepfe et al. (2015) An Untethered, Jumping Roly-Poly Soft Robot Driven by Combustion.

Loepfe et al. (2014) Design, Performance and Reinforcement of Bearing-Free Soft Silicone Combustion-Driven Pumps.

Schumacher et al. (2014) 3D printed lost-wax casted soft silicone monoblocks enable heart-inspired pumping by internal combustion.

Shepard et al. (2013) Using Explosions to Power a Soft Robot.

Stergiopulos et al. (2014) A Soft Combustion-Driven Pump For Soft Robots.

Contributors

Michael Loepfe