Its been a while since my last post. I have been trying to solve some problems associated with the machining of clay using CNC machines. The last object I machined was fired to low bisque at 700℃. It was quite wearing on the tool but also had some breakout near the edges of the form as the clay was brittle which led to a series of investigations. I carried out a series of tests using the CNC machine to cut into clay.
- CNC cut green porcelain that and also green porcelain that has been adjusted with Linseed Oil, Gum Arabic and Glaze Hardener.
- CNC cut grogged green clay
- Create a more open structure and CNC machine
- Use was to reinforce the sides of the green forms
The results are illustrated below.....
Findings from these tests...
- CNC cutting is cleaner and easier on tooling when used on greenware. Using additives; linseed oil, gum arabic and glaze hardener in the measure 1% additive to 99% water by weight seemed to make no difference to quality of cutting on green ware.
- Wax coatings assists with preventing breakout but melts on contact with tooling so clogs up machining area, a harder machinable wax might prevent this but is an expensive option
- Grogged green terracotta clay also cuts well but crumbles a little
- Open forms break easily, they are very fragile
- Try adding gum arabic in greater quantities to see if the green body holds together better during machining.
- Continue exploring forms and ways to create component parts using the CNC machine and designs created on Fusion 360
- Explore creative ways to record methods
- Keep exploring reductive methods of creating forms revealing subsurface structures and pattern.