| Factors | Lower level | Higher level | Optimum |
| Size of raw material (µm) | 50 | 200 | 100 |
| Amount of porogen (g) | 20 | 40 | 30 |
| Amount of clay (g) | 55 | 78 | 66 |
| Amount binder (g) | 2.0 | 5.0 | 4.0 |
| Viscosity of ceramic paste (Pa∙s) | 24.0 | 28.0 | 26.7 |