| Abstract Scope |
Electrical methods of 3D-printing process monitoring are fast and inexpensive. In contrast to cameras, they are amenable to sensing sub-surface defects such as interlayer defects. For nonconductive materials such as polymers, capacitance measurement is suitable. For conductive materials such as metals and polymers with conductive fillers, resistance and inductance measurements are suitable. Resistance measurement requires electrodes of higher quality than inductance measurements, due to the electrode-print interface resistance contributing to the measured resistance. Furthermore, the inductance is more sensitive to current path direction changes than the resistance, due to Faraday’s law. The electrical attributes are affected by in-plane defects (e.g., voids), interlayer defects and the printed line orientation relative to the electrical attribute measurement direction. For example, a defect intercepts the electric field lines from one electrode to the other, thereby affecting the electrical attribute, with the degree of the effect being sensitive to the position of the defect. |