Through hole plug carbon ink PCB

Currently, screen printing serves as the mainstream process for depositing carbon ink on PCB substrates. Carbon film is subject to strict electrical specifications with precise resistance control requirements. Sheet resistance refers to the resistance value measured between two parallel sides of a square conductive thin film material. Its theoretical calculation formula is Rs = ρ/T, where ρ is the inherent resistivity of the conductive material and T is the cured film thickness. For carbon ink of the same formula, the resistivity remains fixed, so the sheet resistance of carbon film is inversely correlated with film thickness. When the carbon conductive pattern and coverage area are finalized in design, the overall resistance is only determined by the coating thickness.

However, the traditional screen printing process cannot achieve precise thickness regulation, resulting in uneven carbon film distribution across the board. Such process limitations cause obvious resistance deviation, making it difficult to stabilize and accurately control the resistance parameters of carbon oil circuits in mass production.