Research On PCB Direct-write Technology With Metal Fused Deposition Modeling

Fused deposition modeling was introduced as to realize the application of PCB direct writing, given the fact that conventional copper etching for PCB layout is with complex procedures, cost-inefficient and not environment-friendly, and also the material for direct writing of new micro-fluid deposition is restricted to functional liquid slurry. To overcome the low endurance of high temperature of PCB, three steps, direct-writing – transference –post-treatment, were adopted, with thermo-stable ceramic board as transition which enables the completion of direct writing and image transference. This technical solution compromises the limited use of micro fluid deposition material and gives rise to a new and feasible technology of PCB direct writing.This paper unfolds the physics of pneumatic fused deposition modeling machines,analyzes the pressure-driven molten metal flow, builds up a nozzle flow model and accordingly highlights the impact of relevant parameters on outflow patterns and quality of deposition models. We have designed and built a pneumatic deposition modelling system, and here present detailed analysis of compositions and functions of movement system, pneumatic control system, temperature control equipment and software operating system.Based on fused deposition modelling and with the experimental material of Sn-0.7Cu,we focus on operating mechanism and properties of extrusion deposition direct writing equipment and demonstrate the feasibility of PCB direct-write technics from the perspective of technical principle. This paper, combining theoretical research and experimental data, elaborates on the influence on the size of the conductive pattern by air pressure, heating temperature, nozzle diameter, distance between the nozzle and board and trace rate; unveils the general patterns of unstable flow that sometimes accumulates or falls short(quality defects) during the direct writing and modeling.We have coordinated the multi-layer influence of each parameter in PCB layout experiments till an ideal solution is reached which can basically solve the quality defects.The solution is a nozzle of 0.2 mm diameter, producing a conductive pattern of 0.15 mmhigh and 0.3mm wide cross section and 10mm·s-1of stable layout efficiency. It reflects the reliability of this equipment and feasibility of PCB layout with pneumatic extrusion deposition technics.