CARNEGIE MELLON Department of Electrical and Computer EngineerJ Manufacturing Mechatronics Using a Recursive Mask and Deposit ( MD ) Process
A new technology for manufacturing mechatronics is described. The technique is based on recursive masking and deposition of thermally sprayed materials. Using these methods, structures can be created that embed and interconnect electronic components, resulting in highly integrated mechatronic devices. A simple, electromechanical artifact was designed and produced to assess the feasibility of these techniques. The details and limitations of this project are discussed and areas of future research are identified which are aimed at realizing the full potential of this emerging manufacturing process.
A Framework for Thermal Spray Shape Deposition: The MD* System
Abstrnct This paper present.s t.he framework for a solid-freeform-fabrication syst.em based on thermal spray shape deposition t.o build mult.i-mat.erial st.ruct.ures by incremen tal build-up of t.hin cross-sect.ional layers. The basis of theMD* System (recursively, Mask and Deposit.) is to spray each layer using disposable masks to shape each layer. A thermal spray approach has the potential to build dense parts with desirable mechanical properties. Metal. ceramic, plastic, laminate, and composite structures can be deposited. Since l11asking enables selective deposition wit.hin a layer, complet.e assemblies composed of different mat.erials can be creat.ed in a single process. For example, int.egrated electronic/mechanical structures are feasible.
Failure analysis for poor solderability of Au surface of PCB
Nonwetting is one of the common problems and is always rejected in electronic assemblies. ENIG pads of a PCBA exhibited nonwetting after lead-free reflow soldering. With the aid of stereomicroscope, SEM&EDS and XRF, a series of analysis was performed. And after visual inspection, surface and cross section analysis, thickness measurement and solderability test, it can be inferred that oxidation of plating surface was the main reason for nonwetting, and corrosion in Ni plating caused an adverse impact on solderalibity.