PCB Fabrication

A number of projects, including my senior engineering design project and instrumentation in the advanced physics lab have required custom PCBs.

Utilizing the dark room in the photo-lab at LMU’s art school, I exposed and etched the following boards using a positive tone photo-resist.  The masks were made from inkjet printable transparent film and the UV source from two 8 watt daylight white CFL bulbs placed 8″ above the mask.  An exposure time of ~8 minutes yielded the cleanest traces.  Ferric Chloride heated between 35-45 Celsius was used as the entchant. Proper disposal of the copper rich etchant was done graciously by the LMU’s chemistry department.

PMT Voltage Divider
A PCB with interesting geometry was needed to provide the bais voltage and stabilizing capacitors to the dynodes of a photomultipler tube (PMT).  The performance of the PMT and base was veridied and the working unit was coupled with a NaI:Tl scintillation crystal and used for the gamma spectroscopy system I designed for the physics lab.

As the geometry of this board was quite unique, I made the mask in SolidWorks as it gave me the most flexibility in defining geometry.

CaptureIMAG1704IMAG1723

Left:          SolidWorks rendering of the mask
Center:     Etched Board
Right:        Post Fabrication Work;    Excess geometry milled away and board propagated with passive components.

Senior Design Project Data Acquisition System
The following boards were used as part of a data acquisition system I designed for my senior design project.  This board holds a NTC thermistor and Honeywell pressure gauge to assay the conditions at various points in our pneumatic system.  Data from multiple boards was fed to the Aduino Micro-controller for processing and logging.  

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