Monday, November 22, 2021

X-ray timelapse of fluid movement in plants, stop-motion animation, sensor teardown/repair

I repaired a large digital x-ray detector and used it to record timelapse and stop-motion animations of plants, a clock, and a camera lens.



Applied Science X-ray backscatter imaging system: https://www.youtube.com/watch?v=H7ldYhzKAp4
Applied Science CT scanner: https://www.youtube.com/watch?v=hF3V-GHiJ78 
Octave (open source MATLAB alternative): https://www.gnu.org/software/octave/index 
Mouse movement recorder software: https://sourceforge.net/projects/mousecontroller/ 
Thank you for your support on Patreon: https://www.patreon.com/AppliedScience 
Thank you, Amir, for the X-ray sensor and software!

Saturday, September 25, 2021

Underwater laser cutting and silver sintering to make ceramic circuit boards

 

Thermal stress cracking can be completely avoided by CO2 laser cutting thin alumina sheets underwater.  I also show how to formulate and apply silver paste, then sinter in a kiln to produce double-sided ceramic printed circuit boards with conductive vias.

60W CW CO2 laser at 80% power.  10mm/sec.  Standard lens focal length (50mm).  2mm water above ceramic.  180 passes to cut through 0.75mm thick alumina.  

Silver paste: 97% silver powder, 3% glass powder by mass.  Particle size 1 micron or less. Add poly vinyl alcohol mold release until desired consistency reached.

Paste applied with 4 mil thick vinyl stencil.  Dried in air 10 minutes, then rapidly brought up to 900*C, held for 10 minutes, then rapidly brought back down to room temperature.  Total cycle about 45 minutes.

I measured electrical conductivity of the finished traces from my process with vinyl stencils: 4 milliohms per square at 10 micron final thickness.  This is pretty close to the Dupont published spec ( less than 2 milliohm/sq at 16 micron thick)

Underwater CO2 laser cutting reference: https://sci-hub.se/10.1016/J.JEURCERAMSOC.2011.06.015
Raspberry Pi picoReflow oven controller: https://apollo.open-resource.org/mission:resources:picoreflow

Applied Science on Patreon: https://www.patreon.com/AppliedScience

Saturday, July 31, 2021

Atomic Layer Deposition of copper - If you like sputtering, you'll love this!

 



An explanation and demo of atomic layer deposition (ALD) of copper metal on glass.  Precursors are copper(I) chloride and hydrogen, processed in a hot-wall tube quartz tube furnace.


10 torr operating pressure

500 sccm argon sweep/purge gas constantly flowing

75 sccm CuCl argon pulse gas (17 seconds including flow controller lag)

100 sccm H pulse gas (14 seconds including flow controller lag)

7 second purge time between pulses

100mm quartz tube furnace diameter 

415*C deposition temperature

350*C CuCl evaporation temperature

Substrates are mostly borosilicate glass cleaned with RCA clean

The "good" samples shown in the video are about 750 cycles (about 9 hours


Main ref:

https://sci-hub.se/https://doi.org/10.1002/cvde.19970030107

Also helpful:

https://sci-hub.se/https://doi.org/10.1063/1.5087759

https://sci-hub.se/10.1149/2.0261501jss

https://sci-hub.se/https://doi.org/10.1016/0022-0248(92)90191-K


Alicat flow controller manuals (hard to find via website navigation):

https://documents.alicat.com/manuals/DOC-MANUAL-MC.pdf

https://documents.alicat.com/manuals/old/Gas_Flow_Controller_Manual_rev7.pdf

https://documents.alicat.com/Alicat-Serial-Primer.pdf


RCA clean: https://en.wikipedia.org/wiki/RCA_clean


CuCl synthesis: http://wwwchem.uwimona.edu.jm/lab_manuals/c1901exp35.html


Support Applied Science on Patreon: https://www.patreon.com/AppliedScience

Monday, February 22, 2021

Measuring human digestive efficiency vs. a flame

 "200 Calories" on a nutrition label doesn't describe the total flammable caloric content. I explore the differences between digestible and flammable calories using a homemade calorimeter with glass windows.






Pressure sensor:
https://www.digikey.com/en/products/detail/te-connectivity-measurement-specialties/M5842-000005-10KPG/7592854 Schedule 160 pipe on McMaster: https://www.mcmaster.com/7733K259/ 32 ga nichrome wire: https://www.amazon.com/gp/product/B07DL4DSWD/ Power supply (used for ignition wire): https://www.amazon.com/gp/product/B07SS77N7K/ Keithley 6.5 digit multimeter: https://www.tek.com/tektronix-and-keithley-digital-multimeter/dmm6500 Tek MSO 4 series oscilloscope: https://www.tek.com/oscilloscope/4-series-mso-mixed-signal-oscilloscope Soylent: https://soylent.com/ Support Applied Science on Patreon:
https://www.patreon.com/AppliedScience