added initial results

README.md

 # emboss-today
 
 Rapid manufacturing of embossing tooling for permanently marking thin plastic.
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+![101st_impression](img/emboss-today_101st.jpg)
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+![mfg_tool](img/mfg_tool.jpg)
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+## need
+As part of our covid-19 face shield production efforts, we need to permanently mark units that end up in hospitals with a few basic identifiers: a manufacturing batch number and a shortened URL for assembly instructions. The Zund needs to spend its time cutting rather than marking, and doctors have complained about the smell of laser-engraved text.
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+## rapid embossing tool manufacturing
+Several letters were cut out of 0.5 mm Cu stock using our nanosecond laser micromachining system:
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+![oxfording](img/oxfording.mp4)
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+![tool_in_oxford](img/tool_in_oxford.jpg)
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+The coupons were punched out but the letters were left in place for electrochemical deburring in 14M H3PO4, ~1 minute, 3 VDC:
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+![tool_deburr](img/tool_deburr.jpg)
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+Letters were then carefully punched out using a sharp probe under the Lynx Evo inspection microscope. Each 6 mm letter was sanded on two opposing sides to remove remaining cut debris in preparation for soldering. A piece of 0.02 mm Cu sheet was cut with sheet metal snips, fluxed, and the letters carefully soldered on using SAC305 solder:
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+![tool_soldered](img/tool_soldered.jpg)
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+The tool was cleaned with IPA and attached to a desktop rack-and-pinion-style press using double-sided tape:
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+![mfg_tool](img/mfg_tool.jpg)
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+A piece of silicone rubber was similarly attached opposite the tool to prevent bottoming out on the metal platen:
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+![mfg_press](img/mfg_press.jpg)
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+The press was tested 100 times on a scrap of 0.5 mm PETG:
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+![mfg_100_tests](img/mfg_100_tests.jpg)
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+The 101st test was performed on a scrap of 0.75 mm polycarbonate:
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+![101st_impression](img/emboss-today_101st.jpg)
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+Further cycle testing should be done to test long-term durability.