Update README.md

README.md

@@ -38,6 +38,8 @@ Here is a 50% scale flexure (.010" beams, .015" gaps) machined from .020" thick
 
 <img src='images/flexure-0.5-penny.jpg' width=300px>
 
+Here is a paper about micromachining aluminum using tools with diamond-like coatings: <a href='https://pdfs.semanticscholar.org/a9d5/532adaf5fa1b22940a921fc9cdf2ea76b555.pdf'>Diamond coatings for micro end mills: Enabling the dry machining of aluminum at the micro-scale, Heaney et. al.</a>
+
 
 
 ## [Fablight fiber laser](http://cba.mit.edu/tools/display/?type=tool&id=fablight_3000_laser_cutter)