As noted in the previous post, we have been having difficulty cutting the polycarbonate capillaries due to their tendency to fuse together from the heat generated during the cutting process. This week, we tried cutting the tubes to an appropriate length using various new methods, and here are some pictures showing the results:

The results of cuting our capillaries using various tecniques

In our first attempt, we switched to a coarser saw which allowed us to use water coolant, though it resulted in a very rough cut. We tried to smooth the edges with heating, however this was unsuccessful (1). Note the side view demonstrating the burrs and the roughness from using the coarse blade (2). Finally, we filled the capillaries with water and froze them before cutting with the coarser band saw. The ice supported the tubing and burring was significantly reduced, though considerable debris remained from the cut (3).

We are currently working on clearing the capillaries of debris as well as keeping a look out for alternative cutting strategies. Once we have produced the capillary system, we will pursue testing its ability to produce laminar flow in our spirometer.