Edit group documentation

docs/group_assignments/group2/assignment3.md

@@ -15,16 +15,19 @@ authors:
 
 ## Cutting a test piece and measuring the dimensions
 
+First we laser cut a 20.0mm x 20.0mm square. However, closer inspection reveals that is not what we get:
+
 ![kerf](./assets/assignment3/kerf_meas_1.JPG)
 ![kerf](./assets/assignment3/kerf_meas_2.JPG)
 ![kerf](./assets/assignment3/kerf_material_thickness.JPG)
 
 drawing:
-20x20
+20.0 mm x 20.0 mm
 
 measurements:
-19.77x19.87
-thickness 2.85
+19.77 mm x 19.87 mm x 2.85 mm
+
+From this we can calculate the kerf. It is the theoretical width - measured width, which for this material was **0.18mm**. 
 
 ## Testing to change the focus of the laser cutter
 
@@ -34,23 +37,12 @@ The results are shown in the Figure 1. We first used settings for MDF material b
 actually HDF, and we changed the settings. As can be seen from Figure 1, the difference...
 
 ![kerf](./assets/assignment3/cut_focus.JPG)
+Figure: HDF setting used for above and MDF below (both materials are HDF)
 
 ![kerf](./assets/assignment3/cut_focus-2.JPG)
+Figure: Varying focus height
 
-
-
-Figure 1
-
-
-
-Table
-Focused
-1 mm above
-1 mm below 
-4 mm above did not cut out
-4 mm below 
-
-Others were cut through but not the 4 mm above
+We can see that going too far with the focus causes excess burning. Even still, others were cut through but not the 4 mm above. Maybe the next figure explains why:
 
 ![kerf](./assets/assignment3/focus_laser_theory.JPG)
 Schematic figure