additions

UrumbotXYZ/fixed_axis/README.md

@@ -44,7 +44,7 @@ PCB miiling:  Set speed at 4 mm/s.  As seen in the video, the tool is still pull
 
 <img src=./img/pcb.cmp.mp4 width=100%><br>
 
-Here's the board result:  
+Here's the board result:  The channels are much deeper than specified, ~ 0.2 - 0.5 mm.  Some distortion in the trace shapes.
 
 <img src=./img/fixed_z_pcb.jpg width=40%>
 
@@ -54,7 +54,7 @@ And wax milling:  At 10? mm/s.  The 1/8" single-flute endmill runs with some vib
 
 Wood milling result is better than moving-z configuration:
 
-<img src=./img/fixed_z_mill_wood.cmp.mp4 width=100%><br>
+<img src=./img/fixed_z_mill_wood.jpg width=100%><br>
 
 Loading work on the bed:  This frame gives plenty of room to move bed back for tool changes and to move bed forward for access to the work.
 
@@ -64,14 +64,15 @@ Loading work on the bed:  This frame gives plenty of room to move bed back for t
 
 ### Conclusions
 
-This configuration almost works, with dF/dz = 30 N/mm at spindle, and unknown but measurable stiffness in the rest of the mechanism.
+This configuration almost works for both PCBs and wax, with dF/dz = 30 N/mm at spindle, and unknown but measurable stiffness in the rest of the mechanism.
 
 #### Successes
 
  - Separating the axes makes it easier to evaluate and improve stiffness of either.
  - Nice geometry for access to work.
- - 
- - Almost works.  Results from Cam machine indicate that we are close.
+ - Good to have strings underneath frame.  
+ - Motors are all fixed to frame, and connections don't have to flex.
+ - Almost works.  The nice results from the limited-z machine (with 2 mm cam action) on PCBs indicates that we are getting close to sufficiently good resolution and stiffness for PCBs, and the wax results are encouraging.
  - 
 
 #### To be done.
@@ -79,4 +80,4 @@ This configuration almost works, with dF/dz = 30 N/mm at spindle, and unknown bu
  - Stiffen up z-axis
   - Better string, two strings, belt, leadscrew.
   - Evaluate bearing design and improve if it makes sense to do so.
- - Measure plate compliance (better word than stiffness?) and increase roller separation if it makes sense.
+ - Measure plate compliance (better word than stiffness?) and increase roller separation to stabilize if it makes sense.