labsw/LOG: added front plate milling results

labsw/LOG

@@ -32,7 +32,7 @@ PCB milling #2;
 PCB milling #3:
 - changes made:
   - corrected clearance
-  - Tesa 5767 mounting tape
+  - Tesa 5767 mounting tape (no longer available)
 - measurements:
   - column cavity: ~7.6 mm x 10.3 mm (nom. 8.0 x 10.4 mm)
   - board: 102.2 mm x 50.2 mm (nom. 102.0 mm x 50.0 mm)
@@ -84,6 +84,38 @@ Soldered #3:
   - the footprints of the 1 W resistors (R7-R10) are way too short.
     Placed 0805 instead.
 
+--- Sun 2011-09-04 ------------------------------------------------------------
+
+Milled face plate #0:
+- setup:
+  - board is pertinax
+  - locally sourced "W.T." (Taiwan) mounting tape
+- measurements:
+  - board: 104.0-104.1 mm x 35.1-35.6 mm (nom. 104.0 mm x 35.0 mm)
+  - button hole: 12.6-12.8 mm x 11.3-11.6 mm (nom. 12.6 x 11.3 mm)
+- defects found:
+  - engraving depth (0.2 mm) is a bit shallow, probably due to board
+    curvature
+  - got the banana jack diameter wrong: should be 8 mm, not 6 mm
+  - button holes show significant deviation from tool path on lower
+    edge
+- changes for next run:
+  - increase engraving depth to 0.5 mm (board is 1.6 mm)
+  - correct banana jack hole diameter
+
+Milled face plate #1:
+- changes made
+  - increased engraving depth to 0.5 mm
+  - increased banana jack hole diameter to 8.0 mm
+- defects found:
+  - job didn't complete because board became unstuck while milling
+  - the 8.0 mm hole is still a bit too tight if jack sleeve is at
+    upper end of tolerance range
+  - noticed that the button holes are milled last, after cutting the
+    board outline. This explains the poor accuracy.
+
+---------------------
+
 (next run)
 - changes made
   - made 5V relay traces go clearly for the centers of the respective pins