Preliminary-Design.md

 # Preliminary Design
 
 This page serves to collect thoughts and concepts related to the project design, to be considered before agreeing on a final design.
+
+## Specifications
+
+### Panelisation (please review and copy to final)
+
+A SMT panel is **four devices large**, in a two column matrix. The SMT engineer is responsible for the panlisation, which specifies individual boards (can be rotated 180°) with no offset.\*
+
+\* That means the bottom edge of each row of boards is aligned, and the left edge of each column of boards is aligned.
+
+### Dimensions (please review and copy to final)
+
+The maximum width of each device is **64mm**.
+
+* 145mm SMT tooling maximum width
+* 5mm rail edges
+* 2,5mm tabs
+
+#### Notes
+
+There is probably a way to gain a few millimeters, for example by using V-cuts or routing to mouse bited rail edges without tabs.
+
+A radical measure would be to abandon two column matrix panels and specify a device area up to 145mm wide in that case.
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