Fab Lab Rwanda · Group work
Electronics Production
Our group workflow covers two fabrication paths: establishing the lab PCB process limits and preparing a board for an external manufacturer. Toolpath generation, machine control and design-rule verification are recorded as separate steps.
In-house design-rule test
We will use a labelled coupon with several trace widths and isolation gaps, plus representative pads and board edges. The source should make the nominal dimensions explicit. For a milling process, the effective width of a V-bit depends on its geometry and cutting depth, so a nominal tip diameter alone does not establish the minimum gap.
We will identify the substrate, cutter, CAM software, origin, spindle speed, feed, plunge, depth per pass and total depth. Isolation and outline operations should have separate settings and workholding checks.
| Check | Observation | Decision |
|---|---|---|
| Toolpath preview | Whether every intended isolation channel is generated | Revise the geometry or CAM settings before milling. |
| Milled coupon | Trace survival, copper bridges, burrs and edge quality | Choose rules from repeatable successful features. |
| Electrical check | Continuity along traces and isolation between neighbouring nets | Confirm the visual result electrically with power removed. |
| Assembly | Pad condition after soldering and handling | Check that the chosen rule is usable beyond the bare coupon. |
CAM and machine-control workflow
Toolpaths must be generated and inspected before they are sent to the controller. OpenBuilds CONTROL can serve as the machine-control stage; it is not a substitute for the preceding CAD/CAM decisions.
For troubleshooting, we will keep the actual console message, the relevant toolpath line and the controller version together. An error number without that context is not a portable diagnosis. After changing a setting, a small repeat cut should show whether it resolved the issue.
External board-house preparation
We will choose a manufacturer and apply its published capabilities to the actual board: layer stack, minimum features, drill sizes, clearances and board outline. The production export should include copper layers, solder mask, silkscreen where used, drill files and a closed outline in the manufacturer's requested format.
The comparison continues through the manufacturer's final submission stage: inspect the uploaded layer preview, dimensions, drill interpretation, selected options and any DFM warnings. We will retain the submitted export and screen captures of that review. Placing or paying for an order is not required for this workflow.
Comparing the two routes
The in-house process gives immediate access to the board, but its usable feature sizes depend on the measured coupon and assembly result. A board house offers different process capabilities and lead times. Our comparison should use the actual local test and chosen manufacturer's submission, rather than assume a universal trace width.