Double Sided Milling

Here’s an update about some work we’re doing on Athena (which we’re currently crowdfunding at Indiegogo) at the moment.  We’re constantly improving it!

As you have seen on video, Athena does a good job at milling printed circuit boards.  However, what you saw was a single sided board.  So you may wonder: does it do double sided boards as well?

The short answer is yes.  But the complete answer is more complex.  Keep reading if you are interested.

Before milling a side of the board, the surface must be probed.  For probing to work, the copper layer must still be intact.  That means the holes must not have been drilled yet.  And that is a problem for two reasons.

First of all, the holes should be used for aligning front and back of the board.  There is a simple workaround for that: drill two holes outside the board from the front, and use those for aligning front with back.  Drill the rest of the holes after milling the back side.  We have not tested this, but there is no reason it wouldn’t work.

But there is a reason we haven’t tested it.  Double sided boards aren’t very useful unless the holes in them are plated with copper.  With the method described above, that is not possible.  The reason is that electroplating will connect traces that have been milled.  So it must be done before the traces are milled.  So that is the second problem.

The solution is simple, and it has been done by others as well: the probing code must know where the holes are, and avoid them.  When that is implemented, drilling the holes will be the first step in the process.  That is followed by electroplating, then both sides of the board are milled in turn.  Finally the board is cut out from the sheet. So the slightly longer answer is: we’re working on making Athena do usable double sided boards, and it’s almost working.  Once it is working, people who bought Athena will get the upgrade to Franklin, so they aren’t missing out on anything.

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