How can I make an inner board outline cut-out

• How can I make an inner board outline cut-out
  Posted by ARQuattr on 17 Feb, 2012 04:48
• I'm trying to define an outline for a round board with a large hole in the centre.  If I make the circles and select them both, and try to do 'Design -> Board Shape -> Define from selected objects' that doesn't seem to work.  Is there a way to do this, or should I just draw the outlines on a mechanical layer and leave the board shape defined by the outer circle?  Thanks
• #1 Reply
  Posted by Psi on 17 Feb, 2012 06:10
• I've not used it to get a board done, but i did notice that there's a menu option/tool for placing a board cutout.
  
  From the menu,  Design - Board layout - Define board cutout.  (then click the corners you want.)
  
  But im not sure if thats the correct why to do it.
  
• #2 Reply
  Posted by ARQuattr on 17 Feb, 2012 12:42
• Thanks Psi, not sure how I missed that - it's even on the same menu. 
  
  That does allow the inner cut-out, but as far as I can tell I can't make a circle with that option.  I tried making lines with the arcs in four corners and the changed the radius of each, but it's a little cumbersome.  Is there a way to just make it a circle?
• #3 Reply
  Posted by dfnr2 on 05 Mar, 2012 02:48
• You can define 2D regions then click the "Board Cutout" checkbox to create cutout regions.  This makes square cutouts, but you can then click on the region, place the cursor over a corner, then while holding down "Ctrl-A", drag the corner inward.  That will create a rounded corner.  You can drag it inward to increase the radius, so if you start with a square with edge length of the intended diameter, then change the grid so a grid point is on the center of each edge, then you can turn the square into a circle.  Then click "Board Cutout" in the properties dialog.  I searched for a way to create a region from primitives or polygons, and couldn't find it.
  
  I expected the Board Shape <-> primitives tools to include cutouts, but I tried and couldn't make that happen.  Perhaps I missed something.
  
  The easiest way is to have a mechanical guy do the board, including cutouts, in a MCAD program and export a STEP file, then create the board from the STEP.  That's what I do when I can.  If you don't have a mechanical guru working with you, but you are decent with an MCAD program and have one available, I'd say it's still the best way. 
  
  Dave
• #4 Reply
  Posted by ARQuattr on 05 Mar, 2012 04:42
• Thanks.  Right, I agree importing a STEP or DXF is a lot easier and generally how I do it - I was just hoping there was an easy way to do this directly in Altium for simpler board shapes.
• #5 Reply
  Posted by Rufus on 05 Mar, 2012 12:04
• Quote from: ARQuattr on 05 Mar, 2012 04:42

  Thanks.  Right, I agree importing a STEP or DXF is a lot easier and generally how I do it - I was just hoping there was an easy way to do this directly in Altium for simpler board shapes.
  

  
  From Tools | Convert you can create a region from selected objects then change the region properties to be a board cutout.
• #6 Reply
  Posted by ARQuattr on 07 Mar, 2012 12:51
• Perfect! Thank you.  Actually there's also Tools->Convert->'Create Board Cutout from Selected Primitives' in Summer '09 which saves a step.
• #7 Reply
  Posted by EEVblog on 07 Mar, 2012 13:08
• You could also place a pad, with zero pad size and a large drill hole.
  
  Dave.
• #8 Reply
  Posted by ARQuattr on 07 Mar, 2012 13:13
• Thanks Dave, good idea.  I assume if it's big enough the PCB fabricator would know to route and not drill it, even though it would show up in the drill file?  Is that a human-made decision or do they have automation that works that out?