FablabSU

For this tutorial we will be making an Xbee shield for the Arduino Nano. The goal of this sheild is to have the XBee S2 linked directly to the Tx/Rx pins while allowing for a series of analog and digital pins to be connected to some headers. The circuit also has a battery input and 3 digital outputs linked to mosfets for high power switches (used for motor/servo control). This circuit is double sided to make it as compact as possible (while using through-hole components).

For the sake of this tutorial, we can consider this circuit a “worst case scenario” as it will require us to understand many options/controls for the CIF and Galaad's Percival software. The respective files are found by contacting me at roycesflorian@yahoo.com

1. The first thing we must do is open the software “Gallaad Percival” Found in the Start Menu
2. Once loaded, you will be introduced to the “part view” with 2 header menus:
   1. Open Project
   2. Calcul Contours
   3. Calculate Surfacing
   4. Center Holes
   5. Final Result
   6. Export to CIF
3. We will select “Open Project” which will bring us to a classic “Select file box”
4. Once here, make sure we have selected “allow all formats” options
   1. We are interested in gerber formats. They will be listed as .GBL and .GTL formats
   2. We will start by importing “Theia-B.cu.gbl”
5. We have one side of our double sided circuit imported with a “rough dimension” that we will modify shortly
6. Hover over the “Open Project” button until a drop menu appears
   1. Select “Import additional layer”
   2. Select “Theia-F.cu.gtl”
7. We have no imported our second layer into the Percival work environment.
   1. Notice that the two surfaces are not alligned
   2. NOTE: We can cycle between the multiple surfaces: front/back/both/none by pressing“TAB”
8. We must now allign the two surfaces
   1. Select “Tab until” you have one of the two individual faces
   2. using the arrow keys move the circuit left/right or up/down to allign two know pastilles
   3. ZOOM into the work environment using the mouse roller to increase resolution
9. The two faces are now alligned but since we are using through-hole technology we must place our holes into the board
   1. NOTE: Standard hole diameter for MOST components is 0.8mm (800microns)
   2. NOTE: Header pins (also for Arduino) are slightly larger and I will be using 1.2mm
   3. NOTE: To easily determine the Via holes, I have selected a smaller diameter 0.3mm
10. Right click on a given pastille and select “modify all similar pastilles”
11. A menu will pop-up
    1. From this menu, know that it is possible to change the diameter/shape of any pastille
    2. We can equally change the thickness of a given track
    3. We CANNOT however change the placement or location of any given track/pad
    4. Pastille shape/diameter : default
    5. Pastille hole diameter: 0.8mm (for all but via/arduino/mosfets)
    6. Repeat this process until all holes have a drill hole placed in the center
12. Once all of the holes have been placed, select “parameters/tool selection”
    1. Engraving Tool:
       1. Tool: 3mm 30deg engraver
       2. Depth: 0.01mm (This will allow us to compensate for a lack of precision when finding the xy surface later on, REMEMBER the foil thickness is 0.15mm)
       3. Margin: 0.1mm (this is a tool off-set for the contours traced around the tracks)
       4. Engraving speed : 10mm/s is a good safe speed
    2. Surfacing Tool:
       1. Tool : 3mm 30deg engraver
       2. Depth: 0.1mm (ensures that we pass the foil)
       3. Margin: 0.02
       4. Surfacing Speed: 50mm/s
    3. Cut out tool:
       1. Tool: 3mm roughing mill (Remember that the project has been placed with a 3mm clearance around it's position on the CIF work table)
       2. Depth: 1.7mm
       3. Speed: 5mm/s
    4. Centering tool
       1. Tool: 0.8mm drill works fine
    5. Drilling Tools (VERY IMPORTANT)
       1. Not understanding this field is the cause of the majority of tool destruction while operating the CIF)
       2. We will select the third option “For each hole, use the tool with the next greatest diameter, WITHOUT hole boring”
       3. Select all of the given tools that you will need for your project
          1. 0.3mm
          2. 0.8mm
          3. 1.2mm
       4. This field merits some minor discussion. Imagine we only had a 0.8mm drill and we chose to drill 1mm holes. If we were to choose “For each hole, use the tool with the next greatest diameter, WITH hole boring” then the drill would first drill, then bore. The problem is that a drill is not designed for boring, and this will break the drill. If on the other hand we chose to drill 0.6mm holes with the same drill, it will drill a 0.8mm hole and may decrease the pad size where it is unusable.
       5. The option ““For each hole, use the tool with the next greatest diameter, WITH hole boring” should only be used IF AND ONLY IF you have chosen an end-mill as a drilling tool as it is designed for boring.
13. Select “OK”
14. Select “Center Holes” (2 holes is sufficent)
    1. Place the two holes (which are fixed to the same Y axis) on the board. Be carefull to avoid any tracks/pads. I placed my center holes outside of the circuit by a couple milimeters.
15. Select “File/dimension”
    1. Select the option “Reframe around the existing circuit with a margin of: 1mm”
16. Select the button “Calculate Contours”, wait for galaad to finish calculating
17. Inspect that all Pads and Tracks are properly seperated from one another
    1. The Yellow/Red contours define the tool path, Zoom into tight areas of the PCB to make sure that each and every track/pad has a continous contour.
    2. If any two zone are not seperated, the tool will not pass and the track/pad will have a false contact and the circuit will not work
    3. Select the “Final Result” button. To some people this view is more clear as you can see that everything in copper is the the copper that will remain on the board. Visually inspect the board for any tool defaults.
18. If there are any defaults select the faulty pad/track and change dimensions as explained in Step 11
19. Select “Calculate Surfacing”, wait for galaad to finish calculating
    1. NOTE: This step is not required in most circuits
       1. It should only be used when pads/tracks are grouped very closely together
       2. By removing all excess copper, the task of soddering is made much easier
       3. The downside of this operation is that it is generally very time consuming
          1. EXAMPLE: this circuit takes 30mins to engrave/drill/cut WITHOUT surfacing
             1. This circuit takes 50minutes just for the surfacing task then the 30 minutes of engraving/drill/cut
20. Save your project. You are now done with the Percival calibration portion of this tutorial and your job will be exported to the classic CIF machiene control interface.
21. Select the “Export to CIF” Button

Step 3: Machine Parameters calibration

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