Double Sided PCB

Introduction

Using previous knowledge from your First PCB you can create a double sided PCB, meaning both the top and bottom sides of the copper FR4 material gets utilized. A similar approach will be used to create the double sided board, the only difference being the LPKF Contac S4 machine to create the through hole plating. 

Start by opening the board template called "DoubleSided_GalvanicTHP.cbf". The Galvanic plating is the LPKF Contac S4 machine that will be used in later steps.

Follow the First PCB steps to open your gerber files in the software. Choose the top copper, bottom copper, and profile outline. You should be here:

If you have trouble defining the layers or need help, refer back to the First PCB tutorial.

Fiducials

Fiducials are used by the Protomat to know exactly where the board is placed when moved around. As the board flips, the machine is able to understand the coordinates of your board to create the double side. 

To create fiducials, press the fiducials icon and place ~1.5mm fiducials around your board. We recommend placing 4 on each corner. 

Here are the finished fiducials:

At this point you can press "Process all" and go through the necessary checklist such as material thickness and placement. Again, if you don't remember the process for this part refer back to the First PCB tutorial. The milling machine will now complete stages up to the "DismountMaterial" stage.

When the job reaches the "DismountMaterial" stage, release the now board and follow the steps for the Through Hole Plating tutorial to create the vias. Here is the tutorial for the Contac S4 machine.

Now that you finished the through hole plating, it is time to mill the bottom side of the board. Firstly, change the material thickness by a factor of 18um as that is the added copper from the plating machine. ***

Now under the operate window, select ReadFiducialsBottom and press start. The camera should now start detecting the fiducials. Confirm each fiducial by selecting "Yes" for each one. If it does not line up, select "No" and retry the scan.

Once done, move to the next operation or simply click the middle button to do the rest automatically.

The bottom side will now be milled around the vias that you created. 

Once done, the software will ask you to flip the material horizontally. Continue by processing the top milling step. The machine is ready to mill the top side and complete the rest of the board.

Once the board is completed, you should have a naked double sided PCB and ready to use the LPKF ProtoFlow S4 oven to solder your components! 

Add finished project photo