Following on from an old discussion thread about making your own PCBs, this information describes the manufacturing process.
“I’m using EAGLE at the moment. It’s okay as freeware and is reasonably priced for professional use. Almost all of the EDA tool vendors charge for their products, but EAGLE has a free of charge version that’s subject to terms, conditions and some limitations (see http://www.cadsoft.de/freeware.htm). It’s the main reason why Arduino used it.
I used several packages now, including Protel EasyTrax/98/99, Proteus, Orcad and ViewDraw. In principle they’re all doing the same job in a similar kind of way, but they have different user interfaces, e.g. key bindings, methods of doing “draftsman” stuff, general structure and accessibility of tools etc.
All Schematic/PCB software expects some preparatory work. You need to:
1. Invent something.
2. Analyse what you need to make it work.
3. Research what electronic and mechanical parts you could use and decide parts that best fit.
4. Collect the product data sheets of the chosen parts.
…then, you start work with the schematic design entry:
5. Open up a new page for your schematic, set the page size and border/frame, complete the designer’s information.
6. Browse the predefined component libraries for the devices you need. Curse when they’re not found.
7. Find the tutorial PDF to learn how to create new devices and save them in your custom library.
8. Find/create symbols and footprints for ALL of the parts you need.
9. Add the parts to your schematic, enumerate their identifiers and set their values. Curse when a single sheet isn’t enough.
10. Arrange the symbols on the sheet and connect them up accordingly with buses and nets.
11. Run the DRC/ERC tool to check that you’ve done step 10 correctly.
…then it’s PCB entry time:
12. Judge the required dimensions of the PCB. Often your choice of enclosure dictates this.
13. Export a netlist from the schematic and read it into the PCB tool.
14. Reposition the components so that they occupy their own space within the dimensions of the PCB. Take special care with connectors and any part that has lots of connections that may cause routing congestion.
15. Hit the auto-route button and go make yourself a drink.
16. Tweak the efforts of the auto-router, in particular up-size tracks that carry power.
17. Check that the component footprints have correctly spaced solder pads.
18. Run the ERC/DRC checker to flag up any silly mistakes like incomplete connections and overcrowding.
…then it’s make the PCB:
19a. Export the CAM file and upload to a PCB manufacturer of your choice.
19b. Print the “PCB artwork” onto lightbox drafting film or press’n'peel film, then complete the PCB etching and drilling as a DIY chore.
20. Assemble your circuit board.
So, there’s lots of value-add to the skills of the electronics engineer, which is why developing hardware will never be cheap!
HTH
- Rick”
