Vinyl Etching PCB Boards - 5V regulated power supply.

Intro

I've been dabbling with various methods to prototype PCB boards, and I thought I would share some of my latest work.

I've previously tried using the Sharpie + Ferric Chloride method and various perf/strip board methods but haven't been thrilled with the results.  I recently decided instead to start building a mini CNC based on the Mantis 9.1 design, but that work won't be ready for a while.  In the mean time, my coworker [2] showed me how to use our Silhouette Portrait to create a vinyl mask for etching, and it works remarkably well for both through hole and surface mount.

The design below is based on [victordas]'s Instructable design [1].

The Process

First, I started with the board layout provided from [1].  Alternatively, Eagle Cad can be used to create your own board layouts.  I also have a brief tutorial on Eagle Cad elsewhere on my blog.  Once the board layout has been create in Eagle Cad, turn off all of the layers (except for the traces, through holes, and surface mount pads) and save the image as a monochrome bmp file (not png or other filetype).  The bmp file format saves the correct scaling whereas png does not.  This is VERY important when you load the file into Silhouette.  

Fig 1.  Original board layout from [1].  I was fortunate that someone had already created my circuit, but normally I would need to draw it in Eagle Cad.  

While this is a great start, I really need a monochrome image of Fig 1. without all of the text and part outlines.  After a bit of work in Gimp and MSPaint (I know that I need to learn big boy image processing, but I'm procrastinating), I came up with the following image.  I didn't do it in this example, but I typically use mspaint to mirror the image about the y-axis so that I don't end up with a mirrored final product as shown in Fig. 6.

Fig 2.  Monochrome version of original layout.  This gets fed into the vinyl cutter.  

Fortunately, the scaling of the above images correctly matches the physical layout of the parts (e.g. each pin spacing of the IC is correctly spaced at 0.1 inch, etc).  

Next, I imported this image into Silhouette Studio, traced the outline, and created the vinyl mask with the vinyl cutter.  Fig 3. shows the vinyl mask placed on a single sided copper board.  Here is a copy of the Silhouette File I used to to make the mask.  

Fig 3.  Vinyl mask is placed on a single sided copper board and is ready for etching.  

Next, the board is placed in Ferric Chloride, and the resulting board is shown in Fig 4.  The etching fluid leaked under the vinyl a bit in a few places.  

Fig 4.  Ferric Chloride has etched away the exposed copper from Fig 3, and visible copper traces remain after the vinyl is removed.  

The next image shows the board after it has been polished (steel wool) and drilled.

Fig 5.  The board has been polished and drilled.  

 This final image shows the final board with all of the components mounted and soldered.  I didn't have a 2.2Ohm/1W resistor so I used 4x10Ohm/0.25W resistors in parallel.  As I mentioned before, I should have mirrored the monochrome image so that the final product was backward.

Fig 6.  The components have been mounted and soldered.

Conclusion

The vinyl cutter isn't particularly inexpensive [3], but it is significantly easier and less trouble to use than perf/strip boards or the sharpie etching method.  I strongly recommend this to anyone willing to spend less than $200 for a relatively quick and trouble free PCB prototyping setup.  

I'm hoping my mini CNC will be even better than this, but the amount of work to build my own CNC (even using the pre-existing Mantis 9.1 design as a baseline) has taken a fair amount of work/time/money.

References

[1] http://www.instructables.com/id/Super-clean-5V-power-supply/

[2] https://www.youtube.com/channel/UC8KeMEKSLE5paGtjatYALRg/videos

[3] Silhouette Portrait