Synthetos

How to make an Eagle Solder Mask Stencil for an Laser Cutter

Hide the all of the layers.  Then display only the Dimension and Tcream.  (Note: in the screen shot its the document.. it needs to be Dimension).  Also change the fill style for the cream layer.  It is a “hatch” looking pattern by default.  We want a solid color pattern.  I left the color Grey.  When we print the PDF it will turn it black anyways so it does not matter. Click ok.

Now you need to click Print and then click the PDF button.  This is going to get us a vector format of the stencil.  However, for some weird reason the PDF writer in EAGLE creates some sort of non-standard PDF (not sure exactly).  This does not allow us to just import this into Corel Draw (corel is what the vector cutting drivers work  for the epilog laser cutter).

So scroll down to see the next step.

Now you will need to download Ghostscript and Gview for your platform.  Here is the windows links.
http://mirror.cs.wisc.edu/pub/mirrors/ghost/GPL/gs864/gs864w32.exe – Ghostview
http://mirror.cs.wisc.edu/pub/mirrors/ghost/ghostgum/gsv49w32.exe – Gview (Windows GUI for Ghost Script)

Ok once those are installed go ahead and open Gview and then open the PDF we created above.

Now click File >> Convert.  Select the EPS Write and type in 1200 dpi.  Then click OK and save it. You now have the file you will be loading into the epilog laser cutter.

Open up Corel draw… Ungroup everything (if needed) and check the outside lines for duplicates.. Meaning select a outer line and delete it… If you see another line.. Delete that one until the lines are no more.. Then just undo the last delete.  Why do we do that?  For some reason Ghostscript from time to time adds multiple lines on the outside.. Not sure why.  But if we do not delete them we will have the laser cutter going over everything (at least the outter edges) 2x or 3x.  Ok so you have removed all duplicated lines and now you are ready to select all and make the line width a “hairline” width.  This is something that corel calls it.  This is the #1 reason that you can only use Corel draw to do cuts (vector stuff) with the epilog.  So anyhow.. Now you should print it out.  Setup your desired epilog settings (based on your material) and have at it.

Your done!   (DFX is here: Goodget 2.1 stencil dxf)

Tags: laser, Laser Cutter, laser cutting, pcb, smd, smt, solder mask, soldering, stencil

PCB Cyborg Art

So I had some free time while waiting for Alden to proof my xproto breakout board I designed for the tinyG system that we are working on.  So I took some time to try to mimic the results that Joe Grand of Grand Idea Studios did on his professional PCB mill.  I think the results were pretty good.  In fact they were even better than you see on the final version.  I say this because currently I have a very coarse wire brush on my grinder and did not take the time to switch it to a much finer wire gauge.  I was lazy.  As you can see some of the building is coming off.

Also in the middle there was some “over burn” where I left it in contact too long.

This has kind of inspired me to do some neat graphic / electronics.  Not sure what I am going to do but this would have been much cooler if the cyborg’s eye lit up and would blink faster / slower based off of the temp in the room etc…

Tags: art, defcon, etching, laser, pcb

Magnetic Linear Encoder – and it works :)

For awhile now I have been meaning to try to find a way to close the stepper motor “loop” on CNC devices.  What started as an need / idea turned into reality last night.  A few weeks back cruising thingiverse.com I found a post where Zach had created a magnetic linear encoder.  However his design was off and needed fixing.   Instead of re-inventing the wheel with a different linear magnetic chip I decided to use the same setup as Zach.  I contacted him about fixing the problem with the board (the footprint was off) and in about 3 hours after emailing him he had it fixed.

I have blogged about laser etching PCB’s in the past (you can read about it here).  The inherit problem with laser etching PCB’s is that is it very hard to get aligned if its a double sided board.  So I modified Zach’s design to be a single sided board.  Its tight in some spots but if you use the solder mask I created and have a somewhat steady hand its doable.  Here are some pictures of the process and a video of it working!

The AS5306 can be found here:
http://www.austriamicrosystems.com/eng/Products/Magnetic-Encoders/Linear-Encoders/AS5306

Thingiverse entry and files here:
http://www.thingiverse.com/thing:1409

Tags: arduino, AS5306, austria micro systems, linear encoder, linear motion, makerbot, pcb