Saturday, January 8, 2011

Printed Circuit Board challenge, using an ordinary Cricut

I love making electronic hardware, I have been only at it for under 3 years but it is a rewarding hobby. I sometimes worry about the reliability of the things though if I ever decide to get into the manufacturing business and selling my creations. I have been researching different ways to do up printed circuit boards to give my amps and pedals more reliability and durability.

For Christmas, the wife and I were given a used Cricut by the parents. It was due to them upgrading to the next larger model, but I have been thinking of other ways to use it besides cutting and/or drawing on paper/vinyl/foam, it's intended use. Now scrapbookers have quite a community for the Cricut but they are constrained by the cost of the $80 font cartridges that are required for the Cricut to operate.

Looking around on Youtube revealed some interesting things, namely 3rd party software out there that does not require the use of the expensive cartridges to operate the thing. One software package, Sure-Cuts-A-Lot, eliminates the requirement of the cartridges altogether, and allows you to 'print' TrueType fonts and custom layouts using the Scaled Vector Graphics (SVG) format directly through the USB port. Another is to flash the Firmware which will open up the device completely and allows you full control of the steppers and solenoids, the Open Source FreeCut (GPL), but this will obviously void the warranty, as there is no way to reflash the original Firmware back onto the device. This thing is a hacker's dream to turn it into a general purpose CNC machine.

My challenge has been figuring out how to either physically cut out a Copper-clad Garolite G-10 epoxy board into traces, quickly and easily without destroying the Cricut itself. This will cost a lot of blades to do this...or an even better solution is to get my hands on the pen-holder and find an etch-resist pen that will fit it, that I can draw out a mask and drop the printed board in Ferric Chloride and etch away the exposed copper.

Unfortunately the form-factor of the Cricut only allows miniature pens and markers...and no pen-manufacturer produces a miniature industrial-grade marker that can withstand Ferric Chloride or other etching agents. I could probably disassemble the Cricut and give the carriage more head-room by removing the keyboard assembly to allow for full-size etch-resist pens to fit...or I could hack and replace the guts of a mini marker with the industrial grade ink, to fit the Cricut without modding it.

More on this as I come up with more info...and Pics and video will be included as the project unfolds.

2 comments:

  1. See my blog post the other day on this very topic..

    http://everhack.blog.atxhackerspace.org/2011/03/12/pcbs-on-the-cricut/

    -David

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  2. To answer your question, yes, I do run the board through the machine directly. I'm using the thinnest 1-sided board I could find, 0.015 thickness. However, in taking the machine apart I noticed the pressure roller should be able to easily handle a "regular thickness" PCB. You'll just need to make sure your cutting/scratching implement will still clear the board.

    There's no modification necessary to the machine, just find a good scratching tool like a nail or deck screw and wrap some metal or packing tape around it to the proper thickness for holding tightly in the clamp.

    I did find that my acrylic paint resist didnt scratch off all that evenly, wanting to "chip", but I read that Future floor wax or maybe a lacquer spray paint might be a good alternative.

    Since I don't use the blade, it doesn't dull it, and it's not cutting the copper anyways, only scraping off the etch resist coating. Trying to use the blade only adds a bunch of inaccuracy to your output with the swivel offset.

    -David

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