Champaign-Urbana Community Fab Lab

Inspired by a post on Adafruit Industries blog about someone who engraved "Don't Panic" on their Kindle 2, I decided to personalize the Kindle DX Graphite that I purchased to read large the huge stack of PDFs that my professors hand out in class.  This project turned out to be a mixed success; I hope that anyone thinking about using an Epilog laser can use what I've learned.

Knowns:

Gregor Reisch, Margarita Philosophica, 1508

• The folks at Adafruit used settings of 80% power and 100% speed on their 35 watt Epilog Laser cutter/engraver.
• The CUC Fab Lab has a 50 watt laser, so assumiong that power is linear and the mechamisms for both lasers run at the same speed, a setting of 56% power and 100% speed should be appropriate for our laser cutter.
• The dimensions of my Kindle DX Graphite are approximately 10-3/8 H x 7-1/4 W.  I also decided that I needed 2-1/4" on the top, a 1-3/4" margin on the bottom, and 1/4" on the sides so that I didn't overlap the manufacturer's printing.  The 1/4" margin is there so that I don't print on the curved edges of the device -- the engraving is likely to be at a different effective power and/or distorted there.
• When laser-engraving on metal, Cermark Spray is often used to blacken the engraved area.  I e-mailed the Adafruit folks asking if they used such a spray on the Kindle in the blog post, and they said that they hadn't used it.  Even so, I was still unsure about what color the engraved image would be.
• Putting my name on my Kindle will look good, regardless of what color the resulting text is.  The image I selected (an ancient drawing of the algorist and the artihmetist) wouldn't look as good if it were printed in the negative.

Unknowns:

• What color will the engraved image be?  Will it be lighter or darker than the metallic back surface of the Kindle DX Graphite?
• When it comes down to it, what material is the back panel of the Kindle made out of?  It certainly looks metallic, but it may be electroplated plastic.  Will we get the worst of both worlds when engraving on it?

How did it go?

Kindle Engraving Results

It was a mixed success.

The engraving did, indeed, produce black text without Cermark spray, but the black proved to just be ash from the engraving process and came off with a paper towel and a little bit of water, leaving a gray engraved surface.  Also, the smaller text (my e-mail address) wasn't fully engraved -- I used a non-bold font, and the small vertical lines just didn't punch through the electroplated exterior, leading to unreadable text.  Only horizontal lines seemed to get enough heat to make it through.  It looks like it could be some sort of "geek language" (as my friend Johann put it), but I know what I meant to engrave on there.  Also, I noted several scratches on the Kindle that could only have come from reflected laser beams.

I decided not to proceed with engraving the image, since it contains some fine details, and since engraving gray on "brushed aluminum" isn't likely to be aestetically pleasing.  But my Kindle is personalized, and I can easily identify it if its ownership ever comes in to question, so that is a success in this respect.

What I would do differently:  

On this particular material, I suggest only engraving very large lines.  It would take some experimenting on expensive personal electronics in order to figure out exactly where the cutoff is, but it's somewhere between the two text sizes in the attached SVG.  At the very least, bold text is a requirement, and very large bold text seems to work pretty well.  

Johann suggested that laser-reflections that scratched Kindle can likely to be preventing by attaching some adhesive paper to the device before engraving.

Conclusion:

All in all, this project was a mixed success, but I fully intend to try something like this again on other personal electronics.  I have a generic looking MacBook Pro that could use some identifying marks and decoration, so I may do that one next -- after learning everything that I can from the collected notes of the Fab Lab and Maker communities on this topic!