Replacing $100K diagnostic chip fab with Shrinky-Dinks and a laser-printer | Hacker News Reader

Replacing $100K diagnostic chip fab with Shrinky-Dinks and a laser-printer

boingboing.net

36 pointsandrewbadera13 comments

Open articleView on HN

Topic background info links (for others like me that had no idea what Microfluidics entailed):

http://en.wikipedia.org/wiki/Microfluidics

http://en.wikipedia.org/wiki/Shrinky_Dinks

http://en.wikipedia.org/wiki/DNA_microarray

http://en.wikipedia.org/wiki/Lab-on-a-chip

Anyone know what scale factor shrinkage you get out of this stuff? I'd quite like to experiment with optical effects, but I don't know what feature size you can get and I haven't got any expanded polystyrene handy for testing.

"When heated in an oven or with a heat gun, the plastic shrinks by about 5/8ths and becomes thicker and more rigid, while retaining the colored design."

http://en.wikipedia.org/wiki/Shrinky_Dinks

Seems like you would be able to get pretty small feature sizes if you had a really high resolution printer to begin with...

It surprises me that 5/8ths is enough of a difference to be useful, but then I guess it's the way it bunches and forms a ridge that's important for the microfluidics, not the absolute feature size. Hm.

It didn't strike me that 5/8ths wasn't actually a huge amount until I thought about it.

If the ability to form troughs/ridges is the important thing then I think that the PCB etch/make mold technique would be just as useful. But I'm not sure what the smallest feature size is that you can make with this method:

PCB etch/make mold method:

Laser-print an inverse pattern mask on clear plastic film

Expose a UV sensitive photoresist PCB using the mask

Etch the PCB

Make a polymer mold (or mold the final part) using the troughs/ridges formed by the etched/unetched copper on the PCB

I know this method has been used for replicating fingerprint patterns in the past (Mythbusters!) and I remember hearing it being used for a few other things...

The dearth of women in software development and the preponderance of women in biotechnology are probably not unrelated phenomena.

What is the link that you see?

I don't see one, but that doesn't mean it doesn't exist.

Now that's an impressive hack. You, Madam, win the internets.

In case you're wondering, I think you're being downmodded for using the term "internets".

(It drives me nuts that when people downvote you, but don't give an explanation)

Given your karma and how long you've been here, you should know better! FOR SHAME!

No he got downmodded because his comment didn't add to the conversation. One-line, humorous comments with no meat are generally frowned upon and become easy targets.

Additionally, this comment is fairly reddit-esque so I'm guessing there is even more incentive to kill it before it goes any further.

On Slashdot that would qualify as a 4 "Funny"

Reply on news.ycombinator.com