CGFigures Presents: Little Boxes
One of the simpler things I did during my studies was create custom 3D printed boxes for storing my devices. In many case that meant solar cells, but in reality it could be any small form factor thin film device. The basic premise was to design a form fitting storage solution that would securely hold glass slides (mine were 1” by 1”), would take up as little space as possible, and would be cheap and easy to produce. Naturally, I turned to 3D printing as a solution. In fact, my Ender 3 Pro was originally purchased so that I could make the little boxes at home and for a stretch of a few months I would come home after a day at work and I would load up a simple routine to make five new boxes, each capable of holding about 10 samples. I recently found out they are still in active use in my former lab and have been repurposed by new students. In fact some are about to ferry samples across the Atlantic to France for X-ray analysis.
Of course, one might reasonably ask “why this decision?”. The short version is that I was scaling up my device fabrication and needed a better storage solution. For reasons that escape me device chemists and engineers often use a really horrible selection of off-the-shelf components for things. They also tend to borrow these from biological sciences. On the surface it makes sense. And it is the surface that is a concern. Most device fabrication starts with very carefully cleaning your surface. For many labs that process involves sonication and if there is one thing my time in biomaterials taught me it was that all the lab supplies for sonicating slides are the property of biologists, particularly the ones that use microscopes. So, inevitably the glass chambers used for cleaning microscope slides are appropriated by materials scientists for cleaning their ITO, FTO, and standard glass substrates (as well as Si wafers and all manner of other things). And these work quite well. Where it all falls apart is when the materials scientists start using petri dishes to store all their samples.
I despise petri dishes as a storage solution. For some bizarre reason they have managed to worm their way into many device labs in different forms. The single use 1.5” diameter ones, the large glass ones (which double as plasma cleaner inserts), and my most hated, the four chamber (X) petri dishes. All of them made of a transparent plastic (typically polypropylene), many with loose fitting lids, and all of them with absolutely abysmal capacity. If you make thin films (<500 nm) the last thing you want is your films rattling around on top of each other since even a small scratch can ruin a device. So at best in a four chamber dish you have four substrates. Also, if you make these types of films they are often identical to the eye and if any accidental jostling occurs good luck ID’ing your substrates if you haven’t marked them in some way beforehand. And if your films are light sensitive prepare to wrap everything in aluminum foil six ways from Sunday.
At this point I wouldn’t blame you for saying that my vendetta with these dishes seems a bit over the top. Yes, that is correct. But in the words of Pedro Pascal, “Life is good, but it can be better”. And with that sentiment in mind we return to the idea of little boxes. Little 3D printed boxes. Each made to precisely fit the substrates in question. And just like that 100 devices can be stored in 10 boxes instead of 25 X-petri dishes, or 100 single use petri dishes. Suddenly there is more space in the glovebox, suddenly all the devices from one experiment can be kept in the same container. Suddenly the container has some directionality that lets you label things. No more jostling, no more substrates flying around, no more wasted plastic. And because PLA filament is cheap (~ 30 CAD per kg) you can custom design a lot of storage space. When I did the math (and of course I did the math) the 3D printed boxes were more cost effective than the petri dishes. And if you’re worried about water because of PLA’s hygroscopic nature, use ABS.
Then there’s all of the customization options. Interlocking or stacking boxes. Device “drawers” and repositories (which were adopted by some large research groups I know). Custom colours for different types of devices. Built in labels for experiments or individual researchers. But mostly, no more loose, rattling, space consuming petri dishes. The video says it all.
