A 3D Printable Raman Probe

February 4, 2018 by Jenny List 12 Comments

Scientific instruments are expensive. In a lot of cases, really expensive, so if you have spent any time in a well-equipped lab, the chances are that it would have been one backed up by the resources of a university, or a large company. Those experimenters who wish to pursue such matters outside those environments have traditionally had to rely on obsolete instruments from the surplus market. A fascinating endeavor in itself, but one that can sometimes limit the opportunity to pursue science.

It has been interesting then to see the impact of the arrival of affordable 3D printing on the creation of self-built scientific instruments. A fantastic example has come our way, [David H Haffner Sr]’s 3D printable Raman probe. A Raman spectroscope is an instrument in which the light scattered from the sample exposed to an incident monochromatic source is collected, as opposed to that reflected or transmitted through it. Scattered light can be a huge magnitude weaker than other modes, thus the design of a Raman probe is critical to its success. (If you are curious, read this multi-part explanation on Raman spectroscopy.)

This is a work in progress at the time of writing, but it still makes for an interesting examination of Raman probe design. Interestingly the sensor is a standard DSLR camera, which though not a cheap device is possibly more affordable than a more dedicated sensor.

This isn’t the first Raman spectrometer we’ve seen on these pages, we’ve also brought you a Fourier transform spectrometer, and plenty of more conventional instruments.

Towards Sensible Packaging For 3D Printer Filament

February 3, 2018 by Brian Benchoff 66 Comments

Filament-based 3D printers are remarkably wasteful. If you buy a kilogram of filament from your favorite supplier, the odds are that it will come wrapped around a plastic spool weighing about 250 grams. Use the filament, and that spool will be thrown in the trash. Very, very few products have such wasteful packaging as 3D printer filament, with the possible exception of inkjet cartridges or getting a receipt with your purchase at CVS.

For the last few years, [Richard Horne], better known as RichRap, has been working towards a solution to the problem of the wasteful spools for 3D printer filament. Now, it looks like he has a solution with the MakerSpool. It’s the perfect solution for a 3D printing ecosystem that doesn’t waste 20% of the total plastic on packaging.

The design of the MakerSpool is fairly straightforward and also 3D printable. It’s a plastic filament spool, just a shade over 200mm in diameter, consisting of two halves that screw together. Add in some RepRap ‘teardrop’ logos, and you have a spool that should fit nearly any machine, and will accept any type of filament.

The trick with this system is, of course, getting the filament onto the spool in the first place. Obviously, filament manufacturers would have to ship unspooled filament that’s somehow constrained and hopefully vacuum packed. Das Filament, a filament manufacturer out of Germany, has already tested this and it looks like they have their process down. It is possible to ship a kilogram of 1.75 filament without a spool, and held together with zip ties. Other filament manufacturers also have packaging processes that are amenable to this style of packaging.

Whether this sort of packing will catch on is anyone’s guess, but there are obvious advantages. There is less waste for the environmentalists in the crowd, but with that you also get reduced shipping costs. It’s a win-win for any filament manufacturer that could also result in reduced costs passed onto the consumer.

3D Print A 3D Printer Frame

February 3, 2018 by Jenny List 26 Comments

It is over a decade since the RepRap project was begun, originally to deliver 3D printers that could replicate themselves, in other words ones that could print the parts required to make a new printer identical to themselves. And we’re used to seeing printers of multiple different designs still constructed to some extent on this principle.

The problem with these printers from a purist replicating perspective though is that there are always frame parts that must be made using other materials rather than through the 3D printer. Their frames have been variously threaded rod, lasercut sheet, or aluminium extrusion, leaving only the fittings to be printed. Thus [Chip Jones]’ Thingiverse post of an entirely 3D printed printer frame using a 3D printed copy of aluminium extrusion raises the interesting prospect of a printer with a much greater self-replicating capability. It uses the parts from an Anet A8 clone of a Prusa i3, upon which it will be interesting to see whether the 3D printed frame lends the required rigidity.

There is a question as to whether an inexpensive clone printer makes for the most promising collection of mechanical parts upon which to start, but we look forward to seeing this frame and its further derivatives in the wild. Meanwhile this is not the most self-replicating printer we’ve featured, that one we covered in 2015.

Thanks [MarkF] for the tip.

Repairs You Can Print: 3D Printing Is For (Solder) Suckers

February 2, 2018 by Kristina Panos 17 Comments

[Joey] was about to desolder something when the unthinkable happened: his iconic blue anodized aluminium desoldering pump was nowhere to be found. Months before, having burned himself on copper braid, he’d sworn off the stuff and sold it all for scrap. He scratched uselessly at a solder joint with a fingernail and thought to himself: if only I’d used the scrap proceeds to buy a backup desoldering pump.

Determined to desolder by any means necessary, [Joey] dove into his junk bin and emerged carrying an old pump with a broken button. He’d heard all about our Repairs You Can Print contest and got to work designing a replacement in two parts. The new button goes all the way through the pump and is held in check with a rubber band, which sits in a groove on the back side. The second piece is a collar with a pair of ears that fits around the tube and anchors the button and the rubber band. It’s working well so far, and you can see it suck in real-time after the break.

We’re not sure what will happen when the rubber band fails. If [Joey] doesn’t have another, maybe he can print a new one out of Ninjaflex, or build his own desoldering station. Or maybe he’ll turn to the fire and tweezers method.

Continue reading “Repairs You Can Print: 3D Printing Is For (Solder) Suckers” →

Printed Nexus 7 SIM Tray Is Good ‘Nuff

February 2, 2018 by Tom Nardi 9 Comments

When repairing something, there are in effect two schools of thought: you can craft a repair that seamlessly blends into the original hardware and doesn’t look like a repair, or you can slap that thing together and keep it moving. A lot of variables go into this decision making process, such as the complexity of the repair, the available materials, and of course whether or not you need to keep the fact you broke the thing from your significant other.

When the SIM holder on his Nexus 7 tablet broke recently, [Alex Whittemore] did the mental arithmetic and came to the conclusion that it wasn’t worth his time trying to figure out how to model an exact replacement. But he was able to print something that works well enough for his purposes, which is all that matters in the end. A perfect entry for our ongoing “Repairs You Can Print” contest.

Apparently the SIM holder in the 2013 Nexus 7 is notoriously poor, and of course since this is a known issue, online retailers are trying to get as much as $100 USD out of you for a tiny sliver of plastic. Sometimes it really seems like Google was determined to run the Nexus line into the ground before bailing on it.

Printing such a tiny part, especially with the little details like the channel for you to hook your fingernail into, requires a fairly well calibrated printer. If you can’t muster up a 0.1mm first layer you might as well sit this one out; and if you haven’t mastered the art of bridging, that little valley to help you get the SIM back out may end up overflowing into a river of tears.

For [Alex], the piece ended up working perfectly. It might look a little weird, but if you’ve got the tablet in a case you’ll never see it anyway. It’s also worth noting that this design may work on other devices with a similar SIM arrangement, or at the very least, might be a good starting point to work from if you’ve got to come up with your own.

Remember, there’s still plenty of time to enter your own printed fix into our “Repairs You Can Print” contest. The top 20 repairs will take home $100 in Tindie credit, and for the best repair done by a Student or Organization, there’s two Prusa i3 MK3 printers with the Quad Material upgrade kits on the line.

Repairs You Can Print: Racing The Clock For A Dishwasher Fix

January 31, 2018 by Dan Maloney 38 Comments

No matter how mad your 3D printing skills may be, there comes a time when it makes more sense to order a replacement part than print it. For [billchurch], that time was the five-hour window he had to order an OEM part online and have it delivered within two days. The race was on — would he be able to model and print a replacement latch for his dishwasher’s detergent dispenser, or would suffer the ignominy of having to plunk down $30 for a tiny but complicated part?

As you can probably guess, [bill] managed to beat the clock. But getting there wasn’t easy, at least judging by the full write-up on his blog. The culprit responsible for the detergent problem was a small plastic lever whose pivot had worn out. Using a caliper for accurate measurements, [bill] was able to create a model in Fusion 360 in just about two hours. There was no time to fuss with fillets and chamfers; this was a rush job, after all. Still, even adding in the 20 minutes print time in PETG, there was plenty of time to spare. The new part was a tight fit but it seemed to work well on the bench, and a test load of dishes proved a success. Will it last? Maybe not. But when you can print one again in 20 minutes, does it really matter?

Have you got an epic repair that was made possible by 3D printing? We want to know about it. And if you enter it into our Repairs You Can Print Contest, you can actually win some cool prizes to boot. We’ve got multiple categories and not that many entries yet, so your chances are good.

The Engineering Analysis Of Plastic-Dissolving Lubricant

January 31, 2018 by Brian Benchoff 31 Comments

Over the years, E3D has made a name for themselves as a manufacturer of very high-quality hotends for 3D printers and other printer ephemera. One of their more successful products is the Titan Extruder, a compact extruder for 3D printers that is mostly injection-molded plastic. The front piece of the Titan is a block of molded polycarbonate, a plastic that simply shouldn’t fail in its normal application of holding a few gears and bearings together. However, a few months back, reports of cracked polycarbonate started streaming in. This shouldn’t have happened, and necessitated a deep dive into the failure analysis of these extruders. Lucky for us, E3D is very good at doing engineering teardowns. The results of the BearingGate investigation are out, and it’s a lesson we can all learn from.

The first evidence of a problem with the Titan extruders came from users who reported cracking in the polycarbonate case where the bearing sits. The first suspect was incorrectly manufactured polycarbonate, perhaps an extruder that wasn’t purged, or an incorrect resin formulation during manufacturing. A few whacks with a hammer of each production run ruled out that possibility, so suspicion turned to the bearing itself.

After a few tests with various bearings, the culprit was found: in some of the bearings, the lubricant mixed with the polycarbonate to create a plastic-degrading toxic mixture. These results were verified by simply putting a piece of polycarbonate and the lubricant in a plastic bag. This test resulted in some seriously messed up plastic. Only some of the bearings E3D used caused this problem, a lesson for everyone to keep track of your supply chain and keep records of what parts went into products when.

The short-term fix for this problem is to replace the bearing in the Titan with IGUS solid polymer bushings. These bushings don’t need lubricant, and therefore are incapable of killing the polycarbonate shell. There are downsides to this solution, namely that the bushings need to be manufactured, and cause a slight increase in friction reducing the capability of the ‘pancake’ steppers E3D is using with this extruder.

The long-term solution for this problem is to move back to proper bearings, but changing the formulation of the polycarbonate part to something more chemical resistant. E3D settled on a polymer called Tritan from Eastman, a plastic with similar mechanical properties, but one that is much more chemically resistant. This does require a bit more up-front work than machining out a few bearings, but once E3D gets their Tritan parts in production, they will be able to move back to proper bearings with the right lubrication.

While this isn’t a story of exploding smartphones or other disastrous engineering failures, it is a great example of how your entire supply chain goes into making a product, and how one small change can ruin an entire product. This is real engineering right here, and we’re glad E3D finally figured out what was going on with those broken Titan extruders.