Good job on another end of semester. Hopefully it’s all gone well. If you’re hanging about this summer, remember that we’re here year-round!
As we enter our busy season towards the end of the semester, please note that due to the small scale of our service, we cannot guarantee deadlines. If you have a project due in two days, we’ll try to accommodate you, but we make no promises.
Congratulations on what was hopefully a successful end of semester.
We hope you all have a happy holiday season. If you come up with a great idea for something to print, make sure to drop us a line!
A little while ago, a student contacted me for help with designing things with moving parts such as hinges. I thought I’d put some of the links in my reply here, for some light Thanksgiving reading:
Designing 3D printed pin hinges, no assembly required: This person unfortunately doesn’t seem to mention the type of printer they used (since different types of 3D printer might make a certain design easier or harder). The pictures look like the kind of thing we print, though (the layered look suggests it).
You could look over some examples of how other people have designed hinges:
You can try to bring in some models into Tinkercad by using the Import function on the right hand sidebar; if you import from a file, it needs to be STL format. There is a file size limitation, though. Unfortunately, the nature of Tinkercad makes it so that if you import the STL, you can’t really pick it apart very well (other than just creating holes and subtracting parts of the original model); but it might still be a useful exercise to wrap your mind around how the item was designed, especially if you start cutting away into it to see the insides.
Here’s another hinge design, this one made in 123D Design.
For the sake of information, I’ll point out “living hinges”, although this type of hinge will not work with our printers since the plastic we use is more rigid than the nylon-type used in this example. 🙂
Lynda.com video course – Desigining replacement parts with Tinkercad: this doesn’t address moving parts but I think the section 3 on printing and testing seems useful.
I’m having a bit of a tough time finding information on designing hinges specifically for 3D printing, so some more general information might be useful as well.
Hope that’s useful to somebody out there!
Just in time for busy season, the Makerbot’s been repaired and you should be able to see it at work in the glass cage by the printers in the Science & Engineering Library.
Welcome back, students! We had a rather quiet summer in the library but we’re going to hit the ground running in the Fall semester. Subscribe to our newsletter and stay informed of all the cool stuff we’ll be offering this year.
In the meantime, you may have noticed the Makerbot has been inactive lately. We’re waiting on a replacement part so we can do surgery on it, and then (fingers crossed) it will be good as new. The Flashforge has been picking up the slack, though, so prints are still being steadily produced — check out our policies and instructions from the menu above and send us your models!
A concerned citizen pointed us to this 2013 ZDnet post in which the potential dangers of 3D printing are highlighted.
The ZDnet post mostly cites a Phys.org post which cites the original article by Stephens et al. (2013), and as is usually the case with most scientific reporting these days, a lot of nuance gets lost in this process.
One main issue with the 2013 paper is that while they measured particulates emitted by printers using both ABS and PLA, they did not analyze the chemical identity of these emissions. It was a useful first approach but the mere presence of particulates in high concentrations does not in and of itself tell you anything about health hazards. One must also consider that we are surrounded by particulates from a variety of sources at all times, as one paragraph from Stephens et al. points out:
Several recent studies have also reported size-resolved and/or total UFP emission rates from a variety of other consumer devices, appliances, and activities such as laser printers, candles, cigarettes, irons, radiators, and cooking on gas and electric stoves (e.g., Dennekamp, 2001, Wallace et al., 2004, Wallace et al., 2008, Afshari et al., 2005, Buonanno et al., 2009 and He et al., 2010). Unfortunately, it is not straightforward to compare our results directly to results from many of these studies because they have varied in both their minimum and maximum measured particle sizes, as well as in their definition of UFPs. However, Buonanno et al. (2009) reported total UFP emission rates over the same size range as ours measured during various cooking activities. For comparison, our estimate of the total UFP emission rate for a single PLA-based 3D printer (1.9–2.0 × 1010 # min−1) was similar to that reported during cooking with an electric frying pan (1.1–2.7 × 1010 # min−1). The same 3D printer utilizing a higher temperature ABS feedstock had an emission rate estimate (1.8–2.0 × 1011 # min−1) similar to that reported during grilling food on gas or electric stoves at low power (1.2–2.9 × 1011 # min−1), but approximately an order of magnitude lower than gas or electric stoves operating at high power (1.2–3.4 × 1012 # min−1). Regardless, the desktop 3D printers measured herein can all be classified as “high emitters” with UFP emission rates greater than 1010 particles per min, according to criteria set forth in He et al. (2007).
I had previously posted about this topic citing a more recent study (with Stephens now as the senior author) in which particle emissions were measured from a variety of filaments; they took the extra step of characterizing the chemical composition of the emissions, finding that printers using ABS emitted some rather nasty stuff. We only use PLA in our printers and part of its appeal (aside from printing characteristics) is the fact that PLA is biodegradable and in fact is widely used in applications where you want something that will dissolve away without harm in the body.
As more studies come out, I predict that the bad characteristics of the other widely-used 3D printing material (ABS) will become more prominent; I also predict that, given the quality of media reports on such things, the difference between ABS and PLA will not be emphasized, and the general public might become more wary of 3D printing in general.
With respect to the Columbia community visiting our printers in the Science & Engineering Library, I want to point out that we do not operate in a vacuum — Environmental Health & Safety has paid us a visit (as well as other 3D printing locations around campus) to obtain air samples while the machines were in operation. They are monitoring the literature and our specific environments and I assure you that we would not be allowed to operate in the current manner if there were concerns about air quality around the printers.
We don’t have a hot glue gun around the library, but if you’re reading this and have access to the necessary items, this video shows a pretty simple way to build some articulation in your models.
Please visit our Getting Started page!
tl;dr: maybe you should avoid having a 3D printer in your dorm room firing off ABS models.
Azimi, P., Zhao, D., Pouzet, C., Crain, N. E., and Stephens, B. (2016). Emissions of ultrafine particles and volatile organic compounds from commercially available desktop three-dimensional printers with multiple filaments. Environ Sci Technol, DOI: 10.1021/acs.est.5b04983.
Previous research has shown that desktop 3D printers can emit large numbers of ultrafine particles (UFPs, particles less than 100 nm) and some hazardous volatile organic compounds (VOCs) during printing, although very few filament and 3D printer combinations have been tested to date. Here we quantify emissions of UFPs and speciated VOCs from five commercially available filament extrusion desktop 3D printers utilizing up to nine different filaments by controlled experiments in a test chamber. Median estimates of time-varying UFP emission rates ranged from ∼108 to ∼1011 min–1 across all tested combinations, varying primarily by filament material and, to a lesser extent, bed temperature. The individual VOCs emitted in the largest quantities included caprolactam from nylon-based and imitation wood and brick filaments (ranging from ∼2 to ∼180 μg/min), styrene from acrylonitrile butadiene styrene (ABS) and high-impact polystyrene (HIPS) filaments (ranging from ∼10 to ∼110 μg/min), and lactide from polylactic acid (PLA) filaments (ranging from ∼4 to ∼5 μg/min). Results from a screening analysis of potential exposure to these products in a typical small office environment suggest caution should be used when operating many of the printer and filament combinations in poorly ventilated spaces or without the aid of combined gas and particle filtration systems.
For PLA printing (which is what we use in the library), the primary volatile organic compound detected was lactide, and that at much lower levels than some of the nastier stuff detected from other types of filaments. Lactide is the cyclic diester of lactic acid (which is the LA in PLA), and according to this paper,
We are not aware of any relevant information regarding the inhalation toxicity of lactide, the primary individual VOC emitted from PLA filaments.
So, good news? It’s still early days in the analysis of this rapidly-growing technology from a general consumer perspective, so it’s probably prudent to operate your printer in a well-ventilated area, particularly if you’re using filaments other than PLA.