Tag Archives: 3D printing

3D Filament and Humidity - Why My Prints Keep Failing

Awhile back I talked about some weird issues with my 3D printer filament being damaged by UV radiation from the sun. I'm back with more stories of 3D printing though and my current attempt at solving the issue.

I was printing some parts and kept having issues with the layers coming apart and/or having a bubbly, uneven surface texture. I generally print with ABS plastic, even though others seem to have more issues with it, I've always had better luck than with PLA. I decided to try some PLA and also had problems with it sticking and with the filament becoming very brittle and shattering. This problem was slowly driving me crazy as I usually can get high quality prints with little fuss.

First off I moved the printer further away from the window to be sure no hot/cold convective air currents were interrupting the printing process. I even hung some cardboard sheets around the side of the print area. If I had the space I'd make a full enclosure for the printer to cut off all air currents from the room, but that will have to wait for awhile. (It would also dampen the noise, which is a bonus in an apartment!) I still was getting "bubbly" prints though.

Cardboard baffles taped onto the printer in an effort to reduce air currents near the print surface.

Cardboard baffles taped onto the printer in an effort to reduce air currents near the print surface.

After reading more online I decided that my filament must be too moist. The plastic is adsorbing moisture from the humid air and that turns to steam in the print head, causing little blow-outs and my bubbly texture. After consulting with a colleague that does a lot of printing, he confirmed that this is an issue and even cited his tests showing that filament over a few weeks old produced weaker prints. There are a few ways I can think of to help with the issue: 1) put filament in a bucket with a light bulb as a heater to keep the humidity low, 2) keep the filament in vacuum packs, 3) lock it in a low humidity environment with silica gel beads. Based on cost and convenience, I ended up going with the third option. While this technique won't give filament an infinite life, I was hoping to salvage some of mine.

I went to a craft store and bought a plastic tub that had a soft air/water tight seal; specifically the Ziploc Weathertight series container. I also ordered a gallon container of silica beads that are commonly used to keep products dry during shipping. While the products were on their way, I collected a bunch of plastic containers and drilled many small holes in them. When the beads arrived I filled the containers with them and placed them and my filament in the large box.

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In an effort to see how good of a job the silica beads were doing, I also taped a humidity indicator inside the box. I hadn't used these simple indicators before and had no idea how accurate they were, so I whipped up a quick sensor with a MicroView (Arduino) and checked it. To my surprise, it was dead on, even when exposed to the higher room humidity. If you only need 5-10% accuracy (like when seeing if the silica beads need to be baked because they are saturated) these seem to do the trick.

A close-up of the microview showing 17% RH inside my container.

A close-up of the microview showing 17% RH inside my container.

The humidity indicator also shows below 20%, matching the electronic sensor.

The humidity indicator also shows below 20%, matching the electronic sensor.

Once I verified that this solution might work, I put the rest of the filament and anything else I wanted to stay dry in the tub. Still lots of room left for future filament purchases, unpainted parts, and all of the surface mount sensors that need to be stored in a dry environment.

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After letting the filament sit in the box for a few days, I tried another print. To my surprise, there were no more blow-outs! I still have a problem with part of my print bed not adhering very well, but that's another story and another, currently only partially solved, mystery. For now, this box solution seems to have part of my 3D printing problems solved. I have noticed that old filament does produce weaker prints, so I'm going to start stocking less filament and print most things in a single color (probably just black and white unless a special need arises).

PSA About ABS - Follow Up

Just a very short follow up about my previous ABS post. I was able to paint the part with a brush and some IKEA BEHANDLA Glazing paint. This is the paint I used on my pine night-stands in 2012, so it is a little old, but it did the trick. The smooth surface on the bottom of the stand didn't hold paint very well, but that's okay. The textured sides where the printer slowly built up the part gave lots of surface area to color and it looks like it belongs. Happy accident, but worth remembering if you want a fake wood texture. You could even expose different parts of the roll of plastic intentionally for a very interesting color pattern, but go easy or you may hurt the plastic's integrity.

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While researching about ABS damage from UV exposure, I found out that there are now UV sensitive plastic filaments available. The world of 3D printing moves very fast and I was apparently not up to speed on some of the new materials that are out there. Below is a video of the filament being exposed (not me or my filament obviously).

Getting Up and Running with a 3D Printer

I recently received some money to purchase a 3D printer to aid my laboratory experiments. I thought that it would be good to share how I decided on the printer that I did and how hard/easy it was to setup. Currently I've only run a few simple test prints, but will be printing some mounting equipment for laboratory experiments within a few weeks.

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Choosing a Printer

When choosing a printer, there are many factors to consider. The consumer 3D printer movement is still very young, so there are many different designs available that require different amounts of tinkering to work and have vastly different capabilities. To help decide, I made a few requirements and decision points :

1. I must be able to print something that is at least 8"x8"x8". Print area is an important consideration and is one of the biggest influences on cost. With this print size I can make most prototypes, brackets, etc that we need. Larger parts can always be printed in sections and joined, but it's not the strongest or easiest thing to do.
2. Print material and method. There are printers that can print in many types of plastic and even in wood. Some printers fuse plastic in layers in an "addictive manufacturing" process. Others can fuse a liquid into a plastic with a process referred to as stereo lithography. Most consumer level machines with a large print area are the type that extrude plastic. There is a large matrix of advantages and disadvantages, but we will just leave it at this for now.
3. The final factor I considered is the development of the machine. Informally this is the "tinker factor." How much are you willing to modify and experiment with the machine to get increased versatility vs. how much do you want a machine that is a push button that just works? I've always been the tinkering type but there is a balance. Some more experimental and low cost machines are not as reliable as I would prefer, but something that is fully developed like the MakerBot line doesn't leave as much versatility. The other portion is the licensing of the software and hardware. I've always been a proponent of the free and open source movement. It's how we are going to advance science and technology. Companies like MakerBot are not fully open source and that just doesn't sit well as it prevents the community from fixing problems in a piece of equipment that was rather expensive.

With all of those considerations and lots of research, I decided on the Taz 4 printer by Lulzbot. You can purchase the printer from Amazon, but I decided to purchase through Sparkfun Electronics since they are a small(ish) business that really supports education and the maker movement. I ordered the printer within a few hours of passing my comprehensive exams and it was on the way!

Setting up the printer

I received the printer and followed all of the setup instructions. This involved assembling the axes and removing the packing protection. I've never done this before, but overall it was very straightforward and took about 45 minutes. The next steps were what made me nervous.

To get quality prints the printer surface must be level with relation to the print head track. There are various end stops and leveling screws to adjust. Using a piece of printer paper as a gap gauge, I just followed the instructions and had the print bed leveled in about 20 minutes. There is also a test print pattern that prints two layers of plastic around the base plate to let you make sure the level is right on. Everything must be kept clean and adjusted as with any precision bit of gear, but overall I was impressed with the design.

The printer ships with an octopus test print that was my first object. I loaded up the file and hit print. The printer ran for about an hour and at the end I had the print shown below!

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What's Next

I've got some plans for what to print next. Currently I'm designing some new brackets to hold sensors in place during experiments and a few new parts like shields and pulleys to improve the quality of some of our demonstration apparatuses in the lab. I'm sure some of the results will end up as their own blog posts, but you can always see what's new by following me on Twitter (@geo_leeman). I also would like to thank Hess energy and Shell energy for their support of various aspects of these projects and of course the National Science Foundation for supporting me and many aspects of my lab research. Everything I've said is of course my own opinion and does not reflect the views of any of those funding organizations. Next post we will likely return to more general topics like seeing trends in data or go back and look at more Doppler radar experiments.


I was able to print my first laboratory parts, a set of brackets to make a magnetic holder for a displacement transducer.  I will be posting the cad files to my github account under an open license.


3D Printing in the Lab - Will Lab Hardware Follow Software into Open-Source?

Today I read the article "Building Research Equipment with Free, Open-Source Hardware" by Joshua Pearce from a recent Science Perspectives section.  I'd like to share some thoughts on the article as I thought it introduced what may be the next "want" item in many labs.

In the modern scientific lab there is a large assortment of sophisticated hardware necessary to conduct increasingly complex research.  Generally scientific hardware is some combination of turn-key or off the shelf equipment and equipment designed and built in house.  In recent years laboratory software has progressively become part of the free and open-source software (FOSS) movement; hardware is now following the same trend with the advent of open-source 3D printers from the hobbyist community.

Open-source hardware became popular in the late 90’s with the basic stamp “board of education” microcontroller circuit boards, but the Arduino has taken over the hobby market with its $30 price tag.  Arduino has a number of modules, or shields as they are called, ready built with significant code libraries available.  With the Arduino circuit boards scientists can perform basic hardware control with digital and analog outputs in addition to basic analog-to-digital conversion.  

The RepRap open-source 3D printer is driven by the Arduino and can be constructed for <$1000.  The machine prints the parts required to make another RepRap printer, so building a machine is approached by entering the RepRap community with a parts request.  Users also post 3D designs on Thingiverse for download and printing by anyone.  A sufficient amount of laboratory equipment from test tube racks and filter wheels to Dremel tool adapters are already online.  

Printing laboratory equipment may not only reduce the cost of research, but allow the same flexibility, innovation, and rapid development cycle enjoyed by scientific software.  Being able to create a custom bracket, holder, mold, or sample jig could be advantageous to almost any laboratory and allow research to be conducted more efficiently with less focus on coordinating development with engineers at commercial manufacturers.  The open-source nature of the parts library will reduce duplication of work between those in a common field of research and allow cross-lab standardization of sample preparation techniques.  

There are limitations to what can be easily constructed in the lab, such as 3D printing with metal.  The technology to do this exists, but is too complex and expensive at the present time for individual applications.  While working at Oak Ridge National Laboratory I got the opportunity to see 3D printing with titanium.  The video below is a titanium ball... bouncing. (Apologies for the portrait video and quality, this was taken several years ago with an early iPhone.)

Like all community projects, the RepRap is being updated to have greater capabilities.  According to the project website a major milestone will be printing with electrical conductors to manufacture rapid prototype circuit boards without milling away copper clad board material.  

Just as sometimes labs must use commercial software, it is likewise not expected that all lab hardware will become open source.  Some tolerances are too tight for the parts to be constructed by simple printers and some materials are not practical to print in the lab.  With all this in mind it is worthwhile to monitor the progress of open-source hardware such as the RepRap, Arduino, and the new RaspberryPi single board computer.  These tools may provide teaching support also as controlling and displaying data from classroom demonstrations is easier than ever and does not require the resolution/precision of research grade instruments.