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Getting Started in 3D Printing

Being involved with Protospace, our local hackerspace, I've been exposed to laser cutters and 3D printers for the past year or so. Laser cutters require some special considerations that make them somewhat unsuited for a home based office. Poison gas resulting from cutting some things tends to demotivate the staff. So, while this technology is amazing (and fun!) to play/work with, it wasn't really an option for us. 3D printing on the other hand has few such downsides.

I'm not going to go into what 3D printing is, as there are plenty of articles out there, and videos. A quick Google Search will tell you every thing you want to know.

So, I opted to get a 3D printer. specifically, the latest MakerBot Industries model - the Replicator. The remainder of this post is a journal of my experiences with it so far.

We ordered our Replicator on Jan 24th, 2012. At the time, MakerBot was indicating a 6 week turn around. So we were expecting the delivery at the beginning of March. About mid way through this period, MakerBot updated their website to indicate an 8 week turn around. Did this apply to new orders? Or did it apply to all outstanding orders. So we sent a note off to MakerBot to clarify - we were now looking at an 8 week delivery window, which moved the expected arrival towards the end of March. My only issue with this change is that we were not notified of it. I can easily understand delays due to shipping a new product, an unexpected demand for that product, and other typical business issues that could add to delay. But I feel that if the terms of an order change - even something simple like the expected delivery date - then the customer has to be notified so they can decide to cancel or not. But, we exercised patience, and decided to wait.

March 20th came and went, and there was no delivery. Long story short, it took 11 weeks for the order to arrive. At 10 weeks, MakerBot did send out a notice thanking us for our patience and offering a free spool of plastic as way of recognizing the frustrations with the delay. But I can tell you that the day the order arrived, we didn't get any other work done.

It was magical when the platform and gantry first moved. The words "IT'S ALIVE!" sprang from my lips involuntarily. But then the loud grinding noise as the gantry tried to move out of the case became alarming. The problem was that the gantry was not contacting the limit switch on the X-Axis properly. This means the electronics didn't know the print heads couldn't physically move anymore so kept turning the motors resulting in the grinding noise as the gears and belts skipped. At first I thought the problem was the limit switch itself - the Y-Axis switch has a metal lever, while the X-axis switch does not. And I read somewhere about someone having a similar problem and the cause being a faulty switch.

But before I contacted support to work through this, I took a look at the Troubleshooting guide. The question labelled "My Stepstruder is stuck/making a weird grinding noise!" was spot on. It turns out the gantry was twisted just a little. This caused the print head to contact the motor that drives the Y-Axis and would wedge itself to a stop just before fully engaging the limit switch. The fix was to un-twist the gantry. Holding the left side in place and then gently pulling forward on the right side resulting in a two "snaps" as things reset themselves. Moving the gantry to the front of the case then, I could see that it would contact the pulleys on either side at the same time, suggesting it was now properly aligned. When I fired up the next print job, there was no grinding noise, and things just worked as expected. Problem solved.

Now, with the Replicator, there are two ways to print a model. You can use the built in SD Card reader, or you can connect a computer via USB and send print jobs from ReplicatorG. For my initial prints, I was just using some of the sample files on the SD Card. But I wanted to take advantage of the models at Thingiverse. To do this I needed ReplicatorG.

Installing ReplicatorG is easy. Download it, decompress the file, run the program - it's a Java application. However, setting up the environment to make sure it CAN run may be fun. In my case, I was running on a 64bit version of Ubuntu. The required Python files would not install for me. I ended up not installing the python-psyco package, and ReplicatorG still runs fine - I've yet to see an issue. The next hurdle is the version of Java. Some computers will not display your model with the open source versions of Java installed. So, you have to jump through some hoops to make sure you have Sun's Java 6 JRE package installed. This process is documented, and/or searching for "install sun java 6 on ubuntu" results in a number of guides. Once this is done, you can see your models (if you couldn't already), and things begin to make much more sense.

Using ReplicatorG is easy.

  • Use the Machine menu to select your machine/printer, and the port you connect to it on. Then click the Connect button on the toolbar (second from the right hand side). Connections can be finicky. Sometimes ReplicatorG reports it can't find your device even though you have all the right settings and it is connected and powered on. I found that rescanning your ports pausing a few seconds, then selecting the port again sometimes works. Other times the connection was found after disconnecting the USB port, pausing a moment or two, then plugging it back in and rescanning the ports/reconnecting. It only takes about a minute to go through this and get your connection.
  • Select the model to print. FILE->OPEN to find a *.stl file.
  • Adjust the view so you can see your model and platform. You can use your mouse button to rotate your model, and the scroll wheel to zoom in/out. The white box represents the printable area of your device, and the blue pane is the actual printing platform. NOTE: Always make sure you click the "View" button on the right hand side before rotating the view area. What happens when you click depends on what mode you are in. If you are in the MOVE mode, then clicking will result in you moving the model around and NOT rotating the view.
  • Position your model on the platform. Click the MOVE button on the right hand side, then click the CENTER or "PLACE ON PLATFORM" button.
  • Scale the model, if needed. Click the SCALE button on the right hand side. You can either drag with your mouse to change the scale, or you can type in a scale value. A value of 1 means you do not want to change the model. A value of 2 will double the model in size. A value of 0.5 will halve it. Note: These values are relative to your CURRENT size. If you enter 0.5 and click the scale command twice, then your model will be 1/4 of the original size. (half, then half again).
  • Rotate if needed. (I've yet to have to rotate in ReplicatorG!) Yep, you guessed it - click the ROTATE button on the right and then rotate your model as needed. You should always try to have the flatest part on your platform or the least number of overhangs.
  • Print! If you have your device connected, you can now just send the model to the printer by clicking the left most button on the toolbar. This will use the most recent settings for generating your G-Code (see below), or the default values. If you have made changes to the model (like positioning it on the platform or scaling it), make sure you save your changes. It seems that ReplicatorG works against the stored file and not the model in memory. At least for calculating the time estimates. Your model should begin printing.
  • Alternatively, you can manually generate your G-Code and build a file for the SD Card. Under the G-CODE menu item, click GENERATE. (or click the "Generate G-Code" button on the right. Either way will open a dialog where you can change things.
    • First, set which stepstruder will be used - right or left. This happens to correspond to what color plastic do you want to print. If you are not using a Replicator printer, then you probably only have one extruder and don't have an option here.
    • Next indicate if you want a "Raft". This is a grid of plastic that helps address mis-calibration of the build platform, and imperfections in the surface (the kapton tape will get damaged over time and need to be replaced - you get a roll of tape with the printer....). However, some models print best without a raft. Most don't care either way. It's up to you. But, I'd recommend "when in doubt, use a raft". The last number of models I've used were raft-less. This isn't bad but does require that your platform alignment is pretty much spot on, and does seem to cause more wear & tear on the kapton tape on the platform (when removing the items).
    • Indicate how solid you'd like the printed item to be. Setting the Fill option to 100% results in a solid item. Setting it to 0% results in a hollow item. I'm finding that 20 or 30% is sufficient. I did try a model at 5% but it didn't come out so well.
    • The remaining default options should be good for most models. If your model has over-hangs, you probably want to turn on supports. If you want finer surfaces, you can try smaller sizes for your layer height (setting it to zero can have unexpected results!). If you want thicker walls you can increase the number of additional shells (you will always have a 1 layer shell, setting this value indicates how many more you want).
    • Generate your G-Code. Click the Generate button. How long this process takes depends on how large and complex the model is. It usually takes about 1 minute for the models I've been doing. But I have tried a couple of large models that were taking more than 2 hours before I cancelled the process.
    • Create your *.s3g file. Once you have the G-Code created you can create the file to put on the SD-Card. Clicking the second button from the left on the toolbar will begin this process. Indicate where you want the new file saved. This process goes very quickly. When it's done copy the file to the SD Card and you are done. Then put the SD Card into the Replicator, select Print from SD Card, and find your model. The printing will start.

For USING the Replicator, that's it. You should be printing at this point and being mesmerized as the Replicator works.

Dwelving deeper is beyond the scope of this post. There are still maintenance issues, design issues, and more. Design though is just "open a 3D modelling tool, build a model, and then export it as a *.stl file". Blender and Google SketchUp are both good candidates here. How to actually use the tools and design specific objects, well, these areas are worthy of books and posts on their own.

Additional observations:

  • I was surprised to hear the Replicator SING! Depending on the model being printed, the sounds the motors make as the head moves around can be very melodic. As I was printing a Portal Companion Cube (everyone needs a friend!) I could have sworn the Replicator was singing the classic Spiderman theme! This effect seems most pronounced when the object is mostly round in the X/Y axis.
  • Thingiverse has some amazing models! I just wish a) it was easier to browse the models and b) it wasn't so much fun to look through there - I've lost hours already just checking things out.
  • Waste is a concern. While the Replicator seems to use little plastic to print the items, I still have a collection of rafts building up that I'm hesitant to throw into the local land fill. It would be great if these could be easily re-used. If not, I'll throw them in with the regular house-hold recycling.
  • The novelty does wear off. While I'm still enjoying printing things, I'm moving away from the easy to print items, and starting to look at more complex items - mechanical, larger, etc. Luckily I also want to design some models myself, so the Replicator will get more and more breaks as I shift to items that take longer to setup.
  • There is a smell to the plastic being melted into place. It is not unpleasant, but is noticeable.
  • Do not for a second think that "printing" a physical model is as fast as printing a page of paper. There are large time commitments needed to printing the models. It takes time to heat up the build platform and extruders when the print starts (about 5 to 10 minutes if everything is at room temperature). It takes time to print a raft - 30 seconds to 10 minutes, depending on the size of your model. These values are NOT reflected in the time estimate from Replicator. A small model seems to take between 30 and 60 minutes to print. The fastest model I did was 10 minutes (after the heating period) but that was a failed model - too thin with a raft results in a raft that can't be removed without destroying the model. Larger models take longer to print. And the settings you indicated for your G-Code affects the print time as well - smaller layers mean more layers to print, additional shells mean more time, etc. I've been seeing hints of some models that take more than 48 hours to print.
  • How you shop immediately changes. Today I went to buy some paint for some of the models. A few of the things that would aid the painting (storage containers, mixing bins, etc) are plastic. I immediately thought "I can just print those" and left them behind. And I've seen this in other areas too - like salt and pepper shakers, and wire guides, and headphone hangers, and.... the need to "consume" seems to have been replaced with a need to "make". I realize this may not be as convenient (for $3 I can just buy the paint mixer bin, or I can spend 2 hours designing one and then another hour printing it...). But, if I build the model and post it online, someone else doesn't loose the design time and a 1 hour period to save $2 may be reasonable.

Overall, I've been enjoying the experience. I think this technology will change the world if it continues to catch on. I think the ramifications of the technology are LARGE. But it will take time to sort things out (legal implications of printing a physical copy of something, etc.) Check back with me in 5 or 10 years and we'll review what happened.