3D Printed Interplanetary Rocket

Inspired by NASA's new SLS (Space Launch System), this Interplanetary Rocket is a scale model of a multi-stage space exploration system is a fun way to learn about space travel through 3D printing. Using a Dremel Idea Builder, I was able to make an intricate set of parts that fit together just like the real thing!

This project is a great lesson in the engineering of multi-stage rocket building. While many of us may think of a rocket as a monolithic object that fires into space in one piece, the reality is that an interplanetary rocket like the NASA SLS is made of more than a dozen discrete stages that each perform a critical role in getting astronauts into space. 3D printing your own interplanetary rocket is a hands-on way to explore the construction of the rocket as well as getting a sense of its massive scale in relation to us tiny humans.

Step 1: Design in 3D

INSPIRATION

I was inspired by NASA's SLS (Space Launch System). They call it "the biggest, most capable rocket ever built for entirely new human exploration missions beyond earth's orbit", which pretty much says it all. It's designed for versatility- the rocket can be used to move either cargo or crew, and will be a crucial part of the manned mission to Mars.

I love the idea of modularity because of its efficiency. The SLS rocket's modularity makes for an interesting scale model, because you could print new parts for different uses and interchange them with the other parts you've already printed.

DESIGN
I designed the model in Fusion 360 because it's easy to create precise models and keep track of changes. It's also a dream when it comes to 3D printing- just right click on the model, save as STL, and send it to your print utility. Unlike a lot of other programs I've used, I've never had any issues with the geometry translating to a solid printable model.

Fusion 360 is free for students and hobbyists, and there's a ton of educational support on it. If you want to learn to 3D model the kind of work I do, I think this is the best choice on the market. Click the links below to sign up:

Student/Educator

Hobbyist/Startup

I printed this project on the Dremel 3D Idea Builder. This machine is a workhorse! I found it to be reliable and consistent with quality prints, and it's much quieter than a lot of the other FDM machines I've used. You can buy one at Amazon, Home Depot, Lowes, or Best Buy.

I wanted the model to be as realistic as possible, so I designed it to be made of a bunch of separate parts that fit together. The parts are...

1. Core Stage
   • Engines (4)
2. Solid Boosters (2)
   • Engines (2)
3. Launch Vehicle Adaptor
4. Cryogenic Stage
   • Engine
5. Spacecraft Adaptor
6. Service Module
   • Engine
7. Crew Module
   • Heat Shield
   • Forward Bay Cover
8. Abort Stage

ASSEMBLY

All the parts are friction-fit, meaning everything snaps together without the need for glue. The tolerances that seemed to work best were .05mm for parts that are supposed to be fixed, and .1mm for parts that need to move freely (like the gaps between the modules and the adaptors). The Core Stage is in two parts that are glued together- this makes for a clean surface on both halves of the model.

FILES IN THIS STEP:

• .f3d File: This is the Fusion 360 file for the entire model. Feel free to play around with it and tweak it for your own diabolical purposes.

Step 2: Export Parts for Printing

To get the model parts to the Dremel Dream Builder, I exported STL files. In Fusion, you can send the file directly to Meshmixer (or a couple of other 3D print utilities), but I guess I'm old school- I like to save the STL files in a folder so I can keep track of what I'm doing. Sometimes prints don't work the way you'd hoped, and it's helpful to have a clear list of parts with date stamps so that you can revise the parts you need to.

In Fusion, you can right-click on any component or body and save as an STL. It's important to pay attention to the way your components or bodies are constructed. It's possible to have a single component with multiple bodies that need to be printed separately, so you have to keep track of which parts can be exported as components or as single bodies. The settings I used for every part on this model were the default "High" refinement settings. This seemed to work well with all the parts and assemblies.

FILES IN THIS STEP:

• .stl Files: These are the individual parts of the model exported for 3D printing. These don't have support structures or orientation optimized for printing.

Step 3: Prep Using Meshmixer

I used Meshmixer to prep my files for printing because it gives you a lot of control over the model while providing useful default settings that you can tweak slightly to get the results you want. Meshmixer has settings loaded for the Dremel Idea Builder (build volume, etc.) that help you position your model and create support structures. Here are the steps for prepping a model for printing.

1. Position the model: This may seem like a no-brainer, but you have to think about how the printer works. FDM printers lay down strands of molten filament that basically solder to each other. This means that the orientation of your parts matters, especially for small parts.
   • A thin linear element will snap in half with no effort if it's printed vertically on a bed. That's because the layers of filament are creating slices along the short axis.
   • What I've found from printing on the Dremel is that parts less than 3MM thick need to be oriented so that the layers of material are parallel to the build platform. This makes for a strong, resilient, flexible, durable part. The diagram in this step illustrates what I mean here.
   • The "bottom" of the model should touch the bed in most cases. In the case of the shell in the screenshots, the rim at the bottom is touching the bed.
2. Create Support Structures: When creating support structures, I found I had the best results when I used the default settings within Meshmixer for the Dremel Idea Builder, but I increased the density of the support structures from 50 to 75. With a lot of the prints a density of 50 was fine, but I found that with significant overhangs (like the openings of the hatches in the shell model in the screenshots) 75 yielded better results without being too much of a pain to clean up. The support structures generated by default in Meshmixer have narrow tips and narrow bases, so it's very easy to snap them off of the finished models. Under Advanced Support, be sure to check "Allow Top Connections". It's important to have this feature checked for this model because there are a lot of overhangs and open holes.
3. Send to the Dremel 3D App: Clicking the "Send to Dremel 3D" button brings you to the next step.

Step 4: Print Using the Dremel 3D App

After clicking Send to Dremel 3D in Meshmixer, it's time to build the model. All you have to do in Dremel 3D is click Build.

BUILD SETTINGS LAYERS: I used Resolution: High for all of the prints. I had good results without tweaking any of the other options on this tab.INFILL: I used Fill Pattern: Hexagon for all the models. I changed the density from the default 35% in a few of the models. I found that especially on smaller parts, 75% density made for much sturdier parts.SPEED: Default settings.TEMP: I increased this to 230ºC from the default 220ºC. I did this because I've had better results with higher temperature in other FDM printers, and I found the same was true with the Dremel Idea Builder.OTHERS: Default settings.The software gives you an estimate of the build time and the material used when it's done creating the file (which is awesome). You can send the file to the SD card or directly to the printer with a USB cable.

FILES IN THIS STEP:

The .g3drem files in this instructable are ready to print on a Dremel Idea Builder. Just put them on an SD card or send them directly to the printer.

Step 5: Prep the Build Platform

If you're doing lots of prints, I find it's very helpful to have a disposable surface you can replace quickly. I use 3M ScotchBlue 2090 Painter's Tape as a build surface because it's large enough to cover the whole bed- this way you don't get any seams.

1. Apply the Tape: The first step is to line up the tape on the bed so that it doesn't cover up the slots for the built platform clips. It's really important to smooth out the tape so there are no bubbles. I've found that my driver's license is the best tool for this job.
2. Sand with 220 Grit Sandpaper: This removes the slippery finish on the tape, allowing the filament to stick to the bed easily.
3. Wipe Down with Isopropyl Alcohol: This removes the sanding dust and any oil from your fingers that might still be on the tape.

Give it a few seconds to dry and you're ready to go.

Step 6: Level the Build Platform

The build platform must be level for prints to build properly. I've found that with near constant use, I only had to level the platform once in three weeks. If the filament doesn't seem to be sticking to the bed at the very beginning of a print, there's a good chance the build platform isn't level.

The instructions on the touch screen are pretty straightforward. Basically you just put a piece of paper between the nozzle and the bed and adjust the screws until the gap is just right. The paper should easily slide in and out in the gap while having a very small amount of friction. There are only three adjustment screws, so it's easy to level the platform quickly.

Step 7: Unload / Load Filament

UNLOAD

To unload the filament, just follow the menu. It'll heat up the extruder if it isn't already preheated, then ask you to press the extruder intake spring and pull the filament out. To avoid filament jamming, push the filament in for about half a second, then pull it out. I've found that this clears the extruder of any leftover filament blobs, which can create jams if you let the extruder cool down again before loading more filament.

LOAD

To load filament, just follow the menu again. The motor will run automatically for a few seconds to load the filament into the extruder. Check the nozzle and make sure a little filament has come out before printing. You may need to go through the load process again to make sure it's totally full. If the extruder isn't full when a print starts, it's possible that filament won't come out at the very beginning of a print, which can cause problems with your print down the line.

Step 8: Preheat and Print

Preheating is a good way to ensure that the extruder is warmed up and ready to go. I had the best results by preheating the machine for about 5 minutes, then loading the file.

Loading a file to print is really easy with this machine because the touch screen gives you a preview of the model! Just pop in the SD card, select the model from the list, and tap Build.

NOTE: Files may FAIL if they're not in the MAIN DIRECTORY of the SD card. I found that using sub-folders on an SD card made about half of the files fail, so be sure to keep everything on the main directory.

Step 9: Remove and Clean Up

Most models can be popped off of the bed by hand, but the Idea Builder comes with a multi-functional plastic spatula that will do the trick if your fingers won't.

Believe it or not, I found the best tool for scraping the support structures off of the models was the can opener on my Leatherman Multitool. It's not sharp enough to cutyou if you slip and poke yourself, and the pointy end is great for digging into the little crevasses.

Step 10: Assembly

Most of the parts on this model snap together without the need for glue. Here's the sequence of steps:

1. Glue the two halves of the Core Stage together using the Core Key to align the two. I used hot glue for this step.
2. Insert the rocket boosters. These are press fit and won't need glue. The rocket boosters for the Solid Booster parts insert the same way.
3. Insert the rocket boosters for the Cryo Stage and the Servie Module.
4. Press in the Crew Module Cap and the Crew Module Heat Shield to complete the Crew Module.

Once all the stages are assembled, you've got all the parts necessary for making a complete Interplanetary Rocket.

Step 11: Blast Off!

This model is a fun way to learn about the way a multi-stage rocket works. The most striking thing about it for me was getting a sense of how tiny the crew module is compared to the whole thing. The core stage of the rocket is scaled down to half its height- it was the only way I could get print it so that the crew module wasn't microscopic!

In another iteration, I'd like to work on the way the modules interconnect. The clips could definitely be improved, or there could be a shallow screw connection between the modules.

I hope to see IMadeIts of this project- post yours here and I'll send you a free 3-month pro membership!