3D printing is one of the most valuable prototyping tools you will learn in this course. It allows you to quickly and easily create prototypes of complex parts while bypassing the entire machining process. In this tutorial, you will learn how to 3D print on Duke's printers, most of which are located in the POD, the Foundry, and the CoLab.

Step 1: Designing a Part

The first step in the 3D printing process is designing something to print. In your first-year classes, you'll be using Autodesk Fusion 360 to design your parts. You can install this software from the Autodesk website at https://www.autodesk.com/products/fusion-360/students-teachers-educators and create an account with a free education license using your Duke email. Once you've created a part in Fusion, export it as a an STL file (.stl).

Step 2: Uploading to 3DPrinterOS

Once you have your STL file, you need to upload it to Duke's 3D printer management software, 3DPrinterOS. Go to the 3DPrinterOS website, click "Sign In", then click "SSO", and sign in with your Duke credentials.

When you log in, you'll be taken to the "My Files" page. On this page, you can see and print files that you've previously uploaded. Hit the "Add Files" button and upload your STL file.

Step 3: Laying Out and Slicing Your File

Once you've uploaded your file, you'll see it in the list of "My Files". Before printing, you'll need to adjust the file's layout to ensure it prints in the correct position on the printer: hit "Layout" to open the layout editor.

In the layout editor, you'll see your part positioned on a virtual print bed. Use the move and rotate tools to move your object to an appropriate location. Parts will print better in certain orientations than others. As a general rule of thumb, try to rotate your part so the side with the most surface area is on the bed. When you're placed your part, hit "ON BED" to move your object so that it's sitting on the print bed. This step is very important! If you don't place your object on the bed, the printer will try to print in midair -- which will inevitably fail.

When placing your part, try to stay away from the edges of the print bed -- leave roughly an inch of clearance on each side. The print bed heats unevenly towards the edges, so doing this helps you avoid warping on the bottom of your part.

If you'd like to add another part to the layout, press "Add File". This function allows you to print multiple parts in one print job by combining multiple files into one layout. Try to group multiple parts close together to reduce print time.

Once your parts are laid out correctly, press "Save and Slice". Slicing is the process of generating gcode, a set of instructions for the 3D printer that tells it explicitly how to print a part. When you press "Save and Slice", a screen will appear with a set of options for slicing. At the top left of this screen, choose your printer type -- you'll likely be printing on an Ultimaker 2+, although the CoLab also has some Ultimaker 3's available.

After you select your printer, you can choose parameters like layer height, wall thickness, and infill density. Layer height is the height of the layers that the printer extrudes. Increasing the layer height decreases the resolution of the final part, and vice versa. 3D prints are largely hollow, so wall thickness is the thickness of the outer walls of the part. Infill density is the amount of material printed inside the part. A part printed with 0% infill is hollow, while a part printed with 100% infill is completely solid. By changing these three parameters, you can change the quality of the print and, more importantly, the printing time. When printing a large number of pieces (for example, creating several prototypes in rapid succession), you can significantly decrease the printing time by increasing layer height, decreasing wall thickness, and decreasing infill.

Another important option that you might want to change is whether to generate support. This setting allows the printer to print extra support material to hold up overhanging part features. In general, you will want to check this option, especially if your part has large overhangs.

Once you've finished setting your options, press "Slice" to finish the slicing process.

Step 4: Printing Your Part

Once you've laid out and sliced your part, you're ready to print! On the new gcode file that appears, press "Print". A list of printers will appear. On this list you can see all of Duke's 3D printers. Some will be ready to print, some will be idle, and most will be in use. Find an available printer on this list -- if a printer is available, the "Print" button will turn orange; otherwise, it will stay grayed out.

When you find one, make sure it has enough plastic filament to print your part. The filament you need for your print is displayed at the top of the page, and the filament left in the printer is displayed next to the printer's color. Additionally, check the printer's live view to make sure the print bed is clear. If it isn't clear, don't start your print -- printing on a bed that isn't clear can break the printer. If the printer has enough filament, go ahead and start your print. You'll receive an email confirming that it's started and another one when the print finishes. About half an hour after starting your print, check the live view on 3DPrinterOS to make sure it's still printing successfully. If it isn't, cancel the job and troubleshoot! If you're having trouble finding a printer, head to the CoLab and ask one of their staff if there are any printers they can clear. Many times, when a print finishes, its owner won't be able to pick it up right away. If this happens, the finished print might sit on the print bed for a while. If you see an idle printer with a finished print sitting on it, a CoLab staff member can clear it off and mark the printer as ready for you.

Step 5: Troubleshooting

If your print fails, it could be for a number of reasons. Sometimes, a printer is just broken. It could be miscalibrated and start spewing out a mess of filament where it should be printing your part. The print head could become clogged and stop extruding filament, leaving your part partially completed. Sometimes, a printer can be reserved -- if you try to print to a reserved printer, its user will likely cancel your print.

If any of these happen, try again! Pick a different printer and print your part again. Don't try to print to the same printer again. It's likely that the printer is still experiencing those issues, and printing to it again will likely lead to the same result. Sometimes, a print can fail because your part is just hard to print. 3D printers have progressed a long way in the past few years, but they still struggle with some part features. In particular, small details and large overhangs without support can cause trouble. If you suspect that a print is failing because of part design, try to redesign or re-layout your part to solve the problem.