3D printers, also known as 3D rapid-prototypers, are capable of taking digital geometry in the form of a stereolithographic file (.stl) and producing small models. Here at Taubman College we currently have three ABS 3D printers available to students. The necessary file can be produced from a variety of different 3D modeling software, such as Rhino, 3D studio max, and Digital Project. Regardless of what software one is using, the file must be "watertight," that is no open edge.
All 3D Print Lab assistants are available for consultation and walk up file preparation/execution during their posted shifts (see calendar below).
Lab Assistant Shifts
The College currently has three ABS printers, which operate in the same manner, but have different build volumes. The uPrint SE Plus build volume is 8"x8"x6", the 768SST's build volume is 8"x8"x12", while the 1200es is slightly larger at 10" x 10" x 12". Models with a wall/column thickness less than 0.04" or 1 mm are printed at the student's own risk and expense. Print times can range from 1 hour up to 50 hours. After the print is complete, the structural support is removed by placing it in a chemical bath for around 12 hours.
One of the most difficult tasks when it comes to 3D printing is creating a clean file. Here we will go over different techniques in creating proper geometry, checking meshes and repairing meshes. While the methods described below will aid in creating a printable model, sometimes a file is too difficult to overcome. If you are unable to successfully create a proper file, contact a LA to seek further advice. They may be able to correct the file, but please note that this is not always the case. Sometimes the only way to make a file printable is to recreate it altogether.
Note: These following methods primarily apply to the 3D modeling software Rhino.
Checking Nurbs File
If you have a polysurface in Rhino and you would like to know if it could be printed there are a few things one can do in order to check. First, before converting the file to a mesh (STL file), check to see if the file is a closed polysurface or an open polysurface. If it is an open polysurface, your geometry is not "watertight". One simple way to check if it is a solid (closed polysurface) is to go to properties -> details (F3 brings up the properties dialog box). If the file is closed, then proceed to export it as an .stl (mesh). You can also do a quick “volume” command, which will likely confirm if the object is watertight. This will help determine the approximate cost of the print, but will not account for support material which may be needed.
Trouble Creating a Solid
If you find that your object is not a closed polysurface, there are many different ways to proceed. It is best to fix the geometry here, rather than converting it to a mesh and then trying to repair it. The first step would be to turn on "naked edges" in the Analyze toolbar to find where the geometry is open. For further information on how to close an open polysurface please visit this link.
Exporting to STL
If you have a closed polysurface, the next step is to export the geometry as an STL file. Select the geometry you wish to export and go to "File", "Export Selected." Select "Stereolithography (.stl) and click "save." A new dialog box should appear. Usually the default is sufficient, but if you wish to adjust the tolerance of the object (number of polygons) it can be done here. Select "Ok." A new dialog box appears. You don't need to change anything here, binary is fine, just hit "Ok." You can also convert an object directly to a mesh in Rhino by the command "mesh," but remember to do a "save as," so as not to overwrite your nurbs based file.
Checking STL Mesh
Once you have created an stl file, even if the original geometry was a closed polysurface, it is a good idea to verify that the mesh is a good mesh. To do this open the STL file, select the geometry and type in "CheckMesh." It should read, "This is a Good Mesh" at the top and contain no naked edges or degenerative faces. If this is the case, your file should be suitable for 3D printing. If this is not the case, it often times is best to go back to the Nurbs Rhino file and fix the problem area there as oppose to the mesh file. If you are having trouble resolving it, a LA can try repairing the mesh with Z editPro in the 3D Print Lab.
1. Have an Idea
The first step is to have an idea in mind of what you would like to produce. How large does it need to be? How thin are the members? What does the geometry look like? All 3D Print Lab Assistants are available for consultation and walk up file preparation/execution during their posted shifts (see calendar above). We highly recommend meeting with a 3D Print LA first if you have never submitted a 3D print request.
2. Become Familiar with Equipment
It is important to be at least loosely familiar with the equipment. This will be informative in how the file is created, if it is feasible to print, and how much the print will approximately cost. Reading the overview above of the equipment is a good start. Additionally, if this is your first 3D print, it would be a good idea to talk with a 3D Print LA to see how the equipment works as well as view sample prints in the lab. It is best to do this early on, so as not to spend a lot of time working on a file, only to find out it is incapable or problematic to print. A 3D print LA can be contacted via email at email@example.com. Once a schedule is set for each semester, it will be posted in the calendar above and on the door of the 3D Print Lab; making it easier for a student to meet in person with a LA.
3. Create the File
Often times the most challenging part of the 3D printing process is creating the actual file. If the file is not "watertight" when submitted, there is a good chance it won't be able to be printed. The 3D Print LAs may be capable of repairing an erroneous STL mesh, but it is in your best interest to submit a clean file from the start, otherwise you risk delaying the process. While there are many different 3D modeling softwares capable of producing a STL file, Rhino is the most prevalent within the College, and therefore is the software that is addressed. For help preparing and verifying a file for 3D printing please see the file preparation section.
4. Submitting the File
You MUST be logged onto your University of Michigan domain (firstname.lastname@example.org) in order to access the form, you cannot use an alternative email domain.
In order to submit a STL file to print, carefully fill out this 3D print submission form with all the important information. You may only submit one STL file per form with a maximum size of 100MB - there should be no reason for a file to be any larger. The file should only include the items you need printed, DO NOT send working files with multiple iterations or hidden geometries. Please nest ALL parts of your geometry within the X,Y,Z volume limits. The closer you nest your individual pieces next to others the cheaper and faster the print will be. If you have multiple large prints which need multiple trays, please submit a separate form for each of those prints. If you have questions about your STL file, please visit the 3D Print Lab during a 3D Print LA shift to discuss the file before you submit the form.
5. Edits to the 3D Print Submission Form and/or STL file
You will automatically receive an email receipt of your 3D Print Submission Form responses and you will be able to make edits to the responses then resubmit. However you will NOT be able to upload a new version of the STL file. You would have to submit a new 3D print submission form. Therefore, please be sure to submit the correct file the first time. A 3D Print LA will reach out to you via email if there are any issues with your file, and in that case you may communicate via email with an updated STL file or visit the 3D Print Lab with an updated STL file on a USB drive. If you do submit another 3D Print Submission Form with an updated STL file, please use the “Notes” section of the form to communicate this.
6. Pay for the 3D Print at the Media Center
Once you receive an email that your 3D print is finished, pick up the 3D Print Order Form from the 3D Print Lab, which the 3D Print Lab Assistant will fill out, and pay for it at the Media Center. Place the paid receipt in the mailbox outside the FABLab Office (room 1225) prior to removing your 3D print from the 3D Print Lab.