3D Printing Basics

Design, Build, Perform

Good 3D printing can be broken down into 3 simple steps.  Understanding each of these steps and how they affect the final project are instrumental in producing a good quality part:

 

  1.  Know your software

  2.  Know you printer

  3.  Know your material

There are numerous methods to accomplish each of these steps.  The normal process at USNA can be outlined as follows:

Step 1:  Know your software

  • Most USNA users will use SolidWorks to create a SLDPRT or SLDASM.  It is very important to understand the differences (1 part or an assembly) and in most cases the best final method is to save a part as a single SLDPRT file unless parts are going to be printed individually.

  • The part should then be saved as a STL file.  STL files are notably much smaller than normal CAD files and only contain info on the geometry of the part.  STL files are difficult to edit so normally changes should be made to the original CAD file and then exported as a new STL file.

  • Each printer vendor has different processes for taking an STL file and printing the part which brings us to Step 2.…

Step 2:  Know your printer

  • One of the most common questions is “which printer should I use?”  This is a very loaded question and you must know the answer before you go any further with your part.  In many cases maximum size may be the determining factor or maybe whether the part must be solid or not is a determining factor.

  • Each printer vendor has some software package (e.g. Print for MakerBot, Preform for Formlabs, and Cura for LulzBot and Ultimaker) that is generally a very intuitive GUI to arrange a full build.

  • The first objective is orientation of parts on a build platform.  Multiple STL files can be arranged and in general build plate arrangement is very straightforward.

  • The next objective is slicing which essentially creates the tool path for every layer of the build.  The slicing process can be buried in a software package or it can be its own process (Cura is an open source slicing software package).

  • The final step (which actually occurs before slicing) is selecting both printer parameters and material parameters.  This can be very simple and straightforward (such as for MakerBot and Formlabs) or can be complex and customizable (such as for Cura).

  • Once completed, you will now create an electronic file that has the following characteristics built into it:  your part geometry, your printer parameters, and your material parameters.  This electronic file is a GCODE file which is close to man-readable.  Some vendors (e.g. MakerBot) do not make this GCODE file readily available to users but others do (e.g. Cura).  MakerSpace USNA strongly encourages users to have an in depth knowledge of what is in the GCODE and in some cases the GCODE file will be directly handled.

 

Step 3:  Know your material

  • The next most common question is “what material should I use?” although most users already have a reasonable idea of what type of material they want (e.g. ABS, PLA, PETG, etc.)

  • Type of material and printer are connected and you must know what material you are slicing for before creating your GCODE file.  Not all printers will print all materials and vice versa so next to physical size, type of material is the next most common decider for what printer to use.

  • Do not forget that most 3D printed parts are hollow!  Do not select a material solely based on its “strength” because normally amount of material (i.e. infill) is more relevant than type of material.

 

With these three steps complete, all you need now is an understanding of the resources in the MakerSpace in order to create your first 3D printed part!

SolidWorks used to create a STL file from a SLDASM file saved as a single SLDPRT.

Many simple problems can be avoided by simply using good logical orientation of the build plate.

Supports can be a major source of frustration and must be accounted for in the planning portion of a part.  In this image, SLA supports are managed differently than FDM supports.

Final printed part with supports removed.

We get this question all the time and everyone you will ask will have a different opinion on it.  There are entire articles that are dedicated to deciding on whether you should manufacture a part from 3D printing or traditional manufacturing.

And the answer is you should almost always make a part from traditional manufacturing (casting, forming, etc.).  One of the most frequently discussed advantages of 3D printing is the ability to make complex parts, and every 3D printing company prints small complex shapes that are really nothing more than demo pieces.  There really are not that many parts that cannot be easily made from traditional manufacturing.

So why and how do we use 3D printing at MakerSpace USNA?  

The answers from our practical standpoint are pretty simple:

-  Often we can make parts in a fraction of the time.

-  3D printing allows for rapid redesign and prototyping.

-  3D printed parts often require less post processing (but that does not at all mean that 3D printed parts require no post processing).

-   Yes, we can make more complex geometries than traditional manufacturing.

Often these simple reasons are reason enough to make parts from 3D printing.

Happy printing!

The above intake pipes (the gray parts) were made from 3D printing. Using simple 3D printing, these parts could rapidly be redesigned and tailored to the application. 

What should I and what should I not 3D print?