There are several different underlying technologies behind how a 3D printer can work. In this post, I’ll explore Fused Deposition Modeling (FDM), the only professional 3D printing technology that uses production-grade thermoplastics, so parts are unrivaled in mechanical, thermal and chemical strength – the same thermoplastics found in traditional manufacturing processes.
Essentially, FDM is when a 3D printer deposits melted plastic in thin layers on a build plate, fusing the layers together as it builds upward. Here’s how it works:
Pre-Processing
The first step for FDM printing is to use build-preparation software that slices and positions a 3D CAD file and calculates a path to extrude thermoplastic and any necessary support material.
In this case, I’ve designed a simple test part using 3D CAD software SolidWorks. If you’d like to follow along, feel free to download the STL file we’re using in this example:
[button size=”medium” link=”http:/ /amtekcompany.com/STL/BH_sample_part.STL” style=”simple” linking=”new-window”]Download STL File [/button]
With a Stratasys FDM printer, you’ll use two materials: model material, which is the plastic that will form the final part, and support material, which is material that helps to hold the part in place as it prints in real-time.
The Stratasys Catalyst software makes pre-processing easy by converting your CAD program’s STL output into 3D modeling print paths, including any needed support structures. Model material will appear in red and support material purple.
For a four inch tall part, there may be 400 layers or more, depending on the layer resolution (the layer resolution determines how detailed your part will be). This part is 0.72” tall, and has 72 layers. Viewed from the right, each layer shows as a line:
Production
This is when the 3D printer heats the thermoplastic to a semi-liquid state and deposits it in ultra-fine beads along the extrusion path. Where support or buffering is needed, the 3D printer deposits removable support material, which essentially acts as scaffolding.
During this process, it is important for the build tray to remain secure so that each layer is deposited precisely and accurately. The tray has a textured surface so that the plastic will mount to the tray, but will still be able to scrape off when it’s finished.
The Catalyst software builds each of the 72 slices of this new structure via a combination of model and support material. Here are different stages of this build:
Post-Processing
This is when the part is snapped off the tray and, in this case, the support material is dissolved in a bath of sodium hydroxide.
Here is the finished part!
For a more in-depth look at FDM technology, feel free to download the white paper 3D Printing with FDM.
