3D Printing General Process

CAD

MESH

(STL File)

G-Code

3D Printer

3D Printed Part

3D Printing General Process

Introduction

3D Printing (also known as Additive Manufacturing or rapid prototyping) is a method of digital manufacture utilizing CNC (Computer Numerical Control) where a digital model is converted to a physical one by building up layers of material to create a solid object.

While there are many different 3D printing techniques, the general process from design to the final part is almost the same. Whether the final part is a quick prototype or a final functional part, the general process does not change.

1. Digital Model

A digital model is the first step in the 3D Printing process. Whether this model was designed using a CAD software, reverse engineered from a mesh file of even generated using a 3D Scanner.

If you are using a CAD software, several design considerations should be evaluated when designing for 3D printing, depending on the technique used, these design considerations vary between overhangs, feature geometry limitations, or escape hole.

You don’t have to be a design expert to 3D Print, nowadays there are numerous libraries for 3D models ready for 3D Printing like:

  • Cults 3D

  • Pinshape

  • 3DShook

  • Thingiverse

  • GrabCAD

  • 3D Warehouse

  • CGTrader

  • TurboSquid

  • 3DExport

CAD Model

2. Getting your file ready for 3D Printing

 

The most common file type for 3D Printing is STL (stereolithography) file. STL is a type of MESH files that use triangles to describe the surface of an object. Resolution of STL files is controlled by the number and size of these triangles, as triangle count goes up and size goes down, you get a higher resolution and vice versa.

Most of CAD software are able to export STL directly, or a converting software will be needed to obtain STL files from CAD files. Whether you export directly or convert you file, please make sure that your STL is watertight. Unwatertight files might cause problems later.

MESH File Containing Millions of Triangles

3. Slicing

After the CAD phase is finished, it’s time for CAM (Computer Aided Manufacturing) phase. The CAM process for 3D Printing is called Slicing where a software is used to slice the imported STL to layers.

Slicers take inputs from user controlling every aspect of the 3D Printing process (Layer Height, shells, infill, supports, …, etc.)  and generate a simulation for the 3D printing process for the user to inspect and modify if needed. You can also control model scale and orientation.

Once you are happy with the settings and simulation, software will generate a G-Code. G-code is a numerical control (NC) programming language. It is used in computer-aided manufacturing (CAM) to control automated machine tools (including CNC machines and 3D printers). It containing a list of numerical ordered for the machine to carry out. This file is then transferred to the machine via SD-Card, USB stick or USB connection.

You are now ready for the magic.

Slicer (Cura) Model View

Slicer (Cura) Layer View

4. 3D Printing

 

3D Printers consist of complicated mechanical and electrical parts that need to be well maintained and calibrated to ensure getting the best and accurate result the user requires.

Most of these 3D Printers do not require user monitoring after print starts. The machine will carry our orders supplied by the gcode unless there is an issue. Depending on the technology, issues generally only arise when the machine runs out of material or there is an error in the software.

There are a lot of 3D printing technologies used today to manufacture everything from plastic prototype to functional parts serving the aerospace industry.

Example of 3D Printing  (Clay 3D Printing

5. Post processing

 

Depending on the technology used in 3D Printing, Post processing might be just removal of supports and simple finishing and it also might be soaking the printed part in certain fluids.

SLA parts require to be cured using UV light while metal printed parts often require to be stress relieved in an oven while FDM parts are ready to go from the printer after removal of supports (if any).

Post processing also includes a wide range of finishing options, you can sand, spray paint, or even electroplate your products depending on technology and material used.

Painting of a 3D Printed model

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