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Additive Manufacturing Process Chain

Learn about the process chaining in Additive Manufacturing.
Submitted by Akash Periyasamy, on June 09, 2022

From CAD description to physical result, AM involves several steps. The process will vary depending on the product. It is likely that smaller, simpler products make use of AM only for visualization purposes, whereas larger, more complex products may incorporate AM at multiple stages and iterations throughout the development process. Also, in the early stages of product development, rough parts may be needed, and AM is generally used due to its rapid fabrication capability. As parts advance through the process, they may need cleaning and post-processing (such as coating and sanding) before they can be used; in this regard, rapid prototyping is useful due to the complexity of forms that can be created without involving tooling.

Step 1: CAD

CAD models that fully describe the external geometry are required for all AM parts. Any professional CAD solid modelling software can be used to create this, but the final product must be a 3D solid or surface model. To create such an image, reverse engineering equipment (for example, laser and optical scanning) can also be used.

Step 2: Conversion to STL

Upon completion of the digital model, the STL (Standard Tessellation Language) file format must be used to create the stereolithography. Nearly every CAD system supports this format, which is how AM machines communicate. The STL file serves as the basis for calculating the slices of the model.

Step 3: Transfer to Machine

In the third step, the STL file is transmitted to the AM machine. As a result of this step, it is possible to adjust the build so that it is positioned and sized correctly. A computer controls the AM machine. The AM machine is controlled by the computer, that computer only generates the required instruction in the form of G-codes and M-codes based on the given process parameters. It generates instructions automatically, if any correction is needed for the betterment of the part to be built it can be corrected.

Step 4: Setup

Before the building starts, the equipment has to be set up. The settings can constitute power, speed, layer thickness, and other several parameters related to material and process constraints, etc.

Step 5: Build

The fifth step is the actual building of the CAD model, melting layer by layer. This process can be semi or fully automated but some online monitoring is often conducted, so that the machine does not run out of material or that some software error occurs.

Step 6: Part Removal

Once the part is manufactured it has to be removed from the process, which is normally done manually. This may require interaction with the machine, which may have safety interlocks to ensure, for example, that the operating temperatures are sufficiently low or that there are no actively moving parts.

Step 7: Post-processing

After the build, the part might need some post-processing before it is completely finished. Of course, depending on the material and AM process used, some parts might need machining, cleaning, polishing, removal of support structures, hot isostatic pressing (HIP), and heat treatments.

Step 8: Application

At this stage, the part can be ready for use. Nevertheless, it could also need some additional treatments, like painting, or assembling with other components before it is fully usable. For example, they may require priming and painting to give an acceptable surface texture and finish. Treatments may be laborious and lengthy if the finishing requirements are very demanding. They may also be required to be assembled with other mechanical or electronic components to form a final model or product.