How to Fully Leverage CAD in the Additive Manufacturing Process

Thu Sep 02, 2021

The main phases involved in additive manufacturing are that of design and the manufacturing process. Practically, the design work is done on a computer aided design (CAD) suite such as SolidWorks (and others), while the physical production phase - i.e. 3D printing - is facilitated by exporting the CAD file (e.g. SLDPRT) to STL, a format that can be read by 3D printers with 3D XML viewer.

However, there are several major steps in both phases of the additive manufacturing process.

For engineering teams and manufacturers alike, productivity will depend on the effectiveness of their design tools, be it the quality of their CAD suites or their ability to interoperate with parties using different CAD suites. For example, the time spent on file healing and working around the technical issues of using certain file formats (such as STL) is time added to time-to-market.

In this piece, we examine these factors in the additive manufacturing lifecycle and highlight how application developers and 3D printer manufacturers can position their products as solutions.

What is CAD?

Be it additive manufacturing or even subtractive manufacturing, the design process of almost all products begins in CAD. SolidWorks is among a number of popular CAD suites on the market, it is used to design a product - be it as a collection of individual parts or as an entire system - as well as test and qualify its design attributes ahead of manufacturing.

What is STL?

STL (short for STereoLithography or Standard Tessellation Language) was launched in 1987 to enable stereolithography 3D printers to read CAD files. Like IGES, STL is now in wide use in the 3D printing industry, especially as a means to enable teams with different CAD suites to readily interoperate with one another as part of a broader product development project.

 


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Understanding the Engineering Workflow

Design

The engineering and product development workflow begins in a CAD suite. Today, CAD users can leverage an array of tools to design objects not only in 3D, but with the ability to incorporate a large number of details such as color, texture and other design elements.

In fact, SolidWorks also offers specialized tools to incorporate sheet metal, molds, weldments and surfacing into their core design work. In other words, the CAD design file could effectively reflect the intended real-world product with complete fidelity.

SolidWorks also equips engineers to approach their design work in different ways. For example, an engineer that designs with manufacturability in mind can design, store and retrieve individual parts as SLDPRT files and combine those SLDPRT files into one SLDASM file (see this article to understand the differences between SLDPRT and SLDASM files).

Analysis

The ability to design CAD files with the intended real-world design - such as aesthetics, surface geometries, mechanics, colors and materials - also opens the door for design teams to test and verify the design’s viability virtually (i.e. before physical prototyping).

Granted, the quality of analysis - which includes simulation and visualization - depends on the capability on offer by the CAD suite (SolidWorks includes these features). However, simulation enables designers to reduce their prototyping needs and physical testing costs by identifying as well as correcting design issues during the core design phase.

For example, SolidWorks’ analysis tools, which use the Finite Element Analysis (FEA) method, include static linear, time-based motion and high-cycle fatigue simulation in the standard tier. In higher tiers, engineers can determine their designs’ durability, topology, natural frequencies and conduct a range of non-linear static and non-linear dynamic tests.

Preparation

With current-day CAD suites, the physical prototyping and testing stage should be shorter in the consumption of time and fiscal resources. However, designers must generally export the original CAD file into STL in order for 3D printers to properly interpret the original design file.

Converting to STL has its advantages and constraints. On the one hand, it certainly enables an original design file made in CAD to be manufactured through 3D printing. However, STL will not read your original design’s colors, textures and other design elements (including metadata).

Moreover, changes made to the STL file will not automatically be reflected in the original design file in CAD; rather, the the process is one way wherein changes must be made to CAD for them to reflect the STL file. This adds a layer of inefficiency to the prototyping process (which makes the simulation and visualization work done in CAD all the more important).

Finally, refinement done with STL files must be done with care. Though you could encode the STL file in ASCII and work on increasing the number of triangles to decrease coarseness, you run the risk of drastically ballooning the size of your STL file such that it is too large for 3D printers to read.

Printing

Today, STL’s widespread adoption and technical maturity makes it a necessity for 3D printing.

To supplant STL, the 3MF Consortium (of which Spatial’s parent company, Dassault Systèmes is a founding member) is working to have the additive manufacturing industry adopt 3MF.

The new format uses ASCII in XML to enable 3D printers to read CAD design files in full-fidelity - i.e. with the colors, textures and other design elements intended by the original designer. It is also meant to be extensible and adaptable to emerging 3D printing technology.

However, 3MF is a long-term factor. As of today, STL is still the dominant file format in use by the additive manufacturing industry. Those developing applications and hardware for those in the 3D printing space must accommodate for STL handling.

 Why Leverage 3D InterOp

With STL an essential element to bridging the design and production phases in 3D printing, it is critical that end-users are capable of minimizing the time spent on file healing (i.e. from CAD to STL), be it from SolidWorks or other CAD suites. In fact, interoperability is essential as not every engineering workflow uses SolidWorks.

Spatial’s 3D InterOp software development kit (SDK) equips application developers to integrate interoperability into their offerings for additive manufacturing companies. Be it 3D printers or for applications meant to view different CAD file formats, 3D InterOp enables you to rapidly equip your offerings with the baseline requirements of the additive manufacturing industry.

You need these capabilities, and while adding them is possible, it will simply add to your time to market and costs. Contact Spatial today to rapidly integrate these commodity features and focus your limited business resources towards differentiation and accelerating time to market.

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