Best Practices for Optimizing Your CAD Designs and Converting to STL for FDM

Investment casting has stood the test of time. One of the world’s oldest manufacturing methods, it is used for the low-volume production of highly-accurate metal parts with excellent surface finishes.

But after thousands of years, additive manufacturing is helping to improve the process and increase its efficiency.

Traditionally, investment casting starts when a wax pattern is coated in ceramic slurry, which hardens to create a shell around the pattern. After it is heated, the wax melts and leaves behind a hollow ceramic shell. The shell is filled with molten metal and after it cools, the ceramic material is blasted off to reveal a completed metal part.

Many investment casting applications use injection-molded wax patterns. But they can also be made faster and with less expense with additive manufacturing technologies like Fused Deposition Modeling (FDM).


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Our guide, Design for Additive Manufacturability

 CAD Output for FDM, explains these unique considerations for Fused Deposition Modeling (FDM) and highlights best practices for designing and exporting files, including in-depth guidelines on:

Striking a balance on file resolution: When exporting CAD data to STL files, it is important to maintain a manageable file resolution that is fine enough to capture intricate details of a design without being too large to slow down the export and increase lead time. We outline the best file sizes to maximize quality AND lead time.

Customizing part density: You can adjust the interior of a part, or raster, to alter part strength, weight, build time and overall cost. FDM parts can be built with a lattice, honeycomb interior to reduce weight and cost, or with a negative air gap to increase density and strength, based on what your application requires. The guide lists the achievable densities and best practices for implementation.

Meeting tight tolerances: You can achieve tight tolerances in additive manufacturing but it is important to note critical tolerances within your STL file. FDM machines build parts one layer at a time. Consult the guide to learn how to adjust the height, or slice thickness, of these layers and choose the right slice thickness based on part dimensions.

Building assemblies, nested or tabbed parts: Saving these components as individual files makes quoting easier and allows for a faster delivery. When you break these parts up into individual files, Stratasys Direct Manufacturing engineers can build each one in an orientation that increases its functionality.

Looking out for file discrepancies: Ensuring you have a clean, watertight STL file, without any missing or overlapping surfaces, makes it easier for the FDM machine to process it and helps decrease production time. Learn how to spot areas of concern within your file to help avoid delays in production.

The possibilities with additive manufacturing are seemingly endless, but knowing how to prepare your files allows you to fully embrace and use the technology to your advantage.

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