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Design Guidelines for Using Metal 3D Printing

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Metal 3D Printing enables you to produce highly complex designs that are lightweight and solid, making them suitable for applications such as motorsport, aerospace, and medicine. To get the best out of Metal 3D Printing, you must follow certain basic engineering and design principles. These guides will provide you with 7 basic design tips for metal 3D printing.

Just like you wouldn't expect a complicated sheet metal component to be thrown at a sand-casting foundry, you shouldn't expect a traditional CNC machined part to be thrown at a Metal 3D Printing firm. So, if you have no prior experience designing for Metal 3D Printing, you can consult with your supplier before beginning to design your component and get their advice.

There are two basic forms of Metal 3D Printing technology available: The first is laser or beam-based technology, and the second is multi-jet printing technology. Nowadays, most laser or beam systems are used to heat the powder directly in the printing machine, resulting in an almost 100 percent solid metal component of the right dimension. Most Multi-Jet Printing processes, on the other hand, use a kind of resin to tie metal particles together, and the resulting pieces are sintered in a secondary phase. This typically results in a 50% shrinkage by length, although this does not always imply that they are intrinsically unreliable. The shrinkage is a foregone conclusion. The build time for laser-based direct metal melting technologies is very closely related to the amount of material used, and to a lesser extent the height of the build; while for Multi-Jet-Printing with sintering technologies, the height of the build is the primary concern and volume is a secondary one, save for the expense of the material itself. If you want fat bits, Multi-Jet and sintering are definitely the best options; but, if you want accurate and almost 100% solid metal parts of extremely high strength, you'll need to place your parts on a diet and keep their weight to an absolute minimum.
There are several fantastic 3D CAD programs available that can assist you with this type of design. This frameworks evolve the concept through several iterations, mimicking nature's performance and allowing you to use the bare minimum of materials.

So many people demand high precision from Metal 3D Printing, and although the precision of these methods has improved significantly over the last ten years, plastics in CNC machining are still not precision machining. Typically, +/-0.1 to 0.2mm is to be anticipated, although this is not a hard and quick law. Parts will buckle and twist due to shape or volume, so you can sometimes see parts that are 1 or 2 mm off from CAD. It is uncommon, but it does occur when the basic principles of Metal 3D Printing are violated. If you want to achieve high precision features, we highly advise you to use a secondary machining method. After writing, tap holes, reamed or bored holes, and certain important faces or features may all be finished. This way, you get the best of all worlds: impossible-to-machine architectures with a few high-precision features used only when necessary.

Being too thick is bad, but being too thin can be much worse. We highly advise you to keep wall thicknesses above 0.5mm; otherwise, the features can deform due to the temperatures involved.

Keep the horizontal or vertical circular holes, slots, or openings larger than 0.5mm in diameter, or they will fuse with the opposite wall and disappear from the build.

Keep any overhangs in the component to less than 0.5mm if you don't want us to use fillet supports, which are costly to remove. There is a 0.5mm theme going on here, as you might have noted. Our test samples show that when we make a horizontal square or rectangular opening, the larger the hole, the more likely the flat ceiling would collapse due to a lack of support in the powder bed. To prevent this, use rounded or slanted ceilings to mitigate the effect. Sloping ceilings are by far the most effective and can be used up to the widest gaps since the 45-degree slope is self-supporting, while rounded ceilings begin to fail as the diameter exceeds 4 or 5mm.

Companies commonly use a Quick EDM Wire Eroder to remove the key supports, in which we would use a rotary grinder and other industrial equipment to remove the remainder. Building and removing supports for laser melted components takes time and money, so we highly advise against designing for them in the first place. If you grasp the Metal 3D Printing technique, you can do this. You should plan the component so that it is self-supporting in the build's Z direction. The walls that are greater than 45 degrees to the horizontal will be self-supporting and will not need any extra supports.

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