Five Unique Considerations for 3D Printing Production Parts

Additive manufacturing has been making a transition from prototyping, to a legitimate way to produce end-use parts. This has been a goal of the industry for some time, and many companies are embracing this change and looking for ways to use 3D printing to improve their product manufacturing. As with any process, engineers need to understand and take in to account what is unique about additive manufacturing when designing components that will be printed. Most aspects are the same as any process, but there a five key differences that should be taken into account.

Materials


Each technology offers one or more unique materials with unique properties and design constraints. Manufacturers are working on adding materials that increase the end-use application opportunities, with new materials coming out about every six months. When choosing a material for end-use, designers need to know what options they have and consider strength, stiffness, voids, non-uniform properties, chemical interaction, UV sensitivity and a host of other properties.

Supports

Every manufacturing method has something you need to work around, in additive manufacturing it is supports. As layers are deposited, supports must be used to constrain any overhanging material or gravity will pull the layer down. And with metal, supports are needed to conduct heat away and hold layers down against thermal strains. Even if that support material is powder or water soluble, every design needs to consider the following - the amount of support material required, the added cost, the removal process, and what the surface will look like, after removal, where the supports were connected. The best option is to remove as many supports as possible. Additionally, make sure that supports are not attached to any critical surfaces, if they are, expensive and time consuming post processing will be required. The removal of supports on plastic is fairly straightforward, often automatic, but with metal the material needs to be cut or ground off. Making sure that there is access to do this can be one of the biggest design challenges for metal end-use parts.

Orientation


Additive manufacturing is… additive. Almost all 3D printing methods build a part by creating one layer at a time. This creates directional material properties, as well as small stair steps on the outside surface. Strength, stiffness and Poison’s ratio are not uniform. Any design should consider what the variation is and take it in to account. The part should be oriented in the machine to minimize, or even take advantage of, the impact of a layer-based process.

Machine Constraints


Just as with any process, the limitations of the machine being used to make a part should be considered. The most obvious constraint is size. Although parts can be glued together or welded after printing, this is an added step and cost. The other significant machine constraint is layer height and minimum horizontal resolution. Every technology has a layer thickness that is discreet, so the dimension of a part or feature in the build direction must be a multiple of this thickness. Likewise, the resolution in the horizontal plane is a hard constraint.

Critical Dimensions and Features

Although accurate features and key dimensions can be a challenge with any additive processes, it is OK. Parts can still be machined. A good design minimizes the number of machining operations, but if used wisely, the machining cost will be much less than traditional methods and still deliver highly accurate critical features and dimensions.

Every manufacturing process has its strengths and weaknesses, and additive manufacturing is no different. As more and more parts are found that can benefit from this method, a good designer can take what makes it unique into account and design cost effective and durable components.

Eric Miller is a principal at PADT Inc. He is often called on to speak on the use of simulation and 3D Printing to enhance product development. His involvement in the startup community includes angel investing and mentoring. He can be reached at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

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