OpenAT Design Guide
Many of the devices in the MMC library use the same components, but all use slightly different dimensions when adding the parts into the design. The designers frequently reference other, older designs that use the part for the correct dimensions to use, but there are so many different dimensions used that this leads to several different ‘standards’ being used across devices for the same part. This guide is an attempt to standardize the dimensions for parts across designs, and to serve as a central reference point for use designing devices.
In the first section, the guide covers the commonly used commercial parts in MMC designs, and how to integrate them into 3D printed components. This includes the right size holes to use for screws, the best ways to secure a switch to a component, and what size openings to use for various USB connectors.
The second section covers common design elements used in MMC devices, such as 3D printed threads, cotter pins, and shadow lines. This section focuses less on exact measurements and dimensions than the previous section, as the designer has control over the dimensions of all the components involved. Instead this section focuses more on the necessary design considerations and minimum/maximum sizes of the features.
The third section of the guide is primarily a link to the Hydra Research Design Rules for basic 3D printing tips, such as wall thicknesses, overhangs, and filet sizes. It also breaks out the section on printing overhanging holes for easy reference, and gives a brief overview of the printers used in the design of the devices mentioned in the guide, and how that affected the tolerances used in the guide. It also covers how these tolerances can be changed for other 3D printers to make them fit better.
About Makers Making Change
Makers Making Change is a program of Neil Squire, a Canadian non-profit that uses technology, knowledge, and passion to empower people with disabilities.
Makers Making Change leverages the capacity of community based Makers, Disability Professionals and Volunteers to develop and deliver affordable Open Source Assistive Technologies.
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