Tolerance analysis is a best practice in design for manufacturing. You should always perform a complete component and assembly tolerance analysis during the design phase and prior to production release to ensure that each component has proper form, fit, and function.
The tolerance analysis is an integral part of the design process. Due diligence early on will help prevent issues during the manufacturing process. A thorough and accurate tolerance analysis requires a strong understanding of tolerancing standards and practices, as well as product application.
There are two types of tolerancing—limit tolerancing and GD&T (Geometric Dimensioning and Tolerancing). The GD&T standards are ASME Y14.5, primarily practiced in North America, and ISO 8015, practiced in Europe and globally. Both tolerancing standards are acceptable, and it’s typically up to the organization’s preference.
The most common and widely practiced limit tolerance analysis is the 1D (worst-case) tolerance stack. The 1D stack is linear and the most basic form of tolerance analysis that addresses the acceptability of limits. The other option is the more complex statistical analysis, which considers the part variation probability based on the manufacturing processes and capabilities. For most situations, a 1D stack is a sufficient approach.
An output of a thorough tolerance analysis is corrections to part and assembly drawing dimensions and tolerances. Common dimensioning and tolerancing mistakes include incorrectly matched tolerances to manufacturing processes, specifying title block tolerances without regard to the practical components’ requirements, dual dimensioning, over-tolerancing or under-tolerancing, and more. These issues arise when designers are not sufficiently trained in dimensioning and tolerancing practices, are unaware of standard manufacturing practices, or make simple oversights.
Fortunately, many of these issues are identified during the tolerance analysis process, and we can help you address them. After performing the tolerance analysis, GMI designers may work with clients to adjust the drawings, specs, and design to make the product better, more durable, and mitigate any concerns.
When we take on a new project at GMI, our engineers perform a documentation scrub to ensure desired manufacturability using an I/O tracker. The I/O is based on the customer-supplied documentation package, and typically includes drawings, CAD models, BOMs (bills of materials), and specifications, where the input is the customer-supplied documentation to GMI, and the output is GMI’s scrub response to the customer. The I/O tracker is based on components identified for risk, and serves the purpose of tracking, documenting, and closing out GMI’s concerns. The I/O scrub is an extremely valuable exercise, sometimes requiring several iterations. It results in a manufacturable design package thoroughly understood by GMI, the customer, and the supply chain.
At GMI, we’re dedicated to communicating clearly and sharing our knowledge base with our customers to ensure that they get the best end product results possible. Tolerance analysis is a crucial part of this process. To learn more about our processes and quality control measures, please reach out to our team via our company profile (linked above).
We’re here to deliver your project to meet and exceed your expectations.