Tolerance analysis is about finding the right balance between precision and manufacturing costs. Fully integrated in Inventor, tolerance analysis allows you to make better informed decisions about required manufacturing tolerances.
It was perfect in CAD, wasn't it?
A final manufactured component is never the same as the initial 3D design . The allowed deviation is the tolerance. Tolerance analysis is about finding the right balance between precision and price, because the lower a tolerance, the higher the manufacturing costs. Therefore, the following principle applies: Tolerances should always be defined as roughly as possible and as precisely as necessary.
Why is the final manufactured component never the same as the initially designed 3D model?
In manufacturing, deviations from the initial design can occur for many reasons. Everything from tool wear, component deflection, vibrations, operational temperature and precision of the machine can result in variation from the initial design. Depending on the characteristics of the differences, each will be evaluated as a surface roughness, shape or dimensional deviations.
Traditional engineering tools
Currently tolerances are often chosen based on experience or mental arithmetic, a detailed investigation often is not done. For critical tolerance stack-ups, hand calculations on paper or in Excel spreadsheets is most times the method of choice. With these methods, long-term archiving is often a challenge and physical prototypes are rarely built due to the associated cost.
Inventor Tolerance Analysis
Fully integrated in Inventor, tolerance analysis allows you to make better informed decisions about required manufacturing tolerances. The tolerance analysis is done directly within the CAD model and can also be viewed later, at any time. The tool allows you to inspect several tolerance stack-ups in the model in parallel and while running the analysis you can switch easily between arithmetic and statistical tolerance calculation with just one click. Detailed reports can also be generated to collaborate with manufacturing and quality engineers.
Worst-case
This traditional method of tolerance analysis is based on the concept of complete interchangeability. All tolerances of a stack-up are summed up to their most unfavorable state. This assumption results in very small tolerances, which causes high manufacturing costs. This method is mostly used for function-critical or safety-relevant tolerance stack-ups.
Statistical variation
The statistical variation analysis model is based on probabilities. So, it is assumed that the sum of all individual tolerances in a stack-up in its most unfavorable state is very unlikely. The result is much more realistic than an arithmetic tolerance calculation. This analysis method allows to choose the individual tolerances of stack-up larger, thus saving manufacturing costs.
Summary
Fully integrated in Inventor, tolerance analysis allows you to make better informed decisions about required manufacturing tolerances. By easily switching between Worst-case and Statistical variation, you can quickly decide which tolerance is required for your design. Detailed reports can also be generated to collaborate with manufacturing and quality engineers.
