Somehow you don’t hear much about tolerance and tolerance analysis. Obviously geometric dimensions and tolerances are a big part of every engineer’s life and, as with anything so everyday, yet vital, software has been created to help.
As engineers examine the interaction of critical components in systems, they are typically performing some level of tolerance analysis.
First let’s look at the reasons to perform tolerance analysis? We’ve discovered a number of them.
To test and improve geometric dimensioning and tolerancing.
To Determine gap and flush conditions based on manufacturing processes.
To optimize these processes by simulating and optimizing manufacturing and assembly.
To reduce overall product variation.
To control rework and scrap
To resolve manufacturing issues, which can be done by using measurement data
To resolve issues with the CAD model.
Software producers include Sigmatrix, of McKinney, Texas, which makes Cetol 6σ tolerance analysis software–just updated to version 10.2. The tolerance analysis software helps product development teams understand the impact of dimensional and assembly variation on their designs.
This allows them to make necessary adjustments before problems appear in manufacturing or, even worse, in their customers’ hands.
The software includes intuitive messages based upon the user’s step in the process. These “Advisor” messages show the users what they need to do when they need to do it.
Dimensional Control Systems of Troy, Mich., offers the tolerance analysis tool 3DCS Variation Analyst, which lets users analyze the relationship between their parts, and track part sources. The software simulates both part and process variation, meaning engineers can analyze their manufacturing process and how it affects the assembly of the product and how it will function when produced.
Geometric Stackup is a tolerance stackup analysis software. It automatically assesses minimal and maximum tolerances on assemblies using worst-case analysis scnearios
These solutions work directly with CAD geometries. Engineers no longer need to manually enter nominal values from the CAD model to Excel spreadsheets, as in the “olden days.” Geometric Stackup, for example, is integrated with SolidWorks and WindChill, so users of those systems don’t need to leave them to access the tolerance analysis tools.
Like many types of engineering software, today’s tolerance analysis software today is also designed for the nonspecialist. It’s easy to use, with a short learning curve.
Another tool, called TolAnalyst is included with the SolidWorks premium package. The information is uses has been brought into the system by a tool called DimXpert that automatically includes manufacturing and inspection dimensions with tolerances based on data the engineer inputs.
In fact, DimXpert is included within all SolidWorks package. With it, users can input surfaces as data. The result is a part that is defined with dimensions and tolerances according to the requirements of ASME Y14.41-2003 and ISO 16792:2006. Users with TolAnalyst can then perform stack analysis on assembles.
So why is tolerance analysis important? A Sigmatrix specialist offers an example.
As electronic devices get smaller and more densely packaged, the importance intensifies to more precisely understanding the interaction of manufacturing variation and design tolerances.
And that’s true for other industries as well. Likewise, in the aircraft, automotive and medical device industries, liability continues to grow, so companies need to understand more precisely what may cause a failure.
