About Geometric Stackup
Need for Tolerance Stackup Analysis
What is Tolerance Stackup analysis?Stackup analysis is done to find out the minimum and maximum distance between two datums.
- It is not possible to manufacture the parts with precise dimensions. This creates dimensional variations in the manufactured parts
- These variations are additive. They can cause problems at the time of assembling. Either the parts may not fit into the assembly or there could be functionality issues
- This results in wastage of material, quality issues and cost overheads
- It is therefore necessary to be able to predict what percentage of parts will assemble properly. These predictions are made using tolerance stackup analysis
- Design problems can also be addressed by using stackup analysis at an early stage
- Operating Systems (32 & 64 bit) – Windows 7, Windows 8, Windows 8.1 and Windows 10
- Monitor – 1280 X 1024 or higher resolution with support for 32-bit color
- RAM – 4GB or more recommended
- Internet Explorer version 9.0 and above
- Microsoft Excel 2007 and above
- Graphics Hardware supporting OpenGL 1.4 and above
Supported CAD FormatsGeometric Stackup supports CATIA V5, NX, I-DEAS, Pro/ENGINEER, Creo Parametric, SOLIDWORKS, Inventor, SolidEdge, 2D file formats like DWG & DXF and neutrals like STEP/STP, IGES/IGS, and Parasolid
How it works?
Open the part
Define the gap
The Input Dimensions Window indicates the dimensions selected by the user. User can modify the tolerance values, add assembly shift and GD&T or delete a dimension if required for further analysis. Use the icon in the dimension table if you want to delete a particular dimension.
The GD&T Window appears when user clicks on any row of GD&T column. It allows user to add applicable geometric tolerance on selected entity. Use the icon or "Delete" key to delete the selected GD&T value and the icon or key "Enter" to add GD&T value. To update any existing GD&T value, select the required row and use the icon or "Enter" key to update the value.
Supports Assembly Shift
The Assembly Shift Window appears when user clicks on a row of ASMShift column. It allows user to add assembly shift tolerance. Use the icon or "Enter" key to add the ASMShift value.
Supports Assembly Shift
To add assembly shift for non-fastener features, different window will appear by automatically detecting features other than fasteners.User may add 'Min Shift' and 'Max Shift' values respectively.
Supports Worst Case & RSS Methods
The Results Window provides the results for worst case and RSS analysis. RSS results are available upto 6 sigma variation. User can specify the specification limits by using the upper and lower limit text boxes. Yeild indicates the percentage of parts that can be manufactured for the given tolerance limits.
The Distribution Chart indicates the distribution of parts that are manufactured with the given manufacturing tolerance limits. The central yellow line on the bell curve indicates the nominal value around which most of the parts will be manufactured. The green area indicates the total yeild. The orange line indicates the lower limit meaning that the parts manufactured below this limit are considered as scrap. Red area under the bell curve indicates the scrap amount. The blue line indicates upper limit meaning that the parts manufactured above this limit can possibly be reworked to achieve success. The sky blue area indicates the rework amount.
The Contribution Chart gives an idea about how the dimensions are contributing to the gap that is being analyzed. The manufacturing tolerance for the gap under analysis can be adjusted by knowing which is the maximum contributing dimension. For e.g in the contribution chart shown in the image, Dim5 is the maximum contributing dimension. User can change the tolerance for this dimension to achieve the desired manufacturing tolerance limit for the gap under analysis. To change the nominal value for a component, user will need to update the model in native CAD.