Managing large assemblies in NX can be challenging, but the right practices make a noticeable difference. A few foundational habits can improve performance, reduce complexity, and keep projects moving smoothly. This blog outlines five practical tips to help you work more efficiently with large assemblies in NX.
1. Garbage in, garbage out
In computer science, garbage in, garbage out (GIGO) is the concept that flawed, biased, or poor-quality (garbage) information or input produces a result or output of similar (garbage) quality. The saying points to the need to improve data quality in, for example, programming. Rubbish in, rubbish out (RIRO) is an alternate wording.
When GIGO is applied to NX, it refers to individual components and sub-assemblies containing anything from invalid sketches and features to unsolved assembly constraints. Individually, these “garbage” issues can be of little to no consequence. When added together (especially in a large assembly), they can compound to form large amounts of impossible-to-calculate data. This will cause NX to slow down to a crawl, wasting valuable time. By investing a little of that time up-front and creating good data, opportunity and sanity are saved when it is required most.
2. Reference Set configuration
Like GIGO, Reference Sets are critical in maintaining high levels of performance when dealing with large assemblies. By spending a few moments during the modeling and sub-assembly phase, it is easy to set your largest assemblies up for success. A few benefits of good reference set management are:
- Customization: Tailor reference sets to the exact components, attributes, or concepts needed.
- Performance: Faster loading, reduced memory consumption, and cleaner displays. Don’t forget, NX redraws every pixel displayed in the GUI each time a model or assembly is moved.
REMEMBER: Less GUI data displayed = less data to process = less time waiting
- Consistency: Standardized display, parameters, information treatment across projects, and more coherent models and assemblies.
- Error Reduction: Minimizes unnecessary clutter and helps avoid processing irrelevant information (see ‘Performance’ above).
3. Simplify your assemblies
Another useful command in NX is Simplify Assembly. This allows you to remove unnecessary complexity in large assemblies. You can select components or features to hide, which lessens the burden on your PC resources. It also has the added benefit of keeping the focus on what is important during your work session.
4. Assembly load options
One of the biggest headaches when dealing with large assemblies is the time it takes to load and display them before you can work. Load options give the flexibility needed to quickly and accurately display what is necessary. By optimizing what is loaded, you can improve the overall performance of your work session. Load options work best when paired with reference sets, providing you with only the most pertinent information. So, you can work at the highest efficiency level.
5. Symbolic threads
One of the easiest ways to manage time with large assemblies is to use Symbolic threads. Assemblies, especially large ones, can contain a multitude of screws, nuts, threaded holes, and their ilk. Detailed threads add unnecessary convolution and weight to an intricate system. Detailed threads should always be saved for drawings of threaded parts and holes. If both are needed, threaded parts should contain an extra reference set for detailed threads. But only when critical to the design process.
Conclusion
Before I leave you, I would like to share a personal experience. While consulting for a large aerospace manufacturer, their top-level assembly (200k+ components) took more than 30 minutes to open. They had tried everything to speed up the load – minimal load, lightweight components, etc. The C-Suite had to wait 30 minutes to see the work being done.
After a day of searching, testing, and waiting, I found the culprit. Giant PCBs in the assembly. 14,000+ components per PCB. Fifteen of these PCBs per assembly. Add that up, and you start to see the issue. The insane thing was that the bosses did not need or want to see the PCBs in question. One reference set for the PCBs (with components removed) and the top-level opened in 7 minutes– fully loaded. No lightweight components. One simple reference set made all the difference in the world.
Just remember, a little forethought goes a long way.
By Corey Anderson
PLM-NX Integration Engineer