Dealing with a large assembly can have its frustrations however SolidWorks has some tools to help. One such tool is called Defeature. This tool lets you remove details from Assemblies, Multi-body Parts, and Parts to simplify the geometry. This in turn will speed up your open/rebuild times. This tool can also be used to remove proprietary information you would not like others to see.
Let’s start with a model of a Miter Saw. Take a look at Video 1 below. You will notice lots of detailed features as well as a maintained motion.
Video 1
This assembly is relatively small compared to normal large assemblies. In Figure 1 you can see that there are only 309 components. In most cases we will not consider it a large assembly until there are at least 500. However, I choose this example since it was very detailed and had lots of movement.
Figure 1
Using AssemblyXpert I was able to see the full rebuild time for this assembly (Figure 2). Let’s see if we can use Defeature to create a model with a faster rebuild time.
Figure 2
You can find the Defeature tool under Tools > Defeature. See Figure 3.
Figure 3
Figure 4
Figure 4 shows the first screen of the Defeature tool. Let’s break it down each of the checkboxes and options.
1. Internal Components: This check box will allow Defeature to remove any component that is completely encapsulated inside your assembly.
2. Small Components: This box will allow you to specify a percentage and any component that is smaller than that percentage will be removed.
3. Display: This option will allow you to see all the components, which components are being removed, or which components are left behind.
4. Exceptions: You can place components in this box to make sure they are not removed.
5. Section View: Sometime it can be hard to see and choose components. So, we can temporally section the assembly to help see the inside of our assembly.
6. Next: Moves to the next screen of the Defeature tool.
Figure 5
Figure 5 shows the choices I made for our Miter Saw. You will notice that I added one part to the “Exceptions”. This part can be seen in Figure 6.
Figure 6
Figure 7 shows the second screen of the Defeature tool. Let’s go over its options:
Figure 7
1. Create Group: This will allow you to create groups of components that have no movement between them. IF you want movement between components they would be in separate groups.
2. Delete Group: Will allow you to remove groups.
3. Mates: This box will list out an mates that Defeature assumes you will want to maintain between your groups.
4. Section View: Once again you can create section views to help you choose components.
5. Next: Takes you to the third screen of the Defeature tool.
Figure 8 shows the creation of my 6 groups for the Miter Saw.
Figure 8
Figure 9
On Figure 9 you will see the Third screen of the Defeature Tool. It’s options are:
1. Features to Keep: This box will allow you to keep features that are important to your model. For example, you might want to keep mounting holes.
2. Select All Holes: Will allow you to make sure that none of the holes are removed.
3. Select holes between: Gives you a size range to determine which holes are removed.
4. Section View: Same as before
5. Next: Takes you to the Forth Screen of the Defeature Tool.
Figure 10 shows the selections for the features I wanted to keep for the Miter Saw.
Figure 10
One example is in Figure 11. I wanted to keep the slot feature.
Figure 11
SolidWorks will then remove the un-needed feature from the parts as seen in Figure 12.
Figure 12
Figure 13
The forth screen is found in Figures 13 and 14. Many of the features have been removed at this point but there may be some you would like to add. You can see in Figure 14 that is shows to version of the assembly. The left screen is the original model and the right screen is the new Defeature version. You can use the options in Figure 13 to choose which features still need to be removed.
1. Items to remove: This will allow you to select additional features to remove.
2. Section View: Same as before.
3. Next: will take you to the final Defeature screen
In Figure 14 you can see that I selected to remove the hash marks and numbers.
Figure 14
Figure 15 will show you the final comparison between the original model and the Defeature version.
Figure 15
Figure 16 is the last screen of the Defeature tool. Here you can choose what you want to do with the new model. I chose to save the model as a separate file.
Figure 16
In Figure 17 you can see both versions of the Miter Saw and compare the differences.
Figure 17
Take a look at Video 2 an you can see that the mates that allow movement are still intact.
Video 2
Now it is time for the true test. Figure 18 shows we are down to just 10 components.
Figure 18
Figure 19 shows that the rebuild time is now 95 milliseconds compared to the original time of 386 milliseconds.
Figure 19
What you do with your streamlined Defeature model is up to you. You could send on to a customer or use it as a sub assembly or place it on 3DContent central for others to download.
