Part2 of using iMates, this will take two posts as there are several attachments.
We are going to create an assembly with a bearing flat, two 8-32 screws and two lock nuts along with iMates that can be quickly added to structural parts. In the past I used to do this the hard way, something like this.
- Add two work axis using intersecting planes into two square holes of the structure. Offset each work axis by 0.091" to place it in the center of each square hole.
- Place a bearing flat and add three constraints, the two end holes to the work axes and a mate to the flat surface of the structure.
- Add two screws, constrain each to the holes in the bearing flat.
- Add two nuts, each nut gets two constraints, one to the axis of the screw, the other to the underside of the metal structure.
Lots of work, 5 parts and 9 constraints.
So to make this easier we will create this assembly.
Start in the usual way by creating a “Standard.iam” assembly. Add the bearing flat as the first part. The bearing flat in my library is not located at the origin, life is easier if we move the part to the origin and constrain it to the X, Y and Z planes of our coordinate system. The reason for this will become clear at a later stage.
The part will be initially grounded as it is the first part placed, unground the part and then add three mate constraints (to the XY plane, XZ plane and XY plane) to relocate it to the origin. Finally add an angle constraint between one edge and an origin plane to stop it rotating. This is how things should look, the origin planes have been made visible for clarity.
Next (and this is optional) add three iMates to the three holes, these may be useful in the future depending on how the final assembly is used.
Add two 8-32 screws 0.5" long. Constrain them using an insert constraint into the two end holes, in the image below the screws had the iMate from my last post so this could be used to make this step quicker.
Now we need to add the two lock nuts. Each nut has two constraints added, the first is the hole in the nut to the axis of the screw. The second mates the flat surface of the nut to the underside of the bearing block, this constraint has a 0.046" offset applied which is the thickness of the steel structural parts.
Now we need to add the iMates to be able to constrain the bearing block assembly to the square holes in the structure. The square holes are exactly 0.182" square. Unfortunately there is nothing suitable to use on the bearing flat, the small protrusions on the underside are angled and cannot be used, the sides of the bearing flat are also angled. To achieve the necessary geometry we will create two work planes, as we have already located the bearing flat at the origin this is quite easy. Offset a work plane from the XZ plane of the origin by 0.091" (half of 0.182), add a second work plane offset by 0.091" from the XY plane of the origin. With the planes visible it should look as follows.
continued in the next post …