Using Inventor iMates with Fasteners

The use of  iMates is far from one of the most used features of Autodesk Inventor for a number of reasons.  The leading one is the time it takes to create iMates or composite iMates.  If your component is used only once or a few times, it hardly justifies the time it takes to create an iMate constraint.  

There is a great use for iMates that is often overlooked, and that is the constraining of Content Center fasteners into your assembly.  Content Center fasteners, supplied with Inventor, are all configured with predefined iMates.  When you select a fastener in an assembly the iMate icons pop up, with a lot of users scratching their heads as to their use.

The symbols you see represent the iMates assigned to this fastener.  I wish I could zoom up on them for clarity but as you will find out, you cannot.  The ones on this socket head cap screw are a mate constrain to the shoulder of the head, a mate to the centerline of the screw and an insert one one of the edges of the shoulder.  Compare the small icons to the symbols shown in the Place Constraint dialog box and you will soon easily recognize them.  They also generally appear near the feature that are attached to.

The process of using them is very easy.  First of all decide which constraint you would use to place the screw in the plate hole.  Most all users will elect to use the insert constraint since it combines two mate constraints at the same time, one between the centerline of the screw and the hole and one between the bottom of the screw head and the surface of the plate where the hole begins.

Once you decide, hold down the Alt key and left click select and start dragging the insert iMate on the screw.  It will turn green as you drag.  At this point you should let go of the Alt key but do not left go of the left mouse button.  Notice the edge of the screw that highlights and also the insertion arrow at the end of the screw.

Continue with you left click drag until you hover over the edge of the plate hole you want to use as the other side of the insert command, it will also highlight.  At this point release the left mouse button to apply the insert constraint. 

With a little practice you can become very fast with this process easily placing screws, washers and nuts in your assembly must faster than using the Place Constraint command.

The one downside in the use of iMates is that you cannot edit the offset value of any iMates, the offset value when they are created is set.  Take the insert iMate I created above.  If I find it in the browser, notice the icon is a bit different than a normal insert constraint, and edit it, the offset spacing is grayed out.

You can use this method of applying assembly constraints on components that do not have previously created iMates but it will take a little more practice, especially if you want to switch the type of assembly constraint being applied on the fly.  I will not go into how to perform this task in this article but you can easily find the process in the Inventor help file.

To finish off, I wanted to post a video of the use of iMates to finish placing the screws, washers and nuts and also placement of the yellow pin, which does not have any predefined iMates.  Remember as you watch this video I am doing the same process outlined above with the Alt key and the left mouse drag.