When it comes to creating holes, cylinder height is critical because it is the only accurate way for manufacturing to measure hole depth. As designers though, you will encounter situations where you must know where the hole actually ends, lest the drill bit breaks through the model. NX 11 includes a new way to define hole depth, along with a new way to add dimensions in drafting when creating hole callouts. You will see both of these demonstrated today.
Start with a simple part, in this case a cube. To place a hole, choose the Hole command and select the face you would like, then pick a location for the center of the hole. There are options for Hole Type, in this case we chose a Threaded Hole, and you can specify Hole Depth by entering values.
Prior to NX 11, there was only way to define the depth of a hole that wasn’t a through-hole, and that was to define the cylinder height. Cylinder height is the length from the top of the hole to the bottom of the cylinder. However, the drill tip makes a point that is slightly deeper in the center of the hole.
Design engineers run across instances—such as a manifold or other confined, small area—where it’s necessary to control the depth of the hole based on the tip length so as to prevent the drill bit from breaking through the model. Now instead of doing calculations to figure it out on your own, there is an option in the Hole dialog under Dimensions. The default Depth To is Cylinder Bottom, but you can select Cone Tip in order to get the full hole length.
Irrespective of the method used, when you document these holes in drafting, symbols and dimensions on drawings will display the information that manufacturing requires: cylinder height.
That brings us to the second change we will look at in NX 11 today: a new way to define drafting dimensions in a hole callout. When creating a hole symbol, you have the option to add additional information like thread depth and depth of the hole. You can also create a symbol with the side view using the same hole callout in a linear format.
In NX 11, there is a third option. You can create all linear dimensions automatically with a single operation. In the Linear Dimensions dialog underneath measurement there is a check box to create secondary dimensions for depth. Place the callout size for the hole, and notice NX automatically creates thread depth and hole depth dimensions. These are not all one symbol, but rather three separate, editable dimensions.
NX 11 allows you define and dimension details like holes in a fashion that is more suitable for design engineers and meets their concerns with models. Watch John Baker demonstrate these capabilities in the latest NX Quick Tips video.