Thread Milling Process

This function, in conjunction with a thread milling tool, allows the user to easily mill OD and ID threads. The thread milling process is similar to the drilling process in that it requires that either points or circles be selected for the process. Each of the items in the thread milling dialog is described below.

Thread Mill Entry/Exit Diagram

The Entry and Exit Clearance Planes function as they do in the other Process dialogs. The Thread Start Point and Thread End Point positions entered in the diagram specify the actual start and end of the thread specified on the blueprint. The system will add a 45° helix to the start and end of the threading toolpath to provide for a smooth transition into the thread. The start and end points of this helical entry move will be higher and lower in Z than the actual Thread Start and End Points entered by the user in the dialog. The tool can thread up or down, meaning that the start point can be at a higher or lower Z position than the end point.

This selection determines whether an OD or ID thread will be created. The Thread Mill Entry/Exit Diagram will change depending on the selection made as shown above.

This selection determines whether the thread will be created in a clockwise or counter-clockwise direction.

On an OD thread, the tool cuts in to the minor diameter. On an ID thread, the tool cuts out to the major diameter.

On an OD thread, the tool will retract to the Clearance Dia. after completing the thread before going to the exit clearance position. On an ID thread, the Clearance Dia. should be equal to or less than the size of the hole that is being threaded. For ID threads, the tool diameter is less than the clearance diameter which is less than the cut diameter. For OD threads, the cut diameter is less than the clearance diameter.

This value specifies the number of threads per inch. The threads per inch and pitch text boxes are interactive. When one value is entered the system calculates the other. This allows the user to enter whichever specification is given on the blueprint, be it the pitch or TPI. When creating a metric part, this value specifies threads per millimeter.

This value specifies the pitch of the thread which is calculated by taking the inverse of the TPI.