Threading Options
aPriori supports the following thread-making operations:
• Tapping
• Thread Turning
• Thread Milling
Users can indicate that a hole is threaded by either applying a cosmetic thread feature in the CAD system or by manually setting the Threaded property of the GCD to true. For more information on editing GCD properties, see the "Editing values in the GCD properties table" section of the aPriori User Guide.
The following options are available by locating the thread-making operation of interest in the Manufacturing Process pane, then right-clicking the specific hole GCD of interest under the thread-making node:
• Thread Pitch: distance between adjacent threads. Select one of the following options:
o Default Value: a value of 1 millimeter is used.
o User-specified: enter a value that uses the units specified by the option Thread Units–see below. The default units are millimeters.
• Thread Units: units used by the option Thread Pitch—see above. The default is millimeters. Select one of the following options:
o TPI: thread per inch.
o mm: millimeters (default).
• Requested Tool Cutting Speed: how fast the tool turns in unit distance per unit time; that is, the speed at which a point on the outer edge of the tool moves along the circular path around the center of the tool. This value is used to help determine tool axis speed and cu t time. See
Operation Cycle Time and Cut Time Calculations for more information on how speed contributes to cutting time.
Select one of the following options:
o Use Computed Tool Cutting Speed: aPriori determines this value by interpolation from data tables based on tool series, tool diameter, and material cut code--see
Tool Selection. This value is adjusted to compensate for various factors, including stock hardness and machine limitations. The value is also adjusted by multiplying by the cost model variable
drillSpeedAdjustment. The adjusted value is used to help determine tool axis speed and cut time.
o Override Tool Cutting Speed: enter a speed in meters per minute. This value is adjusted to compensate for various factors, including stock hardness and machine limitations. The value is also adjusted by multiplying by the cost model variable drillSpeedAdjustment. The adjusted value is used to help determine tool axis speed and cut time.
Thread milling provides the following additional options:
• Thread Length: length of the threaded portion of the hole. Select one of the following options:
o Default Value: thread length defaults to 10 millimeters.
o User-Specified: enter a value in millimeters.
• Thread Form: defaults to metric 60 degrees. Select one of the following options:
o Metric 60 deg (default)
o NPT (NT)
o UN 60 deg