Surface Rough Milling Options

Rough milling provides the following options:

  • Roughing Depth: casting material allowance. This defaults to the value of the cost model variable finishAllowance. To override the default, use the following option:

    • Casting Depth: enter a value in millimeters greater than or equal to 0.1.

  • Material Removal Rate: rate at which material is removed during chipmaking. By default this is based on feed, speed, engagement width, and cut depth (see Chipmaking Time for Surface Rough Milling). Use the following option to override the default:

    • Override: enter a value in cubic millimeters.

  • Requested Tool Diameter: diameter of the selected tool. Larger diameters can decrease engagement time; see Operation Cycle Time and Cut Time Calculations--and have a more favorable length-to-diameter ratio. Smaller diameters have better corner accessibility.

    Select one of the following options:

    • Use Computed Tool Diameter: aPriori chooses a tool diameter based on a number of factors, including overall part size, accessibility of the GCD’s corners (if any), and the values of setup options that constrain tool size. See Tool Selection for Machining for more information.

    • Override Tool Diameter: enter the tool diameter in millimeters.

  • 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 (along with feed, tool diameter, and cutting width) to determine area removal rate. See Operation Cycle Time and Cut Time Calculations for more information on how speed contributes to cutting time.

    Select one of the following options:

    • Use Recommended 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 for Machining. This value is adjusted to compensate for various factors, including machine spindle speed limitations and stock hardness. The value is also adjusted by multiplying by the cost model variable millSpeedAdjustment. The adjusted value is used to help determine area removal rate.

    • Override Tool Cutting Speed: enter a speed in meters per minute. This value is adjusted to compensate for various factors, including machine spindle speed limitations and stock hardness. The value is also adjusted by multiplying by the cost model variable millSpeedAdjustment. The adjusted value is used to help determine area removal rate.

  • Requested Feed per Tooth: distance the tool travels along the surface of the part per tooth of the tool during one rotation. The number of tool teeth times this value is the distance the tool travels along the surface of the part per rotation of the tool. This value is used (along with speed, tool diameter and cutting width) to determine area removal rate. See Operation Cycle Time and Cut Time Calculations for more information on how feed contributes to cutting time.

    Select one of the following options:

    • Use Computed Feed per Tooth: aPriori determines this value by interpolation from data tables based on tool series, tool diameter, and material cut code; see Tool Selection for Machining. aPriori multiplies this value by the number of teeth to derive tool feed. This value is adjusted to compensate for various factors, including tool reach and required tolerance. Tool feed is also adjusted by multiplying by the cost model variable millFeedAdjustment. The adjusted value is used to help determine area removal rate.

    • User Override: enter a value in millimeters. aPriori multiplies this value by the number of teeth to derive tool feed. This value is adjusted to compensate for various factors, including tool reach and required tolerance. Tool feed is also adjusted by multiplying by the cost model variable millFeedAdjustment. The adjusted value is used to help determine area removal rate.

  • Number of Teeth: number of tool teeth. This value together with feed per tooth determines feed (which affects area removal rate); see Operation Cycle Time and Cut Time Calculations.

    Select one of the following options:

    • Number of teeth: aPriori determines this value by interpolation from data tables based on tool series, tool diameter, and material cut code; see Tool Selection for Machining. aPriori multiplies this value by the feed per tooth to derive tool feed. This value is adjusted to compensate for various factors, including tool reach and required tolerance. Tool feed is also adjusted by multiplying by the cost model variable millFeedAdjustment. The adjusted value is used to help determine area removal rate.

    • User Override: enter a value greater than or equal to 2.

      If you supply a user override for both Number of Teeth and Requested Feed per Tooth, aPriori multiplies the two values together to derive tool feed.

      If you supply a user override for Number of Teeth, and you do not specify a user override for Requested Feed per Tooth, aPriori sets the unadjusted value for feed as follows:

      Feed = Interpolated Feed * (Specified Number of Teeth / Interpolated Number of Teeth)

      (Interpolated feed and interpolated number of teeth are derived from data tables during tool selection; see Tool Selection for Machining.)

      In either case, the value is adjusted to compensate for various factors, including tool reach and required tolerance. Tool feed is also adjusted by multiplying by the cost model variable millFeedAdjustment. The adjusted value is used to help determine area removal rate.

  • Radial Cut Depth: engagement length as a percentage of the tool diameter. Radial cut depth helps determine contact area and cut time. See Chipmaking Time for Surface Rough Milling. The default is 50% in aPriori starting point Digital Factories. Use the following option to override the default:

    • User Override: enter a whole number between 0 and 100, inclusive.

  • Axial Cut Depth: cut depth as a percentage of the tool diameter. Axial cut depth helps determine contact area and cut time. See Chipmaking Time for Surface Rough Milling. The default is 50% in aPriori starting point Digital Factories. Use the following option to override the default:

    • User Override: enter a whole number between 0 and 100, inclusive.

  • Machine Spindle Speed Override: by default, tool cutting speed is adjusted to compensate for various factors, including machine spindle speed limitations and stock hardness. If you set this option to true (it is false by default), aPriori to ignores machine spindle speed limitations when it calculates the adjustment to tool cutting speed. See also Requested Tool Cutting Speed, above.