Sheet Material Stock Options

The Sheet Material Stock process provides the following setup options:

• Part Spacing (trim around the part) for True-Part Shape Nesting

• Part Spacing (trim around the part) for Rectangular Nesting

• Step Angle for True-Part Shape Nesting

• Sheet Length Trim Strip—Margin along Material Length

• Sheet Width Trim Strip—Margin along Material Width

Part Orientation

Specifies whether the part’s tightest bend (that is, the bend with the smallest radius) is parallel to or perpendicular with the sheet grain (see Grain Direction). Select one of the following options:

• Not Specified. This is the default.

• Position Bend with Smallest Radius Parallel to Grain. Bends are sometimes oriented parallel with the grain, for example, in order to minimize cracking.

• Position Bend with Smallest Radius Perpendicular to Grain. Bends are sometimes oriented perpendicular to the grain, for example, to maximize strength.

This option affects part nesting.

Part Spacing (trim around the part) for True-Part Shape Nesting

By default, the width of the trim around each blank is specified by one of the following:

• For Laser Cut routings: default trim size is the product of the blank thickness and the cost model variable laserKerfMultiplier (0.5mm in starting point VPEs).

Default Trim Width = Blank Thickness * laserKerfMultiplier

Default trim width is bounded above by the cost model variable kerfWidthMaxLaser (20mm in starting point VPEs).

A routing is considered a Laser Cut routing if and only if it has a node with the node attribute isLaserCutRouting.

• Four Router Cut routings: default trim size is specified by the cost model variable routerToolDiameter (3.175mm in starting point VPEs). A routing is considered a Router Cut routing if and only if it has a node with the node attribute isRouterCutRouting.

If the current routing has no node with either attribute isLaserCutRouting or isRouterCutRouting, the default trim width is specified by the cost model variable defaultSheetStockPartSpacing (20mm in starting point VPEs).

With this setup option, you can override the default.

Note that the trim surrounds the addendum, if any, that has been added to the blank (see Addendum Added to Blank Size).

Part Spacing (trim around the part) for Rectangular Nesting

By default, the width of the trim around each blank is specified by one of the following:

• For Laser Cut routings: default trim size is the product of the blank thickness and the cost model variable laserKerfMultiplier (0.5mm in starting point VPEs).

Default Trim Width = Blank Thickness * laserKerfMultiplier

Default trim width is bounded above by the cost model variable kerfWidthMaxLaser (20mm in starting point VPEs).

A routing is considered a Laser Cut routing if and only if it has a node with the node attribute isLaserCutRouting.

With this setup option, you can override the default.

• Note that the trim surrounds the addendum, if any, that has been added to the blank (see Addendum Added to Blank Size).

Grain Direction

Specifies how the grain is oriented on the sheet. Grain can run parallel to the sheet’s width or length. These options are provided:

• Parallel to Sheet Length

• Parallel to Sheet Width

See also Part Orientation.

Step Angle for True-Part Shape Nesting

With true-part-shape nesting (see Material Utilization and Part Nesting for Hydroforming), the cost engine uses an internal algorithm that considers multiple candidate nesting arrangements using a variety of part orientations. By default, the various orientations differ by an angle specified by the cost model variable defaultUtilizationStepAngle (90° in starting point VPEs).

With this setup option, users can specify a step angle for the cost engine to use in order to generate candidate orientations—smaller nesting angles result in the consideration of a greater number of candidate nesting arrangements (which increases costing time, but may result in more efficient nesting).

Sheet Length Trim Strip—Margin along Material Length

By default, the size of the margin of material along the stock length is determined by properties of the available machines. The default margin width is the largest value that appears in the Sheet Length Trim Strip field for any machine. If no machine has a value for this field, the default margin width is the value of the cost model variable standardLaserCutLeadInAmount (10mm in starting point VPEs).

You can override the default with this setup option.

Sheet Width Trim Strip—Margin along Material Width

By default, the size of the margin of material along the stock width is determined by properties of the available machines. The default margin width is the largest value that appears in the Sheet Width Trim Strip field for any machine. If no machine has a value for this field, the default margin width is the value of the cost model variable standardLaserCutLeadInAmount (10mm in starting point VPEs).

You can override the default with this setup option.

Addendum Added to Blank Size

This is the width of an offset to be added all around the perimeter of the flattened part. You can enter a non-zero value in order to do one of the following:

• Add additional material for the purpose of holding the blank during the forming process, which is subsequently trimmed away.

• Compensate for cases in which aPriori underestimates flattened blank size, for example, for highly deformed parts.

Select one of the following options:

• Let aPriori Decide: this is the default, computed based on form depth and edge tolerance, using the lookup table blankAddendumWidth. See below.

• No Addendum: addendum size is set to 0.

• User Override: enter a value greater than or equal to 0.

If you choose Let aPriori Decide, aPriori adds addendum in all the following cases:

• Deep-draw part: the current routing is a deep draw routing (the CSL code checks for the existence of a node in the current routing with a deepDrawFormed attribute).

• Formed Fluid-cell part: the current routing is a fluid cell routing and the part has at least one significant form whose Sub Type is EMBOSS. An emboss form is considered significant if it takes up a sufficient fraction of the main surface (that is, if the product of the emboss’s SER Length and SER Width is greater than the product of the main surface’s Convex Hull Area and the cost model variable mainSurfAreaMultiplier—0.75 in starting point VPEs).

• Tight-tolerance edge: at least one blank edge has tolerance less than the cost model variable looseEdgeToleranceThreshold (2mm in starting point VPEs).

The width of the addendum is looked up by aggregate form depth (excluding forms of type CURVED_BEND) in the lookup table blankAddendumWidth. For folded parts (those with no significant emboss) that have tight tolerance, aPriori chooses the smallest addendum listed in blankAddendumWidth.

Aggregate form depth is the sum of the depths of all forms whose Sub Type is not CURVED_BEND. Each form’s depth is the value of the property Depth Up or Depth Down, whichever is nonzero.

Note that when an addendum is present (whether calculated or user-specified), aPriori adds a secondary Machining operation, Profile Trimming on the 5-Axis Mill, which trims the addendum off. If no addendum is present, Blanking is assumed to provide the final shape.