Material Cost

Material Cost

Material Cost = Total Material Cost from Child Operations + Scrap Cost

Per-part material cost is the sum of the following:

• Total material cost from child operations: sum of the material costs accounted for by the Layer Material child operations. There is one occurrence of the Layer Material operation for each Layer GCD in the part. For a given occurrence, which materials are accounted for depends on the type of layer associated with the occurrence. See the formulas below.

• Scrap cost: see formula.

Material Cost Non-bottom CU =

(Copper Panel Cost + Prepreg Panel Cost) / Number of Boards per Panel

The Layer Material operation for a Solo CU layer that is directly above prepreg (that is, a CU layer that is not the board’s bottom layer) accounts for the cost of both the copper and the prepreg beneath it. It depends on the following:

• Copper panel cost: see formula for Default Copper Panel Cost. Users can override the default with the setup option Panel Raw Material Cost.

• Prepreg panel cost: see formula for Default Prepreg Panel Cost. Users can override the default with the setup option Panel Raw Material Cost.

• Number of boards per panel: determined by aPriori’s material nesting calculation—see Part Nesting Type.

Material Cost 2PT =

2-Ply Core Panel Cost / Number of Boards per Panel

The Layer Material operation for the top layer of 2-ply core (that is, a 2PT layer) accounts for the cost of the whole core: the two copper layers and the core insulator. It depends on the following:

• 2-ply panel cost: see formula for Default 2-Ply Panel Cost. Users can override the default with the setup option Panel Raw Material Cost.

• Number of boards per panel: determined by aPriori’s material nesting calculation—see Part Nesting Type.

Material Cost 2PB = Prepreg Panel Cost / Number of Boards per Panel

The Layer Material operation for the bottom layer of a 2-ply core (that is, a 2PB layer) accounts only for the material cost of the prepreg beneath the layer. It depends on the following:

• Prepreg panel cost: see formula for Default Prepreg Panel Cost. Users can override the default with the setup option Panel Raw Material Cost.

• Number of boards per panel: determined by aPriori’s material nesting calculation—see Part Nesting Type.

Material Cost Bottom = Copper Panel Cost / Number of Boards per Panel

Board’s bottom layer: The Layer Material operation for a multi-layer board’s bottom layer (a CU layer with no prepreg beneath it) accounts for the cost of just the copper. It depends on the following:

• Copper panel cost: see formula for Default Copper Panel Cost. Users can override the default with the setup option Panel Raw Material Cost.

• Number of boards per panel: determined by aPriori’s material nesting calculation—see Part Nesting Type.

Material Cost 1-Ply = 1-Ply Core Panel Cost / Number of Boards per Panel

The Layer Material operation for the copper layer of 1-ply core (that is, a 1P layer) accounts for the cost of the core: the copper layer and the core insulator. It depends on the following:

• 1-ply core panel cost: see formula for Default 1-Ply Panel Cost. Users can override the default with the setup option Panel Raw Material Cost.

• Number of boards per panel: determined by aPriori’s material nesting calculation—see Part Nesting Type.

Default Copper Panel Cost = Copper Panel Cost per Mass * Panel Mass

Copper panel default cost is the product of the following:

• Copper panel cost per mass: specified under Unit Cost in the materials table for copper with the current layer’s thickness—see Layer GCD.

• Panel mass: product of the following:

o Panel area: product of length and width—see PCB Panel Size.

o Panel thickness: specified under Overall Thickness in the materials table for copper with the current layer’s thickness—see Layer GCD.

o Panel density: specified under Combined Density in the materials table for copper with the current layer’s thickness—see Layer GCD.

Default Prepreg Panel Cost =

Prepreg Panel Cost per Area * Panel Area * Number of Prepreg Sheets

Prepreg panel default cost is the product of the following:

• Prepreg panel cost per area: specified in the Material Stock tool shop for the thickness of each sheet of prepreg beneath the current copper layer—see Prepreg Sheet Thickness Beneath Current Layer.

• Panel area: product of the panel length and width—see PCB Panel Size.

• Number of prepreg sheets: number of sheets of prepreg beneath the current copper layer—see Number of Prepreg Sheets per Layer.

Default 2-Ply Core Panel Cost =

2-Ply Core Panel Cost per Mass * Panel Mass * Core Cost Factor

The default cost for 2-ply core panel is the product of the following:

• 2-ply core panel cost per mass: specified under Unit Cost in the Material Stocks table for a 2-ply core with the thickness of the current copper layer—see Layer GCD—and the thickness of the core insulator beneath the current copper layer—see Core Insulator Thickness.

• Panel volume: product of the following:

o Panel area: product of length and width—see PCB Panel Size.

o Panel thickness: specified under Overall Thickness in the material stocks table for a 2-ply core with the thickness of the current copper layer—see Layer GCD—and the thickness of the core insulator beneath the current copper layer—see Core Insulator Thickness.

o Panel density: specified under Combined Density in the material stocks table for a 2-ply core with the thickness of the current copper layer—see Layer GCD—and the thickness of the core insulator beneath the current copper layer—see Core Insulator Thickness.

• Core cost factor: looked up in the lookup table tblGlassTransitionFactor by the Glass Transition Temperature for the current layer.

Default 1-Ply Core Panel Cost =

1-Ply Core Panel Cost per Mass * Panel Mass * Core Cost Factor

The default cost for 1-ply core panel is the product of the following:

• 1-ply core panel cost per mass: specified under Unit Cost in the material stocks table for a 1-ply core with the thickness of the current copper layer—see Layer GCD—and the thickness of the core insulator beneath the current copper layer—see Core Insulator Thickness.

• Panel mass: product of the following:

o Panel area: product of the panel length and width—see PCB Panel Size.

o Panel thickness: specified under Overall Thickness in the material stocks table for a 1-ply core with the thickness of the current copper layer—see Layer GCD—and the thickness of the core insulator beneath the current copper layer—see Core Insulator Thickness.

o Panel density: specified under Combined Density in the material stocks table for a 1-ply core with the thickness of the current copper layer—see Layer GCD—and the thickness of the core insulator beneath the current copper layer—see Core Insulator Thickness.

• Core cost factor: looked up in the lookup table tblGlassTransitionFactor by the Glass Transition Temperature for the current layer.

Scrap Cost = Layer Processing Scrap Cost + Non Layer Processing Scrap Cost

Scrap cost is the sum of the following:

• Layer processing scrap cost: cost of material scrapped during all layer processing cycles. This is the sum across cycles of cycle scrap cost (see formula). When a stack is scrapped during a given cycle, only the cost of material comprising the stack in that cycle counts towards scrap cost. The cost model assumes re-use of not-yet-added material that was slated for later use in the scrapped stack.

• Non layer processing scrap cost: cost of material scrapped during all processes that do not occur within a layer processing cycle. See formula.

Cycle Scrap Cost = (Cycle Layer Material Cost / Final Yield) – Layer Material Cost

Cost of material scrapped during a given occurrence of Layer Processing Cycle. Cycle scrap cost depends on the following:

• Cycle layer material cost: cost of the materials comprising the stack in the given cycle.

• Final Yield for the given occurrence of Layer Processing Cycle.

Non Layer Processing Scrap Cost =

((Total Layer Material Cost / Final Yield) – Total Layer Material Cost) –

Layer Processing Scrap Cost

Cost of material scrapped during a process that does not occur within a layer processing cycle. Non-layer processing scrap cost depends on the following:

• Total layer material cost: sum of the material costs accounted for by all the Layer Material operations.

• Final Yield for the Material Stock process.

• Layer processing scrap cost: cost of material scrapped during all layer processing cycles. This is the sum across cycles of cycle scrap cost (see formula).