Surface Treatment Machine Selection

This section has the following subsections:

• Anodize Machine Selection

• Black Oxide Machine Selection

• Conveyor Abrasive Finishing Machine Selection

• Conveyor Processes Machine Selection

• Degrease Machine Selection

• Manual Paint Machine Selection

• Mask Bench Machine Selection

• Mask Spray Machine Selection

• Oven Cure Machine Selection

• Passivation Machine Selection

• Powder Coat Cart Machine Selection

• Shot Blast Machine Selection

• Shot Peen Machine Selection

• Vibratory Finishing Machine Selection

• Wet Coat Line Machine Selection

Other surface treatment processes always select the default machine.

Anodize Machine Selection

aPriori selects the feasible machine with the lowest estimated cost per part, given the annual production volume of the current scenario.

The machine feasibility rules require the following:

• The machine property Anodizing Type specifies the type of anodizing in the current routing. The following types are supported:

  • Anodizing Type I

  • Anodizing Type IB

  • Anodizing Type IC

  • Anodizing Type II

  • Anodizing Type III

    Note: Anodize Type II machines support both type II anodizing and type IIB anodizing; see Anodize Process Overview and Routing.

• Part length is no greater than the machine property Loadbar Window Length.

• Part’s shortest dimension (width or height, whichever is smaller) is no greater than the machine property Loadbar Window Width.

• Part’s middle dimension (width or height, whichever is greater) is no greater than the machine property Loadbar Window Height.

• Part surface area is no greater than the machine property Loadbar Max Load Surface Area.

  Cost per part is estimated with the following formula:

  Cost Per Part= ((Minimum Batch Cost * Number Of Load Bars) +
  (Total Overhead Rate * Number Of Load Bars)) / Production Volume)

Estimated cost per part depends on the following:

• Minimum batch cost: specified by the machine property Min Batch Cost.

• Number of load bars: annual production volume divided by the Number of Parts per Load Window.

• Total overhead rate: sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate.

• Production volume: annual volume specified in the Production Scenario tab of the Cost Guide.

Black Oxide Machine Selection

aPriori selects the feasible Black Oxide machine with the lowest overhead (specified by the sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate). A machine is considered feasible if it passes the following checks:

• Part size check: The dimensions of the part must be able to fit within the dimensions of the Black Oxide bath. aPriori checks whether the part fits in one of the following six orientations in which every dimension of the part is aligned with some dimension of the bath (aPriori considers only 90-degree rotations within these dimension-aligned orientations):

  1. (Part Length <= Bath Length) and (Part Width <= Part Width) and (Part Height <= Part Height)

  2. (Part Length <= Bath Length) and (Part Height <= Part Width) and (Part Width <= Part Height)

  3. (Part Width <= Bath Length) and (Part Length <= Part Width) and (Part Height <= Part Height)

  4. (Part Width <= Bath Length) and (Part Height <= Part Width) and (Part Length <= Part Height)

  5. (Part Height <= Bath Length) and (Part Width <= Part Width) and (Part Length <= Part Height)

  6. (Part Height <= Bath Length) and (Part Length <= Part Width) and (Part Width <= Part Height)

• Max weight check: The total mass of the parts in the bath must be less than the maximum weight limit of the machine (as specified by the Black Oxide machine property Max Allowable Weight). The total mass of the parts is calculated as either:

  • The product of the finished mass of the part and the number of nested parts selected by the user as a setup option (see Number of Nested Parts).

    Or, if the user has not overridden the setup option:

  • The finished mass of the part.

• Black Oxide method check: The temperature type of the selected Black Oxide solution (Low / Medium / Hot, as specified by the Black Oxide tool shop materials property Solution Temp Type) must match the method type of the selected machine (as specified by the Black Oxide machine property Method Type).

aPriori prioritizes preferred machines, provided the cost model variable usePreferredMachines is set to true. A machine is considered preferred if it has the Is Preferred property set to true. You can find Black Oxide machines in the Digital Factory under Surface Treatment > Machines > Black Oxide.

Conveyor Abrasive Finishing Machine Selection

aPriori selects the feasible machine with the lowest overhead rate per part. Overhead rate per part is the sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate. A machine is considered feasible if all the following hold:

• Opening height: machine property Max Opening Height is no less than part height (see Part Dimensions for Conveyor Abrasive Finishing).

• Conveyor belt width: machine property Conveyor Belt Width is no less than the sum of part width and an allowance specified by the cost model variable cafPartSpacing (15mm in starting point Digital Factories). (See Part Dimensions for Conveyor Abrasive Finishing.)

• Deburr: if the setup option Deburr Required is set to true (the default in starting point Digital Factories), the machine property Can Deburr has value true.

• Round edges: if the setup option Round Edges Required is set to true (the default in starting point Digital Factories), the machine property Can Round Edges has value true.

• Surface finish: if the setup option Surface Finish Required is set to true (the default in starting point Digital Factories), the machine property Can Surface Finish has value true.

• Remove oxide skin: if the setup option Remove Oxide Skin Required is set to true, the machine property Can Remove Oxide Skin has value true.

• Remove slag: if the setup option Remove Slag Required is set to true, the machine property Can Remove Slag has value true.

• Conveyor belt length: machine property Conveyor Belt Length is populated with a valid value greater than 0.

aPriori selects only from preferred machines, if there is a feasible preferred machine and the cost model variable usePreferredMachines is set to true (the default in starting point Digital Factories). If there is no feasible preferred machine, or if the cost model variable usePreferredMachines is set to false, aPriori selects from all machines. A machine is preferred if the machine property isPreferred (typically displayed as Is Preferred) is true.

Conveyor Processes Machine Selection

The Conveyor Processes branch node (under the Paint node) incorporates the following surface treatment processes that are connected by a conveyor system:

• Conveyor Part Loading – see Conveyor Part Loading Machine Selection.

• Conveyor Shot Blast – see Conveyor Shot Blast Machine Selection.

• Conveyor Conversion Coating – see Conveyor Conversion Coating Machine Selection.

• Conveyor Dry – see Conveyor Dry Machine Selection.

• Conveyor Powder Coating – see Conveyor Powder Coating Machine Selection.

• Conveyor Oven Cure – see Conveyor Oven Cure Machine Selection.

• Conveyor Part Unloading – see Conveyor Part Unloading Machine Selection.

Degrease Machine Selection

aPriori selects the default machine if it is feasible; otherwise, aPriori selects the feasible machine with the lowest overhead (specified by the sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate). The machine feasibility rules require that all the following hold:

• Size constraint: If the user specifies the number of parts at a time to fit through the conveyor entrance (see the PSO Number of parts that can fit across conveyor entrance), the parts can be accommodated by the entrance dimensions, as specified by the machine properties Conveyor Window Height, Conveyor Window Width and Conveyor Spacing Factor. (The spacing factor is the fraction of tightly packed parts that can fit when parts are spaced appropriately.) This assumes that the part’s longest dimension is aligned with the length of the conveyor belt, and the two shorter dimensions are aligned with the entrance’s width and height (whichever height/width alignment maximizes the number of parts that can fit in the entrance).

• Size constraint: If the user does not specify the number of parts at a time to fit through the conveyor entrance (see the PSO Number of parts that can fit across conveyor entrance), at least one part can be accommodated by the entrance dimensions (see previous constraint).

• Weight constraint: If the user specifies the number of parts at a time to fit through the conveyor entrance (see the PSO Number of parts that can fit across conveyor entrance), weight of all parts in a window does not exceed the machine property Conveyor Weight Limit. Part weight is the product of part volume and material density. The number of parts in a window is the product of the following:

  • Number of parts in entrance (see the first constraint above)

  • Number of parts in a single row (machine property Conveyor Window Length divided by the part’s longest dimension)

• Weight constraint: If the user does not specify the number of parts at a time to fit through the conveyor entrance (see the PSO Number of parts that can fit across conveyor entrance), weight of at least one row of parts does not exceed the machine property Conveyor Weight Limit. Part weight is the product of part volume and material density. The number of parts in one row is the machine property Conveyor Window Length divided by the part’s longest dimension.

• Speed constraint: Calculated or user-specified conveyor speed (see the PSO Speed of conveyor) does not exceed the machine property Conveyor Speed Limit.  Calculated speed is the fraction of Conveyor Speed Limit specified by the cost model variable conveyorSpeedRateRatio (0.1 I aPriori starting point Digital Factories).

Manual Paint Machine Selection

aPriori selects the lowest-overhead machine (paint booth) that can accommodate the part dimensions. aPriori also checks that the total number of parts does not exceed the maximum allowable in the booth (see Number of Parts per Booth), assuming that the parts occupy the fraction of the paint booth area specified by Manual Paint Spacing Factor.

Mask Bench Machine Selection

For the Mask Bench process, aPriori selects the default machine, which represents the work area in which individual features are masked.

Oven Cure Machine Selection

aPriori considers a machine to be feasible if the part can be accommodated within the dimensions of the Oven Cure oven. aPriori checks this by comparing the six possible 90-degree orientations of the part against the oven dimensions:

1. (Part Length <= Oven Length) and (Part Width <= Oven Width) and (Part Height <= Oven Height)

2. (Part Length <= Oven Length) and (Part Height <= Oven Width) and (Part Width <= Oven Height)

3. (Part Width <= Oven Length) and (Part Length <= Oven Width) and (Part Height <= Oven Height)

4. (Part Width <= Oven Length) and (Part Height <= Oven Width) and (Part Length <= Oven Height)

5. (Part Height <= Oven Length) and (Part Width <= Oven Width) and (Part Length <= Oven Height)

6. (Part Height <= Oven Length) and (Part Length <= Oven Width) and (Part Width <= Oven Height)

To maximize the number of parts in the oven, aPriori selects machines in descending order of their Is Preferred, Oven Height, Oven Width, and Oven Length machine properties, before selecting the machine with the lowest overhead (specified by the sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate).

aPriori prioritizes preferred machines, provided the cost model variable usePreferredMachines is set to true. A machine is considered preferred if it has the Is Preferred property set to true. Otherwise, aPriori selects from all machines.

You can find Oven Cure machines in the Digital Factory under Surface Treatment > Machines > Oven Cure.

Passivation Machine Selection

aPriori selects the default machine if it is feasible; otherwise, aPriori selects the feasible machine with the lowest overhead (specified by the sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate). The machine feasibility rules require that the part dimensions can be accommodated by the machine working zone, as specified by the machine properties Machine Window Length and Machine Window Width.

Mask Spray Machine Selection

aPriori selects the feasible machine with the lowest power (specified by the property Machine Power). The machine feasibility rules require that the part dimensions can be accommodated by the dimensions of the paint booth (specified by the machine properties Usable Length, Usable Width, and Usable Height).

The cost model assumes that the part is on its side, that is, with its width oriented along the height of the booth. So part width must be no greater than booth height, part height must be no greater than booth width (sometimes referred to as “depth”), and part length must be no greater than booth length.

Powder Coat Cart Machine Selection

aPriori selects the feasible Powder Coat Cart machine with the lowest overhead (specified by the sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate). A machine is considered feasible if it passes the following checks:

• Part weight check: aPriori checks whether the machine’s Cart Weight Limit is greater than or equal to the combined weight of the parts nested on it. aPriori calculates the combined weight as follows:

  • If the user has overridden the Number of Parts Per Cart setup option, aPriori calculates the product of this value and the finished mass of the part.

  • Otherwise, aPriori uses the finished mass of the part.

• Part size check: aPriori checks the part dimensions against the selected machine’s booth dimensions (specified by the Booth Height, Booth Width, and Booth Length machine properties) to ensure that it can fit. aPriori orientates the parts to maximize the surface area facing machine operators and checks the following four orientations:

  • (Booth Height >= Part Width) and (Booth Length >= Part Length) and (Booth Width >= Part Height).

  • (Booth Height >= Part Width) and (Booth Length >= Part Height) and (Booth Width >= Part Length).

  • (Booth Height >= Part Length) and (Booth Length >= Part Width) and (Booth Width >= Part Height).

  • (Booth Height >= Part Length) and (Booth Length >= Part Height) and (Booth Width >= Part Width).

aPriori prioritizes preferred machines, provided the cost model variable usePreferredMachines is set to true. A machine is considered preferred if it has the Is Preferred property set to true. Otherwise, aPriori selects from all machines.

You can find Powder Coat Cart machines in the Digital Factory under Surface Treatment > Machines > Powder Coat Cart.

Shot Blast Machine Selection

aPriori selects the feasible Shot Blast machine with the lowest overhead (specified by the sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate). A machine is considered feasible if it passes the following checks:

• Weight check: The batch weight (the combined weight of the total number of parts on a hanger) must be less than the selected machine’s weight capacity (specified by the machine property Weight Capacity). The batch weight is either:

  • The product of the number of parts that can fit on a hanger and the finished mass of the part, if the number of parts that can fit on a hanger is greater than 1.

    • aPriori assumes that a hanger is circular with one or more rows that can be filled with parts. A machine may handle multiple batches if it has multiple hanger positions (see Number of Hanger Positions in the Shot Blast Cycle Time Calculation). The default value for number of parts takes into consideration the maximum number of parts that a hanger can support, the maximum weight limit of a hanger, and the part batch size. Users can override this using the Number of Parts in the Batch setup option (note that this may force a change in machine selection to accommodate the overridden batch size).

  Or otherwise:

  • The finished mass of the part.

• Part size check: The part is checked in all orientations to ensure that it can fit within the chamber dimensions (length, width, and height) of the selected machine.

aPriori prioritizes preferred machines, provided the cost model variable usePreferredMachines is set to true. A machine is considered preferred if it has the Is Preferred property set to true. Otherwise, aPriori selects from all machines.

You can find hanger-style Shot Blast machines in the Digital Factory under Surface Treatment > Machines > Shot Blast.

Shot Peen Machine Selection

Shot Peen selects the default machine, if there is one. Otherwise, it selects the lowest-overhead machine, that is, the machine with the lowest overhead rate, given by the sum of the machine properties Direct Overhead Rate and Indirect Overhead rate.

Vibratory Finishing Machine Selection

If possible, machine selection picks the smallest (by Container Volume) feasible machine that can accommodate, in a single cycle, a whole production batch. (The size of a production batch is specified in the Production Scenario tab of the Cost Guide.) The batch size that a given machine can accommodate in a single cycle is described in Vibratory Finishing Batch Size.

If there is no feasible machine that can accommodate a production batch, machine selection picks the smallest feasible machine.

A machine is feasible only if all the following hold:

• Vibratory Finishing Batch Size for the machine is at least 1.

• Part Volume is less than machine Container Volume.

• Part mass (the product of part Volume and material Density) is no greater than machine Weight Limit.

• The machine container's largest two dimensions (among Container Width, Container Depth, and Container Radius) can accommodate one part's largest two dimensions (among Length, Width, and Height), for a part orientation that aligns each part dimension with a container dimension.

Wet Coat Line Machine Selection

aPriori selects the default machine if it is feasible; otherwise, aPriori selects the feasible machine with the lowest overhead (specified by the sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate). The machine feasibility rules require that all the following hold:

• Part dimensions can be accommodated by machine window, as specified by the machine properties Loadbar Window Length and Loadbar Window Height.

• Part weight (the product of part volume and material density) does not exceed the machine property Loadbar Weight Limit.