Surface Treatment Machine Selection

This section has the following subsections:

• Shot Peen Machine Selection

• Manual Paint Machine Selection

• Powder Coat Cart Machine Selection

• Wet Coat Line Machine Selection

• Degrease Machine Selection

• Mask Spray Machine Selection

• Mask Bench Machine Selection

• Anodize Machine Selection

• Vibratory Finishing Machine Selection

Other surface treatment processes always select the default machine.

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.

Manual Paint Machine Selection

Manual Paint selects the lowest-overhead machine (paint booth) that can accommodate the part dimensions.

Powder Coat Cart Machine Selection

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

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

Wet Coat Line Machine Selection

• 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.

Degrease Machine Selection

• 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:

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

o 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 VPEs).

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.

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.

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:

o Anodizing Type I

o Anodizing Type IB

o Anodizing Type IC

o Anodizing Type II

o Anodizing Type III

Note that Anodize Type II machines support both type II andodizing and type IIB anodizing—see Anodize 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)

Esitmated 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.

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

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.