Ultrasonic Cleaning

This process is automatically included only if the current routing has a node with the attribute requiresUltrasonicCleaning. Otherwise, this process must be manually included.

This section has the following subsections:

• Machine Selection for Ultrasonic Cleaning

• Process Time for Ultrasonic Cleaning

• Setup Options for Ultrasonic Cleaning

Machine Selection for Ultrasonic Cleaning

aPriori selects the lowest overhead machine whose basket dimensions can accommodate the dimensions of one part, assuming a buffer around the length and width of the part. The default buffer is specified by the cost model variable basketNestingAllowance (38.1mm in starting point VPEs). Users can override this default with the setup option Basket Nesting Allowance (see Setup Options for Ultrasonic Cleaning).

Overhead, here, is the given by the following:

((Number of Batches *

(Direct Overhead Rate + Indirect Overhead Rate)) / Production Volume)

where

• Number of batches is the number of batches needed to achieve the production volume, given a batch size consisting of the maximum number of parts that can be accommodated by the machine (see below).

• Direct overhead rate is specified by a machine property.

• Indirect overhead rate is specified by a machine property.

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

The maximum number of parts that can be accommodated by the machine is the smaller of the following:

• Maximum number of parts that can fit in the machine basket, assuming the parts are arranged in a rectangular array with a buffer around the length and width of each part. This buffer is also added around the edges of the basket. The default buffer size is specified by the cost model variable basketNestingAllowance (38.1mm in starting point VPEs). Users can override this default with the setup option Basket Nesting Allowance.

• Maximum number of parts that satisfy the following constraint regarding the ratio of basket volume to total part surface area:

Tank Volume in Inches / Total Part Surface Area in Inches >= 1

o Tank volume in inches. This is the product, in inches, of the machine properties Machine Length, Machine width, and Machine Height.

o Total part surface area in inches: the product of part Surface Area in inches and the number of parts.

Process Time for Ultrasonic Cleaning

Cost is based primarily on the following formulas:

Process Time = Ultrasonic Cleaning Time Per Part + Rinse Time Per Part

Process time is the sum of the following:

• Ultrasonic cleaning time per part (see formula)

• Rinse time per part: by default, this is specified by the cost model variable ultrasonicCleaningRinseTimePerPart (30 seconds in starting point VPEs). Users can override the default with the setup option Ultrasonic Cleaning Rinsing Time Per Part (see Setup Options for Ultrasonic Cleaning).

Ultrasonic Cleaning Time Per Part =

(Ultrasonic Cleaning Run Time / Computed Max Number Of Parts)

Ultrasonic cleaning time per run depends on the following:

• Ultrasonic cleaning run time: by default, this is specified by the cost model variable ultrasonicCleaningTimePerRun (600 seconds in starting point VPEs). Users can override the default with the setup option Ultrasonic Cleaning Time per Batch (see Setup Options for Ultrasonic Cleaning).

• Computed max number of parts: this is the maximum number of parts that can be accommodated by the machine—see Machine Selection for Ultrasonic Cleaning.

Setup Options for Ultrasonic Cleaning

Ultrasonic cleaning provides the following setup options:

• Ultrasonic Cleaning Time per Batch: by default, this is specified by the cost model variable ultrasonicCleaningTimePerRun (600 seconds in starting point VPEs). Users can override the default with this setup option.

• Basket Nesting Allowance: aPriori selects the lowest overhead machine whose bed dimensions can accommodate the dimensions of one part, assuming a buffer around the length and width of the part. The default buffer is specified by the cost model variable basketNestingAllowance (38.1mm in starting point VPEs). Users can override this default with the setup option Basket Nesting Allowance.

• Ultrasonic Cleaning Rinsing Time Per Part: by default, this is specified by the cost model variable ultrasonicCleaningRinseTimePerPart (30 seconds in starting point VPEs). Users can override the default with this setup option.