Work Order Quantity and Time Calculations

The Work Order module uses information from Operation Code Maintenance, Routing Maintenance, Work Order Entry, and Bill of Materials Maintenance, if appropriate, to calculate the quantity and time requirement information for a work order.

Calculating Quantity Planned

All extended quantity calculations for the work order are based on the quantity planned. The Qty Planned field on the Work Order Entry Header tab is calculated by applying the yield percentage to the quantity ordered.

The calculation for the quantity planned is:

Quantity Planned = Quantity Ordered / Yield Percentage

Calculating Quantity Planned Example

If the manufacturing process has a 90 percent yield factor and the quantity ordered is 100, the quantity planned is 100 / .90 or 111.

The yield percentage is used to determine the quantity of finished products that must be planned to compensate for anticipated manufacturing losses. If the Bill of Materials module is installed and the parent item code for the work order is a bill, the yield percentage defaults to the percentage from the bill.

If the Bill of Materials module is installed, and the unit of measure for the current bill is defined as an integer unit of measure in the Integer Units of Measure field in Bill of Materials Options, the quantity planned is rounded to the nearest whole number.

Calculating the Extended Quantity

The extended quantity is the amount of the component item that is planned to be used for the work order. The Extended Qty field on the Work Order Entry Materials tab is calculated by multiplying the quantity per parent by the quantity planned, and factoring the scrap percentage of the component item.

The calculation for the extended quantity is:

Extended Quantity = Quantity Planned * Quantity per Parent / (1 - Scrap Percentage)

Calculating the Extended Quantity Example

If 12 tables are planned for a work order (quantity planned = 12), and 4 leg components are required for each table (quantity per parent = 4), and the scrap percentage for the component is 20 percent, the extended quantity is 12 x 4 / (1-.2) or 60 legs.

The scrap percentage is used to increase the calculated gross requirements of specific component items to compensate for anticipated losses during the manufacturing process. If Bill of Materials is installed and the parent item code for the work order is a bill, the scrap percentage for the component item is defaulted from the bill.

Calculating the Extended Time Per Step

The Extended Time field on the Work Order Entry Operations tab is calculated based on the standard run type, run time, parent item type, and factor specified for a step, along with the number of parent items to be produced (for example, finished products or subassemblies) to determine the total time required to perform a step.

The Standard Run Type field on the Work Order Entry Operations tab identifies how the run time for the step is defined.

Select Hours per Operation to express the standard run time in terms of hours per operation.
Select Fixed Time per Lot to express the standard run time as a fixed amount of time per lot, regardless of the quantity produced.
Select Operations per Hour to express the standard run time in terms of operations per hour.

The standard run type defaults to the Hours/Operation, Hours/Lot, or Operations/Hour field specified for the operation code for the step but can be overridden in either Routing Maintenance or Work Order Entry. Depending on the standard run type selected, you can specify either hours per operation, hours per lot, or operations per hour to indicate how much time is required per operation.

Generally, if it takes more than 1 hour to complete one operation, Hours per Operation is the most convenient method to use. If you complete more than one operation per hour, the Operations per Hour method is the most convenient.

The Parent Item Type field and the Factor field on the Work Order Entry Operations tab define how many parent items can be processed per operation. Select Operations/Parent if the operation must be performed more than once to produce one parent item. You can enter the number of times the step operation must be performed per parent item in the Factor field. Select Parents/Operation if performing this operation once produces more than one parent item. You can enter the number of parent items that are produced each time the step operation is performed in the Factor field. If the standard run type is Fixed Time per Lot, both fields are ignored because the step is performed only once per work order, regardless of the number of parent items produced.

The calculation for the Extended Time field is based on your entries in the Standard Run Type and Parent Item Type fields as illustrated in the following table.

Standard Run Type	Parent Item Type	Extended Time
Hours per Operation	Operations/Parent	Hours per Operation x Quantity Planned x Factor
Hours per Operation	Parents/Operation	Hours per Operation x Quantity Planned / Factor
Operations per Hour	Operations/Parent	(Quantity Planned x Factor) / Operation per Hour
Operations per Hour	Parents/Operation	(Quantity Planned / Factor) / Operations per Hour
Fixed Time per Lot	--	Hours per Lot

Calculating the Extended Time Per Step Example 1

In the construction of a table, you must perform a sanding operation on four legs to produce one table. If it takes 15 minutes to sand one leg, and you need to produce 10 tables, the following calculation is used.

Standard Run Type = Hours per Operation

Parent Item Type = Operations per Hour

Hours per Operation = .25

Factor = 4

Extended Time = .25 x 10 x 4 = 10 hours

Calculating the Extended Time Per Step Example 2

In the manufacture of steel washers, you must perform an operation in which a stamping press stamps out 100 washers from a strip of steel each time the step is performed. If it takes 5 minutes to stamp one sheet and you need to produce 6000 washers, the following calculation is used.

Standard Run Type = Operations per Hour

Parent Item Type = Parents/Operations

Operations per Hour = 12

Factor = 100

Extended Time = (6000 / 100) / 12 = 5 hours

Calculating the Extended Time Per Step Example 3

To prepare the stamping press in Example 2 for operation requires 15 minutes. The standard run type is Fixed Time per Lot and hours per lot is .25. The following calculation is used.

Extended Time = .25 hours

For more information, see:

Operation Code Maintenance

Routing Maintenance

Work Order Entry