Line Design and Balancing Procedures

This chapter describes the steps to design Flow manufacturing lines.

This chapter covers the following topics:

Overview of Line Design and Balancing

The following illustrations show the process flow of line design and balancing in Flow Manufacturing, including the process flow for assemble-to-order (ATO ) final assemblies.

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Assemble-to-Order (ATO) environments are used to create final assembly orders according to customer orders. ATO items enable you to apply attributes for standard, model, and option class items.

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Operation Sequence: Add the event sequence number to each of your items on the bill of material. For Flow Manufacturing, the, operation sequence on the bill of material indicates the event sequence. The events you assign to your optional items are used to create a routing specific to the options a customer orders. A single optional component can be tied to multiple events.

Planning Percentages: Assign planning percentages to each of your optional items in the material control region. The program uses these percentages to calculate the average Operational Cycle Times and Total Product Cycle Times for your ATO Model.

Important: If you do not assign planning percentages, cycle times will be inflated because they will be a sum of all events in the line, instead an average based on option chosen.

Product Synchronization

Product Synchronization is the process of defining your product's process flow. This is done through the Flow routing where you are able to define processes, events and operations for your flow line. You can then define the process network, add process yield information, and calculate operation times, yields and total product cycle time.

Standard processes and standard operations must be created before adding them to your flow routing. They are created either on the Graphical Line Designer Workbench, or in the Standard Processes or Standard Operations windows. See: Creating the Graphical Network

To create product synchronization for standard items

Defining Flow Manufacturing Standard Processes

Standard Processes can be created and used only with Oracle Flow Manufacturing. Processes are generic activities that often comprise multiple events which are performed in a specific sequence.

Note: Processes and standard processes can also be created on the Graphical Line Designer Workbench. See: Creating the Graphical Network

Prerequisites

To define a Standard Process for a flow manufacturing line

  1. Navigate to the Standard Processes window.

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  2. Enter the line identifier, sequence number, code, and description.

  3. Select a department.

  4. Optionally, enter a display sequence and minimum transfer quantity.

  5. Save your work.

Defining Flow Manufacturing Standard Events

Standard Events can be created and used only with Oracle Flow Manufacturing. Events and standard events can only be created and used with Oracle Bills of Material. Events and Standard Events can also be created on the Graphical Line Designer Workbench. See: Creating the Graphical Network

Note: When using Oracle Flow Manufacturing, the Operation Sequence on the Bill of Materials refers to the Event Sequence.

Prerequisites

To define a Standard Event for a flow manufacturing line

  1. Navigate to the Standard Events window.

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  2. Enter the code and description.

  3. Choose the Event Resources button to define resources.

    When defining events, you must choose whether a resource is scheduled or not scheduled. In Flow Manufacturing, a nonscheduled resource is a resource that is used in parallel to a scheduled resource. Unscheduled resources are included in the total time for the resource type (labor or machine), but is not included in the total elapsed time for the process. Scheduled resources are included in both.

    Therefore, in the case of parallel processes, the activity with the longest resource time should be scheduled because the system elapsed time calculation should always consider the longest resource time.

  4. Save your work.

Related Topics

Calculating Operation Times

Defining Flow Manufacturing Standard Line Operations

Standard operations for Flow Manufacturing enable you to create line operations for a regular manufacturing line and a flow manufacturing line. In Oracle Flow Manufacturing, operations are used to group events into balanced work groups. They are generally defined and assigned after viewing the mixed model map, although they can be entered at any time.

Note: Operations and standard operations can also be created on the Graphical Line Designer Workbench. See: Creating the Graphical Network

Note: When using Flow Manufacturing, the operation sequence on the bill of material refers to the event sequence.

To define a Standard Line Operation for a flow manufacturing line

  1. Navigate to the Line Operations window.

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  2. Enter the line identifier, sequence numbers, code, and description.

  3. Select a department and optionally choose the remaining options.

  4. Save your work.

Flow Manufacturing Line Balance

To balance a Flow manufacturing line

  1. Generate a mixed model map for a line, product family, or forecast. You can also assign a boost percentage, number of days, and number of hours per day for the line.

    The Mixed Model Map Workbench displays the line takt time, process takt times, and weighted average times. See: Overview of the Mixed Model Map Workbench

  2. Create line operations for the current line.

    See: Creating the Graphical Network

  3. Assign line operations to the product level routings.

    Note: You can copy or reference all the line operations for the current line into the routing to reduce data entry effort.

  4. Regroup events on each product level routing into line operations to approximate takt time.

    You can do this by assigning the line operation in the Parent Line Op field of the event.

  5. Create a routing network for operations.

  6. Optionally, add yields to operations.

  7. Save your work.

  8. Regenerate the mixed model map by line operation to review and confirm that the line is balanced. The mixed model map will also show the resource (machine/labor) and IPK requirements. See: Overview of the Mixed Model Map Workbench

Creating a Flow Routing

To create a product synchronization you can design a flow routing including events, processes, and line operations. You can create a routing manually, copy an existing routing, or reference a common routing.

Prerequisites

To create a flow routing

  1. Navigate to the Routings window.

  2. Select the item, or product family or product family members, for creating a flow routing.

    Note: For ATO Items, the ATO Model Flow Routing will be used for line balancing, and will be used to create the configured routings during autocreate config. Therefore, define a routing for the model that contains all possible events, processes and operations for all possible options in your model. Then assign the model routing as a common routing for all option classes.

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  3. You can assign an existing routing or copy a routing to this Item:

    • To assign a common routing, choose Assign Common Routing from the Tools menu and select an item to copy.

    • To copy an existing flow routing, choose Copy Routing From in the Tools menu and select an item to copy.

  4. If you are creating an alternate flow routing, enter an alternate. For a primary flow routing, do not enter an alternate.

    Note: To create a standard (nonflow) routing for the same item, use the Bills of Material responsibility.

  5. Optionally, select the Capable to Promise.

    Capable to Promise describes an available to promise calculation that considers both available material and capacity of manufacturing and distribution resources. You are able to define one and only one CTP routing for each item.

  6. Enter the line for the flow routing.

  7. If you are updating an existing flow routing, enter the routing revision and the effective date.

  8. Optionally, enter a value in the Total Cycle time field.

    The total product cycle time can be manually input now, or can be calculated by the application after you have defined processes and events.

  9. Select a display option to display All, Current, or Future and Current operations effective as of the revision date you specify.

  10. There are several ways to set up events, processes, and operations:

    • Use the Graphical Line Designer, see Creating the Graphical Network

    • In the list of values, choose Processes and enter the first process sequence and code. Choose the All Events and enter all events for that process. Close and repeat for all processes. When you are ready to balance your line, choose Line Operations to enter operation sequences and codes. Then assign events to the operations in the All Events region.

      Note: The sequence number determines the order in which the processes are displayed in the Mixed Model Map Workbench.

    • Choose Processes, and enter in all process sequences and codes. Optionally, choose the Line Operations, and enter all operation sequences and codes. Choose All Events tab, and enter in each event in sequence, assigning each to a process, and optionally operation.

    • Choose the Process tab, and enter in the desired processes. Optionally, choose the Operations tab and enter the desired operations. Choose All Events, and enter the desired events.

  11. If you are using nonstandard events or editing standard events, choose Event Resources and define resource values. For an event, you can also define a department, parent process, and parent line operation.

    Note: Processes and line operations must already be assigned to the routing before you assign them to events.

  12. Enter effective date ranges.

  13. For operations in ATO model and option class flow routings, indicate if the event is option dependent. An event is option dependent when the event is dependent on the choice of an optional component. A configured routing will contain all selected components and their related events, all mandatory components and their related events, and all events which are not assigned to a specific component.

    Note: All processes and operations will always appear on the configured routing, regardless of whether or not any events assigned to them are included.

  14. Choose the WIP tab to indicate whether to backflush components on shop floor moves at this operation. A backflush transaction automatically pulls operation pull components from inventory. Work in Process also pulls all Operation pull components at nonbackflush operations preceding this operation using the previous completed backflush operation.

  15. Choose the Operation Times tab to define or view operation times and yields.

  16. To view rolled-up operation times, select Calculate Operation Times from the Tools menu. Optionally, enter user defined times. Either can be used in Mixed Model Map Workbench calculations.

  17. Switch to the Operation Times tabbed region and optionally enter operation yield values for processes and/or line operations.

    Note: Operation yield values are required to perform calculation of cumulative and reverse cumulative operation yields.

  18. Create a routing network. See: Creating the Graphical Network

  19. Once the routing network is created, calculate cumulative yield, reverse cumulative yield, and net planning percent, by selecting Calculate Operation Yields from the Tools menu. Choose Update Events to add these yields and calculations to events. This is required if you want kanban planning to consider process yields when calculating kanban sizes.

    Note: You can also manually insert these values.

  20. To calculate Total Product Cycle Time, choose Calculate Total Product Cycle Time from the Tools menu.

  21. To enter completion subinventory and locator information, view a common flow routing, or enable the routing for use in the Mixed Model Map Workbench, choose the Routing Details.

  22. In the Routing Details window, optionally, enter a priority. Lowest priority routing will be used for backflushes and during autocreate config on ATO items.

  23. Save your work.

Creating a Routing Network

In defining product synchronization you must specify the network of processes through which the item is routed. This includes specifying alternate processes, planning percent, rework loops, rework percentage, and feeder lines. The routing network is created in the Graphical Line Designer Workbench.

Related Topics

Creating the Graphical Network

Modifying the Line Operation Tree and Process Tree

Calculating Operation Times

You can calculate machine time, labor time, and elapsed time for your processes, line operations, and events defined in your flow routing. You can also enter your own machine times, labor times and elapsed times in the Flow Routing window.

Prerequisites

To calculate operation times

  1. Navigate to the Flow Routing window.

  2. Place your cursor in the Total Cycle Time field in the header.

  3. Select Calculate Operation times from the Tools menu. Choose to calculate either process times or operation times.

    Note: In the Flow Routing window the unit of measure for all times is hours.

    Note: You must re-perform the operation times and total product cycle time calculations any time you make a change to events, processes or operations.

    Note: You can also enter your own machine times, labor times, and elapsed times in the Flow Routing window. To do so, manually enter this information in the User Machine Time, User Labor Time, and User Elapsed Time fields. You determine when creating a mixed model map, whether the calculations are based on rolled-up or user entered times.

Operation Times Calculations

The operation times calculations are based on resources in the Flow Routing which have the resource unit of measurement (UOM) in the UOM class associated with the BOM profile option, BOM: HOUR UOM.

Calculated Labor Time

Calculated labor time per event is the sum of both scheduled and unscheduled labor resource usage rates for the event. Calculated Labor Time per process or operation is the sum of the labor times for all the events underneath each process or operation. If you enter events by lot, it will temporarily convert the number to an item basis for the purposes of this calculation.

Note: For ATO model routings: The program goes to the multilevel BOM for the model, and searches for the planning percentage on items that are assigned to specific routing events. It then multiplies the calculated labor time for this event by the planning percent to get a weighted value for the event time. If an event is NOT assigned to any part on the multilevel BOM, planning percent is assumed to be 100%.

Note: This will work only if you define a routing for the ATO model, and then use it as a common routing for all the option classes that follows it.

Note: Each Option on the routing must belong to a unique event for operation calculations to be successful.

Calculated Machine Time

Calculated Machine Time is the same as Calculated Labor time, only it uses the scheduled and unscheduled machine resources for each event.

Calculated Elapsed Time

Calculated Elapsed Time for each event is the sum of the scheduled Labor and Machine usage rates for each event. Elapsed time per process or operation is the sum of the elapsed times for all the events that fall under each process or operation. If you enter events by lot, it will temporarily assume that the time entered is per item for the purposes of this calculation.

Times for ATO model routings are adjusted based on the planning percent of the item assigned to an event, as described in calculated labor times.

Calculating Total Product Cycle Time

You can calculate the Total Product Cycle Time (TPCT) for your line. TPCT is the sum of all elapsed event times along the longest path on your Flow Line.

Prerequisites

To calculate Total Product Cycle Time

  1. Navigate to the Flow Routing window.

  2. Place your cursor in the Total Cycle Time field in the header.

  3. Select Calculate Total Cycle Time from the Tools menu. Choose to calculate either process times or operation times.

    Total Product Cycle time is always calculated using the rolled-up (system calculated) elapsed times, even if you enter manual elapsed times. You can manually enter a Total Cycle Time as well.

    You must re-perform the operation times and total product cycle time calculations any time you make a change to events, processes or operations.

    Once the routing network and the Total Cycle Time for a routing are finalized for each item on your flow line, return to the organization item master and update the fixed lead time to equal your total cycle time. The takt time (which is displayed on the MMM) for the line should be entered in the variable lead time.

    Note: In the Flow Routing window, the unit of measure for all times is hours.

Calculating Operation Yields

The system will calculate the cumulative yield, reverse cumulative yield and net planning percent for each process and line operation. This information is used in Mixed Model Map Workbench calculations and kanban planning.

Prerequisites

To calculate operation yields

  1. Navigate to the Flow Routing window.

  2. Place your cursor in the Total Cycle Time field in the header.

  3. Select Calculate Operation Yields from the Special menu.

  4. Select process or operation. Choose update events to translate yields and net planning percent to events.

    Important: You must update events (manually or by choosing to update events when you perform the calculations) if you want kanban planning to consider yields when sizing kanbans.

    Note: If you have yields in your line, you must either calculate or manually enter operation yields for each process/line operation for the mixed model map results to be accurate.

Operation Yields Calculations

The system will calculate the cumulative yield, reverse cumulative yield and net planning percent for each process and line operation. This information is used in Mixed Model Map Workbench calculations and kanban planning. The following diagram displays an illustration of the setup used in the example calculations.

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In the above example, the primary path is operation 10 through 50. The numbers in parentheses are the yields for the operation number above it, as entered by the user. The percentages on the network paths represent the network percent assigned to each path. Blank paths assume 100% network percentages. (The incoming network percentage for the first operation and the outgoing network percentage for the last operation are always 100%.)

Note: Any alternate path must skip at least one operation (or process) on the main line for the yield and planning percent calculations to work properly.

Net Planning Percent

The system calculates the net planning percent by using the following formula.

N c = S (Pp * I c) + Sr (Io*Wo),

where

N = Net Planning Percent, in decimal format

S = sum over all paths

P = Planning Percent = (Pp * I c) (system calculated - not displayed)

Note: Planning percent for the first operation is always 100%.

I = Incoming Network Percent, in decimal format (from Routing Network)

Note: Incoming network percent for the first operation is always 100%.

p = previous operation

c = current operation

Sr = Sum over all rework loops within which is this operation

W = Rework percent (from the routing network)

o = Operation originating the rework

In other words, the system calculates the net planning percent by taking the sum over all primary and alternate paths of the product of the network percentages along that path, then adds a rework calculation if the operation is within the rework loop. The planning percent and incoming network percent for the first operation on the primary path are always 1. The planning percent for the Feeder line is always the same as the operation to which they feed.

The rework calculation is equal to the planning percent of the rework's originating operation, times the rework percent coming from that operation (in this example, OP50 is the originating operation for the rework, and its planning percent is 100%, and the rework loop is 5%. Therefore, the rework calc is 100%*5% = 5%. This value is added to all operations in the loop (30, 40 and 50).

The number of paths is determined by working backwards along primary and alternate paths from the end of the line (so in the example, operations 30, 40 and 50, each have two paths due to the alternate path).

Caution: If a rework loop returns to an operation that is also fed by a feeder line, the feeder line will include the rework loop percent in the Net Planing Percent.

Operation Incoming Network Percent Planning % Calculation + Rework Calculation Net Planning Percent
10 100 1 * 1 + 0 1
20 80 1* 0.80 + 0 0.84
25 20 1* 0.20 + 0 0.20
30 100 (1 * 0.80 * 1) + 1 *.05 1.05
40 100 (1 * 0.80 * 1 * 1 + 1 * 0.20 * 1)
+1 *.05
1.05
50 100 (1 * 0.80 * 1 * 1 * 1 + 1 * 0.20 * 1 * 1)
+ 1 *.05
 
100 feeder - uses network% from 20 0.80 + 0 0.80
200 feeder - uses network% from 20 0.80 + 0 0.80

Cumulative Yield

The cumulative yield for the first operation along the main line and any feeder lines is the yield entered by the user. The system calculates the cumulative yield for all other operations using the following formula:

C c = Y c * S (Cp * Pp * I c / Pc),

where

C = Cumulative Yield

Y = Yield (User entered)

S = sum of all paths

P = Planning Percent, in decimal format (P = Net Planning% - Rework Calc)

I = Incoming Network Percent, in decimal format (from Routing Network)

p = previous operation

c = current operation

For example, operation 20 in the example above:

C20 = Y20 * S(C10 * P10 * I20 / P20) = 0.90 * (1 *1 * 0.8 / 0.8) = 0.9

Starting from the front of the line, the results for the example are:

Operation Yield Entered Incoming Network % Plan % Cumulative Yield Calculation Cumulative Yield
10 null 100 1 1 = 1
20 0.90 80 0.8 0.90
* (1 * 1 * 0.8 / 0.8)
= 0.90
25 null 20 0.2 1
* (1 * 1 * 0.2 / 0.2)
= 1
30 null 100 0.8 1
* (0.9 * 0.8 * 1 / 0.8)
= 0.9
40 0.95 100 1 0.95
* (0.9 * 0.8 * 1 / 1)
+ (1 * 0.2 * 1 / 1)
= 0.874
50 0.98 100 1 0.98
* (0.874 * 1 * 1 / 1)
= 0.8565
100 null 100 1 1 = 1
200 null 100 1 1 * (1 * 1 * 1 / 1) = 1

Reverse Cumulative Yield

The reverse cumulative yield for the last operation along the main line is the yield entered by the user. The system calculates the reverse cumulative yield for all other operations using the following formula:

R c = Y c * S (O c * R n),

where

R = Reverse Cumulative Yield

Y = Yield (user entered)

O = Outgoing Network Percent, in decimal format (from Routing Network)

Note: Outgoing network percent for the first operation is 100%.

n = next operation

c = current operation

S = the sum over all outgoing paths

For example, operation 20 in the example above:

R20 = Y20 * S(O 20 * R 30) = 0.90 * (1 * 0.931) = 0.8379

Operation Yield Outgoing Network % Reverse Cumulative Yield Calculation Reverse Cumulative Yield
50 0.98 100 0.98  
40 0.95 100 0.95 * (1 * 0.98) 0.98
30 null 100 1 * (1 * 0.931) 0.931
20 0.9 100 0.9 * (1* 0.931) 0.8379
25 null 100 1 * (1 * 0.931) 0.931
10 null 80 and 20 1 * [(0.8 * 0.8379) + (0.2 * 0.931)] 0.85652
200 null 100 1 * (1 * 0.838) 0.8379
100 null 100 1 * (1 * 0.838) 0.8379