Create production flows
Production flow versions
To better support continuous improvement, production flows are implemented in time-effective versions. This implementation allows users to copy an existing production flow version, including all related kanban rules, to a future version of the production flow, and then model the future-state production flow before validating and activating it for production.
Existing kanbans from old production flow versions are automatically related to the new version to ensure a seamless material flow on the transition date and beyond.
To map a lean manufacturing scenario to Supply Chain Management, defining a production flow is mandatory. The production flow defines the organizational context of a manufacturing scenario and relates to accounting and costing because you can configure this operating to be used as a financial dimension.
The following fields are used to set up and view the takt and cycle times for the production flow version:
Per cycle unit of measure - Enter the unit of measure that is used to define the product quantity for each cycle. If the Default quantity unit field is set in the production parameters, the value is displayed in this field by default and you can change it. If the production flow version is activated, you cannot change the value of this field. All items that are produced in the production flow that have a different inventory unit of measure must have a conversion factor to convert to this unit of measure.
Quantity per cycle - Enter the product quantity that is produced for every one takt cycle of the production flow version. The default value is 1, but you can change it.
Takt unit - Select the unit of measure to use with takt times and cycle times of the production flow. If the Default time unit is set in the production parameters, the value is displayed in this field by default, but you can change it.
Average takt time - Enter an average takt time for the production flow version. You can use this field to monitor and analyze the performance of the work cell. You can compare the average takt time that you set against the actual takt time that is calculated.
Minimum takt time - Enter the minimum acceptable takt time for the production flow version. If the actual takt time is less than the minimum takt time, the production flow is running too quickly. A warning message is displayed in the cycle time performance indicator on the Kanban schedule board, and the indicator color moves to the red area. The default value is 1, but you can change it.
Maximum takt time - Enter the maximum acceptable takt time for the production flow version. If the actual takt time is more than the maximum takt time, the production flow is running too slowly. A warning message is displayed in the cycle time performance indicator on the Kanban schedule board, and the indicator color moves to the red area. The default value is the average takt time x 2, but you can change it.
Required takt time - For feeder production flows, the required takt time is the takt time that is needed to supply the related downstream activities of the production flow version. The value is calculated from the cycle times of the downstream activities. The following formula is used:
Required takt time = 1 / Σ (ratio (activity relation)/cycle time (downstream production flow activity))
Actual takt time - The takt time that is calculated based on the actual jobs that are completed during a defined period. If the production flow version is active, this field is calculated by using the following formula:
Actual takt time = working hours of cycle time period / quantity produced in cycle time period
The output quantity of the production flow version is determined from the last activity of the production flow. If a production flow version has multiple delivery branches, the quantities from the last activities of all branches are summed.
For example, the working shift is eight hours, from 8:00 AM to 4:00 PM. The cycle time period is two days. The working hours of the cycle time period are 16 hours, which are equal to 960 minutes.
Assuming that 600 pieces were produced during the last 16 hours of working time (on Wednesday at midnight, all jobs that were completed between midnight on Monday and midnight on Wednesday are included), the Actual takt time is: 960 / 600 = 1.6 minutes.
Period for actual cycle time (days) - Enter a number of days for which the actual takt time is calculated. The actual takt time is calculated based on the jobs that are completed during this period. You can change this value on production flow versions regardless of the activation status.
Activity cycle times
The activity cycle times (average, minimum, and maximum) for each activity are calculated based on the takt settings of the production flow version. A cycle time ratio is used among activities within the cycle time calculation of the production flow as well.
The initial calculation is done on validation/activation of the version but can be recalculated with the Recalculate button at any point in time. However, the cycle time for a kanban job is calculated on job creation. The recalculation of the activity cycle times will not affect existing jobs.
Takt and cycle times
The production flow version details specify the takt requirements of the production flow. These details are used at activation to calculate the actual cycle time requirements of each activity in the production flow.
For a single activity production flow, the takt requirements of the production flow version are equal to the cycle time of the activity.
At the validation and activation of a production flow version, the calculated activity cycle times are verified against the capacity of the assigned work cells. If the capacity that is needed to support the average cycle time is higher than the available capacity of the work cell, a warning message is displayed.
Cycle time ratio
When adding a successor or predecessor, you need to enter a value to describe the ratio between the cycle times of the related activities. The cycle time ratio defines how many cycles of a predecessor activity are required to supply the material or semi-finished products that are needed for one cycle of the successor activity.
The ratio is used to calculate the average cycle times for all activities of the production flow. The ratio is also used to calculate the Required takt time of a feeder activity that is related to a downstream (successor) activity of a different production flow. You can include a scrap factor in the ratio.
Example
A cycle time ratio with the value of 1 means that the activity cycle time is equal to the Average takt time of the production flow version, which is the default value.
A cycle time ratio with the value of 2 means that the activity must feed two activities for each cycle time. Item A is produced in work cell A. Item A consumes two units of item B, which is produced in the upstream work cell B. The cycle time ratio is 2.