Sequence-dependent setup times

Reduce downtimes and operational costs while optimizing resource use with (lightweight) SDST = Sequence Dependent Setup Times

With the VAPS, we typically schedule by production order to help customers complete their orders on time through prioritization methods like “apply all” and “fill idle times.” However, optimizing the sequence of operations on key machines to reduce setup times can also increase throughput and reduce late orders. Sequence-dependent setup times (SDST) support this by grouping certain operations on specific machines to minimize overall setup times.

The SDST function of the VAPS works based on item attributes so we enhanced the "Item Attributes" card accordingly:

Clicking on this button will open the new SDST configuration list for the selected attribute:

Meaning of the columns in detail:

• No: Used for identifying and referencing configurations for work and machine centers that will follow the SDST configuration.

• Description: Provides additional information for users.

• Handling Rule: Can be set to "Additive" or "Biggest Only."

  • "Additive" means the regular setup time of the production order routing line, the default setup time defined in the next column, and either the same value setup time or special case exception setup time will all be summed up.

  • "Biggest Only" will choose the longest setup time from the list.

• Setup Time Unit of Measure: Defines the unit of measure for all setup times on this page or for the exceptions.

To add special cases for switching between distinct attribute values, click "Edit Exception" on the action bar or click the "…" in the "No" column.

In the Exceptions list, you can define exceptions to the rule when one operation with a certain attribute value follows another with a different attribute value. Enter the values to check against in the "from" and "to" columns. Clicking "…" here will give you a list of all attribute values entered in regular BC so far, including option attributes, number (integer, decimal), and text attributes. You can also enter values directly via the keyboard. The setup time here follows the same unit of measure defined in the main SDST configuration for this attribute.

After setting up the SDST attributes, you need to assign the resources to which SDST will be applied. This can be done either

• on the Item Attributes List page:

or

• on the MC/WC cards: 

In both cases, a dialog appears where you can define which Item Attribute SDST Configuration should be applied to which work or machine center. Note that you can set the same configuration for multiple work and machine centers and set multiple configurations for one work or Machine Center.

Once the setup is complete, add the relevant attributes and values to items to be used in production orders. After that, you can load a simulation with the configured data and apply the SDST Configuration. This will prompt the scheduler to go through the operations and apply the correct setup times according to their sequence on the resources.

Please note:

• Currently, there is no easy way to see which operation or production order line has which attributes and values but we are working on a solution. For the time being, we recommend using item colors.