Slack, as defined in our system, differs slightly from what is sometimes called allowance or other similar terms.
So, a production process has a given raw materials allowance or range within which raw materials can vary - either upwards or downwards. This is defined by raw material in the Bill of Materials table in the Quantity Slack on the Component (%) column:
When the production process actually runs the user needs to input the actual quantity consumed. This determines the slack.
The slack is entered in the Production Order when returning materials after the run has finished - see here for more details on the process.
The returned material quantity will need to be within the allowance percentage.
Example Scenario:
Allowance: You plan to produce 1,000 units of a product. Based on historical data, you know that 5% of materials are usually lost due to waste. So, you apply a 5% allowance, meaning you allocate materials for 1,050 units.
Slack: During production, you actually consume materials for 1,020 units. The 5% allowance ensured you had enough material to complete the production without running out. Now, you might use a slack percentage to determine how much of the remaining material can be returned to inventory or to manage slight overconsumption.
Summary:
Allowance is a proactive measure added during planning to ensure sufficient materials are available, accounting for expected variations.
Slack is a reactive adjustment used during or after production to manage material consumption discrepancies, often related to how much of the allowance was used and what can be returned.