Constraint Types

The list below give the current list of constraint types supported and their purpose. They are listed in order of relative importance.

Production Line Capacity - It ensures that utilisation will be minimised on each Line. Setting up as a “Hard” Constraint ensures that only available capacity is used as one cannot go above the stated capacity. Note that setting this as a soft constraint enables you to view what capacity would be needed in an ideal situation in case of capacity constraints.
Min Lot Size - Minimise the number of times producing a batch less than the minimum lot size. This can be set as a Hard or Soft constraint and typically is set as a Hard constraint to support production efficiency.
Max Lot Size - Parameter that enables a Change over to occur onto itself for a SKU, when the Max Lot size is reached with the notion that afterwards production on the same SKU may continue. This typically occurs when a line needs to be cleaned after running the Product for 24 hours for example.
Step Size - The step size enables volume to be rounded to the set step size. An example is a step size of 20k whereby the minimum lot size is 100k with a max lot size of 200k. Depending on the demand the Proposed Production plan will be at least 100k and multiples will be rounded in quantities of 20k up to a maximum of 200k before a max lot size is reached.
Service Agreement (Unit) - Minimise the number of violations not meeting forecasted demand. We recommend setting this as a "Soft" constraint in group 1. This tells the solver to optimise for service level above other "Soft" constraints. Using the Unit service version aims to favour high running products above low volume products.
Service Agreement (Percent) - Minimise the number of violations not meeting forecasted demand as a percentage of demand, thus allowing lower volume items a fair share of capacity. This typically is set as a Soft Constraint and an example would be a Product that has a demand of 1000 vs. another Product of 1 million. By using this profile the Product with a 1000 units of demand will have the same chance of being produced vs. the Product with a 1 million Demand. This scenario is mostly used where the Demand Profile of Product is severely different.
Minimise Change Over Cost - Similar to Priority Costs that are linked to Resource, this constraint is created to provide users with a 2nd grouping opportunity and to run certain products together. In order to do so similar products need to be given the same Cost. It again needs to be assigned for all products whereby the lowest assigned priority wins and is produced first as a group. This constraint typically is used in combination with Minimise Job duration.
Safety Stock (Unit) - Minimise the number of times going below the set Safety Stock levels whereby high running Products obtain a higher penalty versus lower volume Products.
Safety Stock (Percent) - Minimise the number of times going below the Safety Stock levels as a percentage of Safety stock. This provides an even prioritisation amongst the Products. This is mostly used in case the safety stock in volume is very different per Product.
Max Stock (Unit) - Minimise the number of times going above the set Max Stock level. In case trade offs have to be made, the solver will assign a greater penalty score for a high running product vs. a low running product.
Max Stock (Percent) - Minimise the number of times going above Max Stock levels as a percentage of Max stock. Products that have a low demand are treated the same as a product with a high demand as a % score is used as a penalty score. This is mostly used in case the max stock in volume is very different per Product.
Target Stock (Unit) - The Deviation from the Target is expressed as a penalty score and the constraints aim to minimise the penalty score as much as possible. Products with a high demand profile when not producing in line with the Target Stock will obtain a high penalty score and will get priority over Products with low demand
Target Stock (Percent) - The deviation from the Target stock is managed as a percentage of Target stock. This ensures that SKU with a much lower Demand Profile of for instance 2000 do get produced in an orderly fashion versus a Product with a 1 million demand. This is particularly relevant for products that are perishable.
Minimise Job Duration - Minimise the time spent using resources in each time period. In other words, reducing the amount of Change Over (CO) time spent on the production line. Note The penalty is expressed in time and the weighting should therefore be set fairly high in order to be able to complete with other dimension such Minimise Current Stock
Minimise Current Stock - Minimises stock holding whilst meeting the Demand.
Minimise Priority Cost - Minimise production costs by utilising the resource with the cheapest cost. In order to ensure that a Product will run on the assigned line, the priority costs needs to be set low, resulting in a low penalty score. Other Products must be assigned to a higher score to ensure a higher penalty is created and the lowest score wins.
Required Input - This is used for multilevel scenario planning. It means that the final product/group cannot be created without the input product/group being available.
Required Route - This is used for multilevel scenario planning. It establishes that a final outcome cannot be achieved unless its required prerequisites are first completed in a specific sequence. Each step must follow its designated pathway.
Dependent Demand (Unit) - This is used for multilevel scenario planning. It means to minimise the number of violations of not meeting dependent demand, dependent demand being the demand for input products/groups.
Dependent Demand (Percent) - This is used for multilevel scenario planning. It means to minimise the number of violations of not meeting dependent demand as a percentage of dependent demand, dependent demand being the demand for input products/groups.
Minimise Waste - This is used for modelling Shelf Life in a plan. It means to minimise the waste of SKUs going over shelf life.
Production Resource Capacity - This is used for multi-resource scenario planning. It is used to constrain dependent or non primary resources.
Resource Capacity - Labour - It uses labour as a dependent variable and can be monitored as a Hard or Soft Constraints. As an input the solver would need to know how many staff or labourers will be needed for 1 unit.
Resource Capacity - Utilities - This is used for multi-resource scenario planning. It is used to constrain dependent utilities resources.
Resource Capacity - Equipment - This is used for multi-resource scenario planning. It is used to constrain dependent equipment resources.
Resource Capacity - Emmissions - This is used for multi-resource scenario planning. It is used to constrain dependent emissions resources.
Resource Capacity - Warehouse - This is used for multi-resource scenario planning. It is used to constrain dependent warehouse resources.
Required Materials - Require raw materials to be available. As a "Hard" constraint, production without required is prevented, as a "Soft" constraint it is minimised.

If you want to add a new constraint type please contact support@demandchainai.com