About Product Flow

Product flow describes the various relationships that can exist between processes and products. Product flow can, describe how a number of products can be used and/or produced in one process step, or how various steps can produce one product. Product flow applies at several levels:

• At the stage and process step level, we can distinguish three types of product flow: main product, inflow product, and by-product.

  • Main Product - All stages result in main product, except for depletion stages: depletion batches use main product. A product may or may not always be a main product. The main product group in one stage may, for example, form the inflow product group in the next stage.
  • Inflow Product - Inflow products are the products required by a batch to create by-products and main products.
  • By-product - A by-product is produced by a process step, as is a main product. The yield of the by-product is expressed as a percentage (yield factor) of the quantity of the main product. The quantity of by-product produced by a process batch is monitored at an inventory point. For this reason, only decoupled products can be by-products of a process step.

     By-product is not a property of a product. The same product can, for example, be the main product of another process step.

     Unlike a main product, creating batches for the product cannot cover by-product requirements. The by-product is produced - wanted or unwanted - through the creation of batches for another product. Creating depletion batches can reduce the inventory of by-products.

     Return flow of by-products can also be modeled.

• At the batch level, "processing" is manifested as process batches, while the "products" are tank batches, orders or inventory points (depending on the batch type). A batch level flow chain could look like this:

  inventory point => process batch => tank batch => process batch => order

  At this level (as opposed to stage and process step), the definitions product and product flow have been combined, and we can distinguish between coupled product flow (also: flow) and decoupled product flow. Decoupled product flow is flow to and from an inventory point. All remaining flow, whether between process and tank batches or process batches and orders, is coupled. Coupled flow leads to time links.

  Coupled flow occurs between process and tank batches, which together belong to a coupled step. The flow of a product from a tank batch to a process batch and the product flow between end product batches and orders are also coupled. They result in time links between batches.

  Product flow also shows the flows between a particular process batch and related tank batches, and allows you to change the sequence in which inflow occurs from, or outflow occurs to, tank batches. When viewing the product flow of a process batch, you can reallocate the related tank batches to other resources.