Assembly

Assembly nodes are used to combine multiple incoming material streams into a single output. They represent points in your process where components come together to form a finished or intermediate product, such as subassemblies, kitting operations, or final assembly steps.

An assembly node waits until all required inputs are available, then produces one combined output downstream. This makes assemblies useful for modeling situations where multiple parts must be present before work can continue. In practice, this means that shortages or delays on any upstream path can directly affect downstream flow, even if other inputs are readily available.

Assembly nodes do not impose rate limits or capacity constraints, and they do not experience interruptions. Instead, they act purely as logical combination points within the model. Flow through an assembly is governed by upstream constraints and buffers, which determine how quickly components arrive. Because of this, assemblies are typically paired with constraints or buffers elsewhere in the process to represent processing speed or storage behavior.

When building a model, assembly nodes should be placed wherever multiple materials are required to proceed to the next step. As with other node types, it’s best to focus on meaningful process structure rather than physical layout. Replay is especially helpful when working with assemblies, as it allows you to observe how missing inputs can stall downstream flow and identify which upstream paths are driving delays.