Splitting and Merging Parts in BOM Based on Operation Allocations
In the manufacturing industry, most fasteners such as nuts and bolts are assigned as a group. You later split these fasteners into multiple operations. You allocate the fasteners and then distribute them across relevant operations as required by your process., You can manage grouped components such as bolts and nuts using the split and merge functionality in Windchill. You allocate quantities from a group to individual operations without performing explicit splits. For example, from a group of ten components, you allocate two to the first operation, two to the second, four to the third, and two to the fourth. You can perform this allocation directly from the 3D tree picker using drag-and-drop actions. This automatically splits the components and assigns them to the respective operations. That is, the you can allocate occurrences to usage mode process plan.
The Split and Merge Parts in BOM Based on Operation Allocations preference controls the split and merge behavior during part allocation process. The possible values are:
• None (default) – No split or merge is performed.
• Split and Merge – Performs splitting and merging parts based on operation allocations. The system splits part usages when only a few occurrences are allocated to operations. It also merges usages when the same part master is fully allocated to a single operation.
• Split – Splits part usages when only a few occurrences are allocated to operations.
• Merge – Merges usages when the same part master is fully allocated to a single operation.
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• Whenonly a few occurrencesof a part are allocated to operations (i.e., not all occurrences), the systemsplitsthe part usage. This means, the system creates separate usage links for the allocated occurrences, distinguishing them from the rest. For example, if a part has 10 occurrences and only 2 are allocated to Operation A, the system splits those 2 into a separate usage link
• Merge occursonlywhen the same part master isfully allocatedto a single operation.
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Key Points
• In usage mode of a process plan, when you fully allocate the same part master as a single operation, the system allocates the entire usage. You cannot allocate individual occurrences unless you distribute them. I
• Allocation Behavior—In a usage mode of a process plan, allocation behavior is governed by the Split and Merge Parts in BOM Based on Operation Allocations preference setting. When the preference is set to Split, the system automatically divides a multi-occurrence part into distinct usage links during allocation. For example, if a part has two occurrences—A1 and A2—and you select only A2 for allocation, the system splits the original usage into two separate links and allocates only A2 to the specified operation. If the preference is set to Merge, and you allocate A1 to the same operation as A2, the system merges the two distinct usage links into a single usage link, reflecting the combined allocation.
When the preference is set to Split and Merge, both behaviors are active: the system splits and merges usage links during allocation. The system displays the same behavior during the reallocation process.
Merge occurs only when the parts share the same parent assembly, path, and part master. In contrast, parts originating from different assemblies do not merge, even if they are identical. Allocation actions can be performed via drag-and-drop, copy-paste, or tree picker visualization. In visualization mode, disabling the Select Allocatable Parts setting allows you to allocate specific occurrences rather than the entire usage.
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When a part with multiple occurrences is partially allocated (e.g., only A2), the system creates a new usage link for the unallocated occurrences (e.g., A1). If the remaining occurrences are later allocated to the same operation, the system merges them into the original usage link, provided they share the same parent assembly path.
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• Reallocation merges parts only if the preference is set to Merge or Split and Merge. If the preference is set to None or Split, the system does not merge parts during reallocation.
• Operated-On Link Behavior—When you reallocate parts, you must handle operated-on links manually because the system does not retain them during reallocation or merge operations. Reallocation removes all existing operated-on links, and the system does not restore them automatically. Before reallocating, remove any operated-on links associated with the part. After reallocation, reapply the necessary links manually. For instance, if you allocate the first occurrence of a part to Operation 1 and the second occurrence to Operation 2, and then apply an operated-on link from the second occurrence to Operation 3, you must remove that link before reallocating the second occurrence to Operation 1. This behavior reflects a system limitation and requires careful handling to avoid unintended data loss. Always verify and clear operated-on links before reallocating, and re-establish them afterward as needed.
• The system allows you to allocate the same part across multiple operations for a generic process plan. This behavior is also known as overconsumption behavior. If you choose to overconsume, the system bypasses split and merge logic. In this case, the preference value is irrelevant. For more information, see Overconsumption of Part Allocations in Generic Process Plans.
• Limitations
◦ System does not split phantom parts; only leaf assemblies are eligible for splitting.