work in process

Operational meaning

Work in process (often abbreviated WIP) refers to all partially completed products, subassemblies, or lots that are currently moving through a manufacturing process but have not yet been converted into finished goods. It includes:

– Material that has been released to production and undergone at least one value-adding step
– Units or lots waiting at intermediate steps (queues, buffers, inspection points)
– Items temporarily held for rework, additional operations, or in‑process testing

In most accounting and planning usages, work in process sits between raw materials and finished goods in inventory classifications.

Use in manufacturing and operations

In industrial and regulated environments, work in process commonly refers to:

– **Shop floor status:** What is actively being manufactured on lines, cells, and work centers.
– **Production control:** The quantity and location of in‑process units for each order, batch, or lot.
– **Traceability:** The link between materials, process steps, parameters, and quality records for items that are not yet finished.
– **Execution systems:** Items represented as in‑process operations or steps in MES, LIMS, or batch systems.

Systems may model work in process at different levels of granularity, such as individual serial numbers, containers, pallets, or process orders.

Boundaries and exclusions

Work in process generally **includes**:

– Released orders, batches, or lots that have started at least one operation
– In‑process inventory held between operations (queues, staging areas)
– Units undergoing rework or additional processing steps

It typically **excludes**:

– Raw materials and purchased components that have not entered a production operation
– Finished goods that have completed all required processing and are available for shipment
– Tools, fixtures, and spare parts (these are not WIP inventory)

In some accounting practices, very short‑cycle or continuous processes may treat all production as work in process until formal transfer to finished goods, but the conceptual boundary remains the same: items are in an incomplete manufacturing state.

Common confusion and terminology

Two similar phrases are used:

– **Work in process (WIP):** More common in discrete and assembly manufacturing, and in operations/lean discussions.
– **Work in progress:** Often used interchangeably, especially in accounting, though some organizations reserve it for long‑duration projects.

In most manufacturing and MES/ERP contexts, the two terms are treated as synonyms. When precision matters, organizations may define them differently in internal procedures or accounting policies.

Work in process is also sometimes confused with:

– **Workload or labor capacity:** WIP refers to physical product inventory in process, not staff utilization.
– **Backlog:** Backlog is ordered work not yet started. Once material is released and processing begins, it becomes WIP rather than backlog.

Site context: work in process and mid‑shift changes

In regulated operations, work in process is a key concept when handling mid‑shift engineering changes or specification updates. At the change cutover point, teams typically:

– Identify which units or lots are **existing work in process** under the old configuration
– Segregate or label new work in process started under the new configuration
– Ensure MES/ERP, batch records, and labels distinguish old vs. new WIP for traceability

Accurately defining and controlling work in process at the moment of change helps maintain clear genealogy and avoid mixing configurations, especially when batches, orders, and documentation states overlap on the shop floor.