Is high WIP always bad?

In discrete manufacturing, almost always. Some WIP is necessary to keep bottlenecks fed; everything above that is cash tied up in lead time.

How do you reduce WIP without starving the floor?

Release work in pace with bottleneck capacity (drum-buffer-rope, CONWIP) and use the freed time to perform setup reduction and preventive maintenance.

What is the relationship between WIP and OTD?

Inverse, at the levels typical in discrete shops. Lower WIP shortens lead time, which makes promise dates more achievable, which raises OTD.

Work-in-Process (WIP) — Manufacturing Scheduling Glossary

Definition

Work-in-process (WIP) is the dollar value or operation count of all jobs that have been started on the floor but not yet completed and shipped. It is the inventory between raw material and finished goods, and it is the most direct measure of how much work is "stuck in the system" at any moment.

Why it matters

High WIP is usually a symptom of poor scheduling, not too much demand. Jobs released earlier than the bottleneck can absorb them stack up as queue. Average lead time grows in proportion to WIP (Little's Law). Reducing WIP by half typically halves lead time and improves on-time delivery without adding capacity.

Common failure mode

The shop releases all work orders to the floor as soon as material arrives, on the theory that "operators need work to do." The bottleneck builds a 3-day queue. Every job behind it waits 3 days longer than it should. Customers wonder why a 2-week job takes 5.

How Skody approaches it

Skody releases work to the floor only when downstream capacity can absorb it, and synchronizes upstream operations to the bottleneck rhythm. WIP drops, lead time drops, and operator visibility into "what is actually next" improves.

Queue Time

The time a job waits in front of a work center before it actually starts processing.

Queue Buildup

The growth of work waiting in front of a resource when arrival rate exceeds processing rate.

Bottleneck

The resource whose limited capacity governs the throughput of the whole factory.

Load Balancing

Distributing work across alternate resources so no single machine is overloaded while others sit idle.