Just-In-Time (JIT) Production

Just-in-Time production is a practice within lean manufacturing that makes items “just” at the time demand requires, and not for surplus inventory; its purpose is waste minimization.

JIT's Origins: Toyota Production System or Lean Manufacturing?

Just-in-time manufacturing is a key principle of both the TPS and Lean methodologies, and because they tend to overlap, it is difficult to pinpoint the exact birthpoint of JIT philosophy.

Both TPS and Lean have similar goals: the elimination of waste, the standardization of production processes, and a pull methodology for supply chain management.

JIT is a critical element of both – and more – processes.

Contributing Authors to Lean Manufacturing in History

It would be reductive to contribute JIT to a single inventor because there are so many talented participants in creating lean manufacturing as a discipline. Here are some basic differentiations:

• Frederick Taylor – American mechanical engineer for industrial efficiency, operating in the period from the late 19th C to 1915; most known for proposing Scientific Management
• Henry Ford – famous industrialist magnet, Ford invented the Model T, which revolutionized the automobile and transportation industries in the United States in the early 20th C
• Shigeo Shingo – post-war pioneer of Japanese factory management and industrial engineering in Toyota
• Taiichi Ohno – the key industrial engineer behind the creation of the Toyota Production System, which later became the lean manufacturing trend in North America

Some Key JIT Principles

Just-In-Time is more of a philosophy than a checklist, but here are the most foundational elements of JIT. Keep in mind, however, that this list is not exhaustive, and other elements of JIT manufacturing may be more frequently used than others – or not at all – depending on the industry.

Housekeeping

Standard workplace structure and organization, like shift exchange and administrative protocol

Making right the first time

Aiming for the least wasteful and most efficient design and production plan to lower the overall frequency of defects

Setup reduction

Preparing for flexible machinery changeover in least amount of time possible

Uniform plant load

Setting consistent standards of production for reliable output

Balanced Flow

Organizing production flow from beginning to end including interdepartmental communication

Skill diversification

Applying multi-functional skillset development within the workforce

Visual process control

Relying on a stable platform for visual instructions, like work instruction software for assembly operations to ensure quality control

Preventive Maintenance

Operating machinery should be optimized before functioning to eliminate the possibility for failures as much as possible

Usability

The ease of the production process, measured by DFMEA

Compact plant layout

Interior design layout optimized the development of a product’s life cycle in assembly

Streamlined movements

Smooth material handling for least possible human disruption or contamination

Supply networks

Viewed as extensions of factory life cycle

Worker cells

Also known as cellular manufacturing, the organized division of labor including small group responsibilities

Pull manufacturing

As opposed to push manufacturing, pull is when demand dictates the flow of production in order to best meet expectations with least waste possible

Foundational Theme of JIT: Standardization

These days, when it comes to manufacturing methodologies, JIT is pretty much synonymous with lean manufacturing as a guiding principle. Astute readers of this lexicon will notice that many terms tend to overlap. These conceptual differences, from JIT to lean to Six Sigma, have a common constant that defines their occupational success: standardization.

Standardization is an overarching application of Standard Operating Procedures (SOPs) for an entire department or process that needs to be reliably consistent. Standardization is critical to ensure product uniformity regardless of production date or time.

A great example of improvements from standardization is the increased productivity and quality control when using VKS visual work instructions on an assembly line – the coordinated, accessible visuals support the maintenance of a diligent and replicable production process.