Chapter 7: Lean System

Group technology

(1) A methodology for classifying parts (items) based on similar production processes and required resources. (2) A manufacturing cell (cluster of machines, equipment, and workers) dedicated to making a set of parts that share similar routings.

Value stream map

A simple process mapping methodology developed at Toyota Motor Company that highlights waste in a system

Pull systems

A system that determines how much to order and when to order in response to customer demand, where the customer may be either an internal or external customer.

Toyota Production System (TPS)

An approach to manufacturing developed by Eiji Toyoda and Taiichi Ohno at Toyota Motor Company in Japan; some people use TPS synonymously with lean thinking60.

Bottleneck

Any system constraint that holds the organization back from greater achievement of its goals.

Setup cost

In a manufacturing context, the cost to prepare a process (e.g., a machine) to start a new product; in a purchasing context, the cost to place a purchase order; also known as the changeover cost or order cost.

Jidoka

The Toyota Production System practice of designing processes and empowering workers to shut down a process when an abnormal condition occurs; sometimes called autonomation.

Takt time

The customer demand rate expressed as a time and used to pace production

Standardized work

The discipline of creating and following a single set of formal, written work instructions for each process; also called standard work.

Job rotation

The movement of workers between different jobs in an organization.

Kaizen, Kaizen event

small process improvement projects usually done in less than a week.

7 wastes

1. Overproduction - Producing more than what is needed or before it is needed. 2. Waiting - Any time spent waiting for tools, parts, raw material, packaging, inspection, repair, etc. 3. Transportation - Any transportation of parts, finished goods, raw materials, packaging, etc. Waste is particularly apparent here when materials are moved into and out of storage or are handled more than once. 4. Excess processing - Doing more work than necessary (e.g., providing higher quality than needed, performing unneeded operations, or watching a machine run). 5. Inventory - Maintaining excess inventory of raw materials, in-process parts, or finished goods. 6. Excessive motion - Any wasted motion or poor ergonomics, especially when picking up or stacking parts, walking to look for items, or walking to look for people. 7. Defects (correction) - Repair, rework, recounts, re-packing, and any other situation where the work is not done right the first time.

Heijunka

A Japanese technique used to smooth production over time; also called load leveling, linearity, and stabilizing the schedule.

Gemba

A Japanese term for the actual place where "real" work takes place; sometimes spelled genba

Muda

A Japanese word for waste used to describe any activity that does not add value.

Buffer management

A Theory of Constraints (TOC) concept of strategically placing "extra" inventory or a time cushion in front of constrained resources to protect the system from disruption.

Drum-buffer-rope

A Theory of Constraints (TOV) concept that sends a signal every time the bottleneck completes one unit, giving upstream operations the authority to produce

Master production schedule (MPS)

A high- level plan for a few key items used to determine the materials plans for all end items; also known as the master schedule.

Single Minute Exchange of Dies (SMED)

A lean manufacturing methodology for reducing setup time to less than a single digit (e.g., less than 10 minutes); also called Single Minute Exchange of Die and rapid changeover.

Once-piece flow

A lean manufacturing practice of making only one part at a time (a batch size of one) before moving the part to the next step in the process; also called single-piece flow, make-one-move-one, and one-for- one replenishment.

5s

A lean methodology that helps organizations simplify, clean, and sustain a productive work environment. (sort, set in order, shine, standardize, sustain)

Kanban

A lean signaling tool developed by Toyota that indicates the need for materials or production.

Andon light

A lean term (pronounced "Ann-Don") that refers to a warning light, warning board, or signal on (or near) a machine or assembly line that calls attention to defects or equipment problems; also called an andon board; the Japanese word for andon (行灯) means "lamp."

Theory of Constraints (TOC)

A management philosophy developed by Dr. Eliyahu M. Goldratt that focuses on the bottleneck resources to improve overall system performance.

Lean manufacturing

A philosophy and set of practices originally developed at Toyota that seeks to eliminate waste; also known as lean manufacturing or just lean.

Just-in-time (JIT)

A philosophy developed by Toyota in Japan that emphasizes manufacturing and delivery of small lotsizes only when needed by the customer.

Setup reduction methods

Procedures used to reduce the time and cost to change a machine from making one type of part or product to another; also called Single Minute Exchange of Die8 4 and rapid changeovers.

Facility layout

The physical organization of processes in a facility.

Mixed model assembly

The practice of assembling multiple products in small batches in a single process.

Multiple machine handling

The practice of assigning workers to operate more than one machine at a time. This is a common Japanese manufacturing practice that is made possible by the application of jidoka and error proofing principles. Chaku-Chaku is an application of this principle.

Setup time

The time required to prepare a machine for the next order; also called changeover time.

Cellular manufacturing

The use of a group of machines dedicated to processing parts, part families, or product families that require a similar sequence of operations.

Job enlargement

This is also called horizontal job enlargement and adds similar tasks to the job description. In other words, the worker is assigned more of a co-worker's job. For example, the worker who cleans sinks also is assigned to clean the toilets.

Cross-training

Training workers in several different areas or functions outside their normal job responsibilities.