Lean Manufacturing Part 2

Kanban

• A system that uses replenishment signals to simplify inventory management– Signals (usually cards) hold product details

• What to make, when to make it, how much to make, and where to send it

– Cards stay attached to a bin that holds the product– When bin is empty, it is returned to the start of the

assembly line for replenishment– Full bins are returned to the customer, and the cycle

continues

The location where a predetermined standard inventory is kept to supply downstream processes.

Supermarkets are ordinarily located near the supplying process to help that process see customer usage and requirements.

Supermarket

---Learning to See

Kanban Example

Supermarket Ordering System

Benefits of Kanban

• Highly visible systems• Simple, effective, and inexpensive• Reduces inventory and eliminates stock-outs• Improves the quality of service• Improves lead times

Just-in-TimeJust-in-Time

• A carton of milk is removed from shelf

•A stock person restocks the empty location, but only brings what shelf can accommodate

•the supermarket combines visual control, pull system, Kanban, 5S

Supermarket Analogy

Single Minute Exchange of Dies (SMED)Method that focuses on the rapid conversion from

manufacturing one product to the next

Just-in-TimeJust-in-TimeQuick Changeover (Set-up Reduction)

Single Minute Exchange of Dies (SMED)•a series of techniques for changeovers of production machinery in less than ten minutes (single digit minutes)

Set-up Reduction Program Goals•To achieve smaller lots•To maintain consistent quality•To minimize inventory•To reduce lead times•To address frustration of setup personnel

Identify internal vs. external

changeover tasks

Analyze each task’s real

purpose and function

Focus on no/low cost

solutions

Aim to eliminate changeover

time

Just-in-TimeJust-in-TimeBasic SMED Principles

External elements of work can be completed while the machine is still running e.g. get the next tool, get all your clamps, get lifting equipment in place, put equipment away, etc.

Internal elements of work can only be done while the machine is stopped e.g. change the tool, adjust the machine depth, sharpen a tool (which requires the machine to be stopped), etc..

SMED Examples

SMED Examples

No/Low Cost Solution: One-Turn Methods

Pear-Shaped Hole Method

Tighten Here

Attach and Remove Here

Just-in-TimeJust-in-Time

No/Low Cost Solution: One-Turn Methods

Wing Nut Method

Just-in-TimeJust-in-Time

Benefits of SMED

• Increases throughput by reducing setup times• Eliminates setup errors• Increases safety• Reduces the cost of setups• Reduces waiting times and inventory buildups• Decreases the required skill level of the operators

Developing a Lean FactoryDeveloping a Lean FactorySummary - Just-in-Time

•Pull Systems/Kanban•Quick Changeover/Setup Reduction•Single Piece Flow•Takt Time

Lean Production System Goals - highest quality, lowest cost, shortest lead times

Heijunka Standardized Work Kaizen

Just-In-Time•continuous flow•takt time/pace•pull system•triggers

Jidoka•separate man & machine work•identify abnormalconditions•poka yoke

Stable Manufacturing Process

Involvement

JidokaJidokaQuality at the Source

•Source Inspection: Operators must be certain that the product they are passing to the next work station is of acceptable quality.

•Operators must be given the means to perform inspection at the source, before they pass it along.

JidokaJidokaQuality at the Source

Courtesy Sara Lee Intimate Apparel, Villanueva, Honduras

Source Inspection at Molding

JidokaJidoka

Courtesy of National Textiles

“Bull’s Eye” for checking package size

JidokaJidokaPoka-Yoke (Mistake Proofing)

A Poka-yoke device is any mechanism that either prevents a mistake from being made or makes the mistake obvious at a glance.

JidokaJidokaAndon

A visual management tool that highlights the status of operations in an area at a single glance and that signals whenever an abnormality occurs.An andon can indicate production status (for example, which machines are operating), an abnormality (for example, machine downtime, a quality problem, tooling faults, operator delays, and material shortages), and needed actions, such as changeovers. An andon can also be used to display the status of production in terms of the number of units planned versus actual output.

JidokaJidokaAndon

Courtesy of Sara Lee Intimate Apparel

Developing a Lean FactoryDeveloping a Lean FactorySummary - Jidoka

•Quality at the Source•Poka Yoke•Andons

Lean Production System Goals - highest quality, lowest cost, shortest lead times

Heijunka Standardized Work Kaizen

Just-In-Time•continuous flow•takt time/pace•pull system•triggers

Jidoka•separate man & machine work•identify abnormalconditions•poka yoke

Stable Manufacturing Process

Involvement

Leveling the type and quantity of production over a fixed period of time. This enables production to efficiently meet customer demands while avoiding batching and results in minimum inventories, capital costs, manpower, and production lead time through the whole value stream.

Heijunka

---The Lean Lexicon

A tool used to level the mix and volume of production by distributing kanban within a facility at fixed intervals. Also called a leveling box.

A load-leveling box has a column of kanban slots for each pitch interval, and a row of kanban slots for each product type.

Heijunka Box

---Learning to See

The practice of releasing production instructions to work areas and withdrawing completed product from work areas at a fixed, frequent pace.

In this type of handling system, a material handler, or waterstrider, performs a route through a facility at precisely determined time intervals.

Paced Withdrawal

Standardized Work

Establishing precise procedures for each operator’s work in a production process, based on three elements:

1. Takt time, which is the rate at which products must be made in a process in order to meet customer demand.

2. The precise work sequence, in which an operator performs tasks within takt time.

3. The standard inventory, including units in machines, required to keep the process operating smoothly.

--- The Lean Lexicon

Takt Time = 10 seconds

StandardizationStandardization

House of Lean