LEAN MANUFACTURING L ean manufacturing is a manufacturing philosophy that shortens the time between customer order and the product by eliminating sources of waste Waste Is anything that adds to the time and cost of making a product but does not add value to the product> Lean thinking focuses on value added flow and efficiency of the overall system and synchronizing operations so they are aligned and producing at a steady pace THE SEVEN WASTES –MUDA- Lean= م ح ل دون ب ن ه د,
Transcript
LEAN MANUFACTURING
L ean manufacturing is a manufacturing philosophy that shortens the time between
customer order and the product by eliminating sources of wasteWasteIs anything that adds to the time and cost of making a product but does not add value to the product>
Lean thinking focuses on value added flow and efficiency of the overall system and synchronizing operations so they are aligned and producing at a steady pace
THE SEVEN WASTES –MUDA-
Lean= دهن بدون لحم ,نحيل
Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
Factor Description Impact Improvement1- Over-
production
Unnecessarily producing more than demanded
Producing it too early before it is needed
↑ risk of obsolescence
↑ risk of producing wrong thing
↑ Possibility of having to sell those items at a discount or discard them as scrap.
2- Waiting Waiting is idle time for workers or machines due to bottlenecks or inefficient production flow on the factory floor.
↑ Costs e.g. labor costs
Equipment and time-scales planned ahead
3- Over-processing
Over-processing is unintentionally doing more processing work than customer requires in terms of product quality or features such as polishing or applying finishing on some areas of a product that won’t be seen by a customer
Elimination of unnecessary steps in process
4- Transportation
Transportation includes any movement of materials between processing stages that does not add any value to the product, such as moving materials between workstations.
↑production cycle times
Inefficient labor and space
Minor production stoppages
↓ Weight/size of pieces to ease handling
5- Motion Motion includes any unnecessary physical motion or walking by workers which diverts them from actual processing work.
For example o Include walking around factory floor to
look for a toolo Difficult physical movements, due to ↓
designed ergonomics which slow down the workers
Slow down the work
Use effective project planning to ensure efficient performance
6- Defects Physical defects which is directly add to the costs of goods sold
Exampleso Errors in paperworko Late deliveryo Production to incorrect specificationo Use of too much raw materials or
generation of unnecessary scrap
Reworking waste times and materials
Computer modeling minimizes trial failures
7- Inventory Having unnecessary high levels of raw materials, work in progress and finished product
↑ inventory financial costs
↑ storage costs ↑ defect rates
Ensure suitable customer outlets available to buy products so no build up of stock occurs
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Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
1. 5S (HOUSE KEEPING)
Its purpose is to create and maintain an organized, clean, safe and higher performance workplace.Composed of 5 steps:
1. Seiri (Sort)Clearly distinguish needed items from unneeded items using red tags
2. Seiton (Set in order / Straighten)Arrange needed items in a manner which will make them easy for anybody to retrieve when required
3. Seiso (Shine)To remove the dirt and dust from the working areas as a whole.
4. Seiketsu (Standardize)To look after a certain area in such a way to prevent it from getting dirty again.
5. Shitsuki (Sustain)To ensure these standards remain consistent and effective.
2. KANABAN
Kanaban literally means “signboard” or “billboard”, is a concept related to lean and just-in-time (JIT) production.According toTaiichi Ohno, the man credited with developing JIT, Kanaban is one mean through which JIT is achieved.
Kanabans are usually cards, but the can be flags or a space on the floor
3. PULL SYSTEM
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Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
Pull systems control the flow of resources in a production process by replacing only what has been consumed
They are customer order-driven production schedules based on actual demand and consumption rather than forecasting
Implementing Pull system can help you eliminate waste in handling, storing and getting your product to the customer
Push Pull –Customer triggered production-Make all just in case Make what’s needed when we need it
1. Production approximation 2. Anticipated usages3. Large lots 4. High inventories 5. Waste 6. Management by firefighting 7. Poor communication
1. Production precision 2. Actual consumption 3. Small lots 4. Low inventories5. Waste reduction 6. Management by sight 7. Better communication
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Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
4. JIDOKA
It is described as “intelligent automation” or “automation with a human touch” This type of automation implements some supervisory functions rather than
production functions At Toyota this usually means that if an abnormal situation arises the machine stops
and the worker will stop the production line Autonomation = Autonomous بذاته Automation + مستقلMan character is the difference between automation and autonomation
Machine Man Can do repetitive tasks No intelligence
Repetitive tasks errors Intelligence
Build intelligence into machine Autonomation prevents the production of defective products, eliminates
overproduction and focuses attention on understanding the problem and ensuring that it never recurs
It is a QC process that applies the following four principles1. Detect the abnormality 2. Stop 3. Fix or correct the immediate condition 4. Investigate the root cause and install a countermeasure
The purpose of auatonomation is that it makes possible the rapid or immediate address, identification and correction of mistakes that occurs in a process
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Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
Autonomation relieves the need for the worker to continuousl judge wether the operation of the machine is normal; their effort are now only engaged when there is a problem alerted by the machine.
So the difference between automation and jidoka Category Automation Jidoka “autonomation”
People Work easier but people still “machine watching”
Productivity improves when people are multi-process handers
Machines Machines run to end of cycle or until stop button is pushed
Machines can detect errors and stop autonomously
Quality Machines crashes and mass production of defects can occurs
Defects and machine crashes are prevented by auto-stop
Response to problems
Errors are found later, root cause correction takes longer
Errors cause machine to stop and root cause can be found quicker
Jidoka has three components
1- FULL WORK SYSTEM
2- ANDON
Is a manufacturing term referring to a system to notify management, maintenance and other workers of a quality or process problem
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The centerpiece is a signboard incorporating signal lights to indicate which workstation has the problem
The alert can be activated manually by a worker using a button, or may be activated automatically by the production equipment itself
Some modern alert systems incorporate audio alarm, text or other displays
An andon system is one of the principal elements of the Jidoka Quality-Control method pioneered by Toyota as part of the TPS and therefore now part of the Lean approach
Another example of andon system usage is fire fighting system that locate the places of fire.
Also andon lights are found in a lot of machines to signal its status
3- POKE YOKE
Poke-yoke is a Japanese term for “mistake-proofing” Any operation that relied on human element will run into the problem of errors Even by applying 100% inspection, you will never catch more than 80% of errorsThe
success of poka-yoke is to provide some intervention devices or procedures to catch the mistake before it is translated into non conforming product
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Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
The desired outcomes from poka-yoke can be categorized into the following four perspectives:
1. Personnel –Creative2. Process – Right at first time3. Quality -Zero defects4. Mistake – Zero error
5. ONE PIECE FLOW
One piece flow means production of the product moves from one stage to the next stage one piece at a time.
Compare that to lot production where several units are made at a given stage and then all are moved to the next stage at the same time
Most operational excellence practitioners promote one piece movement
One piece movement benefits the manufacturer because there is no idle time between the units
With lot production the first piece made cannot move to the next step until the last piece in the lot is
made so that first piece sits idle To implement one piece flow, connect and synchronize each individual activity
process to eliminate the seven categories of waste This requires improved layouts to minimize the travel distance between successive
operations. In addition the company may implement work cell sot implement one piece work flow
Create and link U-shaped work cells to complete all process activities in the minimal amount of physical space.
The principals of good work cell layout include arranging the work sequentially, locating machines and process close together, and locating the last operation close to the first operation.
8. KAIZEN
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Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
Kaizen is a Japanese work for continuous improvement Kai “change” + Zen “good” This is usually referred to as incremental improvement but on a continuous basis and
involving everyone Western management is enthralled with radical innovation, the enjoy seeing
breakthroughs
The Kaizen strategy involves o Kaizen management: maintain and improves operating standards o Process versus result o Use PDCA cycle: method of improvemento Quality first o Speak with datao The next process is the customer
While most kaizen activities are a long term nature by numerous individuals, a different type of kaizen strategy called “Kaizen Blitz” involves a kaizen activity in a specific area within a short time period
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Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
9. SMED SETUP REDUCTION
It stands for “single minute exchange of die” The concept is to take a long setup change and reduce it to a single digit of time (nine
minute or less)There are 2 myths regarding setup times:
1- The skill for setup changes comes from the practice and long term experience 2- Long run production is more efficient, it saves setup times and uses productive
capacity SMED is a system that reduce the dependence on longtime experience of operators Long run production can lead to excess inventory and extra storage
The first step is to distinguish between internal and external setup SEQ
Start time
Event Elapsed
time
Int. Ext.
1 0 Shut down machine 0:30 0:30
2 0:30 Get machine parts 3:00 3:00
3 3:30 Remove change parts 3:30 3:30
4 7:00 Place mew change parts on machine
3:30 3:30
5 10:30 Return change parts to storage 3:00 3:00
6 14:30 Load material onto machine 1:00 1:00
7 15:00 Generate test piece 0:30 0:30
8 17:00 Measure and inspect 2:00 2:00
9 18:00 Adjust dies 1:00 1:00
10 18:30 Generate test piece 0:30 0:30
11 18:30 Measure and inspect 1:30 1:30
12 20:00 Generate first good piece 1:00 1:00
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What is internal setup?It’s the type of setup that must be done when the machine is shut downWhat is external setup? It’s the type of setup that can be
Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
Total time of setup 21:00
The second step is to re-examine the existing internal setup elements and try to convert more of those elements into external setup.
10. TAKT TIME
It is a term used to define a time element that equals to the demand rate of customer “Takt is a German word for baton used by orchestra conductor This provides a rhythm to the process, similar for heart bean
Takt Time=Net operating time per periodCustomer demand rate
Example Total available time / shift = 480 mins/shift Break = 60 mins/shift
o Net operating time = 480-60=420 mins/shift o Customer demand/ shift (day) = 300 pieces
Takt time = 420mins/ day / 300 units / day = 1.4 mins/unit Every step in the production process must now deliver their contribution to the
product in about 84 seconds
What if there’s a step that can’t deliver in 84 seconds?- Then we have a bottleneck, we’ll produce and sell less than we could
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Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
What if there’s a step that can deliver in less than 84 seconds?- They still deliver every 84 seconds, even if they have to slow down. If they delivered
more frequently we’d build up lots of work in process as other steps can’t use its output faster than once every 84 seconds
Slowing down? Isn’t that inefficient - Yes, but not optimizing the efficiency of a single step. We’re optimizing the whole
value stream.- If a step has a lot of space capacity, this could be used to work on another product,
but only if it doesn’t endanger the delivery of the first product
Case study A line has 5 operators. The times allocated for each station are indicated below:If the takt time for the line is 60 seconds, what’s your observation?ObservationOperator 4 exceeds the takt time and will not be able to maintain the pace
Option 1 Option 2 Option 353 66.25 6053 66.25 6053 66.25 6053 66.25 6053 -- --265 265 240Balance line 7 seconds of slack for each operator
Reduce number of operators and redistribute work load
Eliminate non value added time using kaizen (improvement)
11. TOTAL PRODUCTIVE MAINTENANCE
TPM has the following meanings:1- Total effectiveness in the pursuit of economic
efficiency and profitability 2- It includes preventive maintenance 3- Total participation of all employees
The objectives of TPM are Zero Breakdowns and Zero Defects
Six big losses that have negative impact on machine effectiveness :
1- Equipment failure (down time)2- Setup and adjustment3- Minor stoppages4- Reduces speed5- Process defects (scrap)6- Reduced yield (start up losses)
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Operator
Work time (sec)
1 452 403 604 705 50
Total 265
Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
TPM
METRICS
Overall equipment effectiveness is the prime measure used to evaluate TPMOEE = Availability * Performance * Quality
Availability: it takes into account Down Time Loss, and is calculated as:Availability= Operating time/planned production time
Performance takes into account speed loss, and is calculated as Performance = (total pieces/operating time) / ideal run rate
Quality: quality takes into account quality loss and is calculated as Quality = good pieces / total pieces
EXAMPLE OEE CALCULATION
The data from a process of cream filling was gathered, determine its OEE and evaluate your output
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Item DataShift length
8 hours = 480 min
Short breaks
2 @ 15 min = 30 min
Meal break 1 @ 30 min = 30 min
Down time 47 minIdeal run rate
60 pieces per minutes
Total pieces
19,271 pieces
Reject pieces
423 pieces
Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
Solution Planned production time = (shift length – breaks)
= 480-60= 420 minOperating time = (planned production time – down time)
Lean Manufacturing ToolsSix Sigma Black Belt Dr. Michael Atef
12. VALUE STREAM MAPPING
Technique used to analyze and design the flow of materials and information required to bring a product or service to a consumer across multiple processes
How to implement it ?1- Identify the target product 2- Draw while on the shop floor a current state value stream map, which shows the
current steps, delays and information flows required to deliver the target product or service
3- Assess the current state value stream map 4- Draw a future state value stream map5- Work toward the future state condition
In a build-to-the-standard from Shigeo Shingo suggest that the value-adding steps be drawn across the centre of the map and the non-value-adding steps be represented in vertical lines at right angles to the value stream
Thus the activities become easily separated into the value stream which is the focus of one type of attention and the “waste|” steps another type. He calls the value stream the process and the non-value streams the operations
Information flow moves form right to the left on the top half of the map Materials flow moves from left to right on the bottom half of the map In the map there are process boxes, which have a process data box underneath each
one of them which has information such as: yield changeover time (C/O), equipment reliability (Rel), process time (P/T), uptime “percentage of time that the machine is available for processing and lead time (L/T)
The bottom of the map shows a staggered timeline that compares the processing time (cycle time) for a job to the production lead time of the entire system.
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13. THEORY OF CONSTRAINTS
Goldratt authored a book titled “The Goal” which introduced a system of thought on the theory of constraints
Constraint management could be described as removing bottlenecks in a process that limits production or throughput
Some important definitions according to TOC Bottleneck resources: resources whose capacity is equal or less than the demand
places upon it.Throughput: the rate at which the system generates money though sales (money
coming in)Inventory: all the money that the system has invested in purchasing things which it
intends to sell (money stuck inside)Operational expenses: all the money that the system spends in order to turn
inventory into throughput (money going out) The primary TOC mindset for managing a constrained system is called “Drum – Buffer
– Rope” Drum: is the physical constraint of the system or the “component or operation that
limits the ability of the entire system to produce more” the entire system must march to the beat of the drum.
Buffer: protects the drum from inactivity, so that it always has work flowing to it.Rope: is the work release mechanism for the plant to prevent build up of inventory
and WIP.
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Hence the TOC process seeks to identity the constraint and restructure the rest of the organization arount it, trying to break the constraint.
