Download - Lean manufacturing
Muthu Naveen S
-maximizing profits by reducing waste…
What is lean?? Fundamental objective:
To create the most value while consuming the fewest resources.
How is the objective accomplished?
Lean production is aimed at the elimination of waste in every area of production while producing top quality products in the most efficient and economical manner possible
SEVEN TYPES OF WASTE
WASTE
- one that adds no value to product
TYPES
• Waste due to over production
• Waste due to waiting time
• Waste due to transportation
• Waste due to processing
• Waste due to inventory
• Waste due to motion
• Waste due to defects
LEAN MANUFACTURING PRINCIPLES
cell design (takt) • team roles/resp/rules • kanban • work instruction • 5s housekeeping • one piece flow
SMED • Poka-yoke • TPM • SPC • Continuous improvement
Mix Model manufacturing • FMEA • DFMA • Process Capability • Make to order
CELL DESIGN
Arrangement of resources
Improve process flow & eliminate waste
Design considerations :-
•Adaptation of process to fit takt time
• Reduce material and operator movement
• Eliminate storage, multiple handling, wait time
• Material flow in one direction only
• Layout machines by process sequence
Takt Time = Demand Rate
Takt Time = Work Time Available
1200 Seconds
120 Boards = 10 Sec/Board Takt Time =
Cycle Time
Takt Time = Minimum no of Cells
Number of Units Sold
TAKT TIME
Optimize the Bottlenecks
•Reduce batch sizes
–Eliminate uneven amounts of work
•Put the best people on the bottlenecks
–They set the pace
0
5
10
15
20
A B C D E
Operation
Unbalanced Line
0
5
10
15
20
A B C D E
Operat ion
Balanced Line
Takt Time = 10 seconds
BALANCED PROCESS
Inv Inv
Inv
Inv
C
D E
B Inv A
A
Inv A
A Inv
A
Inv
Inv
Inv
Inv B
B
Inv Inv B Inv
C
C
C
C
Inv
Inv Inv Inv Inv
E
E
E
D
D
D
D
Dept “A” Dept “B” Dept “C”
Dept “E” Dept “D”
D E
C
B A
D E
C
B A
Stage 1
Production in Specialized Departments
Stage 2
Production in Product Cell
Stage 4
Production in Compact Cell with One-Piece Flow and
Separation Man/Machine
Stage 3
Production in Compact Cell with One-Piece Flow
CELL LAYOUT
5S – HOUSEKEEPING
1s - Seiri (Sorting)
2s - Seiton (Straighten or Set in Order)
3s – Seiso (Shine)
4s - Seiketsu (Standardizing)
5s - Shitsuke (Sustaining)
BEFORE 5S AFTER 5S
•Push System
–Resources are provided to the operator based on forecasts or schedules
•Pull System
–A method of controlling the flow of resources by replacing only what has been consumed
PUSH Vs. PULL SYSTEMS
Pull System Flow Diagram
Information Flow
Supplier
Raw
Matl Process
A
Process
B
Fin.
Goods
Kanban
Locations
Process
C Customer
Parts Flow
Definition: Minimizing the time from last good piece of the current product run to first good piece of the next (different) product run
SINGLE MINUTE EXCHANGE OF DIES (SMED)
Separate Internal and
External Setup
Convert Internal Setup to
External Setup
Streamline Internal and
External Elements
Three stages
Transition Steps to Quick Changeover
Preliminary Step 1 Step 2 Step 3
Internal and
External Setup not
differentiated
Separate Internal
and External
Setup
Convert Internal
Setup to External
Setup
Streamline all
aspects of Setup
operations
Ext
Int
Ext
Int
Ext
Ext
Int
Int
Ext
Int
Ext
Int
Pear-Shaped Hole Method
Tighten Here
Attach and
Remove Here
POKA-YOKE
Poka-yoke is a Japanese term that means "fail-safing", "Foolproof" or "mistake-proofing". It is a method of preventing errors by putting limits on how an operation can be performed in order to force the correct completion of the operation.
The three types of poka-yoke are: The contact method which identifies defects by whether or not
contact is established between the device and the product. Color detection and other product property techniques are considered extensions of this.
The fixed-value method which determines whether a given number of
movements have been made. The motion-step method which determines whether the prescribed
steps or motions of the process have been followed
Guide Pins and Cutouts (that limit orientation)
CutoutGuide Pins
Correctly Oriented Incorrectly Oriented
Example - 1
Example - 2
Total Productive Maintenance
Total Productive Maintenance (TPM) is an equipment management program that emphasises operator involvement and ownership of equipment performance.
Goals of TPM:
• Improving equipment effectiveness
• Improving maintenance efficiency and effectiveness
• Early equipment management and maintenance prevention
• Training to improve the skills of all people involved
• Involving operators in routine maintenance
Pillars of TPM
Productivity: – Increases • * Labor & productivity. * Value added per person. * Rate of operation. – Reduces • * Breakdowns.
Cost: Reduction in * man power. * maintenance cost and * conservation of energy.
Delivery: Reduced stock Inventory turn over increased. Quality:
– Reduces • * Defects of in-process material. * Defects in processed material.
Safety: Zero accidents. Zero pollution.
Benefits of TPM
FAILURE TAGS
FAILURE MODE AND EFFECTS ANALYSIS
A failure modes and effects analysis (FMEA) is a procedure for analysis of potential failure modes within a system for classification by severity or determination of the effect of failures on the system
Why we use FMEA?
•Increase probability of DETECTION
•Identify biggest contributor to failures
and eliminate them
•Reduce probability of failure occurring
•Build quality into the product & process
Preparation FMEA Process Improvement
a. Identify the ways in which process inputs can vary (causes) and identify associated FAILURE MODES. These are ways that critical customer requirements might not be met. b. Assign severity, occurrence and detection ratings to each cause and calculate the RISK PRIORITY NUMBERS (RPNs). c. Determine recommended actions to reduce RPNs. d. Estimate time frames for corrective actions. e. Take actions and put controls in place. f. Recalculate all RPNs.
• Tackle highest RPN’s first • Reduce the occurrence • Improve the detection • Where possible apply mistake proofing techniques. • Note :- Mistake proofing process will result in either lower occurrence or detection rankings • Standardization across all products or processes • Employ PDSA cycle
NECESSARY ACTIONS
Design For Manufacture and Assembly (DFMA)
DFMA is a proactive and concurrent design process that allows for early consideration of manufacturing aspects The purpose is to generate an environment where a cross-functional team works together to optimize the design for cost effective manufacturing It is established by design and manufacturing engineers working together
Minimize the number of parts Minimize the number of fasteners Avoid difficult components Use modular subassemblies Use multifunctional parts Minimize reorientation Use self-locating features Avoid special tooling/test equipment Provide accessibility Minimize operations & process steps
DFMA Principles
Bushes are integral to the base Snap-on plastic cover replaces standoff ,cover ,plastic bush, six screws. Using pilot point screw to fix the base, which redesign to be self-alignment.
CONCLUSION
Lean
• Simple and Visual
• Demand Driven
• Inventory as Needed
• Reduce Non-Value-Added
• Small Lot Size
• Minimal Lead Time
• Quality Built-in
• Value Stream Managers
Traditional
• Complex
• Forecast Driven
• Excessive Inventory
• Speed Up Value-Added Work
• Large Batch Production
• Long Lead Time
• Quality Inspected-in
• Functional Departments
Ultimate aim of lean – “better production with fewer resources”
Got Any Questions??