Six Sigma Value Stream Mapping

What is Value Stream Mapping?
VSM is a pencil & paper tool that helps to see & understand the flow of material & information as a product or service makes its way through the value stream.


Why VSM?

• It is a Blueprint for improvement.
• Clear Focus on the Customer
• Best Tool to document current state
• Clear communication of current state to generate
• Easy to identify wastes
• Avoids Sub-optimizing the process

LEAN Basic Tools Concepts - Part 7

VISUAL PROCESS CONTROLS

Purpose - Displays and visual markers that:
•Establishes and posts work priorities
•Visually displays whether expected daily, weekly, monthly work performance/goals were met or not
•Allows for better understanding of work flow and inputs
•Quickly identifies abnormal conditions
•Displays standardized methods in use
•Communicates performance measures
•Displays the status of elements critical to safe and effective operations
•Provides feedback to/from team members, supervisors, management
•Eliminates or reduces the need for meetings

When to use it - Pretty much always

How to do it -
Production Summary Boards (Takt Boards): Monitors the output of a process step or process in order to judge if it is meeting customer demand. Takt boards should provide this information:
- The specific work being done
- The desired speed or completion rate
- Actual completion rate

LEAN Basic Tools Concepts - Part 6

PROCESS BALANCING

Purpose: To balance work across different sub processes
When to use it : When lead time is a problem
How to do it
•Minimize movement
•Stabilize lead time before trying to minimize it
•Maximize resource efficiency
•Minimize number of process steps
•Balance tasks/labor across process steps
•Maximize space utilization
•Minimize Non-Value Add activities (conveyance, standby and motion wastes)
•Minimize the need to rebalance as demand requirements change
•Minimize volume variability (combine product category demand)
•Maximize flexibility for product introductions and discontinuations
•Use training and continual reinforcement to maintain gains

WORK CELL OPTIMIZATION
Purpose - To reduce the time needed to complete a task or set of tasks and reduce mistakes
When to use it - To reduce inefficient workflow (i.e. too much movement of material and/or people)
How to do it - Will never get the design perfect the first time – get it in place then use operator feedback and continuous improvement

LEAN Basic Tools Concepts - Part 5

TOTAL PRODUCTIVE MAINTENANCEPurpose: To reduce scheduled and unscheduled down time from typical levels of 30% to below 5%
 
Preventive Maintenance: Maintenance that occurs at regular time or usage intervals
Predictive Maintenance: Maintenance that is performed based on signals or diagnostic techniques

•TPM Metrics
Operation Equipment Effectiveness or OEE = Availability Level X Operating Level
X Quality Level
MTTF: Mean time between failure
MTTR: Mean time to repair

When to use it -  When planned and unscheduled downtime are contributing to poor

How to do it -
Rework: Assess current operating conditions
•Evaluate machine/resource utilization, productivity, etc.
•Tally maintenance repair costs (parts and labor, extra training time, etc.)
Phase 1: Return equipment to reliable condition
1.Clean thoroughly
2.Place a defect tag (can be color coded) on all equipment showing categories of what needs to be done. Record in a project notebook.
3.Perform repairs
Phase 2: Eliminate breakdowns
1.Review defect tags from Phase 1
2.Eliminate factors leading to failure
3.Improve accessibility to machines/parts
Phase 3: Develop TPM database
1.Document all preventive and predictive maintenance activities
Phase 4: Eliminate defects
1.Provide for early detection of problems by training all relevant personnel in preventive and predictive maintenance techniques
2.Install visual controls (see slides 46-48)
3.Implement 5S housekeeping techniques (see slides 26–31)
4.Regularly review and improve machine performance Improve safety

MISTAKE PROOFING AND PREVENTION (POKA-YOKE)
Purpose : To prevent mistakes from occurring or making it impossible to pass mistakes on to the next step in the process

Examples: Mistake Prevention
•Machine operations that make it impossible or very difficult to produce a defective product. Does not require human assistance
•Electronic checklist built into a product or process/procedure
Mistake Proofing
•Devices or systems that either prevent the defects or inexpensively inspect each item to determine if it is defective
•Software programming that makes it impossible to move onto the next step without accurately completing prior steps
When to use it - When rework to correct errors or process delays downstream are hurting Process

How to do it - There are two basic Poka-yoke approaches
A.Control/Warning Approach
•Shuts down the process or signals personnel when an error occurs
•Dials, lights and sounds bring attention to the error
•Prevents the suspect work from moving on until the process step is complete
•Process stops when irregularity is detected (may be necessary if too costly to implement mistake proofing)
•High capability of achieving zero defects
B.Prevention Approach
•Employs methods that DO NOT ALLOW an error to occur or be produced
•Gives 100% elimination of mistakes (100% zero defects)
 
7 Steps to Mistake Proofing
1.Describe the mistake and its impact to customers
2.Identify the process step where the defect is discovered and the step where it is created
3.Detail the standard procedures where the defect is created
4.Identify errors in or deviations from standard procedure
5.Investigate and determine the root cause of deviations
6.Brainstorm methods to eliminate or detect the deviation early
7.Create, test, validate, and implement mistake proofing devices/procedures

LEAN Basic Tools Concepts - Part 4

5S
Purpose - To create and maintain a clean, safe and high performing workplace. 5S:
•Enables anyone to distinguish between normal and abnormal conditions at a glance
•Is the foundation for continuous improvement, zero defects, cost reduction and a safe work area
•Is a systematic way to improve the workplace, processes and products through employee involvement

5S Definitions
Sort: Clearly distinguish between needed and unneeded items and eliminate the latter
Set in Order (also known as Simplify): Keep needed items in their correct place to allow for easy and immediate retrieval
Shine (also known as Sweep): Keep the work area swept and clean
Standardize: Standardize clean up (the first three S’s)
Sustain (also known as Self-Discipline): Make a habit of sustaining established procedures

REDUCE BATCH SIZE


Purpose: Create minimum safe batch sizes
•Batch sizes often set by management based on industrial engineering formulas or demand for a fixed time period
•Both typically result in lead times and inventory generally 30% to 80% larger than process requires

When to Use It: To create a lean system operating at peak efficiency with lowest cost