Lecture 1
“The endless transformation of waste intovalue from the customer’s perspective”.
---Womack and Jones,Lean Thinking
“All we’re trying to do is shorten the time line…”
---Taiichi Ohno
1. Specify Value from the Customer’s perspective
– What is the customer willing to pay for?
– How does the product meet the customer’s needs?
– Are you meeting the customer’s price goals?
– Is delivery made only when the customer needs it?
– The customer defines which services or product features add value.
– Who is your customer?
2. Identify the Value Streams
– Value streams are the sequence of processes that deliver value to the customer. The enterprise value
stream flows through the total supply chain, from raw materials to finished goods.
– Activities that contribute value are identified.
– Necessary non-value added activities are also
identified and minimized.
– Non-value added activities that are not necessary are eliminated.
3. See the Flow – Flow is movement between value added processes
without delay or interruption.
– Design processes that make the value added and necessary non-value added activities flow.
– Work with as little inventory between process steps as possible.
– Plan the plant and process layouts to minimize unnecessary transportation and operator motion.
– Improve the uninterrupted movement of product or services to the customer.
4. Create Pull
– Only produce what is required by the customer and deliver just-in-time when the customer wants to receive, not when the supplier wants to provide.
– The organization must be responsive to providing the product or service only when the customer needs it.
– Push (batch) production should be avoided and eliminated whenever possible.
5. Perfection – Efforts are repeated to remove non-value added
activity, improve flow and satisfy customer needs.
– Build to customer requirements, the right amount at the right time.
– Work toward zero inventory, zero defects and zero unscheduled downtime. Plan for the best possible solution.
– Continuous improvement in everything we do.
lecture 2 (Page3-38)
A Value Stream is all of the actions (value and non-value added) currently required to get a product to the customer.
Value stream map: A visual representation of material, information, and time flows. Documents performance of the process
! Cycle time ! Takt Time ! Inventory
Before you begin!.ask yourself
! Do you know the value stream in your plant? ! Who owns the value stream? ! Does the person have the power to make
decisions? ! What are your target areas for improvement? ! What are the constraints? ! How do you know? ! What steps will you take to get there?
What to Map....Select A Product Family
! Focusononeproductfamilyatatime. ! Identifyagroupofproductsthatpassthroughsimilar
processing steps (products & information)
MASS LEAN
! Considerhighdollarvaluecommodities,orcriticalcomponents first.
! Createamatrixlistingpotentialcommoditiestobemapped. ! Prioritizethelist.
We measure the length of the Value Stream by calculating TOTAL PRODUCT LEAD TIME
Lead Time (L/T): The time it takes one piece to move through the entire value stream from
start to finish (total elapsed time).
Cycle Time (C/T):
Elapsed time between one part coming off the end of the process to the next coming off (expressed in seconds). How often a part or production is actual completed. Time it takes an operator to complete all elements.
Available Working Time (W/T): Per shift work time at that process less break time (expressed in seconds).
Changeover Time (C/O): Time required to switch from producing one product to another (expressed in seconds).
Value Added Time (VA): Processes that change the product fit, form, or function to meet customer specifications
Work the customer is willing to pay for.
Non-Value Added Time (NVA): The element of production that adds no value to the product, adding only cost and/ or time
Work that the customer is not willing to pay for. Non-Value Added but Necessary Time
Motion time necessary to perform the work, but does not add value to the end product (i.e. getting parts or tools).
Uptime: Reliability running time of a machine or process (percentage).
Takt Time (T/T) (German origin meaning “pace” or “beat”): How often one part/unit should be produced based on rate of sales (demand). Synchronizes the pace of production to the pace of sales.
The time in which a finished part or product is demanded by the customer. Noted in sec/part.
• Jobs Per Hour or CPV can be converted into takt time
If the cycle time (actual time to complete the tasks in a single job) is greater than takt, the operation will be a bottleneck and additional time will be necessary to meet the production schedule.
If the cycle time is less than takt, there will be overproduction or waiting time.
Setting Takt Time
• Work cells should not have Takt Times below 15 seconds (ergonomics).
• Takt Time of 30 to 60 seconds is preferred.
Ten Steps to create your Value Stream Map
1. Draw customer and supplier icons 2. Draw customer and supplier information flows
– Use proper information arrows 3. Draw and label production process boxes
– Fill in production process data boxes 4. Draw inventory triangles for Raw / WIP / Finished
Goods – Identify inventory levels (number of pieces)
5. Draw customer delivery icon – Include delivery frequency as well as quantity
6. Draw supplier delivery icon – Include delivery frequency as well as quantity
7. Draw production scheduling information flows – Use proper information arrows
8. Draw material flows – Use material flow arrows (Push or Pull)
9. Calculate total lead time and process time – Use stepped line to designate value add / non-value add
10. Calculate takt time for the process – Seconds available per day / Daily customer demand
Process flow ---> more on that
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