Pull Systems: Overview, Challenges and Success Factors

© 2016 Osterling Consulting, Inc.

Pull Systems

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Pull Systems: Overview, Challenges and Success Factors

Mike Osterling 619-572-3632

[email protected]

Session Objectives

• Cover the most common types of pull systems

• See some examples of application• Discuss implementation issues• Cover common factors of success

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Pull Systems

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Principles of “Lean Thinking”

1. Specify value from the external customer’s perspective

2. Identify and understand the value stream3. Make value‐creating steps flow 4. Pull

• Flow at the pull of the customer• Pull where flow isn’t possible

5. Pursue perfection

Lean Thinking, Womack & Jones3

Forecast & Orders

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Traditional MRP Execution

Customer

MRP Execution

Supplier

Process 1 Process 2 Process 3 Process 4

Why is this referred to as “push”?

Production Schedule

POs


Pull Systems

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MRP ‐ A Great Execution Tool, if…

• 100% accurate bills of materials• Accurate transactions (receipts, issues, returns). • Accurate counts: WIP, finished‐goods and parts• Accurate forecast: volume, timing and mix• No variation in actual usage versus planned usage• No unplanned usage (engineers, service…)• No lost parts or WIP• Accurate scrap rates. Scrap reporting is 100% accurate• Accurate lead times • Schedule priorities don’t change• Open order status is perfect

Pull Systems ‐ Definition

A method of production control in which downstream

consumption triggers replenishment.

“I used some, you now have permission to replace.”

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Pull Systems

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Purpose of Pull Systems• It’s the schedule• Self control to manage overproduction• Simplified scheduling process (less demand

on planning & scheduling)• Rapid response to changes in demand• Visualize

– Expectations / needs– Performance– Problems

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Types of Pull Systems

• One-piece flow• Kanban

– Pulling specific part numbers• Min / max; re-order point • Vendor managed inventory (VMI)• FIFO Lanes

– Pulling capacity (the next job)• Other (construction, office, software…)

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Pull Systems

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Kanban Signal Communicates:

• What to produce• Where it is made• How much to

produce• When to produce it• Who the customer

is

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Kanban – Purchased Parts

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Multi‐card Kanban System• Fixed quantity per kanban • Adjust number of cards as demand changes• (Relatively) easy to adjust when demand changes

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FIFO

Visual Kanban (no cards) - Subassemblies


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Vendor Managed Inventory (VMI)Vendor: Sets up, reorders, delivers, restocks…

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Pull Systems ‐FIFO Lane:

Pulling the next job; pulling capacity

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FIFO LanesMultiple Suppliers for Single Process

Pull in the Office

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Pull Systems

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Breakout Activity – 2 or 3 people(at least one person with pull in place)

1. For those who work in an operation with pull systems in place: which form of pull is it (excluding one-piece flow)?

2. Pick one – identify who sends what signal to who?

5 minutes

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Type of Pull System Sends Signal to produce

Receives signal to produce

KanbanMin/Max; ROPVendor Managed InventoryFIFO Lane

Common Problems

• Timing (often late, or come in wrong sequence, or unclear priorities)

• Quantity (not enough, or too much, inventory)

• Missed signal (didn’t see it / didn’t pull card)

• Lost signal (where’s the card?)• …?

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Pull Systems

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Breakout Activity – 2 or 3 people(at least one person with pull in place)

• Focus on one of your pull systems• What are the top one or two problems you

are having with execution? (e.g. lost cards, late receipts, missed signals, not enough / too much…?)

5 minutes

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Before you “Fix” it….Make sure you understand root cause!

• 5 Why & Cause-Effect Diagrams (aka: fishbone or Ishikawa)– Facilitates brainstorming of potential

causes of a problem (“undesired effect”)– Start with categories of causes. – Decreases chance that overlook a cause– Doesn’t show how much each cause

contributes, if at all, to the problem– Doesn’t provide solutions

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Cause-Effect Diagram

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Undesired Effect

Potential Causes

Categories

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Root Cause AnalysisCategories – “The Six Ms”

(“man”)

(“mother nature”)


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Breakout Activity – 2 or 3 people(same groups)

• Focusing on one of the two top challenges you have with your pull system, start creating a “cause-effect” (fishbone) diagram– The head of the fish is the “bad thing” (e.g.

“lost kanban cards,” “out of inventory,”, etc.– Categories - 6 M (or other)

• Man, machine, materials, method, metrics, mother nature

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After the Fishbone…

• Narrow down the causes to the significant few

• Design countermeasures (improvements) to address the significant few

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Pull Systems

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Kanban (Fixing the “Bin”)

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Kanban Cart (Visualizing Shortages)

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Pull Systems

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Kanban Scheduling Board (Visualizing the Schedule and Priorities)

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a.k.a. Heijunka Board / (Load Leveling)

Scheduling Board for Signal Kanban (Visualizing the Schedule, Problems & Priorities)

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Visual Status & Prioritization

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Visual Status & Prioritization

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Automation

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FIFO Lanes – Multiple Suppliers & Customers

Output Input


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FIFO Lane with Simple Visual Aids33

Pull system for fab and field work – more flexible, less rework, balanced demand

Pull on Complex Projects


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Keys to Success• Start with the purpose (what problem are you

trying to solve)• Don’t copy what the other guys are doing –

adapt• Pilot & experiment – start small• Early engagement of the frontlines; and train

(but not too soon)• Standardize, document, and change• There will be problems!

– Measure, monitor and perform root-cause analysis

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Resources

• Kanban for the Supply Chain, Cimorelli• Kanban Made Simple, Gross & McInnis• Kanban for the Shop Floor, Productivity Press• Implementing a Mixed Model Kanban System: The Lean Replenishment Technique for Pull Production, Vatalaro

• Video: Kanban Systems, Society of Manufacturing Engineers

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Mike Osterling(619) 572-3632

[email protected]

Thank You!Questions?

Documents

Pull Systems: Overview, Challenges and Success Factors