Lean Six Sigma Midterm

A Six Sigma-level process is one that produces no more than __ defects per million opportunities (DPMO)

3.4

What is Lean?

Lean is a set of concepts and tools aimed at reducing waste. Drives quality, speed, and reduces waste. 

What is six sigma?

Six sigma is about reducing variability and defects and applies statistical tools to business problems

What are the 5 steps in Lean?

1. Specify Value (what customer wants) 

2. Identify Value Stream/Value Chain (every step is adding value) 

3. Make It Flow 

4. Pull (synchronize with customer demand) 

5. Always Improving (Kaizen) 

What is the DMAIC approach to six sigma? 

D - Define M - Measure A - Analyze I - Improve C - Control. It is a data-driven problem-solving methodology used in Six Sigma to improve existing processes.

What is the DMADV approach to six sigma?

D - Define M - Measure A - Analyze D - Design V - Verify. Used for designing and creating new products, services, or processes from the ground up,

What are the barriers of limitation for lean six sigma?

• Culture Limitations

  • Fear

  • Time Pressure

  • Resistance to Change

• Knowledge Limitations

  • Lack of Training

  • Lack of Knowledge

• Management Limitations

  • Lack of Leadership

  • Lack of Commitment

  • Lack of Hands-On Involvement

When did lean six sigma methodology begin?

We don’t know for sure, likely used for thousands of years, but it can be first accurately traced in the Industrial Revolution. Introduced by professors of MIT.

What are the 3 names for interchangeable parts?

1. Interchangable Parts

2. American System of Manufacturer

3. Armory (Store Weapons)

The American System of Manufacturing refers to the 19th-century evolution of mass production techniques, primarily characterized by the extensive use of interchangeable parts and mechanization to create standardized products on a large scale. Eli Whitney.

Who came to be known as the father of scientific management?

Frederick Taylor

What are the principles of scientific management?

• Frederick Taylor

• 16 steps (reach, grab, etc)

• Pick a leader and everyone follows them; efficiency

• Critized for dehumanizing process

• Positive and negative connotations

Who made a time and motion study and for what purpose?

Frank and Lilian Gilberth, they wanted to make everything efficient and eliminate non-value added time. They even timed how long it took to brush their time to not waste time.

What does economies of scale/mass production mean?

The more you produce, the cheaper it is to produce one unit of that thing. A proportionate saving in costs gained by an increased level of production.

What does economies of scope mean?

A company uses the same materials to make different products, overall saving money by being able to have interchangeable parts.

What does EOQ mean and what two things does it balance.

Stands for Economic Order Quantity (EOQ) and is the best balance between the holding cost and ordering costs to determine optimal number of units to order.

What is inventory turnover? What is better, for it to be high or low?

Inventory turnover is how often a company sells and replaces its inventory over a specific period. High inventory turnover is better because they get rid of inventory very often, and low turnover is bad.

What does quality at source mean/represent?

Quality at source emphasizes that it is better to catch a problem/defect early on in the process of manufacturing an item, because it you catch it later on it will cost you more money. It emphasizes building quality into a product or service from the beginning of a process, not just at the end.

What does COPQ stand for, and what does 4 costs does it include?

Stands for costs of poor quality, and includes appraisal costs, prevention costs, internal failure costs, and external failure costs.

What are prevention costs?

The costs of all activities specifically designed to prevent poor quality in products or services. E.G the costs of: 

• Product design 

• Designing production layouts 

• Evaluating capacity of supplier 

• Quality education and training 

What are appraisal costs?

The costs associated with measuring, evaluating, or auditing products or services to assure conformance to quality standards and performance requirements.

• These costs are incurred both before and after manufacturing starts

Non-conformance costs, what are they? Difference between internal and external?

Non-conformance costs results from products or services failing to meet user requirements.

• Internal is when a mistake is caught within the company and occur prior to deliver to customer

• External is when a customer finds something wrong

Quality is _

Free

What are the approaches to quality-at-source and what do they mean?

• Poke-Yoke - A mechanism to prevent an error from happening

• Jidoka - Autonomation; Empowerment to stop machine without boss permission, such as a passenger can stop train with chain in an emergency

• Crew Resource Management - Takes into account that complex activities are done in teams (Senior cockpilot told junior to shut up after making a suggestion)

What does 5S accomplish and what is the correct order of the 5 S’s?

5S is simply good housekeeping; whenever you tidy up something, how you go about tidying it up.

1. Sort

2. Straighten

3. Shine (Cleaning and inspecting)

4. Standardize

5. Sustain

What are the advantages of implementing 5S in your workplace?

It is very easy to understand and practice, it develops teamwork and improves effectiveness, employees are involved in developing the system, and it is a good manufacturing process.

Improves:

• Quality

• Safety

• Morale

Reduces:

• Cost

• Waste

Why is inventory bad?

It holds a lot of capital and space, and the opportunity cost that you could be doing with the space.

Technology Obscolence vs Market Obscolence

Technology obsolence is having too much of an outdated product due to its technology or components being outdated (ex: too much iPhone 8 when iPhone 10 came out). Market obsolence is when a product changing consumer tastes, such as labubus going out of fashion because people think they’re ugly.

Having too much inventory _ problems, while having too little inventory _ problems.

Hides, reveals.

What is layout planning used for?

Deciding on:

• Where do things go

• How production of goods or services will be organized

• Arranging departments, work centers, and equipment

• Applicable to both manufacturing and service layouts

Layout decisions are important because they…

• Require substantial investments of both money and effort 

• Involve relative long-term commitments 

• Have a significant impact on cost and efficiency 

What are some layout planning considerations?

• Physical space

• Rigging considerations

• Maintenance space

• Supporting space

• Material handling

• Proximity to other processes

What are the different types of layouts?

1. Process layout

2. Product layout

3. Fixed position layout

4. Cell layout

5. Service layouts

What is the process layout used for?

Used to process goods or services involving different processes; the focus is on different processes or functions. Customized, low-volume products and not a repetitive process. 

Ex: Hospitals, Banks, Libraries 

What is the product layout used for?

Automated, with no variation, low cost per unit, and labor does not have to be highly skilled.

What is the fixed position layout used for?

For when product is in one place, such as a building construction or ship building.

What is a cell layout used for?

A group of parts, with commonality across every part/similar manufacturing characteristics. 

What is a flexible manufacturing system (fms) used for?

Automated material handling, including, automated retrieval and storage and automated guided vehicles. Gets reduced labor costs and more consistent quality.

What is the main difference between layouts and processes?

Layouts are static, while processes are dynamic.

What are the typical ways of conducting demand forecasting?

• Asking customers (VOC)

• Look at past demand

• Innovative approach (break the mold)

What is capacity planning?

The max amount of product you can hold at once

What are the 4 different process types?

1. Job Shop (process layout, skilled workers)

2. Project (fixed position, one big project)

3. Batch (Moderate volume, customized products) 

4. Continuous (too expensive to stop, like oil refinery)  **Not all types of business fall into one of these types** 

What is a stamping die?

Like a cookie cutter with different shapes?

What is the setup time/changeover time?

The time between the last piece off a run and the first good piece of the next run?

What does SMED stand for?

Single Minute Exchange of Die. It suggests that changeover time be minimized, hospitals are very keen on reducing changeover time due to money.

What are the 3 types of setup time and what do they mean?

• Internal Changeover

  • Cannot be implemented unless machine is stopped

• External Changeover

  • Can be implemented whether or not machine is stopped

• Waste

  • Searching

  • Waiting

What does Heijunka mean?

Evene/Level Production and Mix Order Time

What is the bull whip effect?

A phenomenon in a supply chain where small fluctuations in demand at the retail level lead to progressively larger and more volatile swings in orders as they move up the supply chain to wholesalers, distributors, and manufacturers.

Difference between upstream supply chain and downstream supply chain?

Upstream is closer to supplier while downstream is closer to customer.

What are some causes of the bull whip effect?

• Economies of scale in ordering 

  • Quantity discounts

  • Short term discounts

• Price variations

  • Demand forecasts based on observed demand

• Law of demand

  • As price goes up demand goes down

What is meant by the income elasticity of demand?

As income increases then some types of good will increase in demand.

What are the 3 types of maintenance?

1. Breakdown maintenance (wait until the equipment fails and repair it)

2. Preventative maintenance (includes both periodic and predictive maintenance)

3. Corrective maintenance (improve)

What does TPM stand for and what is it meant for?

Total Productive Maintenance. It is an approach to plant and equipment maintenance and considers maintenance as a necessary part of business.

What does OEE stand for, how do you calculate it, and what are the 6 big losses?

Overall Equipment Effectiveness. OEE = Availability * Performance *Quality

1. Equipment failure

2. Setup and adjustment

3. Idling & minor stoppages

4. Reduced speed

5. Defects in process

6. Reduced yield

What is a visual control?

No one tells you what to do but you know what to do, like traffic lights. Should be well-designed and no need to study.

What is the difference between push and pull systems?

A push system produces goods in advance of anticipated customer demand, driven by forecasts and the goal of cost efficiency, while a pull system produces goods only when there is a confirmed customer order, focusing on reducing waste and inventory through a "just-in-time" approach.

What is the formua for Takt Time?

Takt Time = Available work time / Customer required volume. Customer demand is inversely related to takt time.

What is a kanban card?

A card or other device that communicates demand for work or materials from the preceding station. 

What is a JIT system and why is it significant?

A Just-in-Time (JIT) system is a management strategy that focuses on producing goods and delivering raw materials only when they are needed, rather than holding large quantities of excess inventory.

• Reduces lead times

• However management might not be committed

What is the PDCA cycle under always improving?

Plan

Do

Check/Study

Act

• Introduced by Edwards Demming

What is the difference between a standard and a benchmark?

A standard is a requirement by an authority or marketplace, while a benchmark is something you want to achieve, like a 4.0 GPA.

What are the 7 basic tools of quality?

1. Check sheets (like checklist for grocery store)

2. Control charts (avg commute time to school)

3. Fishbone diagrams (several causes for one effect)

4. Flow charts (represents a process and sequence of events you need to follow)

5. Histograms

6. Pareto Analysis (80/20)

7. Scatter Plots (One variable relative to another)

What is UCL? What is LCL?

Upper Control Unit, and Lower Control Unit.

How many lines are connected to a diamond shape in a flow chart?

3 Lines

What is the 80/20 rule developed by Pareto?

80% of inventory accounts for 20% of the value while 20% of the inventory accounts for 80% of the value. Separates the vital few from trivial many.

What ranges does the correlation coefficient measure from.

-1.0 to 1.0. Inversely related to positively correlated.

What does Kaizen mean?

Always Improving. Emphasizes that new improvement efforts should come from new ways of thinking and should be inexpensive.

What is Kaizen Blitz?

Achieveing quick process improvement in a specific area of manufacturing or service. Focus is on quick implementation of solutions

What is the use of a red tag in 5S?

In the 5S methodology, red tags are used during the Sort phase to identify and isolate unneeded, misplaced, or defective items in a workspace, which are then moved to a designated holding area for a set period.

What are the 7 types of waste in lean?

Transportation

Inventory

Motion

Waiting

Overproduction

Overprocessing

Defects

What is the difference between transportation and motion waste?

Transportation waste is the unnecessary movement of products, materials, information, or customers, while motion waste is the unnecessary movement of people or equipment.

What is the difference between leading indicators and lagging indicators?

Leading indicators predict future performance by measuring proactive activities, while lagging indicators report on past results and are often the outcomes of those activities.

What are the objectives and goal of process mapping?

The objectives and goals of process mapping include gaining a clear, visual understanding of a process to improve efficiency, reduce waste, and identify bottlenecks and redundancies.