MGT 295 Topic 8 quality design and management
responsiveness
How willing, able, and promptly is the service provider to help you?
3 pieces of info for a control chart;
target variability confidence
Armand Feigenbaum
- Control must start with identification of customer quality requirements and end only when the product has been placed in the hands of a customer who remains satisfied. - "Hidden plant" to signify that 15 to 40% of capacity exists to find & fix poor work.
Joseph M Juran
- Over 80 percent of quality defects are controllable by management. - The quality trilogy: Plan, Control & Improve. - Identify the few vital projects. - Discover the causes of the problem!
System approach to management
Decisions should be made holistically, recognizing that decisions have local as well as cross-disciplinary impacts
your job in control charts;
make process variability visible so you can distinguish between specific cause variation and common cause variation
W. Edward Deming
management must accept responsibility for quality
what are the potential sources of variation?
people methods machines materials measurements environment
Quality Dimensions of products
performance, features, reliability, durability, conformance, aesthetics, serviceability, perceived quality
4 quality costs categories
prevention costs appraisal costs internal failure costs external failure costs
to achieve quality at the source, you should focus on the following;
prevention, avoid problems in the first place personal responsibility, promote a stop and fix it mentality standardization, promote standardized work
if cpk is too low,
process suffers from too much variability to consistently produce good parts
Which "Quality of Product" dimension would you be assessing when asking the question, "Does the product consistently perform as it is supposed to over time?"
reliability
Which "Quality of Product" dimension would you be assessing when asking the question, "Is the product relatively easy to maintain and repair?"
serviceability
Kaoru Ishikawa
Developed Quality Control Circles (QCCs) & "fishbone" diagrams. Expanded TQC to all non-specialists & labeled it Company-Wide Quality Control (CWQC). Emphasized statistical methods on factory floor.
conformance
Does the product conform to design specifications?
reliability
Does the product consistently perform as it is supposed to over time?
Aesthetics
Does the product look, sound, taste, or smell the way it should?
Philip Crosby
Doing things right the first time adds nothing to the cost of your product or service. Doing things wrong is what costs money.
Cause and Effect Analysis
Edward Deming; plan, do, check, act
involvement of people
Employees are your organization's most important asset. Their engagement is key to success.
perception
For any dimension that cannot be observed directly, does the product seem like a high quality product?
reliability
How dependably can the service provider provide promised service?
assurance
How knowledgeable and courteous are the service employees and how well do they convey trust and confidence?
durability
How long will the product perform or last, and under what conditions?
tangibles
How pleasing is the appearance of the physical facilities, equipment, personnel, and communication materials?
empathy
How well does the service provider provide caring, individualized attention to its customers?
Serviceability
Is the product relatively easy to maintain and repair?
process approach
Leaders should focus on managing processes as well as the inputs and outputs that tie these processes together.
k =
(T-process mean) / (USL - LSL/2)
cpk =
Cp(1-k)
fact-based decision making
evidence based decision making is good business sense
Genichi Taguchi
- Quality is a virtue of design. The "robustness" of products is more a function of good design than of on-line control, however stringent, of manufacturing processes. - You gain virtually nothing in shipping a product that just barely satisfies the corporate standard over a product that just fails. Get on target, don't try to stay in-spec.
quality defined
- conformance to specifications - whether or not a product/service lives up to customer expectations
ISO's core principles of total quality management
-Customer focused -Leadership -Involvement of people -Process approach -System approach to management -continuous improvement -fact based decision making -mutually beneficial supplier relationships
constructing a mean chart (control chart)
1. define your sampling plan 2. calculate the center line: calc the mean of each sample, then take average of all sample means for the grand mean 3. calc the upper and lower limits; x_bar + z(sigma) x_bar - z(sigma) or using sample range between the largest and smallest values 4. make your results visible
Which of the following indicate that a process is out of control?
A single point plots outside the control limits A run of eight in a row are on the same side of the centerline Any consistent pattern
You have designed n Xbar chart with lower- and upper-control limits equal to 15 and 20, respectively. Each hour you collect a sample of size 4, and plot the mean on the chart. The process through hour 19 has been in control. In the latest sample, hour 20, the four values of X are equal to 16, 16, 18, and 22. What should you conclude?
The process is still in control (i.e., the latest sample indicates random variation due to normal causes)
Shigeo Shingo
Toyota's engineering genius who developed JIT philosophy, Single-minute Exchange of Die (SMED), & "Zero Quality Control" which aims to eliminate inspection through "poka-yoke"—mistake proofing production operations.
Cp=
USL-LSL/6sigma
customer focused
Your organization should understand customers and seek to meet, and exceed, their expectations.
Ishikawa Cause and Effect Diagram
a simple tool that helps you identify, isolate, and break down the major causes of variation
the process capability ratio compares
acceptable tolerances (set by your engineers) with the process' actual variation so you can assess the process' ability to achieve required quality levels
experience matters
actual experience strengthens or displaces a priori expectations, you need to deliver experiences that meet and hopefully exceed customer expectations
Which "Quality of Product" dimension would you be assessing when asking the question, "Does the product look, sounds, taste, or smell the way it should?"
aesthetics
when cpk is too low, you have 3 options;
change the specs modify the process outsource
sigma
common measure of variation or standard deviation
Which "Quality of Product" dimension would you be assessing when asking the question, "Are the product's characteristics consistently inside the design specifications?
conformance
continuous improvement
continual improvement should be an active business objective
the bottom line: if you can measure or count something, you can build a
control chart to make sure the process used to make it produces high quality products
external failure costs
costs failures that are detected after they are transferred to the customer
prevention costs
costs of designing and maintaining the quality management system
appraisal costs
costs of evaluating produced or purchased information, processes, products and services
internal failure costs
costs of failures that are detected before they are transferred to the customer
performance
does the product do what you want it to do?
features
does the product possess the features you are looking for?
quality at the source
doing things right the first time every time
you use a control chart to;
help monitor a process help you identify specific cause variation that causes a process to produce a defective product
pareto chart
helps you make priorities visible by showing the frequency at which each cause occurs, then rank order the causes of variability
expectations matter
if you want to capture customers' hearts, you need to get into their minds and understand how they prioritize each quality dimension
adjusted capability ratio (Cpk)
introduce an adjustment factor k that measures how far your process mean is from the design target
the following indicates that the process is out of control;
single plots outside control limits 8 in a row on same side of center line any consistent pattern that tells you your process includes systematic variation
quality dimensions of services
tangibles, reliability, responsiveness, assurance, empathy
if the target dimension of a product produced always falls within six standard deviations of the mean,
then the process has little chance of creating a defect
ultimately, companies integrated the quality guru's ideas into a holistic approach called
total quality management
common cause variation
unavoidable events
six sigma is built on a critical fact;
variability in a process produces defects, errors and waste
Process Capability Cp
want to make sure that the process replicates as closely as possible the actual day to day operating environment, want to know how the process is going to work in real life
six sigma tools use statistical tools to help you identify
which type of variation is present how to address that variation to improve your process
Process is out of control when...
you experience special cause variation
mutually beneficial supplier relationships
your organization should build strong relationships with key suppliers
leadership
your organization should have clear objectives and employees should be actively involved in achieving them
a Cpk of 1.5 or higher indicates that
your process can meet your desired quality levels