DSCI 304 Final

quality management

Managerial techniques directed to improve the quality at the organizational level

Quality

a good that meets or exceeds customer expectations; has "fitness for use" meaning that the product or service does what it is supposed to do

Quality Management

set of managerial techniques directed to promoting quality in organizations

quality management activities

quality planning, quality control, quality assurance, quality improvement

quality planning

creating a strategic plan for the management of quality, documented in the quality manual

quality control

establishes the techniques to maintain stable physical processes that are consistent with desired quality conformance levels; all about detecting a problem and providing corrective action

quality assurance

overviews the quality system itself to make sure it meets the goals stated in the quality manual; includes making improvements to the quality system and performing audits of the quality system

quality improvement

involves the mechanisms to continuously generate quality improvement projects to take the organization to the next level and provide competitive advantage

in order for a good or service to have good quality:

- its functional goals must be established
- The good or service must be designed according to functional goals
- Then it must be produced according to design specifications

two components of quality

quality of design, quality of conformance

quality of design

product must be designed in the best possible way to satisfy the customer in all aspects of quality

components of quality of design

design for manufacturability, design for maintainability

design for manufacturability

be manufactured efficiently

design for maintainability

disassembled, maintained, and recycled

quality of conformance

degree to which the product conforms to the design specifications, as documented in the design drawings

defective products

when a product does not meet design specifications caused by problems in the production process, human factors, equipment

goal of quality management?

to have continuous improvement

PDCA wheel

plan do check act

plan

define a higher level of quality for your organization and determine the process on how you will meet this specific goal or target

do

implement the improvement plan and produce the product or service

check

measure, analyze, and study the output of the process/ the goal is to validate the effectiveness of the plan

act

design and implement corrective actions that permanently and irreversibly eliminate the root cause of the problem / could be to redesign the product or process

quality revolution

Advances in quality management took place as a result of statistical advancements, as well as need of interchangeable parts used in mass production during Industrial Revolution

industry policy in Japan

introduced to develop steel and shipbuilding companies, that soon included knowledge intensive industries such as automotive, consumer electronics, and precision products

Japanese Union of Scientists and Engineers

group that invited a select few Americans deemed experts in the field of quality to provide statistics and quality training/consulting to Japanese companies

Total Quality Management

This profound change caused by this Japanese influence in quality management is known as

elements of total quality management

- Strategic leadership and quality oriented corporate culture
- Continuous improvement methods
- Quality measurement systems
- People and customer focus
- Eliminating waste

old definition of quality

- Quantity defined by designer
- Change was rare
- Culture that hid defects in products
- Belief that quality costs money
- main goal of increasing output and productivity

new definition of quality

- quality is defined by customer
- change is constant
- culture highlighted defects to eliminate them
- belief that quality saves money
- main goal of continuous improvement where everybody collaborates together to reach goal

dimensions of quality

performance
features
reliability
durability
serviceability
aesthetics
perceived quality

performance

primary operating characteristic of a product EX: speed of a car

features

additional items that increase customer satisfaction EX: car can have self parking feature that customers might like

reliability

probability that the product will not fail in a period of time EX: reliable car starts and works well every time

durability

how long a product lasts, or how much use it provides before it deteriorates or wears out

serviceability

designed to have efficient service and repair EX: a car being able to be serviced quickly, and for a relatively low price

aesthetics

how a product looks to the customer, difficult to quantify

perceived quality

based in image or reputation EX: if we put a prestigious name on a car, most customers perceptions will improve

quality characteristics

individual components or sub-systems that contribute to an overall dimension of quality

cost of quality

as level of quality increases, products become more useful, materials are used more efficiently, there are fewer defects, less liability costs, etc

costs related to improving quality

cost of prevention, cost of appraisal

costs related to poor quality

cost of internal failure, cost of external failure

cost of prevention

all activities directed toward improving products and processes that decrease defect rates using six sigma, continuous improvement programs

cost of appraisal

happens after production to ensure that defective products are not getting to customers and contaminating the supply chain

cost of internal failure

contamination of the supply chain through the identification of defective parts, that are now reworked and sold for lower prices

cost of external failure

take place when defective product is delivered to the customer including customer complaints and product recalls

worst possible outcome of quality management?

failure of both prevention and appraisal activities

six sigma

quality improvement methodology stating that the specification limit is located 6 SD's from the mean, yielding a practical equivalent of 0 defectsg

goal of six sigma?

reduce process variability by improving control over processes and production

tool used in six sigma?

define, measure, analyze, improve, control

quality management standards

set of requirements a company must meet to demonstrate its capacity to manage quality created by ISO(International Organization of Standards)

total quality costs equals?

cost of prevention + cost of appraisal

optimal quantity level?

prevention costs = appraisal costs

what happens first, prevention improvements or appraisal improvements?

prevention improvements

at zero defects ...

cost if improving quality is minimal and cost of failure is zero (although not always acheiveable, companies always strive for this)

for a process to consistently produce conforming products, it has to be:

capable and in control

capable

when output is within specification limits and probability of producing defective products is low

how to make a process capable?

- Reducing common variation using more precise equipment, better worker training, etc
- Centering the process mean closer to the specification target

in control

when its parameters are known and managed over time, making output predictable and stable

capable, in control

Process is stable and well within specifications. Will not produce defective products while in control.

assignable variation

capable, out of control

Process within specification, but unpredictable due to uncontrolled changes in parameters. Corrective action is needed.

irreversible corrective action

not capable, in control

Process parameters are stable but fall outside specifications.

reduce common variation, center the process used

not capable, out of control

process is both unpredictable and out of specifications

irreversible corrective action

process capability

when a product's variability is within the specification limits and therefore doesn’t to generate a high rate of being defective; so there is the expectation that the product will consistently be produced within specifications

specifications

any process has specifications that are determined by customer requirements including a target and a tolerance

target

ideal value of the dimension

tolerance

maximum allowable deviation around the target in order to meet customer requirementsa

a narrow tolerance requires ___ ?

more precise equipment and material quality

USL = ___

target + tolerance

LSL = ____ ?

target - tolerance

process capability ratio

measures capability of a process as a ratio between the width of the specification limits relative to variability of the process

Cp capability ratio

ratio of the width of specification limits over process variability / potential capability if the process is centered

What ratio do you use if the process mean falls exactly on design target?

Cp

Cp = ____ ?

=(USL – LSL) / 6sigma (a process is capable if >_ 1)

Cpk Capability Ratio

used when process is not centered on the target, which is common / shows rate of defects expected in the worst side of the specification

Cpk = ____ ?

min[ (USL – mean / 3sigma) , (mean – LSL / 3sigma) ]

If mean goes up or down, meaning the process isn't centered, what capability ratio do you use?

Cpk

If process is centered Cpk and Cp are different.

False

If process isn't centered, Cpk is more accurate.

True

If process shifts right, use this formula:

= USL - mean / sigma

If process shifts to the left, use this formula:

x bar - LSL / sigma

common variation

can be reduced by using more precise equipment and stable environmental variables, but cannot be eliminated

assignable variation

process parameters always change over time and eventually the process mean or SD will change from the previous mean; makes the process "out of control"

By detecting _____ variation early using control charts, a process can be corrected before a defective product is produced.

assignable

statistical control

a process with no assignable variation present, only common variation is present

a process out of control does not mean that the product is defective

true

control chart

graphical representation of ongoing series of hypothesis tests; used to suggest if an assignable variation is in the production process

Western Electric Rules

when a process is in control, it should generate sample data that follows a random pattern with stable probability distribution, if outside the control limits it is said to have an assignable variation

Type 1 Error

false alarm - assignable variation does not actually exist

Type 2 Error

false negative - assignable variation actually exists

3 Sigma Control Charts

where Z score of control limits is within 3 SD'sR

R Chart

used to detect when our process distribution has become wider or narrower using ranges

X Bar Control Chart

helps control for process means

P Chart for Fraction Defective

The fraction of units that is nonconforming is the proportion of nonconforming units over total units

materials management

process of determining the material needs for business operations and sourcing the inventories needed to satisfy those needs at specific locations and times
Includes demand forecasting, inventory control, and materials sourcing

independent requirements

forecast or actual demand from external customers is translated into what amount of materials that need to be supplied
Unknown until customers place orders, therefore it must be estimated through forecasting, until actual customer orders arrive

dependent requirements

material demand is dependent upon specific production plans internal to the organization / deterministic in nature; can be calculated through MRP processing

materials requirement planning

way to calculate materials needed in dependent requirements or deterministic approaches

inventory control

set of processes that determine the optimal amount of inventory of each material in each location

make to order production

when a product is tailored to a specific customer or the customer has the opportunity of selecting among multiple options, configurations, or variants; production takes place after the order is received, and the customer must be willing to wait until production takes place

what triggers production orders?

independent requirements