OM Test 4 Flashcards
fitness for use
the ability of a good or service to meet customer needs (quality)
Quality of conformance
the extent to which a process is able to deliver output that confirms to design specifications
Specifications
targets and tolerances determined by designers
service quality
consistently meeting or exceeding customer expectations (external focus) and service delivery system performance criteria (internal focus)
tangibles
what the customer sees, such as physical facilities, equipment and the appearance of employees
reliability
the ability to provide what was promised
responsiveness
the willingness to help customers and provide prompt service
assurance
the knowledge and courtesy of service providers and their ability to convey trust and confidence
empathy
caring, individual attention the firm provides its customers
principles of total quality
1) a focus on customers and stakeholders
2) a process focus supported by continuous improvement
3) participation and teamwork by everyone in the organization
ISO 9000:2000
quality standards that are internationally recognized and has set of basic principles for quality management
Deming
reduced uncertainty, 14 points, Deming cycle
Joseph Juran
quality is fitness for use, quality trilogy (planning, control, improvement), used stats
Philip B. Crosby
“Quality is Free”, absolutes of quality management
The GAP model
comparing to a set of expectations, recognizes that there are several ways to mismanage the creation and delivery of high levels of quality
Six sigma
eliminates causes of defects in processes by focusing on outputs that are critical to customers
defect
(nonconformance) any mistake or error that is passed on to the customer
Unit of work
the output of a process or an individual process step
how does the six sigma quantify quality performance?
defects per million opportunities
dpmo=
defects per million opportunities (in service its errors per million opportunities)
dpmo= (number of defects discovered/ opportunities for error) x 1,000,000
Six Sigma perfect quality
3.4
6 key concepts of six sigma
1) dpmo or epmo are standard metrics that can be applied to all parts of an organization
2) provide extensive training followed by project team deployment
3) corporate sponsors are responsible for supporting team activities
4) Create highly qualified process improvement experts
5) Ensure that appropriate metrics are identified early in the process and that they focus on business results
6) set stretch objectives for improvement
DMAIC process for implementing six sigma
1) Define: identify customers and their priorities, identify and define a suitable project, identify CTQs
2) Measure: how to measure process and how it is performing, measure current defects
3) Analyze: determine likely causes of defects and understand why defects are generated by identifying what causes process variation
4) Improve: identify means to remove causes of defects, confirm key variables, modify the process to stay within acceptable range
5) Control: determine how to maintain improvements, put tools in place to ensure that key variables remain within acceptable ranges under the modified process
CTQ
critical to quality characteristics
concepts and methods for implementing six sigma
- elementary statistical tools
- advanced statistical tools
- product design and reliability
- measurement
- process control
- process improvement
- implementation and teamwork
cost of quality
costs associated with poor quality
prevention costs
those expended to keep nonconforming goods and services from being made and reaching the customer
appraisal costs
those expended on ascertaining quality levels through measurement and analysis of data to detect and correct problems
internal-failure costs
incurred as a result of unsatisfactory quality that is found before delivery
external-failure costs
incurred after poor quality stuff reaches the customer
Seven QC Tools
1) flowcharts
2) run charts and control charts
3) checksheets
4) histograms
5) pareto diagrams
6) cause-and-effect diagrams
7) scatter diagrams
flowcharts
process mapping to identify sequences and flows
run charts and control charts
run chart: line graph with data plotted over time
control charts: same but with control limits
histogram
graphically represent frequency of values within a specified group
pareto diagrams
separating the vital few from the trivial many causes
cause-and-effect diagram
fishbone diagram
scatter diagrams
graphical component of regression analysis
root cause analysis
used to designate the source of a problem
5-why technique
identifies chain of causes and source by asking why 5 times
kaizen
focuses on small, gradual and frequent improvements over the long term with minimum financial investment and with participation by everyone in the organization
kaizen blitz
an intense and rapid improvement process in which a team or a department throws all its resources into an improvement project over a short time period
poka-yoke
(Mistake proofing) uses automatic devices or methods to avoid simple human error (ex: flash drives can only be inserted one way
Quality control systems 3 components
1) a performance goal
2) a means of measuring actual performance
3) comparison of goal and actual performance
1:10:100 Rule
if a defect is corrected during design stage, it will cost $1 to fix. if a defect is corrected during production, it will cost $10 to fix. If a defect is discovered by the customer, it will cost $100 to fix.
quality at the source
(doing it right the first time) the people responsible for the work control the quality of their processes by identifying and correcting any defects or errors when they first are recognized or occur
supplier certification and management
(manufacturing) ensures conformance to requirements before value-adding operations begin
in-process control
(manufacturing) prevents defects before they leave
finished goods control
(manufacturing) verifies that product meets customer requirements
Statistical Process Control (SPC)
a methodology for monitoring quality of processes to help find and get rid of unwanted causes of variation
common cause variation
the result of complex interactions of internal variables (materials, tools, machines, info, workers, environment)
- about 80-95% of variation
- controlled by management
special (assignable) cause variation
from external sources that are not inherent in the process, appear sporadically and disrupt the random pattern of common causes
- about 15% of variation
- controlled by front-line employees and supervisors
A process is in control
if no special causes affect it’s output
A process is out of control
if special causes are present
two basic mistakes when attempting to control a process
1) Adjusting a process that is already in control
2) Failing to correct a process that is out of control
How to construct a control chart (6 steps)
1) Preparation: choose a metric to be monitored, determine the size basis and frequency, set it up
2) Data collection: record the data, calculate relevant stats, plot on the chart
3) Determine the trial control limits: draw the center line (process avg) on the chart, compute upper and lower control limits
4) Analysis and interpretation: investigate the chart for lack of control, eliminate, out of control points, recompute control limits if necessary
5) Use chart as a problem-solving tool: continue data collection and plotting, identify out of control situations and take corrective action
6) Determine process capability
continuous metric
one that is calculated from data that are measured as the degree of conformance to a specification on a continuous scale of measurement
discrete metric
calculated from data that are counted
Steps to x bar and r charts
1) calculate the x bar and r for each subgroup (n=subgroup size, k= number of subgroups)
2) calculate the overall process mean and range
3) calculate control limits
control limits for R
UCLr= D4*R
LCLr=D3*R
control limits for X double bar
UCLx=X+(A2*R)
LCLx=X-(A2*R)
D and A values on x bar and r charts are taken from
charts and depend on n value
Control charts: process is in control when
- no points are outside control limits
- No. of points above and below center line is about the same
- points seem to fall randomly above and below the center line
- most points are near center line
Control charts: Identifying a shift in the process
when a lot of points are above or below the center line consecutively
p-chart
monitors the proportion of nonconforming items
p
the fraction of nonconforming in a sample
average fraction nonconforming
P bar= sum of p’s over k
standard deviation
sp = square root of Pbar * (1-Pbar) over n
Control limits in p charts
UCLp= P+3(sp)
LCLp=P-3(sp)
if LCL is negative…
it is automatically set to zero
c-chart
monitors the number of nonconformances per unit when the size of the sampling unit is constant
Control limits for c charts
UCLc=Cbar+(3 times square root of Cbar)
LCLc=Cbar-(3 times square root of Cbar)
sample size in SPC implementation
smaller sample sizes are cheaper, larger sample sizes are more accurate
SPC is a useful methodology for processes that…
operate at a less than or equal to 3-sigma level
Process capability
the natural variation in a process that results from common causes
process capability study
a carefully planned study designed to yield specific information about the performance of a process under specific operating conditions
process capability index
the relationship between natural variation and specifications
Cp = (USL-LSL) / 6s
Process capability index: what the numbers mean
Cp=1 means the natural variation is the same as the design specification width
Cp<1 means a significant percentage of output will not conform to specifications
Cp>1 means nearly all the output will conform
Normal Cp value required
1.66 or more
lean thinking
approaches that focus on the elimination of waste in all forms to obtain higher quality and lower costs
principles of lean operating systems
eliminate waste (non value added activities), increase speed and response, improve quality, reduce costs
5Ss
sort, set in order, shine, standardize and sustain
sort
each item is in the proper place
set in order
arrange materials so that they are easy to find and use
shine
clean work area
standardize
formalize procedures and practices
sustain
keep the process going
visual controls
indicators for operating activities that are placed in plain sight of all employees so that everyone can quickly and easily understand the status and performance of the work system
ex: electronic scoreboards, painted floors showing where certain things should be, signal lights
Single Minute Exchange of Dies (SMED)
quick setup or changeover of tooling and fixtures in processes so that multiple products in smaller batches can be run on the same equipment
batching
producing large quantities of items as a group
single-piece flow
using batch sizes of one
Total productive maintenance (TPM)
focused on ensuring that operating systems will perform their intended function reliably
goals of TPM
1) maximize equipment effectiveness and eliminate unplanned downtime
2) create worker “ownership” of equipment
difference between lean and six sigma
lean focuses on streamlining processes, while six sigma focuses on root causes of problems
Lean: efficiency, intuitive
Six Sigma: effectiveness, requires advanced training
push system
produces finished goods inventory in advance of customer demand using a forecast of sales
pull system
units of production are withdrawn from preceding workstations as needed. Finished goods coincide with the actual rate of customer demand. (minimal inventories and maximum responsiveness)
Just-in-time systems are based on
pull production because it synchs the entire manufacturing process to the final assembly schedule.
kanban
a flag or piece of paper that contains all relavent info for an order, circulated within a JIT system to initiate withdrawal and production of items
-simple visual controls
the number of kanban cards is directly proportional to the amount of
WIP inventory
project
a temporary and often customized initiative that consists of many smaller tasks and activities that must be coordinated and completed to finish the entire initiative on time and within budget
examples of some projects
market research studies, construction, movie production, software development, book publishing, wedding planning
the scope of project management
define, plan, organize, control, close
pure project organizational structure
team members are assigned exclusively to projects and report to a project manager
-results in a duplication of resources
pure functional organizational structure
charters projects exclusively within functional departments
-ignores cross functional issues
matrix organizational structure
lends resources to projects while still maintaining functional control
-minimizes duplication of resources and facilitates communication
all project management decisions involve three factors
time, resources and cost
key steps to plan projects
1) project definition
2) resource planning
3) project scheduling
4) project control
project network
a graphic that has circles (nodes) and arrows (arcs) to define relationships between activities (activity-on-node network representation)
resource planning…
includes developing time estimates for each activity and allocating resources that will be required
critical path
the sequence of activities that takes the longest time and defines the total project completion time
Critical path assumes
- activities are independent of one another
- activity time estimates are accurate
- activities are uninterrupted
Gantt charts
graphically depict the project schedule so that a project manager knows exactly what activities should be performed at a given time
crashing a project
reducing the total time to complete the project to meet a revised due date
crash time
the shortest possible time the activity can realistically be completed
crash cost
the total additional cost associated with completing an activity in its crash time rather than in its normal time
crash cost per unit of time
crash cost-normal cost / normal time-crash time
PERT
project evaluation and review technique
PERT estimates
optimistic time, most probably time, pessimistic time
