Total quality management (TQM) and statistical process control (SPC)

quality

a powerful competitive weapon

DIRTFT

do it right the first time

value based definition

in terms of costs and prices; quality is value for the dollar spent

Critical to Quality (CTQ)

physical, sensory, time

If costs of Type I and Type II errors are high

wide control limits should be used and consideration should be given to increasing sample size and increasing frequency of taking samples.

process improvement tool examples

(1) Benchmarking (explanation follows) (2) Brainstorming (explanation follows) (3) Process Mapping or flow charting (example follows) (4) Pareto Analysis and Histograms (example follows) (5) Cause-and-Effect Diagrams , Ishikawa diagram, 4M diagram, fishbone diagram (example follows) (6) Check Sheets or checklists (example follows) (7) Scatter Diagrams (example follows)

Statistical Process Control (SPC) Tools or Techniques

(1) Control charts: used for higher volume, repetitive processes (2) Acceptance plans: used for lower volume, batch processes

use based definition

- in terms of satisfying the consumers' wants, needs and preferences; e.g., brand name manufacturer versus generic drugs

strategic quality planning

identifying and understanding consumers wants, needs, and preferences and assessing an organization's ability to meet them

cost of type 2 error

scrap, rework, after-the-sale service costs(difficult to measure)

cost of quality

1. internal failure costs-found before it leaves. lost production time, lost revenue 2. external failure costs-failure detected by customer. bad 3. appraisal costs. inspection cost. higher=lower defect cost and vice versa. 4. prevention costs- good quality is a prevention cost

controlling for type 2 errors

alter size of control limits

variability

caused by chance (random variation) causes and assignable(attributable) causes

manufacturing based definition

conformance to requirements; meeting specifications or critical to quality (CTQ) characteristics. physical, sensory, time

type 2 error

consumers risk. null is in control. you accept the null when it is false. you think it is in control when it is not

tqm

continuous , orgnization wide effort to total customer satisfaction and process improvement. Possesses a customer driven philosophy for organization wide continuous or ongoing improvement and waste elimination

confidence interval

larger the _____ more likely we are to classify the process as in control

TQM

possesses a customer-driven philosophy for organization-wide continuous or ongoing improvement and waste elimination. possesses a methodical foundation of numerous principles and tools, experimentation, scientific analysis, and problem solving.

benchmarking

process of comparing one's business processes and performance to industry bests

acceptance sampling

process of randomly inspecting a certain number of items (sample size of n) from a batch of items (N) to determine acceptance/rejection of the lot based upon observed number of defects versus acceptance/rejection criteria.

principle of TQM

produce products of high quality in the first place rather than detecting defective products later through inspection

type 1 error

producer risk. rejecting the null when the null is true. you think it is out of control when is it IN control. null=in control

product design

seek to enhance the manufacturability and conformance to requirements or meeting specifications

TQM

should be viewed as a system of interrelated components: leadership, culture, teamwork and tools.

assignable causes

when _______ are present the process is deemed to be out of control

operational quality management, control, and improvement

assesses operational process outputs in an ongoing manner to ensure conformance to specifications all the while attempting to improve future process outputs as well; examples include control chart and acceptance sampling applications

Statistical process control tools/techniques

attempt to identify presence of assignable causes of variation so that it eventually may be eliminated

process control

attempts to identify assignable causes of variation so that it eventually may be eliminated, typically with the use of control charts and acceptance plans

external customers

consumers, customers, vendors; engaging customers and suppliers and managing the supply chain quality; e.g., Quality Function Deployment (QFD) and the House of Quality (next slide) Focuses planners' efforts on product or service characteristics from the consumer viewpoints QFD process begins with assessing consumers' requirements (listening to the Voice of the Customer), sorting and prioritizing the requirements, and then translating these requirements into specific product or service characteristics House of Quality tool attempts to map customer requirements with product or service characteristics; tool has also proven to facilitate communications among functional units of an organization.

controlling for type 1 errors

increase amount of inspection - frequency or sample size

cost of type 1 error

lost production time, cost of testing for absent problem

is the customer always right?

no but we want to treat them as if they are. our response to a dissatisfied customer has to be good and should occur in a short period of time

fishbone diagram, 6M, ishikawa

organized framework, work from right to left. add the effect then find the root causes. branches begin with M (man, machine, materials, methods, metrics, mother nature)

enhance manufacturability

product standardization, simplicity/fewer parts, robotics, vertical orientation for insertion or assembly, redundancies, improved supplier relations, preventative maintenance

product based definition

quality is a precise and measurable variable where differences in quality reflect differences in the quantity of some ingredient or attribute possessed by a product; e.g., content of multivitamins

Cp ratio

ratio of allowable process variability/actual variability , determined as Cp =(USL-LSL)/6sig

common instances of acceptance plans for SPC

upon receipt if the incoming quality of a batch is suspect, just prior to a batch shipment to a customer, or as batch orders flow from operation to operation; if applied during the flow path of a batch, it is more common to make a decision regarding the disposition of a lot just prior to a costly, irreversible, or covering operation.

acceptance plans

used for lower volume, batch processes to make an "accept" or "reject" decision (lot sentencing), i.e., acceptance plans do not estimate quality, do not provide any direct form of quality control, but rather simply audit quality

internal customer focus

Creation of one's team; engaged employees Quality at the Source (empowered employees) Responsibility is the obligation incurred by individuals in their roles in the formal organization in order to effectively perform assignments. Authority is the power granted to individuals so that they can make final decisions to complete their assignments Accountability is the state of being totally answerable for the satisfactory completion of a specific assignment; Accountability = Responsibility + Authority

use wider control limits

If cost of investigating cause of "out-of-control" decision is high, a Type I error is important and should be avoided.

use narrower limits

If cost of passing on defectives is high, Type II error is important and should be avoided.

interpretation of control charts

Observations should fall within the limits Data points should not reflect any trends Low degree of variability should be observed in the data points No evidence of "runs" in the data

dimensions of quality

Performance - product/service primary characteristics Reliability - consistency of performance Durability - length of useful life Conformance to specifications Aesthetics - appearance, feel, smell, taste Special features - extras Safety After sale service Perceptions - indirect evaluation of quality.

brainstorming

a popular group creativity technique designed to generate a large number of ideas for improving quality It's a small group of people that meet to generate improvement ideas

tactical quality assurance

a proactive set of activities having a goal of adherence and maintenance of product and service quality levels; examples TPM and wellness programs