Need Due to:
- Legal or contract requirements
Recognition of the importance of good quality is indicated by the Malcolm Balridge Award which is awarded annually by the Dept. of Commerce to firms. Considered as having excellent quality programs
Currently the quality management effort by management is described as
Total Quality Management.
This is a comprehensive systematic approach to promote continuous quality improvement in an organization.
Often this requires a cultural change in firms, making everyone aware of the necessity for good quality and motivating its employer to improve the quality of their work.
To accomplish this requires
- Top management interest
- Long term commitment
- Appropriation of adequate funds and resources
- Employee education
- Utilization of quality improvement techniques and knowledge
- An extensive record keeping and documentation system
- Recognition and consideration of the people aspects
· Training how to do this
· Availability of quality specialists for expert advice
Should you hold product till completely bug/defect free
Or ship and make corrections when in use?
- Cost of non-conformance vs cost of correction
- Loss of market share by waiting
Basics of Quality Management
- Market Research
- Customer Requirements
- Required maintainability & repair
- Equipment in place
- Process employed
- Work force skills
- Training done
- Attention by supervision
- Organizational culture
- Receiving inspection to monitor input
· From outside vendor
· From other inside departments
- Prevention of damage to material and work in process
· Careful Handling
· Proper Storage
- Periodic inspection to prevent continued poor quality output
Continuing work on defective products
Scrap & Rework
- Utilization of testing equipment and degree of inspection integration with production
- Maintaining control
- Improving quality levels
Types of Inspection Considerations
No damage to product is permissible
- Visual Inspection
- Go/No Go
Damage to product
- Destructive Testing
Cost and Resource Constraints
Unless 100% inspection is required
- For safety
- Cost of failure too expensive
- Product is sold on that basis
Statistical Process Control is employed instead of 100% uses sampling to make decision about a population
This information is utilized for:
- Investment justification of outlays to improve output quality
- Reduction in Non Value Added Quality costs
- Definition of quality costs to concentrate on
Standard Procedure to reduce quality costs is to:
- Measure present cost of quality
- Identify high cost areas
- Change methods etc.
- Do cost trade offs
- See whether cost improvement occurs
- In well run companies and this is in ongoing process
Practice is to look at quality costs in a systems basis that has the following components:
1. Prevention Cost- Those representing expenditures to prevent failure for example training, design review, prototyping facility readiness inspection, etc.
2. Appraisal - Those representing outlay to check that product or service being produced meets the quality level desired. For example, receiving inspection, test equipment, testing and analysis of test data, audits, work in process inspection.
3. Internal Failure Cost- Those representing outlays made to correct defects in product/service before shipped to customer. For example, rework and scrap costs.
4. External Failure Costs- Those that occur after product/service is in customers possession due to its poor performance. For example, complaint investigation, recall, liability, warranty expenses and lost future profits.
Internal and External Failure Costs
Results of Quality Improvement can be seen in:
· Improved productivity
· Lower production costs
· Reduced cycle time
· Better return on invested capital
· Quicker response to quality problems
· Reduced scrap and rework costs
· Reduced warranty and service costs
· Lower work in process and material inventory
· Lower labor costs- reduced overtime, less idle time
Specifically in reduced cost of quality
Purpose is to familiarize you with these. Specialized courses in TQM, SPC, probability and statistics, quality assurance, maintainability and reliability are recommended to individuals interested in this subject matter in more depth.
1. Parato diagram- used to determine the most important/frequent quality problems from a total. Done by categorization of these into a histogram. Basis is expectation that 80% of the quality difficulties are caused by 20% of the production lines.
2. Time Series- can see quality performance trend over time say % rework required for a T.V. being produced. Shows degree and whether progress is being made.
3. Cause and effect diagram used to identify (often via brain storming) what the underlying reason is for a cause, can be developed into many levels (i.e. what caused the cause). For example the effect is poor attendance at meetings. Some possible causes not notified, held at inconvenient time, place, was scheduled without enough notice, did not consider competing meetings etc. Next level would be what caused these effects.
4. Check sheet that requires routinized procedure to prevent overlooking certain number of checks and allows noting any concerns and who did it.
5. Statistical Analysis
1. Scatter diagram to see if cause and effect exists and quality. Relationship (i.e.quantity produced and number of rejects on a production line)
2. Histograms- Frequency profile outcome- can see degree of satisfactory and unsatisfactory performance (students coming to class on time, minutes ahead or behind).
3. To determine expected level of output and degree of variation. Can be seen from mean and variance (process capability assessment).
4. Data from # 2 can be utilized to develop control charts to monitor performance and take corrective action when indicated.
Ask employees for suggestions how to improve productivity, Often their rework (error) reduction for it to work employees must receive.
· A positive acknowledgement for their effort
· Prompt responsive with respect to the merits of their suggestion
· A commensurate monetary and/or recognition award.
7. Quality Deployment Function
Technique used to integrate customers needs (desired product features) into both the design of the product. Also facilitates design comparison to competitor products.
X- Chart Used to record the variation in the average value of samples takes over time in process.
R- Chart Shows the range (distance between the largest sample size and the s smallest i.e. 60, 64, 55, 58 R= 64-55 or 9 )
Allows monitoring whether range becomes too large
Control chart for attributes
Attributes are used when quality cannot be measured on a production line. (I.e. scratches on furniture, labels pasted on wrong or wrong labels, broken pieces of nnnglass in a set etc.)
Called P- Chart where p- np/n
P= proportion of non nonconforming items in a sample
N= number in sample
NP= number of nonconforming in sample