What are the four major costs of quality?
- prevention costs
- appraisal costs (qc)
- internal failures (defective parts)
- external costs (customer returns)
What are the taxonomy (principals) of inspection?
total or partial
-100% of the products based on a sample study
statistical or not statistical
-based on statistical methods or not
quantitative or qualitative
-number of elements or appearance of the product
based on measures or based on functional traits
-numerical values or without measures
sensory or physical
-through human senses or by means of devices
subjective or objective
-evaluated by a person based on appearance or evaluated base on a specific measurable feature
internal or external
-within the process or as independent activity
What are the shortcomings of inspections?
- they take time and are costly
- not 100% reliable
- inspection detects the problem but does not solve the problem
What is Singo’s approach to inspection based SQC?
it evaluates a product sample, based on the number of defects found it accepts or rejects the lot
Then informs, using feedback analysis to find the problem or cause of the defect.
What are the two main problems with SQC?
- methods do not guarantee the quality of all products
2. feedback and corrective actions are slow and may not even be followed through on
What are two methods to avoid problems with SQC?
inspection with poka-yoke device
self-checking work, for accelerated feedback
What are the two principals of SQC inspections?
- evaluate (using statistical samples)
2. inform (feedback analysis and find cause of the problem)
What is Poka- Yoke?
is any mechanism in a process that helps an equipment operator avoid mistakes & defects by preventing, correcting, or drawing attention to human errors as they occur.
“mistake-proving”
What is a self-check system? pros and cons?
- the worker who makes the part inspects the part
- most efficient method, may mot be objective (people dont like to point out their own mistakes)
What is a source inspection?
- verify that all the inputs to a process are acceptable before the process is executed
eg. process is good, machines are good, people are trained, software is good, raw mats are good
