In my previous article, we already know the 3 main reasons why quality is not free which are all related to design.
In the past most of the manufacturing processes are very
much dependant on human where most of the defect have direct cause are human
error, therefore emphasis on “do it right the first time” was focused on the
manufacturing process.
If a further root cause analysis is done, the final cause is actually due to design per
the example below.
A simple example would be doing a 5 why analysis
From the figure above,
it seems that the manufacturing cause is the cause of the component
damage when we deep dive the root cause is pointed to the design issue where
the component is designed too near to the edge of the board and cause handling
damage.
This will increase the cost of manufacturing due to extra
control, rework, more inspection and risk of shipping defect to customer.
We can move towards quality is free by understanding how to
prevent or minimize the 4 types of
quality cost
|
Category |
Description |
Suggested Mitigation Plan |
|
Appraisal cost |
Cost of performing test and inspection on a product
to screen out potential defect include inspector. |
· Create testing which replicate customer environment |
|
Internal
failure cost |
Cost of rework or
scrapped product which does not comply to the spec |
·
Product design that are error proof |
|
External failure cost |
Cost of poor quality at customer site which involve
warranty cost, product recall, lost of customer trust |
· Plan in quality per prevention cost plan, then
quality is really free |
|
Prevention
cost |
Cost of preventing a
defect through quality planning of design in quality and build in quality |
· Ensure quality
function gets involved during the early design stage · Benchmark on
predecessor product if any to correct the problem · Proper FMEA involve
all downstream function such as production and customer quality · Study how product
being used in customer environment and design the part for customer
convenience |
From the table above,
it is shown that by focusing on preventive cost through proper quality
planning would have minimized the appraisal cost and even eliminate failure
cost. Bear in mind quality issues design
stage will on 1/1000 of the failure cost at the customer site.
Unfortunately, many organizations choose not to put in
effort in quality planning during the design stage and hope the problem will
never surface during manufacturing or customer site. The management mindset does not shed a tear
until they see the coffin (不見棺材不落淚 ) had
caused them to pay for enormous quality cost especially if failure happens at
customer integration.
