Steps used in quality control:
1. Define the quantity specification as
given by customers.
2. Measure actual quality from the
process.
3. Comparison of actual quality with the
specified quality.
4. Whenever there is derivation or
variation between them, then take appropriate corrective action.
Every
manufacturing process has got variability. The variability is of two types:
1. Process is under chance cost
2. Process is under assignable cost
Chance cost
is random, i.e. even though the process is controlled very well, under
identical conditions, but even though every item is varied in dimensions than
the other. This variation has to be accepted because of chance cost. Variation
due to assignable cost is not accepted. This concept is used in SQC
(Statistical Quality Control) as follows:
·
We
draw control charts
A control
chart consists of 3 straight horizontal lines. Middle line is called x bar
which is avg of avg of sample means. Upper control line & lower control
line are called as decision criteria lines which are away from central line x
bar at a distance of 3 бs. The sample points drawn at regular interval from the
production process are plotted on these graphs.
Inference: If all the sample points drawn are
lying within the 2 control lines then, we say, process is under statistical
control i.e. the process is under chance cost only, but if any 1 of the point
falls beyond the control limit, it gives
a signal that process is going out of control statistically, i.e.
assignable cost is introduced in the system, therefore the process is to be
stopped at that point & corrective action is taken. Take correct action so
that sample points will lie between 2 control limits. This process is called as
Statistical Process Control.
TQM is an
integrated approach of the organization in delighting the customer (both,
Internal & External) by not only meeting, but exceeding their expectation
on a continuous basis through everyone involved in the organization on
continuous basis in order to improve products, services & processes along
with problem solving methodology.