Quality is the goal of everything you design, but your work
is wasted unless the manufacturing process properly implements
your design. However many hundreds, thousands or millions of parts
come off the production line, the process must consistently adhere
to the design specifications you've set. That's what quality control
is all about.
Today's quality buzzword is six sigma. The concept of six sigma
was developed by Motorola some 15 years ago and is now accepted
as the quality goal by industries worldwide. The sigma scale defines
defects (i.e. items falling outside specification) in parts per
million (ppm); six sigma quality means that no more than 0.002
ppm (two parts per billion) fail to meet specification.
When you're seeking quality standards at these sort of levels,
the old concept of quality inspection - physically examining each
and every part that comes off the production line - is obviously
unfeasible. Statistical Process Control (SPC), also known as Statistical
Quality Control, is the solution most quality-conscious manufacturing
enterprises adopt. With SPC, the aim is usually to monitor a large
enough sample to be statistically valid, then adjust the process
to avoid the production of defective, out-of-specification parts.
Control charts are the basic tool of SPC. These show the range
of variability built into the manufacturing process, and apply
statistical methods to sample data to identify samples that exceed
or fail to meet defined control limits. Data points that fall outside
of these limits help you determine whether the process is operating
consistently or identify and eliminate the factors that cause variance.
The aims of SPC are to improve both product quality and productivity,
maximise the efficiency of the production process, reduce wastage
and keep costs down - key factors in design as well as process
engineering.
Most general statistics software packages offer the tools to perform
SPC. Increasingly, however, manufacturing enterprises are adopting
dedicated packages that integrate the whole SPC process, from data
collection to charting and analysis, into the production line.
One such is NWA Quality Monitor (http://nwa.adeptscience.co.uk),
which claims to provide a single, off-the-shelf solution for factory
floor SPC.
You can configure this software to collect data in real-time,
directly from measurement devices or through keyboard or barcode
input, from as many Windows-based workstations as you need. NWA
Quality Monitor includes a "visual designer" that lets
you customise its data entry screen, so that operators know what
they're doing and you get the data you need. Combined with its
sister package, the well-known NWA Quality Analyst which produces
the SPC control charts that identify areas for process improvement,
this provides real-time SPC feedback throughout your operation
and can easily be integrated into your manufacturing, process or
laboratory information system.
However good your quality control measures, however competent
and SPC system you have, however close you come to the holy grail
of six sigma, you still have to convince the customer. These days,
you're likely to lose business unless you can show you have achieved
and maintain accreditation to the international ISO9000 standard;
increasingly, organisations just won't buy from non-ISO9000 suppliers.
Adherence to ISO9000 goes further than production line SPC. It
demands implementation of defined quality standards across every
aspect of the business, from customer service to staff training.
Compliance with ISO standards requires careful and consistent documentation
at every stage of the operation, and there are several excellent
software tools these days that help you with this process.
Typically, these are networked packages that manage documents
and communicate information and required actions. They record a
version history of each document (which can be any kind of Windows
application file), protect against unauthorised changes and make
them available for management review. They will prompt corrective
and, ideally, preventive actions, and maintain a fully documented,
cross-reference database of evidence that demonstrates compliance.
As well as managing quality standards, these packages can be used
to managing environmental, health and safety, laboratory calibration
and testing and many other standards. Take a look at Q-Pulse (www.gaelquality.co.uk),
Proquis (www.proquis.com) or the latest, and in some ways most
comprehensive package, Paradigm (www.adeptsoft.co.uk).
Dr Know's recommended download is the NWA Quality Analyst 5.2
Demo - download yours today.