Quality control information systems
Authors: Prior Derek 
Published: July 2007

As competition for world markets becomes more intense and as greater demands are placed on human and natural resources, manufacturers face a formidable challenge — to produce cost competitive products of the highest possible quality.

Nowadays the quality control (quality assurance) department can spend incredibly large amounts of time just collecting the test data they need in order to do their job. Collating and analysing the data is similarly very demanding in terms of how much human time can be expended. Simplification and automation of the tasks of data collection, collation and analysis is possible with a quality control information system.

A microprocessor can form the basis of a quality control information system if application to only a very small area of a manufacturing operation is desired. However, far greater benefits can be derived if a real‐time minicomputer is used instead of a microprocessor. This is because quality control data can then be collected across the entire factory floor. Statistical quality control techniques can subsequently be applied to examine the effect of process conditions in some part of the factor on product malquality exhibited in any other part of the factory. ‘What‐if’ type analyses can also be conducted factory wide.

A quality control information system should be capable of

(a) identifying the product quality problems

(b) determining the causes of these product quality problems

(c) helping to eliminate the causes

(d) monitoring the altered process.

These system functions enable the quality control department to progress from a ‘fix‐the‐product’ mode to a ‘fix‐the‐process’ mode and thereby concentrate on making the product right in the first place, by achieving better control of the manufacturing process.

Application software packages are now available which have been purpose‐designed for quality control information systems. One such example is the Quality Decision Management (QDM) software package from Hewlett‐Packard, which runs on an industrial HP 1000 real‐time minicomputer. On the data entry side a quality control information system should be capable of manual input from menu‐driven terminals and bar‐code wands. Automatic input of test data is also vitally important. This enables such devices as analysers, test instruments, data acquisition units. ATE and other computers to be interfaced to gather test data with no manual intervention. All collected data should be held in a database. The QDM database can be searched to generate a wide range of reports in tabular or colour graphic form, the latter include histograms, scattergrams, control charts (X‐bar, sigma), P‐charts and Pareto diagrams. The reports enable crucial quality control decisions to be taken.

Quality control information systems can be linked to higher level production control computers to form a computer integrated manufacturing (CIM) network. Free movement of data around a CIM network offers enormous flexibility and efficiency in the overall manufacturing process, together with considerable savings in manpower.

Costs incurred in the creation of a quality control information system can be easily won back by virtue of the significant savings that such a system brings about.