Free Case Study: The Role of SPC in the ISO 9000 process

Let's start by making one thing clear: Quality Analyst doesn’t in itself ensure compliance with ISO 9000 standards. What it does do is monitor your processes, identify deviations from your required standards and measure improvements, giving you the data you need to make informed decisions to improve quality.

The purpose of ISO 9000 is to ensure you maintain high quality standards in the goods you produce and the services you provide. The purpose of SPC is to monitor how well you’re achieving this, helping you sail through quality audits. ISO 9000 provides a set of quality standards that apply to a broad range of manufacturing, commercial and service enterprises, providing guidelines for quality assurance and management. The purpose of ISO 9000 is to help organisations maintain high standards of quality in both the product or service they provide, as well as such factors as timeliness of delivery, customer satisfaction, effectiveness of stock control etc. By ensuring that organisations develop a structure to identify and correct errors, ISO 9000 encourages the implementation of sound business practices to eliminate mistakes and increase profitability.

ISO 9000 standards provide a framework for quality systems. How an individual organisation applies this framework to meet its specific objectives and practices will depend upon the type of product and service it offers. To identify non-conformances and make the quality improvements that are necessary to comply with ISO 9000, you need first to monitor your processes to see where things could be better. That’s where SPC comes in. SPC uses statistical methods such as control charts, capability analysis and exception reporting to monitor and control a process. These identify variations within the process that can indicate areas for quality improvement. SPC also shows you how the process functions over time, so you can monitor the effect of improvements and predict how the process will run in the future, based on how it ran in the past. It helps you see if the process is currently capable of producing output that meets or exceeds specifications (and customer expectations) 100% of the time.

SPC control charts identify data that falls outside defined limits, indicating variations in the process that indicate where quality standards are not being met, or where improvements can be made, so that appropriate action can be taken.

Failure Analysis

As an example, let’s imagine a circuit board manufacturing plant. A proportion of finished boards fail the final quality inspection. Some boards may have missing or misplaced components; others may have soldering faults or broken connections. By feeding that information into an SPC program such as NWA Quality Analyst and producing, say, a Pareto chart, it’s easy to identify which is the most common type of fault and therefore the primary area for improvement. By comparing the data taken, say, a month later, you can demonstrate and measure exactly how much improvement there has been – and what is now the main problem that needs to be addressed.

The flexibility of good SPC software, and its ability to maintain data links with corporate database, LIMS and SAPS software, allows you to decide which criteria to measure and address. You could, for example, use a quantitative metric: which component causes the largest number of failures. Or you could prioritise the factors which affect costs and profitability: for example, a controller fuse may fail three times a week, but takes minutes and costs pennies to replace; while a motor which fails three times a year may result in a week’s lost production each time.

In this way SPC provides a tool that identifies where quality improvements can be made, gives you the information to choose which areas of improvement will provide the most benefit, and documents how effective the improvements you make are in achieving better quality. The statistical methods inherent in SPC allow you to predict the effect of corrective actions, and document the accuracy of these predictions. SPC provides the evidence ISO 9000 requires to prove the effect of your quality improvements.

You can apply SPC techniques to just about any operation, not just production processes. For example, you could chart the incidence of customer complaints about the timing of deliveries, or the relationship between accidents at work and shift patterns, to identify where remedial action might be taken. SPC can help you achieve continuous quality improvement across the organisation.

It can be downloaded from the AdeptScience website.

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