Achieve customer specifications through process improvement.

Achieving customer specifications is an important job of the quality assurance professional. Specifications define the difference between acceptable and unacceptable products and are at the heart of customer satisfaction.

The ability to consistently deliver product within specifications often determines whether the supplier will continue to do business with the customer. The most certain way for the supplier to achieve the goal of delivering product within specifications is to adopt statistical process control (SPC) methodologies. SPC provides the means to achieve and maintain stable production processes that are capable of meeting specifications.

We can improve a process first by better coordinating the design of the process with the specifications of the product. A fundamental aspect of this improvement process is to recognize that processes, no matter how closely monitored, will have variation. This variation is well defined when a process is in a state of statistical control, i.e., is varying randomly without large, assignable variations.

The second component is to measure how well the process can meet specifications. This is called process capability. By reducing process variation, the supplier increases his capability to meet specifications and thereby reduces the amount of out-of-specification product.

In order to achieve high quality, the supplier must keep the process in a state of statistical control. This means that the process must not be affected by special causes or unpredictable variation. The supplier can be assured that the process is in statistical control if he properly develops a process control plan and monitors the process using techniques such as control charts.

The final step entails an effort by the supplier to continually reduce the level of process variation using continuous improvement techniques. This in turn improves product quality and further reduces the risk that out-of-specification product will be made. As a result, the supplier can set meaningful specifications, and the processor will worry less about product failure caused by an out-of-specification ingredient.

Since food processing often uses natural products that are frequently non-homogeneous, process capabilities tend to be lower than in industries which use homogeneous starting materials. By using continuous process improvement techniques to push capability as much as possible, the food processor will both reduce costs and the chance of shipping out-of-specification products. SPC software is available from Northwest Analytical Inc.

Further information. John G. Surak, Coordinator of International Programs, 224 Poole Agricultural Center, Clemson University, Clemson, SC 29634; phone: [phone]; fax: [phone]; email: [e-mail]. Jeff Cawley, Northwest Analytical Inc., 519 SW Park Ave., Portland, OR 97205; phone: [phone]; fax: [phone]; URL:www.nwasoft.com.