Effective quality control is not realized by introducing common tools such as control charts and off-the-shelf SPC systems. It should be an integral part of daily operational routines. Installing a ‘control mechanism’ may allow manufacturing processes to run smoothly, that is to say: without incidents, yield losses or unexpected and unpredictable situations.
By Sonja Aarts, Quality & Reliability Consultant, Philips Innovation Services and Jo Mooren, Quality & Reliability Consultant, Industry Consulting, Philips Innovation Services
Control mechanisms are based on measurement, analysis and evaluation of product and/or process characteristics. However, it is vital to measure only the right characteristics. Properties of intermediate or end products can be measured, such as dimensions, visual aspects or material properties. You could also measure process conditions, such as oven temperatures, speed or pressure, or other characteristics.
Distinguishing three control loops
Our approach for organizing quality control in manufacturing organizations ties a number of activities together, places them in a logical sequence and context and adds reporting. This combines appropriate, often advanced measurement techniques and links measurements to technical and organizational control loops. During implementation of the quality control methodology, activities and responsibilities must be clearly established. We distinguish three control loops that have to be defined and organized
1. Installing the first Control Loop: Operator Loop
In the first, the operator who is responsible for a process step takes samples and measures predefined critical parameters and evaluates whether process is still ‘under control’ (i.e. running with the smallest possible variation that could be expected). In an ‘out of control’ situation the operator has, to a degree, authority to correct the process and bring it back to the desired state. In some cases, this first control loop is not executed by an operator but with the aid of test equipment.
2. Installing the second Control Loop: Engineering Loop
In the second control loop the responsible engineer analyzes all ‘out of controls’ and trends that occurred over a certain period, prioritizes and initiates improvement activities. In the third control loop, management organizes and facilitates improvements and tactical & strategy changes (new products, equipment) to plan for the future
3. The third loop: Reporting Structure: Management
To make control loops work effectively, the working method should also be connected to reporting and meeting structures. In the third control loop the management organizes and facilitates improvements and tactical & strategy changes (new products, equipment) to plan for the future.
This can be done by bringing the required competences together: from process, analysis, test and measurement knowledge to management and implementation and (fully automated) in-line measurement tools.
Feel free to get in touch and find out more about analyzing your production, preparing and implementing a quality control plan, building inline measurement systems or a selection of the above.