Process control is the management of inputs to ensure a uniform output, no matter how many times a process is repeated. This can involve everything from water purification procedures to landing space shuttles safely and successfully. In process control, principles of statistics and engineering are applied to a process to ensure regularity and repeatability. Automated systems are capable of exerting process control and can be programmed for various advanced functions.
Technicians very clearly define an outcome in process control, such as a finished product or a successful aircraft landing. This process may require batches; only one aircraft lands at once, for example. It can also be continuous in nature. At an ice cream manufacturing facility, for example, the facility can keep pumping out ice cream continuously, and does not need to take a break between batches.
Awareness of an outcome allows the company to put measures in place to control the process, and to ensure that the outcome will be reliable. The ice cream manufacturer needs controlled temperatures for food safety and quality reasons, for example. It also needs ingredients, personnel to operate the equipment, and supplies ready to package the ice cream for sale. All of these become components of process control.
Some process control can be highly automated. The programming can also teach a system how to compensate for minor problems before alerting technicians. In the ice cream company, thermostats measure temperatures and control chillers. When they detect a temperature spike, they can increase the activity of the chillers, but may send an alarm if the temperature rises above a certain setting. In this case, the system controls the temperature unless a problem arises and a technician needs to be present to address the issue.
The application of statistical analysis and charts to a process can all be elements of process control. Technicians use this analysis to see where processes deviate, and to determine how to prevent such deviations in the future. Their analysis can also provide important information about timing that may play a role in handling orders for products, facility scheduling, and other processes.
Quality assessors may review the outcome to determine whether it is consistent and reliable. They can also initiate audits at any step of the process if they have concerns about safety or reliability. As systems start to break down, processes can become sloppy, and retrofitting along with other procedures may be necessary to restore consistency.
By Mary McMahon
Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All The Science researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.