In Defense of Control Freaks

PLC Probe

An entire field of medicine called psychiatry exists to help people lead what the practitioners consider a "normal" life. Psychiatrists look at the various "peculiarities" of people and help them conform to the norms exhibited by everyone else.

Lay people commonly call the people who exhibit one possible disorder a "control freak." An example might be an individual afraid to ride in an airplane as a passenger because he has no control over the airliner. This article is going to show that control actually is a very normal pursuit today. Control freaks, you can come out of the closet.

In the fields of converting and flexible packaging, control generally applies to any process that may occur during the long road from manufacture of various raw materials to the assembly of the final package. In these processes, "control" means equipment performing any operation can operate only under certain conditions.

These conditions are selected to ensure the resulting product is satisfactory. Being a control freak is the first step toward ensuring customer service problems remain minimal.

Even before the advent of computerized control systems, most companies having any converting process had at least a crude form of process control in place.

For example, they knew that running a specific adhesive to laminate two films required a certain adhesive application weight, running speed, oven temperature, etc. Sometimes this was in the memory of someone in the plant, probably an operator. Or, the information might have been written on a scrap of paper and stored in a file cabinet somewhere.

These methods were crude, but they worked—they helped to make a product exactly the same each time. People’s memories and scraps of paper, however, can’t compare to the efficiency of a computer. With automatic control systems, many converters simply enter the name of a product that a customer desires into the computer.

Depending on the complexity of the control system, the computer then can generate the necessary data regarding mixture of the adhesive and settings for the applicator nip, oven, and speed. It can produce information on proper slitting and packaging and, in certain cases, can set some or all of these parameters automatically.

Truly advanced control systems will monitor production in real time and alert attendants to difficulties as they occur. These might include problems with coating weight running low, an oven temperature that is not correct, etc.

Sometimes the control system can correct the problem as the job is running. Well-designed control systems are operator-friendly, perform multiple functions, connect to a computer that shows values for many parameters during an operation, and store values for retrieval at a later date.

A good control system is extremely helpful in trouble-shooting operations. An operator at a work station can see a schematic of the entire operation and the desired settings and actual values. Passwords ensure the control system maintains the desired degree of security for the operation it is controlling. Control systems can minimize start-up time to acceptable product and greatly decrease the amount of scrap generated.

The description above for a control system sounds almost like we do not need humans to run converting plants any longer. We all know this is not true. Computers can do many things in our lives today, but they will never be any better than the people attending to them.

Leaving everything to a computerized control system, in fact, can cause problems that result in an unsuitable material reaching a customer. When using a control system, a good philosophy is to allow it to do as much work as it possibly can, but oversee and monitor it as you would a regular employee in your operation.

Control freaks, flaunt your obsession! You will be doing yourselves, your companies, and your customers a huge favor.



David J. Bentley Jr. is a recognized industry expert in polymers, laminations, and coatings with more than 30 years of experience in R&D and technical service. Contact him at dbentley@unm.edu.


To read more of David J. Bentley’s PLC Probe columns, visit our PLC Probe Archives.


Subscribe to PFFC's EClips Newsletter