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'Profitable' process control.

`Profitable' Process Control

As shown at the September IDEA `90 show and earlier at INDEX (this past April in Geneva), vendors can supply a wide range of sophisticated on-line computer and process control equipment. However, much of this technology is simply "bells and whistles" unless people can use this technology to actually improve manufacturing profitability.

We need to expand our definition of process control from the traditional "technology centered" concept to include broader operational parameters.

Traditional Process Control

A traditional view of process control concentrates on adding complex electronic sensors and computers to the base manufacturing process.

But if people cannot apply the technology to improve the manufacturing process, the capital investment is wasted. In fact, this technology centered approach can even generate a negative return on investment.

Total Process Control

A broader definition of "total process control" leads to a system where the operator and the automation become part of an interactive network that includes the operator at the center. This interactive concept results in a much more powerful total system.

Additionally, expanding the definition of process control even further to include management activities such as engineering, purchasing and production management will target the technology to achieve measurable business improvement and improve the economic return on process control projects.

Let's look at how this expanded concept of total process control improves profitability when it is applied to both on-line process control and to the larger management or "macro" process.

On-line Process Control

Virtually all of today's production operations utilize some advanced closed-loop control systems. For example, a typical disposables converting operation uses closed-loop control systems for web tensions, web tracking, relative machine speeds and adhesive temperatures.

However, the best process control schemes in our industry go beyond closed-loop controls. They work interactively with the operator to provide him with real-time information. An example is an optimum system that includes on-line computers to support the operator with the following information and analysis:

Production/Efficiency/Downtime. The operator inputs a downtime code each time the machine is shut down. Then the computer automatically compiles a running summary of the downtime and the efficiency lost for each downtime category throughout the shift. The computer also displays the current production and efficiency so that the operators can see where they stand relative to goal during the shift.

Waste. Similar to production, waste is automatically tracked and displayed throughout the shift, including alerting the operator if any individual waste cause exceeds a predetermined limit.

Quality/Process. Finished product quality data and on-line process data are input into the computer in real-time. The computer then compiles and displays control charts to guide the operator in making machine adjustments. Additionally, the computer alerts the operator whenever a control chart indicates that a parameter is beyond the statistically determined control limits.

When well conceived and implemented, this latest generation of real-time interactive process control has proven to be tremendously effective. Can you imagine playing a basketball game without tracking the score? Similarly, providing a structured way to view results during the shift helps operating personnel improve manufacturing performance.

However, the methods to provide this type of interactive information exchange will vary greatly in technical complexity and automation depending on each company's unique situation.

In fact, the automation can sometimes be too complex and too sophisticated. Today's computers can quickly generate more information than a person can absorb. Therefore, collecting massive amounts of information, simply because the computer has the capability, will quickly overwhelm the operator. Instead, only information that is "actionable" by the operator should be presented.

Furthermore, an investment in operator training is generally required to leverage the most value from these interactive systems. This training should include more than "how to push the buttons on the new computer." To get the most value from the automation, training should include basic statistical process control, analytical troubleshooting techniques and other problem-solving skills.

However, there are many parameters of the production process that the operator cannot adequately influence. For example:

* Reducing the variability of raw materials will typically require the cooperative efforts of production management, quality control and purchasing.

* Correcting machine problems requires the efforts of engineering and maintenance personnel.

* Improving operating procedures requires management coordination across all shifts.

Macro Process Control

To manage these "external operating variables," we must look beyond on-line control systems to macro process control that includes management.

In controlling this macro production process, it is management's job to assure that the cumulative variability of the materials, the equipment and the people fit within the available "operating window." For example, it is possible to have excellent control of the raw material and well trained people. But if the equipment variability is too great because of poor maintenance, the total variability will exceed the operating window, resulting in an inefficient operation.

There are a number of specific management systems that have proven invaluable in keeping all of these constantly changing variables within the operating window. These systems include:

* A Materials Certification Program to work jointly with suppliers so that the supplier can certify their materials are within the required tolerances.

* A scheduled Preventive Maintenance Program to assure the regular replacement of worn parts, as well as the ongoing lubrication of equipment.

* A Mid-Range Program to track all key process variables such as set-up dimensions, speeds and adhesive temperatures and to assure they are within their expected ranges.

* Written Machine Set Up and Change Over Procedures to assure consistent machine set up as part of each changeover.

* Start-up/Shut Down Procedures to detail each step necessary to properly start-up and shut down the converting line.

* Standard Operating Procedures to help assure consistent operations shift-to-shift.

* Written Troubleshooting Guidelines to help assure successful troubleshooting techniques are reaplied.

Not only do these systems and procedures improve the stability of the overall production process, they also dramatically reduce the recurring problems that drain management attention in many operations.

Profitable Process Control

To profitably utilize the new process control technology, we must think beyond the latest electronic gadget.

We must expand our definition of process control to include people as well as technology. Furthermore, we must include management activities so we can control and improve the entire management process.
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Title Annotation:nonwoven fabric manufacturing processes
Author:Frankenfield, Jay
Publication:Nonwovens Industry
Date:Nov 1, 1990
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Next Article:IDEA '90: the big show is over, but innovations remain to carry the nonwovens industry through the 1990s.

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