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Do your people understand the implications of on-line (internal) and off-line (external) tasks?

What may be obvious to one person may not seem so to another. This is why – as a manager – you must understand and be willing to teach good machine usage practices to setup people and operators.

When it comes to setup, an on-line (internal) task is one that adds to the amount of time a machine is down between production runs. Indeed, setup time is the sum-total of all on-line tasks. Examples of tasks that are commonly performed on line include mounting workholding devices and loading cutting tools into the machine.

In similar fashion, on-line (internal) production running tasks include any tasks that add to the length of time it takes to complete a production run. And again, production run time is the sum-total of on-line tasks.

While these two statements are at the heart of any setup or cycle time reduction program, I’m not going to dive too deep into setup and cycle time reduction principles. Instead, I simply want to relate some pretty obvious tasks that setup people and operators commonly perform on line that could easily be performed off line. While they may seem obvious, I’m often surprised as I walk the shop floor in many companies. If you carefully watch your people, you may be too.

In one shop I visited, for example, I was watching an operator run a vertical machining center. When the cycle ended, he removed the workpiece from the vise. Then he cleaned it off with a rag, picked up the deburring tool and began deburring. About three minutes later, he put it into the completed workpiece bin. Only then did he go back to the machine and clean the vise. He then picked up the next workpiece to be machined from the raw material basket. But before loading it into the machine, he cleaned it and de-burred it with a file. Finally, he clamped it in the machine vise, closed the door, and started the next cycle.

What’s (obviously) wrong with this picture? Everything just described was done while the machine was down. They were all on-line tasks. Yet four of these tasks (cleaning the completed workpiece, deburring the completed workpiece, cleaning the next workpiece, and deburring the next workpiece) could have been done off-line – while the machine is in cycle. This assumes, of course that the cycle time for the job is longer than the time it takes to perform all the related tasks, which in this particular case, it was.

As you walk your own shop floor, do you ever see setup people and operators performing tasks on line that could be done off line? Unless your company has been involved in setup and/or cycle time reduction programs, I’ll bet you do.

A setup time example includes gathering components for the next setup during a lengthy production run. If the setup person waits until the current production run is completed to begin gathering, all of the gathering time will be on line. If gathering is done for future setups while the machine is still in production, setup time will be reduced by the time it takes to do the gathering.

Whenever you move a task from on line to off line, of course, you reduce the time it takes to complete the setup or production run. While this may sound like a very basic statement, I’m always amazed by how often I see tasks that could be done off line being done on line. In many cases, just a little explaining from the management side can have a big impact on productivity.

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