How Much Documentation Should You Provide?

Companies vary on how much documentation they provide for people setting up and running CNC machines. There may be reasons you document jobs in a certain manner, but there are three major factors that contribute to how much you should document: the percentage of repeated jobs, the number of people involved with a given job and the complexity of the job versus the skill level of the people involved.

Columns From: 5/2/2004 Modern Machine Shop,

Companies vary on how much documentation they provide for people setting up and running CNC machines. There may be reasons you document jobs in a certain manner, but there are three major factors that contribute to how much you should document: the percentage of repeated jobs, the number of people involved with a given job and the complexity of the job versus the skill level of the people involved.

Percentage of repeated jobs: The greater the percentage of repeated jobs, the more documentation you should provide. The more a task is repeated, the easier it is to justify improving it. Ensuring that you provide adequate documentation is almost always the first thing you should do to improve.

Admittedly, some companies (particularly job shops) never see the same job twice. Even if they do get repeat business, they won’t know when they run a job for the first time that they’ll get the job again in the future. For such shops, it can be difficult to justify elaborate documentation.

But consider a product-producing company that runs a finite number of jobs over and over. For this kind of company, there is no excuse for confusion that leads to wasted time at the machine resulting from inadequate documentation. Of course, some jobs will be run more often than others; weeks, months or even years may pass before a job gets run again. For those less frequent jobs, people may forget how to run them. Adequate documentation will ensure that machines don’t sit idle while people figure things out.

The number of people involved with a job: The more people involved, the more documentation you should provide. Again, companies vary greatly in this regard. In many job shops, one person programs, sets up and runs out the entire job. In this case, and especially if the job will never be run again, documenting will only add to the amount of time it takes to complete the job.

On the other hand, companies where several people are involved with each job must have a way to communicate with one another. Consider a product-producing company with ten CNCs. It may have one or two programmers, two or three setup people and as many as 30 operators. Good communication is essential at this kind of company. Even if there are many repeat jobs, different people may run a given job every time. Left to their own devices, it is likely that each person will do things differently.

Complexity of the job versus the skill level of personnel: Documentation for a task should always be aimed at the workers with the lowest skill level that will perform the task. The more people involved with your CNC environment, the more likely it is that there will be variations in their skill levels.

Job shops and tooling-producing companies tend to require a great deal from their people, and they tend to have very skilled people. With this high skill level comes a minimal need for instruction. Again, these companies tend to have a minimal amount of repeat business and have one person performing all tasks related to a given job, which also minimizes the need for documentation.

Conversely, product-producing companies tend to hire people with lower skill levels, especially for the position of CNC operator. Some new CNC operators, for example, may have little or no previous experience with manufacturing, let alone CNC. And because of the number of CNC operators a company must have, this tends to be the hardest position to keep filled, meaning there may be a constant influx of new, inexperienced operators. Remember, the lower the skill level, the more documentation you should provide.

Many companies provide good setup documentation but provide nothing for CNC operators. They either expect setup people to relate the details of how the job should be run (workpiece load/unload, sizing adjustments, tool replacement and so on), or they expect operators to figure it out.

To tell if you’re providing adequate documentation, watch your setup people and operators. Are they struggling to figure out how each task should be performed? Worse, are they making mistakes that cause them to backtrack (duplicating effort) once the mistake is found? Worse yet, are mistakes they make going undetected until they scrap workpiece(s) or damage machines? How often is someone called out to the machine to handle a question or problem? These are all indications of inadequate documentation.

There are two ways to improve: provide more training to increase the skill level of the person performing the task (minimizing the need for documentation), or decrease the skill level required to perform the task. One way to accomplish the latter is to provide a better explanation of how the task must be performed with documentation.

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