Most companies have developed setup documentation to help setup people get CNC machines ready to run production. Information about the work holding setup, cutting tools, program zero assignment, and program location are included to simplify the task of setup and make it possible to gather needed components prior to the time when the machine goes down.
While it is not unusual for companies to go to great lengths to document setup-related tasks, it is also not unusual for companies to minimize what they do to help operators complete production runs.
In some companies, production run documentation may not be necessary. If the person that sets up the machine is also the person that completes the production run (one person sets up and runs production), this person will learn enough during setup to complete the production run without needing much more help.
But in companies that have one person set up a CNC machine and another run out the job (the CNC operator), at least as much effort should go into developing production run documentation as goes into developing setup documentation. Simply consider the skill levels for the people involved. Generally speaking, a CNC operator does not possess the skill of a CNC setup person – and will need more help to understand their responsibilities.
I’m always amazed by how little help CNC operators are given. Many companies expect the setup person to relate the important points about running a job to the CNC operator as the production run begins. But this “blow through” often leaves many questions unanswered – and can lead to wasted time during the production run while the operator tries to figure things out. And consider a company that has two or more shifts. Who explains the job to the second or third shift operator?
Obvious production run- related things that should be documented include part loading procedures (especially when something special is required during loading), tool life expectancies (for dull tool replacing), target values for all dimensions (not just critical dimensions), offset relationships to cutting tools, and instructions for any other tasks operators are expected to perform during the production run (deburring, SPC reporting, secondary operations, etc.).
Many companies consider many of the related tasks to be “self-explanatory” to experienced operators, which is probably the reason why production run documentation is not provided. But without it, there will likely be times when machines sit idle waiting for the CNC operator to figure something out.
One classic example has to do with sizing adjustments. Even the setup sheet will not make it clear as to which tool machines a given surface. Said another way, there is no documentation that specifies which offset is controlling each machined surface on the workpiece. The setup person simply knows that the offset number for each tool corresponds to the tool station number. If tool number five machines a given surface, offset number four will be used to make sizing adjustments for the surface.
Again, the setup person becomes pretty intimate with the job as they make the setup. They eventually figure out which tool machines each surface. But when the job is turned over to an operator, it can be very difficult for the operator to know how to make sizing adjustments.
Simple documentation can solve this problem. A marked up print can be prepared to describe the offset number that controls each machined surface. A color code can be easily developed – each color representing a different offset number. This will make it immediately clear to the operator when an adjustment must be made.
Watch your CNC operators during production runs. Not just for the length of time it takes them to complete a cycle or two, but for enough time to see what they really do during all facets of the production run. It’s likely you’ll find many examples of times when the machine sits idle, waiting for them to figure something out – something that could have been easily clarified with production run documentation.