Teaching CNC with the Key Concepts approach - part ten
Part ten - Key concept number Nine: You must know the key operation procedures
At this point in the class, students should have a good understanding of what they want the CNC machine to do. However, they're probably still pretty intimidated when they look at the operation panels of the machine. In this Key Concept, the goal will be to provide them with the operation procedures they need to run a machine.
Point out that running a CNC machine requires little more than following a series of procedures. As long as you know what you want to do, a procedure can be followed to help you achieve what it is that you want. The trick is having procedures available for help.
Don't have them try to memorize each procedure - it doesn't work. Students quickly become confused and frustrated. Admittedly, there are some procedures that are so often used that students will soon have them memorized. But don't assume they can remember how to perform even the simplest procedures for very long.
We recommend providing an operation handbook for each machine in your lab or shop. This handbook will include step-by-step procedures for the most common things a person must do with the machine. We offer a series of procedures in the student manual that is included with our CNC curriculums. These procedures fall into five categories:
Manual Data Input procedures
Program editing procedures
Program running procedures
Again, each procedure should include step-by-step instructions to accomplish the task at hand. Here are the specific procedures we recommend that you include in each category:
To power up the machine
To do a manual zero return
To manually start the spindle
To manually jog the axes
To use the handwheel
To manually load and remove cutting tools in the spindle
To load tools into the automatic tool changer magazine
To set or reset the relative position display
To measure program zero assignment values
To measure tool length compensation values
To enter and modify tool offsets
To enter and modify fixture offsets
To use MDI to change tools
To use MDI to start the spindle
To use MDI to do a zero return
Program editing procedures:
To enter a program through the keyboard
To load a program from a DNC system
To save a program to a DNC system
To see a directory of programs
To delete a program
To call up a program (make it the active program)
To search within a program
To alter a word in a program
To delete a word in a program
To insert a word in a program
Program running procedures:
To run a verified program
To cancel the cycle
To re-run a tool
These procedures can be used as a crutch until they are memorized - yet some seldom-used procedures will probably never be memorized, meaning students will always have a way to find out how to perform a needed procedure.
Point out that most companies do not provide the kind of operation handbook that you let them use in class. They'll probably be on their own to develop there own operation handbook for each machine they'll be running. Make sure they understand what's involved with developing an operation handbook. You may want to give them some practice assignments to confirm that they can do it.
Documenting each procedure, of course, simply involves writing down the step-by-step procedure - and keeping the procedures organized in a notebook. So as long as someone in their company knows how to run the machine, this person can show them how each procedure is done so that it can be documented.
In our CNC curriculums, Key Concept number nine contains one topic (lesson):
The key operation procedures