In a previous CNC Tech Talk, we described a method of offset entry that allows the operator to simply enter a measured dimension when an offset adjustment is required (as opposed to calculating the actual amount of needed offset adjustment). The column met with rave reviews and is still available on the Web at
In most companies, the largest productivity gain can be achieved by improving the proficiency of people. This is true for just about any task to be performed, but here we’re talking about CNC machine tool use.
With block delete, a slash code (/) in the program works with an on/off switch on the control panel. If the switch is on, the control will ignore programming words to the right of slash codes.
You know that to truly qualify a program (keep it from ever having to be changed in the future), you must eliminate those things that change from one time the job is run to the next. But certain variables may be beyond the control of CNC people.
The following are important time-related definitions presented in past columns.
Setup time: The time it takes to go from making the last workpiece in the most recent production run to efficiently making the first good workpiece in the next production run.
In the May Tech Talk column, I discussed a method of determining cutting motion time in a program. A certain amount of cutting motion time is air cutting time.
The actual act of replacing dull cutting tools on turning centers is usually pretty simple. Most cutting tools use carbide inserts, which, aside from requiring an awkward position of the CNC operator, can be removed, indexed and replaced with relative ease.
How much cutting motion time is in your program? If you’re interested in reducing program execution time, it is helpful to determine how much of the program’s execution time is related to cutting motions (G01, G02, G03 and so on) and how much is related to non-cutting motions including rapid motions, tool changes and miscellaneous functions. Wouldn’t it be nice if all of program execution time is cutting motion time? This is not possible—but unless you know how much of a program’s execution is made up of non-cutting motion time, you’ll never consider improving it.
As you know, computer numerical controls have a series of coordinate manipulation features such as mirror image, coordinate rotation, scaling and axis inversion. But with some control manufacturers, these features are options that you must pay extra to get.
It should go without saying that CNC people directly affect the productivity of the machine or machines on which they work. Because a company’s productivity is directly related to the productivity of its CNC machine tools, CNC people should be considered among the most important people in a company.
Feed rate for all linear axes can be specified in per-minute fashion (either inches or millimeters per minute). For many machines, feed rate can also be specified in per-revolution fashion (either inches or millimeters per revolution).