It is common to machine several identical workpiece attributes from within a single program. Consider the four identical circular counter-bored holes that must be milled in the workpiece shown in Figure 1.
You know that machining centers have tool length compensation, cutter radius compensation and fixture offsets. Turning centers have geometry offsets, wear offsets and tool nose radius compensation.
In my CNC courses, I always ask how many people have access to the Internet. It used to be (as recently as last year) that only a small percentage of hands would go up.
The cutting tools in your turning centers change on a regular basis. To minimize tool change time during setups, many setup people will simply load the tools required for the new job and leave tools in the turret from the last job as long as they don't interfere with the new job.
While we agree that the absolute mode should be your positioning mode of choice for most applications, there are times when incremental mode can be quite helpful. Repeating motions within a subprogram, for example, is one excellent example.
It's common to have to rerun tools. If you find a problem during the program verification with the eighth tool, for instance, you'll want to restart the program from the beginning of tool number eight rather than having to rerun the entire program just to get back to that point.
Some companies store all cutting tools they ever use in the CNC machine's magazine or turret. Others have a number of tools that they keep in the machine on a permanent basis.
Many people determine cycle time by measuring cycle start to cycle start time. As the operator presses the cycle start button, he or she starts the stopwatch.
One definition of waste is any lost time or money caused by disorganization, duplication of effort and misunderstandings. Most setup-reduction programs make eliminating waste a primary goal.
Sometimes you may be able to go ahead and machine the first part of a run on a machining center without having to take trial cuts. When tolerance bands are large, operators or setup people can afford to run the program with the confidence that the cuts will come out somewhere in their tolerance bands and the workpiece will not be scrapped.
Machining soft jaws remains one of the most tedious and time-consuming tasks for turning centers, so anything you can do to organize and simplify this task will speed up your setups. In order to make the workholding setup when soft jaws must be machined, the setup person must
remove the current top tooling from the chuck,
find the set of jaws to be used for the new setup,
mount the jaws to the chuck,
clamp on some form of temporary plug or ring, and
machine the jaws.