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What are the differences between manual, conversational, and CAM system
I was wondering if there is any difference between NC programming and
conversational. One of my co-workers says NC is more accurate and faster.
There are actually three types of programming methods, manual programming
(which I think you're referring to as NC), conversational programming (which is
also called shop floor programming), and computer aided manufacturing (CAM)
system programming. Each has it's place and application.
Generally speaking, manual programming is best when jobs are simple, there
aren't all that many new programs required, and/or there is a need for the CNC
program to execute as efficiently as possible. A programmer prepares the
program in the same language that the CNC machine will execute it, which can be
tedious and error-prone - but manual programming lets the programmer be as
intimate with the CNC machine as possible. This means programs can be written
in a way that they execute as efficiently as possible on the machine. While
some CAM systems can generate pretty efficient CNC programs, I'd still
recommend manual programming to anyone doing ultra high-volume work. You just
can't beat the efficiency of a well formatted manually written program.
Conversational programming is best done when programs must be created while
the machine is down in setup. If, for instance, a company sees a great deal of
repeat business, if lot sizes are very small, and cycle times are very short,
it will be difficult (if not impossible) to prepare programs up front, while
the machine is running production. Conversational controls can be thought of as
a single-purpose CAM system, making it quick and easy to generate a program
right at the machine. With print in hand, the setup person can step up to the
machine and quickly create the CNC program. Conversational controls allow
programs to be entered without any need for math, and take much of the
tediousness out of programming. With one popular turning center conversational
control, for example, average programming time is under ten minutes.
CAM systems are best used when there are a variety of machines to program (a
programmer would have trouble keeping the language for each machine straight),
there is quite a bit of new business (many programs to create), and/or jobs are
quite complex (making it difficult to manually program). Like conversational
controls, CAM systems remove the tediousness from programming. Workpiece
geometry is first imported to the CAM system from a computer aided design (CAD)
system, which eliminates the need for the programmer to define the workpiece
size and shape. The programmer then specifies how machining is to be done. CAM
systems vary dramatically with regard to how machining is defined, but most
allow the programmer to choose machining operations from a menu and specify the
machining parameters in fill-in-the-blanks fashion. The CAM system then
generates a CNC program - the same kind of program a manual programmer will
write. This program is then loaded into the CNC machine and run.
Note that there are some exceptions to what I've said. For example, since
CAM systems are much more reasonably priced today than in years past, almost
all CNC-using companies can afford to have one.
Also note that some companies don't adhere to the general statements I've
made. For instance, some companies will program on the shop floor
(conversationally) even though they have ample time and personnel to do so off
line. Or just the opposite may be true. They may have to prepare programs while
the machine is in setup, but their programmer prepares programs off line
manually or on a CAM system. Both can lead to under-utilization of the CNC