Intro to CNC trade secrets

I’m spoiled. With few exceptions, I machine everything I can on CNC machines. In most cases, jobs are less labor-intensive, less prone to error and are completed faster than when using manual, or conventional, machines. With the user-friendly CNC technology available today, even making one or two simple parts is often easier and more efficient.

This doesn’t mean the end of manual machining is near. There are certain tasks you can do with conventional machines that CNC machines are just not good at, such as “blending.” CNC machines can’t blend flawed features very well, simply because they don’t have “eyes.” They run on numbers. Many jobs that come through the door don’t have any documentation, any exact numbers to work toward.

Often parts than need rework are so beat up, worn out or outdated that, even if you had a print, there’s a good chance the dimensions on the print won’t match the part. Maintenance machining and mold repair come to mind as jobs that often need manual blending of some sort.

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The planning and cutting characteristics of manual and CNC machining are quite similar, with the exception that you can machine parts a lot faster on a CNC machine, such as this Haas DT-1 drill/tap center. Image courtesy Haas Automation.

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There are craftsmen in our shop who know little about CNC machining and CNC machinists who are not craftsmen. The funny thing is that often these people imagine the other as having some kind of supernatural abilities. The fact is little would get accomplished if it weren’t for these two groups working together.

CNC machining involves a combination of machining knowledge, controller familiarity and programming expertise.

Machining is the art of removing material in the proper sequence, selecting and sharpening cutters, setting speeds and feeds, measuring and determining how to hold the work. The planning and cutting characteristics of manual and CNC machining are quite similar with the exception that you can machine parts a lot faster on CNC machines, because they can read numbers quickly and move accordingly. They also don’t take coffee breaks.