Precision Machining Measurement
While you are reading this sentence, there are millions of precision machining
operations taking place. All over the world, highly accurate machine tools are producing the pieces and
components for the things we use every day.
Unlike injection mold making and tool and die making, precision machining is a bit
easier to comprehend for the average consumer. Most likely this is because everybody has seen a lathe or drill
press or other machine tools.
What people do not realize though, is just how precise this work actually is. If you
were to take a cigarette paper and divide it 4 times in the thickness, you would be in the realm of precision
If two mating parts are to fit together and function, this type of accuracy is
required. Obviously, it takes a lot of CNC machine training to have a competent workforce.
Imagine all the jet engine components for a moment. Or at least imagine that there
are tons of moving pieces whirling around at incredible speeds, all humming along to make the engine work. Think
about a shaft as big around as your wrist, spinning around 5,000 times per second, or 30,000 RPM. If this shaft is
not nearly perfect, it will vibrate and finally break or seize up and stop working, destroying a lot along the
How to measure these close tolerances
A precision machinist must know how to use a wide variety of inspection tools, such
as a precision micrometer. Two individuals must be
able to use the same piece of equipment and obtain identical results. If not, there will be no consistency and the
process ceases to work.
It takes practice and training to use precision equipment. For example: a dial
indicator seems straight forward enough. You run the needle over the workpiece and read the number on the dial. In
practice, however, there are numerous variables that must be overcome before you know you have an accurate
You must be certain your granite surface plate is flat and calibrated. If not, how
can you be certain your measurement is accurate?
The height gage, or magnetic base holding the dial indicator must be reliable. If it
does not have a high degree of repeatability, you must resolve that issue before continuing.
The angle that the indicator needle is set at also influences the reading. Each
company has different optimum angles at which the reading is 1:1, if the angle is excessive you will get a false
Your gage blocks or height gage must be calibrated and accurate. If not, all your
readings will be faulty.
This is just one example of why training is necessary for precision measurement. It
is similar with other measuring tools such as:
Pin gage sets
Some of the more common types of precision machining are:
Medical precision machining
Aerospace precision machining
Injection mold making components
Metal stamping dies
Micro machining precision
Precision Swiss machining
The next time you fly in a plane, drive in your car or get a drink from the fountain,
thank a precision machinist for making your life a bit easier and more convenient. CNC machining and manufacturing
are hidden, but very important for so many facets of our daily lives.