If you use the correct cutting tool for the material and the type of machine you are using, the burring should be minimal.

When the tool gets blunt or is the incorrect one for the material the material will not cut cleanly and burrs will be formed.

There will always be a small amount of burring but this is usually easily removed by standard methods.

As for what is a burr and how to measure burrs.... just google 'burrs'

John.

Electropolish will reduce the burr to angstrom-size or even a "sharp" edge.

Yes you are right but electropolish could be too much expensive. if you have not to machine high precision parts maybe tumbling could be more convenient because of the lower cost

Burrs are generally unwanted material remaining after a machining operation such as grinding, drilling, milling, or turning.

Drilling burrs, for example, are common when drilling almost any material. Sometimes it could be necessary to include a chamfer in the holes to remove the burr: It is less expensive then a manual deburring.

Usually if machining parts requiring an highest grade of precision we are usually to ultra son clean parts after deburring.