Essential CNC Machine Tools for Efficient Milling
CNC machines are known for their ability to accurately make products having a complex design. For doing different CNC machining jobs, a machinist requires a set of essential machine tools without which professional machining would not be possible.
This article discusses essential CNC tools that every professional CNC machinist would need for accomplishing a milling job efficiently. CNC milling tools are made up of certain materials which include carbon steel, high-speed steel, ceramics, solid carbide, etc. In this list, carbon steel is the least expensive material and is usually used for operations that require low speed.
High-speed steel is more tough and expensive than carbon steel. Solid carbide has the disadvantage of being susceptible to chipping. Due to the corrosion resistance that ceramics offer, tools made from ceramics can be used in cutting operations involving high temperatures that the tools made from other materials would fail to withstand.
Following are the essential CNC tools that are indispensable for a machinist for carrying out the milling jobs –
End mills usually consist of cutting teeth on one of the ends and at sides. They are suitable for being used in a variety of cutting jobs. For example, a machinist can use an end mill for side milling, in which an edge surface is milled. An end mill can be divided into two parts along its length. The part that is held by a tool holder is known as the shank and the part having the cutting teeth is known as cut length.
An end mill has coatings that help in increasing its life, make it harder and enable it to be used at high cutting speeds. There are end mills having cutting edges in the center that are able to cut straight down into a part. These are known as center-cutting end mills. Other mills known as non-center cutting end mills do not have cutting edges in the center but only on the sides. They require a hole that has been already drilled in the part in order to move straight down.
A ball nose end mill has a hemispherical or ball-shaped end that makes it a perfect fit for making three-dimensional contoured shapes. A bull-nose mill has a large corner radius and it finds its use in roughing.
Face mills are used by machinists to mill the surfaces that are at right angles to the axis of the cutter. From the practical point of view, the cutting work is performed by the teeth that are present on the cutter’s periphery. The springing of the cutter can leave some amount of stock. This is removed by the face teeth when the cutter has been placed in a proper way. This produces a finer finish.
A fly cutter is a single point cutter that is usually deployed as a surfacing tool. Basically, fly cutters are rotary tools used for plane surfacing. They may consist of one or more single-point tools. At high speeds, the high-quality surface finish can be achieved with face milling, but with a fly cutter, you can get a much better surface finish. The reason being that only one cutting insert is used in a fly cutter. By using a fly cutter, you get a single uniform cutting surface.
A twist drill is a rotating cutting tool that is used by CNC machinists for cutting holes in rigid materials. A twist drill has a conical point, cutting lips, shaft and spiral flutes. Chips are directed away from the cutting lips by the spiral flutes. The materials that are usually used to build twist drills are high-speed steel or solid carbide.
Center Spotting Drills
Center spotting drills are deployed by machinists to make a hole before the task of drilling has been performed. This helps in preventing the movement of bits during the process. Combined spotting-countersink drills can do the two jobs in one pass, i.e. drilling and countersinking operations.
Thread Mills and Taps
Thread mills are used to cut a thread by moving along three axes simultaneously. This movement enables cutting of both right and left-hand threads by the same thread mill. This movement also accounts for the creation of threads of different sizes but having the same pitch. With thread mills, a machinist can cut both internal and external threads, but with taps, only internal threads are cut.
A reamer is a rotary cutting tool used to enlarge the size of a pre-formed hole. A precision reamer increases the size of a hole with high accuracy so that the sides of the hole remain smooth. Reamers can also add a good finish to a hole’s surface.
A new CNC machining professional should get hands-on experience with the essential CNC tools discussed above. It’s obvious that not all the CNC machine tools will be required for completing a job as a specific job requires specific tools, but getting acquainted with different tools will help a machinist to handle different jobs with ease.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2019 Norm Grimberg