How to Select the Right CNC Machine Tools

machine tools

Exemplary CNC machine tools enable the machining process very easy and trouble-free. These CNC tools equip the machining process to execute a range of cuts and incisions in a workpiece to convert it into a spectacular custom-designed part.

They are many different types of CNC cutting tools, from milling to turning and drilling, that are compatible with respective CNC machining processes. All these tools have their versatile usages and limitations too. But CNC milling machine tools, are the ones that are used the most. Because these milling cutters provide a tremendous facility to automate the process by allowing the tools on them to change automatically.

It is extremely paramount for you to learn about these machining tools if you are interested in learning CNC machining well. If you are an expert or a novice, it does not matter, you must master the functions and limitations of every tool.

In this article, the most widely used types of milling cutters will be discussed, the materials used in their manufacturing, and expert guidance in choosing the right CNC machine tool will also be briefed. If interested to learn about milling machine tools then read on.

Most Widely Used Types of Milling Cutters

A device that is used to remove material from a workpiece during the CNC machining process is called a CNC machine tool. A cutting tool is placed on the spindle of a CNC machine and guided by computer-controlled instructions to perform the intended task.

The shear deformation process is used for material removal from the workpiece. In this process, a tool rotating at higher speeds interacts with the workpiece and results in many small pieces being removed.

There are numerous different types of cutters and each one of them has its unique function, properties, and limitations. Which tool is to be used depends on your requirements and choosing the right one depends on your expertise. Below we discuss the most widely used types of milling cutters.

1. End Mills

An end mill is amongst the most widely used cutters. It is one end contains sharp teeth and sides as well. The end mill is different from a drill bit in function, application, and shape. Most milling bits are capable of cutting in the radial direction but a drill bit can cut in the axial direction.

This milling cutter is available in many shapes. Such as some have a single flute but others can have eight flutes.

Different types of end mills are given as follows

Flat End Mills

These are flat-faced milling cutters used for general purposes and are proficient in 2D cutting.

Ball Nose End Mills

These are cutting tools having a ball-shaped end and are perfect for 3D contours and curves.

Bull Nose End Mills

These cutting tools have a flat bottom and rounded corners and are suitable for filleting and roughing.

2. Face Mills

Face mills have a very unique body that offers replaceable cutter inserts normally made of carbide. These tools are predominantly used for milling a face on the surface of a workpiece. Since this type of milling cutter has cutting edges placed on the sides of the cutter, therefore, these are only capable of cutting in the horizontal direction.

Cutting inserts replacement facility stands these cutters amongst the most widely used CNC cutting tools, which makes cost-effective than other cutting tools, increase their life and productivity. 

3. Roughing End Mills

These end mills are used for material removal from the workpiece very quickly in substantial amounts during heavier operations.

These cutters have jagged teeth that help to remove huge pieces and allows for little to no vibration but leaves a rough finish.

4. Slab Mills

These cutting tools are used to mill flat surfaces. Slab mills don’t have any side teeth and are helpful to perform general or heavy-duty operations.

5. Involute Gear Cutters

These CNC machine tools are utilized in the manufacturing of metal gears and these metal gears provide useful functionality in the manufacturing industry. These milling cutters are also used in the manufacturing of a special milling machine known as the hobbing machine.

6. Fly Cutters

Fly cutters have a solid body on which one or two tool bits can be attached. These tools help create broad and shallow cuts on a workpiece. These are comparatively cheaper as compared to other milling cutters. A double tool bit fly cutter is also known as double-end fly cutters or fly bars.

7. Ball Cutters

These milling cutters are used to create corner radiuses on the perpendicular faces of a workpiece. These are a special kind of tool and can be easily recognized due to their hemispherical cutting tip.

8. Hollow Mills

These tools have a pipe shape and look like inverted end mills. Hollow mills have their cutting edges inside the pipe shape and are used for creating shapes like full points and form radii.

9. Woodruff Cutters

Woodruff cutters are also called keyseat cutters, are milling tools used to cut key slots into parts, such as shafts. To produce suitable slots for woodruff keys, these cutting tools have their teeth perpendicular to the outside diameter.

10. Side-and-Face Cutters

These cutters have teeth placed on both the sides and the circumference and are used to create slots and grooves. Due to technological evolution, many tools can be used to produce slots and grooves with better quality and durability. Therefore, their use has decreased over time.

Materials Used to Manufacture CNC Machine Tools

Different types of materials are used to make CNC machine tools. It is the material that determines the machining process for which the tool will be utilized and required functionality too. We discussed few important types of materials used in tool manufacturing as follows.

Carbon Steel

Carbon steel is a special category of steel. As its name suggests that it contains a higher percentage of carbon as compared to other kinds of steel. 0.05% to 0.3% is the percentage of carbon that most types of steel contain, but carbon steel has higher carbon content up to 2.5%.

This material is cheaper and not durable. Therefore, it is recommended to use for low-speed operations such as turning. Because it has a melting point of 200oC and if used for high-speed operations then the carbon steel tends to degenerate faster. Due to its low melting point, use it to cut relatively soft materials like plastics.

High-Speed Steel

High-speed steel (HSS) is an alloy of steel that normally contains 18% tungsten, 4% chromium, 1% vanadium, and only 0.5–0.8% carbon. It has high hardness, high wear resistance, and high heat resistance.

It is recommended to use it for tools performing higher speed milling operations and can withstand higher operating temperatures. Even harder materials like steel or aluminum can cut using it.

Cemented Carbides

Cemented carbide is a hard material that is extensively used in cutting tool manufacturing used in high-quality surface finishes. It consists of fine particles of carbide cemented into a composite by a binder metal. This material is harder than high-speed steel (HSS), but it is not tougher than HSS. Therefore, these can be used in higher temperature operations and can still withstand their hardness.

It is recommended to use this material to manufacture tools that perform high-quality surface finishes because it has higher tendencies to crack.

Tips For Milling Cutters Selection

Below are given some tips for milling cutters selection. These tips will be very helpful for you to choose the right CNC machine tool that is extremely important to successfully conduct the machining process.

Tool Material

Above we discussed some types of materials used in tool manufacturing. If you want to make the best tool selection then you have to look, what task you want your tool to perform for you? After that, select the right material suited for that task and hence, the tool.

For example, if you want such a tool that will be used to perform higher speed milling operations then choose that tool made from HSS. But keep in mind that the selected tool must perform the operation that you required.

Tool Coating

To perform a better machining action, tool coating is quite important. If you want your tool to work longer then use coatings like Titanium Nitride. Titanium Nitride is used to improve the lifespan of your tool but the cost also increases. If you want your tool to have surface lubricity and hardness then use Titanium Carbo-Nitride (TiCN).

Number of Flutes

Flutes are helical grooves that run down the exterior of the tool. The number of flutes is directly proportional to the feed rate of a milling bit. The increased number of flutes will help the cutter to have better feed rate. Therefore, as more flutes the cutter will have as better will be the feed rate. But flutes should be selected carefully according to the requirements.

We are amongst China’s leading CNC workshops. We have advanced CNC machines and a large number of tools as well. We guarantee excellent accuracy and durability. Our team consists of seasoned and well-reputed engineers and technicians. What you do is to CONTACT US and leave the rest here.

Cora Feng
Cora Feng

Project Manager working on CNC Machining since 2010

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