Cutting tools are the gems for manufacturing machines; without them, machines are useless. The global metal cutting tools market is multiplying over time. It is expected to grow from 75.97 billion USD in 2022 to 105.46 billion USD in 2029.
Cutting tools offer a variety of operations and make the job quicker and easier. However, there are several types of cutting tools in the market, each specified for a particular function.
People often get confused among various cutting tools. Undoubtedly, it is pretty challenging to choose the right cutting tool for machining the parts. Thus, through this article, you’ll know about the classification of cutting tools and how to choose the right one for your cutting operation.
So, let’s have a detailed account of cutting tools!
What is a Cutting Tool?
A sharp wedge-shaped device used to remove or cut the material for shaping and manufacturing the parts is called a cutting tool. Typically, they are hardened tools made of various materials with unique compositions. The relative velocity between the cutting tool and workpiece is responsible for the cutting action. Generally, cutting tools are designed for cutting metals, but they can also be used for various other cutting operations.
Cutting tools are attached to various machines to provide a variety of cutting operations, including drilling, turning, milling, and many others. Moreover, there are several geometries of cutting tools, with different clearance angles and several edges that make them different.
Classification of Cutting Tools Based on Material
In manufacturing industries, there are various materials to be machined or cut. A different cutting tool is used for every specific material, containing certain unique properties for efficient cutting. Here is a detailed classification of cutting tools based on their composition and properties:
- Carbon steel tool
- High-speed steel tool
- Cemented carbide tool
- Ceramics tool
- Cubic Boron Nitride Tool
- Diamond Tool
1. Carbon Steel Tool
Carbon steel cutting tools are suitable for manufacturers dealing with low-speed machining operations. These cutting tools are typically composed of 0.6 to 1.5% carbon, 0.5% of Mn, and Si. Plus, the addition of Cr and V increases the hardness along with its grain size.
Usually, carbon tool steel is not preferred in most modern machining operations. The reason is that it is not good at tolerating higher temperatures(more than 240°C).
You may find the application of this material in milling tools, twist drills, and forming tools for cutting soft materials, like, brass or magnesium.
2. High-Speed Steel (HSS) Tool
High-speed steel tools comprise many alloying elements, including chromium, molybdenum, tungsten, and vanadium. All these alloys serve to increase wear resistance and toughness. It can tolerate temperatures up to 650°C. Thus, it starts losing its hardness from 650°C onwards. However, you may pass the high-speed steel tool under surface treatments to increase its lifespan.
Primarily, these tools are suitable for broaches, drills, single-point lathe tools, milling machines, etc.
3. Cemented Carbide Tool
Cemented carbide tool is the result of the powder metallurgy process. It composes tantalum, tungsten, and titanium carbide, whereas cobalt acts as the binder. Yet, the tool is termed cermet when nickel or molybdenum is used as the binder. These tools are considered pretty hard as they can maintain their hardness up to almost 1000°C.
Cemented carbide tools with high cobalt are ideal for rough cuts, while the one with lower cobalt is perfect for finishing. Generally, they are preferred for machining non-ferrous metals, cast iron, and non-metallic materials.
4. Ceramics Tool
Normally, aluminum oxide and silicon nitride act as efficient ceramics materials. Ceramics are chemically inert and are not easily bonded to metals. They possess excellent wear, heat, and corrosion resistance in addition to high hardness. Also, ceramic tools perform ten times faster than HSS tools. They can easily maintain their stability up to 1800°C. Thus, no coolant is needed.
Ceramics tools play a significant role in high-speed, hard, and dry cutting. Most importantly, it is used for the cutting of difficult-to-machine materials manufacturing. Ceramics tools are best to be used in CNC machines to meet high-speed operations.
5. Cubic Boron Nitride(CBN) Tool
Cubic Boron Nitride is popular due to its excellent hardness as it is considered the second hardest material in all cutting tools. It is an outstanding thermal conductor and has superb thermal stability. You can easily heat it to the temperature of 10000°C.
Cubic boron nitride tools are perfect for processing all hardened steel workpieces. Moreover, it can easily cut the hard cast iron, cemented carbide, superalloy, etc. Yet, these cutting tools are not suitable for materials featuring high plasticity.
6. Diamond Tool
Diamond is the most expensive and rigid material known in nature. No doubt, it is highly thermal conductive with a high melting point and wears resistance. Diamond tools help you to achieve excellent surface finish and dimensional accuracy. Besides its advantages, it has poor thermal stability, due to which it loses its hardness when the temperature exceeds 700°C to 800°C. Thus it is not appropriate for cutting ferrous metals.
However, diamond tools are known for cutting non-metallic and non-ferrous materials at extremely high speeds.
How Can You Choose the Right Cutting Tools for Machining?
The following are some considerations you must keep in your mind while choosing any cutting tool for machining your products:
1. Number of Cutting Edges
Usually, the cutting tools consist of one or more cutting edges that take part in the manufacturing process simultaneously. For every cutting operation, a specific number of cutting edges participate in the process. So, you need to choose the appropriate one. Generally, the number of cutting edges is classified as follows:
● Single Point Cutting Tool
As the name indicates, a single-point cutting tool only uses one main cutting edge for the removal of the material. These tools are specified for the turning, planning, and shaping operations. Single-blade reamers are an example of single-point cutting tools that play a vital role in expanding the hole size of workpieces.
● Double Point Cutting Tool
Typically, double-point cutting tools feature two cutting edges. Both of them perform simultaneously in a single pass. Only drill falls in the category of double point cutting tool. However, the drill may have two or more than two cutting edges. Thus, if you want a cutting tool to meet your drilling needs, this cutting tool might be considered.
● Multi-Point Cutting Tool
A multi-point cutting tool deals with more than two cutting edges at the same time. The number of cutting edges may range from three to a few hundred. Due to this reason, these tools are super fast in operation and highly preferred in modern manufacturing techniques. Many milling cutters, grinding wheels, broaches, gear hobbing cutters, etc., are examples of multi-point cutting tools.
2. Size of Tool
The size of your cutting tool also matters a lot in attaining the perfect cutting of your workpiece. There are specific criteria for every cutting machine or process. For instance, selecting a small lathe tool might not be good compared to a larger one that is more rigid and effective. Likewise, extra extensive milling tools may spend more time cutting air and are much more expensive. Therefore, always choose an appropriate-sized cutting tool.
3. Determine the Application
When choosing the right cutting tools, you should first determine the application for which the tool is required. Primarily, there are two fundamental applications you may come across. The one is manufacturing which includes sizing, shape-cutting, and drilling holes. Whereas the second is removing, which involves finishing and smoothing the surface. Hence, you must select the cutting tool accordingly.
The most crucial step is to know the material of your workpiece as well as the cutting tool. Not every cutting tool in the market is suitable for the material of your workpiece.
For example, it is impossible if you are thinking of cutting ferrous metals, i.e. steel or cast iron, with a diamond cutting tool. Likewise, carbon tool steel is not suitable for high-temperature applications, and some tools are not effective for slow-speed cutting operations.
Therefore, you must be careful regarding the material of your cutting tools and workpieces to achieve better results.
5. Power Requirements
You also need to get a cutting tool according to the power of your manufacturing machine so that it can offer the best cuts. If you own a 20-hp mill, a cutting tool that uses 80 percent of the power should be bought. In order to follow this consideration, you need to check the power/rpm chart in the manual of the machine’s owner.
6. Chip Control
Undoubtedly, getting excessive bad chips while cutting the parts for manufacturing is not a good sign. The chip represents the performance of your cutting tool. Yet, a good chip is not a problem, but a bad chip is worse. In order to avoid the chip, you should instantly replace your cutting tool or change the radius, depth, speed, feed, etc.
Finally, you are here with enough knowledge about cutting tools. The information given in this post will surely help you choose the better cutting tools for your machining operations. Make sure you always get the tool according to the application and material of the workpiece to enjoy the quality cuts.