CNC machine tools come in wide varieties of sizes, shapes, speeds, and other dimensions. As such, they are regarded as the workhorses of the precision manufacturing and engineering industry. These tools have a wide variety of uses – from milling to fabricating complex automobile, medical, or aircraft parts, to mention but few.
When equipped with varying degrees of automation and software, these tools can help improve the machining process in terms of efficiency and quality of your parts. However, the challenges that mostly affect most engineers are knowing the varieties of CNC machine tools and for your company’s use and selecting the right CNC machine tools. Having such a wide range of machine tools and factors to consider in selecting the right tools, the big question you’ll ask is, “how do you narrow down to the most important?”. To help you answer this question, we have curated the most comprehensive guide to CNC machine tools you’ll ever read.
What is a CNC Machine Tool?
CNC machine tools are referred to as an essential component of a CNC machine. With their presence, manufacturing processes become possible while they help craft perfect custom machined parts and products. Consequently, there seems to be nothing apt CNC machine cutting tools can’t create, ranging from simple structure or super-complex to 2mm piece of 200mm, or 3D shape or 5D, and many more.
Tooling
Tooling in CNC machining does all the cutting work. Typically, tools are mounted in a tool holder and loaded into the spindle when required. In CNC machining, there exist different types of tools to accomplish a task. This means that in CNC machining, there is no one size fits all approach. The following tools are the most common tools used in most machining set up:
1. Milling Tools
Milling is a cutting process that requires a cutter with multiple rotating cutting surfaces. This is done to remove surface material from a workpiece. The milling tools are available in a wide variety of sizes and shapes. They include;
√ Slotting Cutter
This type of milling tool is used to create t-slots along the length of a workpiece. This cutting tool must enter and exit from an open side of the workpiece due to the cutter’s geometry.
√ Face Mill
This mill cutter features carbide inserts that may be of different colors and can be exchanged. This type of milling tool is done using the teeth on the flat surface of the device. The surface of the material must be perpendicular to the axis of the cutter while the teeth are present on the sides of the milling tool.
√ End Mill
This milling tool is applicable for machining the slides and faces of metal workpieces and other materials. The device features a rotating cutting tool that has a cylindrical shank with teeth at the end. In addition, its applicability also lies in vertical milling processes. While the end mill doesn’t lose hardness at increasing high speed, it is created either from high-speed steel (HS or HSS) or cemented carbide. Types of end mill include
- Flat: a multi-purpose flat-faced tool for 2D features
- Bullnose: feature rounded corner and flat bottom for roughing and fillets
- Ball nose: feature ball-shaped end for 3D contours and curves
- Roughing end mill: suitable for the removal of a larger quantity of material with less precision in comparison with a standard end mill.
√ Slab Mills
Slab mills, also known as surface mills or plain mills, are used in applications involving gang milling processes and for broad and large shapes. Users combine its usage with milling flat surfaces and milling cutter axis, which is parallel to the part surface being milled. While slab mills are made from high-speed steel, they feature teeth on the cylindrical surface of the cutter for machining.
√ Gear Cutter
In CNC manufacturing, their CNC mills are for creating metal gears for specific purposes. As such, there are varieties of gear cutting tools to make specific gears as per request or application. In addition, gear cutting sometimes requires a special type of milling machine called hobbing machine.
√ Thread Mill
This milling tool is common in a wide variety of industries. It is designed to create threads by rotation process around the shank in a spiral pattern cutting through to form a thread shape. As a result, it is easily identified according to the spiral motion it features.
√ Fly Cutter
Fly cutter is another milling tool in the industry. It features some non-rotating cutters present in the fly cutter. When a fly cutter has two non-rotating cutters are called double fly cutters or fly bars. Fly cutters are comparatively cheaper in price and highly efficient, making it easy for the cutting process.
√ Drill Bit
CNC machines feature fittings for varieties of drill bits for sorts of cutting operations. Most drill bits feature a conical cutting point and one or more flutes. Examples of drill bit include twist drill used for making holes in a workpiece, ejector drill for deep hole drilling, and center drill, which is used to precisely locate a hole before drilling.
√ Reamers
Reamer is another tool in this category. It is applicable to widen existing holes in a workpiece, an excellent surface finish, and providing an exact hole diameter.
2. Lathe Tools
√ Grooving Tool
Grooving tools are mostly carbide inserts that can be mounted in a special tool holder. They are designed to feature multiple tips, often ground to required shapes and dimensions for specific operations, including cutting a slot and many more.
√ Thread Cutting Tool
This type of tool is applicable for cutting thread on the lathe part. For internal thread cutting, details are held in a chuck while the tools move across the part in a linear motion taking off the parts with each pass. On the other hand, external thread cutting involves holding a piece in a chuck or mounted between center,
√ Turning Tool
Turning tools are of two types, including finishing turning tools and rough turning tools. Rough turning tool functions to remove the maximum quantity of metal in the minimum time that the machine will permit and work. In this type, the cutting angle is excellent ground such that it can withstand maximum cutting pressure. Finishing turning tools are applicable for the removal of small metals. The finishing turning tool is also ground so that it can produce a smooth and accurate result.
√ Parting off Tool
This type of tool is known as a narrow-bladed tool for planning or turning, or cutting a workpiece in two. It is also a tool for cutting off pieces from the main body of the workpiece to be machined and comes in varieties of forms.
√ Boring Tool
A boring tool is used when the need for making an existed hole bigger arises. All it does is bore into the existing hole and widen its diameter to process it into the proper size to fit specific components correctly.
√ Chamfering Tool
This is a traditional edge that exists between two faces of an object, and it is also a form of the bevel. It helps create a furrow or an angle on the part and can also be used to smooth sharp edges on a workpiece.
√ Knurling Tool
Knurling tools are applicable for the production of knurled lathe workpieces by pressing or creating a pattern on a round section that is used as a handle of a workpiece. Examples included designs created on fasteners like nuts.
√ Facing Tool
This tool is applicable for facing operation in the lathe to cut flat surfaces perpendicular to the rotational axis. This is carried out by mounting the tool in a holder that rests on the carriage of the lathe while the facing tool feed perpendicularly across the rotational axis of the part
√ Forming Tool
This tool comes in circular or flat shapes to be used in the lathe. They feature cutting edges ground to the shape of the undercut, groove, or thread desired to be cut.
√ Counter Boring Tool
The operation performed by this tool is counterboring in nature. The cutting edge of a counterboring tool is so ground that it can leave a shoulder after turning. It features multiple cutting edges for different operations.
3. Classification According to Feed Application
Tools can also be classified according to feed application. This can be done from a different direction, hence the name given to them. They include:
- Left-hand tool
- Right-hand tool
- Round nose tool
Material for Tooling
For successful cutting into the solid workpiece, tools must be made from materials harder than workpiece materials. Hence common materials for tooling include:
√ Carbon Steel
This is an affordable alloy of steel that features silicon, manganese, and 0.6-1.5% carbon
√ High-speed Steel
This type of material, known as HSS, is tougher than carbon steel. This property is due to its blend of tungsten, molybdenum, and chromium.
√ Carbide
This material is mostly sintered with other metals, including titanium. While they provide an excellent surface finish, they are wear-resistant and heat-resistant.
√ (TiN) Titanium Nitride
This is a multi-purpose coating that increases the hardness of a cutting using a high oxidation temperature.
√ (AL-TIN) Super-Life Titanium Nitride
It adds hardness and surface lubricity to a cutting tool
√ (TiCN) Titanium Carbo-Nitride
It adds hardness and surface lubricity to a cutting tool.
√ Diamond
It offers a high-performance coating for the cutting of abrasive parts
√ Chromium Nitride
It helps cutting tools to prevent corrosion and increase the hardness of a metal.
Factors to Consider when Choosing the Right CNC Machine Tools
Choosing the right tool for a project could be such a great task. This is true of situations where you have to exercise the tool for cutting or at high temperatures. Here are few things to consider
√ Type of Tool Material
In most cases, high-speed steel remains one of the best material options for tooling. Hence, users will have the best toughness and hardness of the material.
However, users’ needs might have to be determined by the type of tool to select from. For a short-term project, what is needed is a tool that might be better off with cemented ceramides or cutting ceramics.
√ Tool Coating
One of the factors to consider is the type of tool coating for your CNC machining project. Examples of layers to be used include titanium nitride, which improves longevity and also increases its cost. Besides, some coating types can make your toolless sticky, resulting in lubricant use during work.
√ Flute Number
Flutes are referred to as channels on a milling bit. This means that the number of flutes is dependent on the rate of feed of a milling bit. However, having a high number of flutes can result in to have a large milling bit.
√ Difficulty & Complexity of Part
Another factor to consider in CNC machining is the complexity and precision of the parts in question. The complexity and accuracy of parts determine what kind of tools is needed for the project.
√ Other Factors to Be Considered are
- Materials for machining
- Cost per part
Conclusion
One important thing to note in the CNC machining space is choosing the right CNC machine tools for your machining projects. It helps to determine if your project is feasible or not. As a result, professionals and newbies must be familiar with the right tool for all types of CNC machining jobs. If you need more enlightenment regarding the tool type you’ll need for your project; You can reach out to us.