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Indexable End Mills Explained: Advantages



John Abraham
Hey I'm John. I write about Manufacturing, Metalworking, CNCs and Lasers at Mellowpine. If you have any questions related to CNCs or Lasers, I'd be happy to answer them. Reach me at mail@mellowpine.com


Indexable End Mill

In milling, each type of material requires a specific cutting tool made of an appropriate material.

An indexable end mill provides an efficient way to use a single end mill for milling different types of materials.

Indexable end mills consist of an easy-to-replace cutting insert clamped to the tool body, providing the ability to replace the cutting tip when needed. This ability to change the insert makes indexable end mills a cost-effective and versatile solution for machining a wide range of materials.

This article discusses indexable end mills by going through various advantages that it provides and helps you make a choice between an indexable end mill or a standard end mill.

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What is an Indexable End Mill? Why Use it?

Carbide tip indexable end mills
Carbide tip indexable end mills

Indexable end mills are modified versions of solid end mills, used to remove material from workpieces to create the desired product geometry. 

An indexable end mill, also known as an insert end mill, allows for quick and easy replacement of the cutting tip, reducing downtime and maintenance costs.

Unlike solid end mills, indexable end mills provide the ability to replace the cutting head of the tool and reuse it for further machining, thereby saving cost and time.

Whereas with a solid end mill, the entire tool must be replaced when the cutting edge becomes dull or damaged. 

Additionally, the increased number of available inserts makes indexable end mills popular over conventional solid end mills.

Advantages of an Indexable End Mill

Lowers Production Cost

One of the main advantages of using an indexable end mill is its economy compared to single-body solid tools. 

Generally, carbide end mills are preferable over high-speed steel (HSS) end mills because of their better strength and better ability to perform cutting operations.

However, carbide tools are comparatively more costly, making them suitable for large-scale industries only.

An indexable end mill overcomes this limitation by providing the ability to have a tool body made of low-cost HSS, while the cutting insert can be made of carbide.

As a result, these end mills provide excellent machining ability of carbide tools at a comparatively affordable cost.

Moreover, it further reduces the overall cost by providing the ability to only replace the cutting insert rather than having to replace the entire tool.

This yields a significant reduction in the overall cost of the tool, making it more affordable for small-scale operations. 

Good Machining Capability 

Face Milling the workpiece by using an Indexable end mill
Face Milling the workpiece by using an Indexable end mill

Machining different materials require different types of cutting tools to produce clean cuts with a smooth surface finish.

An indexable end mill provides the ability to replace the tooltip with an insert made of the material best suited for that particular application.

As a result, an indexable end mill provides the ability to produce high-quality cuts in different materials by replacing the cutting insert.

Easy Replacement

Indexable end mill with multiple inserts
Indexable end mill with multiple inserts

The ability to easily replace the cutting insert or tip allows for quickly enhancing the performance and capability of the tool without the need to stop the machining process for sharpening the tool. 

In some indexable end mills, different types of tips can be installed on a single body to perform different operations, providing even more flexibility. 

However, not all indexable end mills have the feature of supporting different tips on a single body.

In these cases, the ability to quickly change the indexable tip is still a valuable feature, as it allows the machining process to continue without needing to sharpen the same tool, minimizing downtime.

Moreover, all of the indexable inserts can be sharpened during maintenance time, which ensures that the tool is always ready for use. 

Better Tool Life

End mills and other cutting tools frequently use high-speed steel (HSS) and carbide materials.

HSS is a relatively inexpensive material known for its ability to withstand high temperatures and maintain its strength at high speeds. 

However, it is softer than carbide and tends to have a shorter tool life when used for cutting operations.

On the other hand, carbide is a more expensive material but is much harder and more durable than HSS. 

It can withstand higher cutting forces and maintain its sharp edge for longer, resulting in a longer tool life. 

Nevertheless, carbide tools can be brittle and prone to breaking if subjected to high stress or impact.

Using an indexable end mill with an HSS body and carbide tip can help to achieve a longer tool life without significantly increasing the cost of the equipment. 

Double Sided Design

Double sided End mill by Widia
Double-sided End mill by Widia

Manufacturers such as widia, are producing double-sided cutting tips that can be used to material in any direction, without the need to orient the cutting tip along the direction of the feed.

As a result, the chip load is distributed evenly, providing the ability to increase the material removal rate without affecting the tool’s life.

Reliable Performance

Indexable end mill machining a steel block
Indexable end mill machining a steel block

Indexable end mills are generally made of ceramic or carbide materials that provide excellent abrasion resistance and withstand high temperatures without failing.

This makes it possible for the tool to function properly and maintain its sharpness even during demanding applications like dry or wet machining.

The design of the cutting blades and the geometry of the insert are other elements that affect how dependable a tool is.

Typically, the cutting edges are ground to precise angles and shapes, ideal for a given machining operation, such as facing milling, thread milling, peripheral milling, etc.

A carefully thought-out geometry is used to create the insert to encourage chip flow and prevent built-up edges, which can impair tool performance.

The tool holder also plays a vital role in the tool’s operation since it offers the end mill the support and stability it needs while machining.

It is normally constructed of premium materials and is intended to withstand the forces and vibrations produced during the machining operation.

Indexable End Mill vs Standard End Mill- Which One Should You Buy?

Indexable end mill and standard end mill
Indexable end mill and standard end mill

When deciding between an indexable end mill and a standard end mill, it’s important to consider the specific requirements of your application. 

If your application involves machining different materials that require different cutting tools, it is recommended to invest in an indexable end mill that provides you the ability to use multiple cutting heads for machining different materials.

This allows for a more flexible and cost-effective solution, as you won’t need to purchase multiple single-body end mills for different materials.

Furthermore, the high initial cost of an indexable end mill is compensated by lower replacement costs that involve changing the tooltip, without the need for buying the entire tool.

On the other hand, single-body end mills are generally more durable and are better suited for delivering strong cutting forces with minimal risk of failure. 

They are also a good choice for machining operations requiring a high level of precision, as the cutting edge will remain consistent throughout the tool’s life.

Frequently Asked Questions (FAQ)

Can I use an indexable end mill for high-speed machining?

Yes, indexable end mills can be used for high-speed machining applications. However, choosing the right insert material and geometry for the specific machining conditions is essential. Generally, indexable end mills with positive rake inserts are better suited for high-speed machining, as they produce less heat and offer improved cutting performance.

How do I change the insert on an indexable end mill?

To change the insert on an indexable end mill, loosen the clamping screws on the tool holder, remove the old insert, and replace it with a new one. In addition, ensure to secure the new insert with the clamping screws properly and provide proper alignment before you start machining.

How do I choose the right insert material for my indexable end mill?

The right insert material for your indexable end mill depends upon your specific machining application. Nevertheless, carbide inserts are suitable for a wider range of materials and offer good wear resistance. In contrast, ceramic and diamond inserts are better suited for machining hard and abrasive materials.

John Abraham
Hey I'm John. I write about Manufacturing, Metalworking, CNCs and Lasers at Mellowpine. If you have any questions related to CNCs or Lasers, I'd be happy to answer them. Reach me at mail@mellowpine.com