Your CNC machine uses a whole variety of different high-precision components necessary to complete the machining process. The tool holder is an often-overlooked component of the dynamic process performed by these machines across various machining centers.

In this guide, we'll discuss tool holders, what they are, their importance, and how to keep them well-maintained.

What is a CNC Tool Holder?

Your CNC machine's spindle operates the cutting tool and regulates the recession cutting and milling process. However, interference is necessary to keep your spindle and cutting tool from sustaining damage, and this comes in the form of a connecting element called a tool holder.

A cutting tool can be securely held in a specific spot by CNC tool holders. To prevent tool breakage, certain tool holders allow the cutting tool to float, while others give unmatched accuracy and a solid grip.

To provide the cutting precision and durable performance you require, all holders must be precisely manufactured. It's crucial to invest in the correct holder and keep an eye out for wear because a damaged tool holder can cause significant problems and require expensive replacement.

The Importance of Tool Holders

The tool holder used in high-precision mechanization processes affects the quality of the finished product, the lifespan of the machine, and the level of process noise. Cutting tools that attain extremely high RPMs are frequently used in high-precision operations that require tool holders.

A machine's lifespan could be shortened by its spindle becoming worn down, or the finished product could be harmed by an imbalance between a high-speed tool and the machine. When fitted and maintained correctly, the appropriate tool holder ensures that cutting operations are carried out precisely and securely.

Proper Maintenance of the Tool Holder

A well-maintained tool holder can handle high-performance CNC machining every day. The two most important maintenance measures are a thorough inspection and cleaning. To avoid contamination, corrosion, and other issues, disassemble and clean your tool holders regularly. The specific timing can vary depending on your holder and how much use it receives.

Collets can be changed every two to three months if they are worn continuously throughout the day. Because of a worn collet, your tooling will wander, lowering the quality of your output and shortening the lifespan of your cutting tool.

Working with a respected manufacturer will be beneficial if you are concerned about the longevity of your tools. To maintain your CNC lathe working smoothly, inquire about the optimal maintenance program and discuss any signs of diminished performance.

Types of CNC Tool Holders

There are three basic types of CNC Tool Holders, and in this section, we'll provide a short overview of all three types.

CAT Tool Holders

CAT tool holders, also known as V-Flange Tools, were created for the Caterpillar tractor business. They are of sturdy construction and are used mainly for various applications ranging from heavy-duty roughing to precision machining.

This type of CNC tool holder supports ATC technology, also known as automated tool changer technology, which allows a quick change of different machine tools by the CNC machine itself. A retention knob is used to pull the tool holder body into the milling spindle and center it using the taper contact.

HSK Tool Holders

HSK stands for "hollow taper shank," and these holders lack the retaining knob seen on CAT tool holders in favor of a hollow shank. An HSK tool holder's clamping mechanism is actuated from the inside, with segmented collets that expand in a radial manner under pressure.

When the drawbar is triggered, the collet's chamfer meets that of the inner wall of the shank, allowing it to lock firmly. An HSK tool generates twice as much clamping force on the flange as a CAT tool.

BT Tool Holders

Metric thread pull studs are used in BT tool holders (retention knobs). BT tool holders are symmetrical around the main rotational axis, but CAT tool holders are not, even though both standards employ the identical NMTB body taper. This improves the balance and stability of BT tool holders at greater speeds.

CNC Milling Tool Holders and Accessories

In this section, we'll go over various CNC milling types of tool holders, including collet chucks, heat shrink chucks, and hydraulics.

Collet Chuck and Holders

A collet chuck is another type of work-holding device that exerts force to hold a workpiece in place and allow further operation. While a collet chuck cannot accept a wider variety of workpiece sizes as a jaw chuck, it may provide advantages in speed, precision, and productivity which may be critical for particular operations.

Heat Shrink Chucks

When milling wood panels and other materials, the heat shrink chucks, also known as shrink fit holders for CNC, is a tool-holding cone designed to give the operator greater control and cutting precision. The benefits of a heat shrink chuck stem from its heat-shrinking technology.

An electric heating induction machine is used to heat the receiving end of the tool holder. This allows the steel body to expand, allowing the tool shank to be inserted. After inserting the tool shank, the heating element is switched off, enabling the steel to cool and "shrink" around the tool shank. Simply repeat the step to remove the tool.

Hydraulic Chucks

Hydraulic chucks contain hydraulic fluid that is pressurized when the grub screw (located on the side of the holder) is engaged. This procedure shuts the bore of the tool holder, holding the tool in place with up to 890kN of force (commonly found in high-torque hydraulic chucks).

The hydraulic fluid that is used to clamp the cutting tool also functions as a vibration dampener, reducing vibration and chatter during the machining process. This increases tool life and surface finish while also ensuring improved precision when compared to typical tool holding such as ER collet chucks and end mill holders.

Milling Chucks & Other Tool Holder Types

Milling chucks, also known as power milling chucks, are excellent holders for heavy machining. They use a bearing nut to create extraordinarily powerful clamping forces. They are also quite dependable, especially when compared to hydraulic chucks, which might fail with time.

Shell Mill Holders

A Shell mill, also known as a face mill, is a flat-end circular milling tool equipped with carbide or carbide-tipped cutting inserts along its sides. They are typically used to create a flat face on the surface of a metal bar workpiece.

Face mills may mill faster than fly cutters because they have numerous teeth to spread the chip load. While not always faster than end mills, they often have a larger diameter, allowing for more material stock to be removed.

Tapping Chucks

Tapping chucks, also known as drill chucks and tap holders, are used to drill holes into the material and aid in the cutting of threads. Tap breakage and thread stripping on the exit of a tap are the most common issues encountered while tapping on a machine.

Tapping chucks for CNC machines are typically used with the ER collet system, with compression and extension at the collet end to give play as the machine spindle slows to a halt, then swiftly reverses out. This reduces tap breakage, especially when tapping under M10.

Summary

If you're interested in learning more about tool-holding and work-holding machining components, visit Reid Supply's vast download library filled with professional literature. If you happen to stumble upon a particular component your shop lacks, Reid Supply can source the component for you.