What Is Collet?
A Collet is a cup-shaped component that attaches to a rotating tool, such as a drill or milling machine.
It is used to hold a shaft-shaped tool in place, but is mainly used on CNC lathes and transfer loaders.
The collet chuck of the main unit is divided into a chuck unit and a collet, and the collet is the one that actually grips the workpiece. Unlike the three-jaw scroll chuck, which grips the workpiece at three points, the Collet grips almost the entire circumference of the workpiece.
It plays a very important role in precisely positioning the blade or cutting tool at the tip of the tool. They are also available in a variety of sizes to accommodate tools of different sizes. It is one of the indispensable parts for machine tools to improve the accuracy and stability of tools.
Uses of Collets
A Collet is one of the components used in machine tools and machining. The following are examples of applications of Collet:
- Machine tools such as CNC lathes.
- Loaders for conveyance.
- Drilling and milling machines.
- Routers and engraving machines.
When compared in terms of runout accuracy, overall, collets perform better than scroll chucks, making them suitable for machining workpieces with tight geometric tolerances such as runout and coaxiality.
On the other hand, Collets tends to have a smaller opening allowance than the scroll chuck. This may result in a too narrow bore in the unclamped state, making it difficult to receive workpieces properly, so care must be taken when there is a transfer from a conveyor machine in automatic operation.
Principle of Collet
The basic shape of a Collet is cylindrical, with mortises radially from the center. When inserted into the chuck unit, the outer tapered part is caught by the flange, and the bore is opened and closed by pushing the part with a cylinder or other device.
The Collet distributes the pressure from the gripping evenly, so the workpiece is not easily damaged and can be strongly secured. The advantage is that it can grip soft materials such as copper and aluminum, as well as thin-walled materials such as pipe material.
Collets can accommodate different sizes of shaft-shaped tools because the tool can be easily removed. When removing a tool, the collet is loosened and the tool is pulled out. The Collet is an excellent component that uses frictional force to hold the tool in place precisely.
It should be noted, however, that Collet is a consumable part. The collet gradually loses its springiness through repeated opening and closing movements. In addition, the surface in contact with the workpiece gradually wears out due to repeated machining, and the original runout accuracy is exceeded. To maintain high machining accuracy, the collet must be replaced after a certain amount of use.
Types of Cobalt Magnet
There are various types of Collets. The following are examples of Collet types:
1. Standard Collet
This is the most common Collet and is used for tools such as drills and milling machines. Generally, sizes are available according to the shaft diameter.
2. ER Collet
A high-precision Collet used for precision machining operations; ER stands for Elastic Rigid, meaning a balance of flexibility and rigidity. They can be attached to the spindle of machining equipment and can be easily replaced using a clamp nut, thereby improving work efficiency.
3. MT Collet
This collet is suitable for Morris Taper (MT) standard tools used in boring machines, etc. The tool is inserted into the internal cone that matches the MT shank, and the tool is secured by tightening the collet.
4. Portable Collets
This is a Collet used for hand-held power tools. They can be attached to power drills, routers, etc. Portable collets are available in several sizes to accommodate tools of different sizes.
5. Spring Collets
This is a Collet with a spring built into the body. It is used to secure a tool by elastic force without tightening the tool strongly. There is no handle to tighten the tool, and the tool can be easily secured by simply inserting it.