How to choose thermal expansion toolholders, collet toolholders and hydraulic toolholders?

One: Thermal expansion tool handle

advantage

Simple and symmetrical structure, large clamping force

Made of high-melting, high-temperature, high-quality alloy steel .

It has high positioning and clamping accuracy, tool repeat positioning accuracy and good accuracy retention .

Suitable for high-speed cutting .

structure type

principle

The thermal expansion system usually uses a thermal induction coil to heat the clamping part of the tool holder in a short time, so that the inner diameter of the tool holder is expanded accordingly. At this time, the tool is immediately loaded into the tool holder to produce a high radial clamping. Hold the tool firmly. Therefore, the thermal expansion system is a hot-load tool clamping method that does not involve the Rehe material between the tool and the tool holder. It can solve the extremely important balance, runout accuracy and clamping strength problems in high-speed precision machining .

Note: In the machining system of the tool and the spindle, the tool holder is a key link that affects the concentricity and dynamic balance. The existence and importance in the machining system cannot be ignored. With the increase of the spindle speed, the choice of the tool holder is important for processing. The impact of it is particularly important .

-  the concentricity of the cutting tool can determine the amount of each of the cutting edge portion is uniform in the case of one rotation .

-The  concentricity measurement is as shown in the figure on the right. The concentricity can be adjusted by adjusting the center axis of the tool holder to coincide with the center axis of the spindle .

-  Good concentricity control ensures that all the cutting edges have a uniform amount of processing in the respective directions .

The measurement of dynamic balance requires the adjustment of the tool and the tool holder. When the spindle rotates, the combination of a good dynamic balance tool holder and the tool will not produce any centrifugal force . But in fact, complete dynamic balance does not exist, and the amount of imbalance will be changed when the spindle rotates. Produce periodic vibration, if the imbalance is small, then this vibration will also be very weak .

The mass on the rotating body does not have to be evenly distributed to reduce the centrifugal force, as long as it is balanced, an unbalanced weight can be offset by the same balance force (mass X radius) in any direction , as shown in the figure below .

The PS : In 4D at beating 20 is [mu] m or less for the A -level (normal level)

       It is AA grade (precision grade) when the 4D jumps within 10 μ m

       In 4D at the beating . 3 [mu] m within a super precision .

Two: collet tool holder

structure type

1.        Tool  2. Jacket  3. Tool holder body  4. Nut

Removal / installation

Disassembly method:

Need to clean the inside of the shank nut

Press the outside of the circlip with your fingers and remove the circlip after hearing a "click" .

Note: For specific operations, please refer to the corresponding brand samples. It is recommended to use auxiliary tools for too small diameter circlips .

installation method:

Determine the position of the convex groove in the nut,

The groove on the circlip is installed in it correspondingly, and it can be installed by rotating it .

Note: For specific operations, please refer to the corresponding brand samples .

advantage

Kahuang problems, replacement of convenient, interchangeable .

There are many sizes of circlips, which can meet different processing sizes .

In the case of the same size specification, the accuracy is satisfied, and the cost performance is high

It is suitable for the processing of the axial feed processing of the tool holder .

Disadvantage

When changing the tool, it is necessary to clean the inside of the circlip .

In the case of high-speed cutting, the tool is easy to loosen .

The radial runout of the tool tip depends on the radial runout and accuracy of the circlip head and furniture .

2. Hydraulic tool holder

01 、Structural form

Pressurized bolt  drive piston  seal element expansion wall oil cavity tool holder body tool         

advantage

Good clamping stability and easy operation .

Different tools can be clamped through the reducing sleeve, no other auxiliary tools are needed .

The repeated radial runout accuracy of the inner sleeve clamping tool shank is high .

Disadvantage

High cost, easy to drain oil in the wall .

When the tool does not fully enter the clamping cavity, the inner sleeve will be damaged .

Poor maintenance is prone to tool movement .

Poor resistance to large temperature changes

02 , disassembly / installation

Disassembly method:

Wipe clean the protective oil on the hydraulic chuck before use

Loosen the piston clamping screw and put the tool in the hole to directly touch the push pin ..

Use a wrench to adjust the tool length through the radial positioning adjustment screw or the axial adjustment screw .

After the length is set, tighten the piston clamping screw to use .

installation method:

Clean the inside of the positioning pin .

Check whether there is any oil leakage / iron filings inside the tool holder .

Install the cutter and adjust the correct length of the cutter .

Tighten the positioning pin .