Heat shrink tool holder "is a high-performance tool clamping system widely used in modern precision machining, especially in high-speed milling, high-precision turning, and drilling. Its core principle is to utilize the thermal expansion and contraction characteristics of metal materials to achieve strong, high-precision, and high rigidity clamping of the tool handle.

Working principle

1. Heating: Use a specialized heat shrink tool holder heating device (induction heater or hot air stove) to heat the front end (clamping part) of the tool holder to a specific temperature (usually between 250 ° C-400 ° C, depending on the material and design of the tool holder).

2. Expansion: After heating, the metal inner hole at the front end of the handle will increase in diameter due to thermal expansion.

3. Tool installation: When the inner hole of the tool holder is in an expanded state, quickly insert the cold tool handle (usually a cylindrical handle or a specific taper handle) into the inner hole of the tool holder and ensure that it is inserted to the correct depth.

4. Cooling shrinkage: After stopping heating, the front end of the handle begins to cool naturally or with the assistance of compressed air. During the cooling process, the metal of the tool handle shrinks, and the diameter of the inner hole decreases, resulting in a strong radial contraction force that evenly, tightly, and rigidly wraps and holds the tool handle.

5. Source of clamping force: The clamping force is entirely derived from the enormous radial force generated during the cooling and contraction of the handle metal.

Main advantages

1. Extremely high clamping accuracy and repetitive positioning accuracy:

The contraction clamping method avoids the gaps and errors caused by clamping screws, jaws, and other components that exist in traditional clamps such as spring clamps and side fixed tool holders.

The centerline of the tool coincides with the centerline of the tool holder, with extremely low runout (usually within 3 µ m), enabling ultra precision cutting.

2. Extremely high rigidity and stability:

The entire clamping area is in continuous metal contact, with no weak links or moving parts.

It can effectively suppress vibration during high-speed rotation and provide excellent machining stability, especially suitable for high-speed machining, hard material machining, and high-performance cutting.

3. Excellent dynamic balancing performance:

The structure is simple and symmetrical, without any additional sources of imbalance (such as clamping screws).

It has high manufacturing accuracy and is easy to achieve high-level dynamic balancing, making it particularly suitable for ultra-high speed applications.

4. Excellent concentricity:

The clamping force is evenly distributed throughout the circumference, ensuring that the tool is concentric with the center of rotation of the spindle.

5. Longer tool overhang:

High rigidity allows for longer overhangs than traditional clamping methods while still maintaining good processing performance.

6. Higher metal removal rate:

Thanks to high rigidity and vibration damping, more aggressive cutting parameters can be used to improve machining efficiency.

7. Good chip removal:

The front end of the handle has a simple structure and no protruding parts, providing a smoother discharge channel for chips.

8. Compatibility:

Standard cylindrical shank tools (such as HSK, BT, CAT, CAPTO, etc.) are commonly used and have a wide range of applications.

Main application scenarios

High speed processing: mold manufacturing, aerospace parts processing.

High precision machining: precision parts, optical components, medical device parts.

Difficult to process materials: titanium alloys, high-temperature alloys, quenched and hardened steels, etc.

High surface quality requirement: requires extremely low roughness machining.

Micro machining: clamping of small diameter cutting tools (such as small diameter milling cutters, drill bits).

Five axis machining: occasions that require high rigidity and vibration control.

Precautions for use

1. Special equipment: A heat shrink tool holder heater must be used for tool loading and unloading operations. Do not use open flames (such as spray guns) for heating, as it can cause local overheating, decrease in material properties, and even damage to the handle.

2. Heating temperature and time: Strictly follow the heating temperature and time recommended by the handle manufacturer. The temperature is too low to fully expand, making it difficult to install or clamp the knife tightly; Excessive temperature can damage the material properties of the handle (such as tempering softening) and shorten its lifespan.

3. Cooling method: It is recommended to use natural cooling or even cooling with compressed air. It is strictly prohibited to use water or coolant for rapid cooling, as it can cause excessive internal stress in the material, resulting in cracks or even fractures.

4. Tool handle: Cylindrical handle tools that meet standards, have precise dimensions, clean surfaces, and are undamaged must be used. The diameter of the handle must be precisely matched with the nominal size of the inner hole of the handle (usually a slight interference fit).

5. Depth of tool installation: Ensure that the tool is inserted into the designated depth mark.

6. Cleaning: Before installing the tool, be sure to clean the inner hole of the handle and the handle of the tool. Any oil or impurities will affect the clamping force and accuracy.

7. Lifespan: Frequent heating/cooling cycles can cause fatigue in the handle metal, which has a limited service life. Regularly check the clamping force and accuracy.