The heat shrink tool holder is a commonly used tool holder in modern precision manufacturing and high-speed processing fields. Although the initial investment is slightly higher and there are many troublesome operation specifications, the heat shrink tool holder can truly bring a significant improvement in processing quality and efficiency.
However, during the process of using the heat shrink tool holder, we will notice a rather obvious problem. That is, after heating the blade with the shrink fit machine, the clamping part of the heat shrink tool holder will turn black. In this article, we will elaborate on the types of heat shrink tool holders, the principle behind the blackening of the heat shrink tool holder after heating, as well as some advantages of the heat shrink tool holder, and some maintenance tips for it.
I. Types of Heat Shrink Tool Holder
We mainly classify the heat shrink tool holders based on their wall thickness, the length of the clamped cutting tools, and the interference fit. The main purpose of this classification is to clearly demonstrate how different processing requirements affect the heat shrink tool holders.
| Type | Characteristic | Main application scenarios |
| Standard type | With standard wall thickness and strong versatility | General processing scenarios, such as fine milling, drilling, etc. |
| Enhanced (Heavy-duty Heat Shrink Tool Holder) | Its wall thickness will be significantly increased by up to 8.5mm, resulting in greater rigidity and the ability to withstand high torque. | It is mainly applied in the aerospace field to achieve heavy cutting processing. |
| Lightweight (slender type) | A lightweight heat shrink tool holder with a very thin wall thickness of up to 1.5mm. The head of the tool handle is slender and has a long neck that is larger in size, which can effectively avoid interference. | Suitable for deep cavity processing of molds |
| Ultra-thin type (miniature) | The front end has an extremely small diameter, and this is also to avoid interference. | Mainly applicable to small-scale production and processing of tiny components. |
| Special Function Type | Integrating special functions, such as end face ring spray of coolant, can efficiently remove chips and cool the cutting tools, significantly enhancing the tool life. | Applicable to deep cavity processing |
Of course, we can also classify it based on its structural form. It can be divided into integrated type and modular type. The integrated type of the handle has better rigidity, while the modular heat shrink tool holder offers greater flexibility and economy. We can equip different types of heat shrink tool holders according to different processing requirements.
II. The Principle of the Part That Has Become Black Due to Heating
The blackening of the heating part of the tool holder is caused by two factors: one is oxidation due to high temperature, and the other is the change in the surface material.
1.High-temperature oxidation:
Because the heat shrink tool holder is mainly made of special alloy steel or stainless steel, when it is heated by our heat shrink machine, the part where the tool holder is clamped will reach a temperature of several hundred degrees within a short period of time. This is because the metal material of the heat shrink tool holder will react chemically with the oxygen in the air at high temperatures, and the surface of the tool holder will form a layer of oxide film. This oxide film will then present the black or blue-black color that we see.
2.The surface material:
Due to the differences in material composition and heat treatment processes among various brands of handles, their performance in resisting high-temperature oxidation varies significantly. Moreover, some handles made of ordinary steel are more prone to oxidation and turning black when exposed to higher temperatures. In some cases, repeated overheating may cause the grains to become coarse and the material to deteriorate, thereby affecting our service life.
III. Core Advantages of the Heat Shrink Tool Holder
| Advantage | Expound |
| High precision and low vibration | The tool installation part does not have the nuts and barrel clamps like those on ER tool holders. Therefore, the structure of the heat shrink tool holder is highly symmetrical, enabling extremely high repeatability positioning accuracy and radial runout accuracy (this accuracy is usually ≤ 3 μm). |
| The combination of high rigidity and strength | This is achieved through the principle of thermal expansion and contraction. The 360° uniform contraction provides a very large radial clamping force (this force is 2-3 times that of a regular tool handle), making the tool and the tool holder almost inseparable. This significantly improves the rigidity. |
| Excellent dynamic balance | The structure is simple, symmetrical and has no additional parts. It has excellent dynamic balance performance (pre-set G2.5) and is highly suitable for high-speed rotation, effectively reducing vibrations. |
| Can achieve rapid loading and unloading | Combined with the shrink fit machine, the loading and unloading of the cutting tools can be completed in a very short time. Of course, with high-quality tool holder materials and the cooperation of a good shrink fit machine, it can ensure that the heat shrink tool holder maintains stable accuracy after thousands of heating cycles. |
IV. Maintenance Methods
1.Daily cleaning and rust prevention:
After using the heat shrink tool holder, it is necessary to promptly remove the chips, cutting fluids and other contaminants from the surface. Especially for the holes and fine holes of the oil holes type, thorough blowing and drying are required. If the tool handle has rusted or oxidized, it may cause a significant drop in clamping accuracy, and in more serious cases, the clamping part of the tool handle may crack.
2. Standardize heating procedures:
3. Inspection of the cutting tools and handles:
When installing the tool clamping fixture, it is necessary to check whether the tool shank is free of burrs and scratches. Even minor flaws can affect the clamping accuracy and force. Regularly inspect whether there is severe wear, scratches or abnormal color spots on the inner wall of the tool shank clamping hole. Damaged or overused tool shanks should be replaced promptly.
4. Storage of the heat shrink tool holder:
It is best to place it in a dry and clean environment. It is advisable to use a dedicated knife handle box or knife holder, and try to avoid any bumps or impacts.
In conclusion, the heat shrink tool holder is not merely a simple machine tool accessory. It is a key enabling technology that drives precision manufacturing to new heights. Therefore, we must try our best to understand it in order to use it more effectively.
Post time: Aug-23-2025
