In the production process of profile machining center, tool overheating is an issue that cannot be ignored. Overheating will not only significantly shorten the service life of the tool, but also may affect the processing quality, reduce the accuracy and surface finish of the product. In order to improve production efficiency and reduce costs, preventing tool overheating is a key skill that every technician and operator engaged in metal cutting needs to master.
First, the hazards of tool overheating
The hazards of tool overheating are mainly reflected in two aspects: one is the increased wear of the tool, and the other is the decline in processing quality.
Shortened tool life: Long-term operation of the tool under high temperature conditions will cause the hardness of the tool to decrease, and the cutting edge is prone to wear and chipping. High temperature will also accelerate the oxidation or melting of the tool material, greatly shortening the service life of the tool and increasing the production cost of the enterprise.
Reduced processing accuracy: Overheating of the tool will not only cause changes in the shape of the tool, but also cause fluctuations in the temperature of the machining surface, thereby affecting the dimensional accuracy and surface quality of the workpiece. Especially in precision machining, the problem of tool overheating is more prominent, which may cause the dimensional error and surface roughness of the workpiece to exceed the standard.
Cutting force and cutting efficiency decrease: Overheating of the tool will also affect the stability of the cutting process. In a high temperature environment, the cutting force often changes, which may cause tool vibration or uneven cutting, thereby affecting the processing efficiency and surface quality.
In order to reduce the negative impact of tool overheating, a series of measures should be taken during the production process to effectively control the tool temperature.
Second, how to prevent tool overheating
- Select appropriate cutting parameters
Cutting parameters (such as cutting speed, feed rate and cutting depth) are key factors affecting tool temperature. Too high cutting speed will cause the tool surface temperature to be too high, while too low cutting speed will affect the processing efficiency. Therefore, the reasonable selection of cutting speed, feed rate and cutting depth is the basis for preventing tool overheating.
Cutting speed: During the processing process, too high cutting speed will cause the tool to generate a lot of heat, thereby increasing the temperature. In order to prevent overheating, a suitable cutting speed should be selected according to the type and hardness of the material. Generally, materials with higher hardness require lower cutting speeds, while softer materials can appropriately increase the cutting speed.
Feed rate: Too much feed rate will increase the heat generated in each cutting cycle, causing the tool to overheat. Therefore, properly adjusting the feed rate to ensure even heat distribution can help reduce tool temperature.
Cutting depth: Cutting depth directly affects the tool load and heat generated during each cut. Appropriately reducing the cutting depth not only helps cool the tool, but also improves processing efficiency.
- Use efficient coolant
Coolant plays a vital role in profile processing, especially in high-temperature cutting environments, where coolant can help quickly remove the heat generated during cutting. Using a suitable coolant can effectively reduce the temperature of the tool and prevent it from overheating.
Selection of coolant: Different processing materials and tools require different types of coolants. Water-based coolants are often used for general processing, while oil-based coolants can provide better cooling effects for high-speed cutting or high-temperature material processing. The viscosity and flow rate of the coolant also need to be adjusted according to actual conditions.
Optimization of cooling method: In addition to selecting a suitable coolant, the design of the cooling system is also crucial. By optimizing the spray direction, flow rate and pressure of the coolant, it can be ensured that the coolant can effectively act on the tool and workpiece surface and quickly remove the heat generated by cutting.
- Regularly check tools and equipment
Tool wear and equipment failure are also important causes of overheating. Therefore, regular inspection of tool status, cleaning of cooling systems, and maintenance of equipment in good operating condition are necessary measures to ensure that tools do not overheat during processing.
Tool wear: Regularly checking tool wear and timely replacing severely worn tools can effectively avoid overheating problems caused by blunt tools.
Equipment maintenance: The cooling system and tool replacement system of the machining center must be kept in good working condition. Clean and maintain the cooling system regularly to prevent insufficient coolant flow or poor cooling effect to ensure cooling effect.
By optimizing cutting parameters, using coolant reasonably, and regularly maintaining tools and equipment, the risk of tool overheating can be effectively reduced, the tool life can be extended, and the machining accuracy can be improved.
Third, choose the right tool material
In addition to the use of cutting parameters and coolant, the choice of tool material also plays a vital role in preventing tool overheating. Tools of different materials have different performance at high temperatures. Choosing the right tool material can effectively improve the tool’s high temperature resistance and extend its service life.
Carbide tools: Carbide tools have excellent heat resistance and wear resistance, and are one of the most commonly used tool materials in machining centers. Carbide can withstand high temperatures and cutting forces, so it can effectively reduce overheating in high-temperature cutting environments.
Coated tools: The surface coating of steel tools (such as TiN, TiAlN, CVD coating, etc.) can significantly improve the heat resistance of tools. Coated tools can not only improve the hardness and wear resistance of tools, but also effectively reduce the friction coefficient between tools and workpieces, thereby reducing heat generation.
Ceramic tools: The use of ceramic tools is particularly important for the processing of superhard materials or high-temperature alloy materials. Ceramic tools have very high heat resistance and wear resistance, and can maintain good stability in high temperature environments, reducing the possibility of tool overheating.
Fourth, reasonably control the ambient temperature
The temperature of the processing workshop will also affect the heat dissipation and cooling effect of the tool. At higher ambient temperatures, the tool is more likely to overheat because the heat cannot be quickly dissipated. Therefore, when performing precision machining, control the temperature of the workshop as much as possible to keep it within an appropriate range, which will help reduce the risk of tool overheating.
Fifth, technical staff’s operating specifications
In addition to the selection of hardware facilities and tools, the technical level and operating specifications of the operator are also important factors in preventing tool overheating. The technician should be familiar with the heat generation mechanism during the processing, adjust the cutting parameters in time, and monitor and adjust abnormal conditions during the processing. Through standardized operation, tool overheating due to human error can be avoided.
