How to solve the problem of impurities on the surface of aluminum CNC machining?

December 24, 2024

Aluminum CNC machining is a precision machining method controlled by computers, which involves cutting, drilling, milling, carving, and other operations on aluminum materials to manufacture various high-precision components or products. So, in the CNC machining process of aluminum materials, the appearance of impurities on the surface is a common problem, which may be caused by various reasons. Here are some possible reasons and corresponding solutions:

1、 Cutting fluid issues

Poor quality of cutting fluid

Reason: If the lubrication, cooling, and cleaning performance of the cutting fluid is poor, the chips on the surface of the aluminum material cannot be effectively washed away during the machining process, resulting in residual impurities. Moreover, poor quality cutting fluid may contain impurities that can directly contaminate the surface of aluminum materials.

Solution: Choose cutting fluid with good quality and suitable for aluminum processing. High quality cutting fluid should have good lubricity, which can reduce friction between cutting tools and aluminum materials; Good cooling performance can reduce the temperature in the processing area; And excellent cleaning ability, able to promptly wash away chips and impurities from the processing surface. At the same time, attention should be paid to the brand and composition of the cutting fluid, and cutting fluids containing corrosive components to aluminum should be avoided.

Inappropriate concentration of cutting fluid

Reason: Excessive or insufficient concentration of cutting fluid can affect its performance. Excessive concentration may lead to excessive viscosity, making it easy for chips to adhere to the surface of aluminum materials; If the concentration is too low, it cannot provide sufficient lubrication and cleaning effect.

Solution: Adjust the concentration of cutting fluid according to the specific machining conditions (such as machining method, cutting speed, feed rate, etc.) as recommended by the cutting fluid supplier. Generally speaking, the concentration of cutting fluid in aluminum CNC machining is more suitable between 5% and 10%. At the same time, it is necessary to regularly check and replenish cutting fluid to ensure that its concentration remains within an appropriate range.

Cutting fluid contamination

Reason: During the machining process, cutting fluid may be contaminated by external impurities such as dust, chips, oil stains, etc. Long term non replacement of cutting fluid or poor filtration device in the cutting fluid circulation system can increase impurities in the cutting fluid, thereby affecting the surface quality of aluminum materials.

Solution: Install an effective cutting fluid filtration system, regularly clean the filter, and ensure that the cutting fluid can remove impurities during circulation. In addition, the cutting fluid should be replaced regularly, usually every 1-3 months depending on the strength and frequency of the machining. When replacing cutting fluid, thoroughly clean the cutting fluid tank and circulation system to avoid residual old cutting fluid contaminating the new cutting fluid.

2、 Tool issue

Tool wear

Reason: The cutting tool will wear out after long-term use, and the worn cutting edge will no longer be sharp. When cutting aluminum, more heat and greater cutting force will be generated. This not only leads to an increase in surface roughness of the aluminum material, but may also cause tearing and burrs on the surface of the aluminum material, which can form impurities.

Solution: Regularly check the wear of the tool by observing the wear marks on the cutting edge, measuring the size of the tool, or using tool detection equipment to determine whether the tool needs to be replaced. The service life of cutting tools varies for different processing procedures and the hardness of aluminum materials. Generally speaking, when the tool wear reaches a certain level (such as a tool edge radius exceeding 0.1mm), the tool should be replaced in a timely manner.

The tool material does not match the aluminum material

Reason: If the hardness, toughness, and other properties of the tool material do not match those of aluminum, there may be more chip deposits during the machining process. Chip accumulation tumor is a hard block formed by the accumulation of chips in front of the cutting tool during the cutting process. It will periodically fall off and some will remain on the surface of the aluminum material, forming impurities.

Solution: Choose the appropriate tool material based on the characteristics of aluminum material. For general aluminum processing, hard alloy cutting tools are a suitable choice as they have high hardness, good wear resistance, and toughness. At the same time, the coating of the tool is also important, such as TiAlN coating, which can improve the cutting performance of the tool and reduce the generation of chip deposits. Before processing, you can consult the tool supplier to choose the most suitable tool type and coating for aluminum processing.

3、 Processing environment issues

Dust and debris

Reason: If the environment in the processing workshop is not clean enough, dust in the air and debris around the machine tools can easily fall on the surface of aluminum materials, especially during the processing, when the aluminum surface is exposed and more susceptible to pollution.

Solution: Keep the machining workshop clean and hygienic, regularly clean the ground and debris around the machine tools. Isolation covers or dust collection devices can be installed in the working area of the machine tool to prevent dust and debris from entering the processing area. At the same time, for already processed aluminum parts, the surface should be cleaned and protected in a timely manner to avoid contamination during subsequent storage and transportation.

Temperature and humidity influence

Reason: Inappropriate temperature and humidity can affect the performance of cutting fluid and the oxidation rate of aluminum surface. For example, in high humidity environments, the surface of aluminum is more prone to oxidation, producing impurities such as aluminum oxide; Excessive or insufficient temperature may cause the cutting fluid to deteriorate or evaporate too quickly, affecting its protective effect on the surface of aluminum materials.

Solution: Control the temperature and humidity in the processing workshop. Generally speaking, the temperature should be maintained between 20 ℃ and 25 ℃, and the relative humidity should be between 40% and 60%. The temperature and humidity in the workshop can be adjusted by installing air conditioning and dehumidification equipment to ensure a stable processing environment and improve the surface quality of aluminum CNC machining.

Author:

Mr. zhichengaluminumindustry

E-mail:

zcd.aluminum@gmail.com

Phone/WhatsApp:

+852 64053048