Magnetic polishing machine measured CNC aluminum parts to remove knife marks
In the field of precision machining, residual knife marks have always been a technical pain point that troubles engineers. In the workshop of a certain technology enterprise, a newly introduced Guangu magnetic polishing machine GG8850 is undergoing rigorous testing: can it completely eliminate the spiral machining marks on the surface of 7075 aviation aluminum alloy workpieces? This experiment will unveil the mystery of non-contact polishing technology.
1、 Blade Pattern Challenge and Technological Breakthrough
After CNC machining, the surface of the aluminum alloy is distributed with regular cutting patterns 0.3-0.8 μ m deep, presenting a clear spiral structure under a 20x microscope. Traditional vibration polishing takes 120 minutes to achieve a surface roughness of Ra0.2 μ m, and there is a problem of angular wear. The magnetic polishing machine uses spherical stainless steel abrasive with a particle size of 50 μ m to form a dynamic grinding matrix under a magnetic field strength of 0.5T, and drives the abrasive to perform three-dimensional motion through a high-frequency alternating magnetic field.
Three key parameters were set for the experiment: magnetic field frequency adjustment range of 10-50Hz, processing time gradient of 10-30 minutes, and abrasive to workpiece mass ratio of 1:3 to 1:5. The control group used conventional rolling grinding process and treated with ceramic abrasive at a speed of 60rpm.
2、 Accurate game of process parameters
At a magnetic field frequency of 25Hz, the magnetic abrasive forms a stable eddy current motion mode. When the processing time reached 18 minutes, the surface roughness decreased from the initial Ra0.65 μ m to Ra0.12 μ m, and the SEM image showed that the blade structure completely disappeared. Continuing for 25 minutes, a slight orange peel effect appeared on the surface, indicating the existence of an optimal treatment window.
The abrasive ratio experiment revealed that 1:4 is the golden ratio, where the abrasive can fully contact the surface of the workpiece while avoiding excessive accumulation. Compared to traditional processes, magnetic polishing reduces energy consumption by 40% and does not require the addition of chemical abrasives, resulting in a 70% reduction in wastewater treatment costs.
In the testing of complex structured workpieces, the roughness of the inner wall of the 0.8mm diameter micro hole was improved from Ra1.2 μ m to Ra0.25 μ m, and the dimensional accuracy of the right angle part was maintained at ± 0.01mm, proving that the magnetic field can effectively guide the abrasive into the microstructure.
3、 Technological breakthroughs and industrial insights
This device demonstrates astonishing efficiency in batch processing of automotive oil pump housings: single piece processing time is 22 minutes, and the yield rate has increased from 83% to 98.6%. After being applied by a certain drone hub processing enterprise, the fatigue life test data increased by 30%, and the residual stress distribution on the surface became more uniform.
The technical team is developing an intelligent control system that monitors the polishing status in real-time through acoustic emission sensors and automatically optimizes process parameters using machine learning algorithms. In the future, it will expand to the polishing field of titanium alloy medical devices to address the special requirements of biocompatible surfaces.
The profound significance of this surface revolution lies in breaking the traditional dependence of polishing on physical contact and opening up a new dimension of precision manufacturing. When the last blade pattern disappears into the microscopic world constructed by the magnetic field, what we see is not only a smoother surface, but also a firm step for China’s intelligent manufacturing to move towards the field of ultra precision machining.
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