Magnesium CNC Milling Tips

Due to the problem that the deformation affects the size and shape tolerance of the part in machining, the machining method of high speed, low feed and low depth of cut is used to complete the machining of all relevant dimensions of the part through one clamping, thereby reducing the cost of the part. Deformation caused by excessive cutting force during the machining process avoids the error caused by the failure of the machining datum and the design datum to overlap, and improves the dimensional accuracy and shape and position accuracy of the parts.

Problem:

During the machining process of parts, deformation is often caused by internal stress, especially non-ferrous light metals such as aluminum , Machining of magnesium alloys. Deformations in the form of warping, side bending and twisting caused by internal stress frequently occur, which will seriously affect the Machining quality and Machining efficiency of parts, especially for thin-walled and thin-plate parts. How to minimize or eliminate the deformation of parts and ensure product quality and production efficiency has been our research topic for many years.


Cause Analysis:

In order to improve the Machining and performance of magnesium alloys, it is necessary to increase the strength by means of heat treatment (quenching treatment + aging treatment) before Machining. The material produces a lot of internal stress during the quenching process, and the aging process cannot completely release the internal stress generated during the quenching process.

In the subsequent machining process, new cutting stress is generated. With the continuous removal of material, the equilibrium state of internal stress is broken, and the internal stress is redistributed until the new equilibrium process is reached and deformation occurs, causing the part to lose its stress. Some machining accuracy. And when the stress on the surface of the part exceeds the strength limit of the material, cracks will also occur.


Solution:

For the above reasons, the "sleeve material" method is used for the Machining of magnesium alloy thin-walled and thin-plate parts. The "Nesting" method is a Machining method in which the parts are taken out from the blank after all the dimensions are processed in one clamping.

The nesting process includes milling top →rough milling inner cavity→rough milling shape→finish milling shape→finish milling inner cavity→finish milling bottom surface→point (drilling) hole→cutting and other processes.

Because the whole process is completed in one clamping, before cutting, since the part is connected with the bottom surface of the blank material, the internal stress will not cause the part to be deformed greatly, and the part size is stable during the whole process.

When cutting, the blank material needs to be adhered to the bottom surface of the part material by 0.1mm to ensure that the part has sufficient strength to resist the cutting stress generated during the Machining during the entire "sleeve" process.

After the part is cut from the blank, although the part is deformed due to stress release, the relative dimensions on the part will not change, only need to increase the calibration process to level the bottom surface and all the dimensions and shapes can be restored to correct.
 

Anti-corrosion skills for CNC milling of magnesium alloys

Magnesium alloy Machining mainly pays attention to corrosion problems, mainly to prevent magnesium discoloration, suppress hydrogen, resist hard water, and the liquid does not stink. Finally, choose some well-known brands, such as Meike's magnesium alloy cutting fluid. At the beginning of our factory Machining magnesium alloys, there has been a problem of discoloration. Later, the problem was solved by replacing them.
 

What are the requirements for cutting fluid for magnesium and magnesium alloy machining?

Although the machinability of magnesium alloys is very good, the power consumption during cutting is about 1/3 of that of aluminum alloy and 1/10 of that of steel. It can be used for dry cutting, but it may cause chips and dust to burn. series of problems, resulting in fire hazards, so the machining of magnesium alloys is still the mainstream of wet cutting. Recommend a special magnesium alloy cutting fluid RISSOIL SY 308
 

Which workpieces are generally produced by machining magnesium alloys

Mainly magnesium alloys such as AM60B and AZ91D, and produce automotive instrument panel beams, 3C product shells, aero engine parts and other automotive applications according to market demand , 3C category, magnesium alloy die-casting products for aerospace. The advanced technology and equipment of the original Terim magnesium factory in Canada, the world's most advanced Rauch quantitative pouring holding furnace, Bühler magnesium alloy die casting machine, ABB automatic picking robot, automatic spraying hand and automatic edge trimming machine are used to realize die casting production. Fully automated, suitable for the production of various large and complex die castings, and its production capacity and technical capabilities are at the leading level in the global die casting industry.

Tag: Magnesium CNC Milling Tips