How to judge the processing condition based on the color of iron filings in CNC processing?
In CNC machining, if it is normal dry cutting, it is reasonable for almost all steel chips to appear purple. Today we will talk about the color change of iron filings in CNC processing.
With the increase of cutting temperature, the change rule of iron chip color in dry cutting is: silver white → light yellow → dark yellow → crimson red → dark blue → blue gray → gray white → purple black. The temperature can change from about 200 ℃ to more than 500 ℃.
The process of iron chip color change is the process in which most of the work consumed in the cutting process is converted into cutting heat, and it can also be seen as the process of tool loss (sharp passivation severe passivation scrap) (when there is no chip buildup). Note that the commonly referred to cutting temperature is the average temperature.
Relationship between chip color and cutting temperature:
Silver white: below 200 ℃
Pale yellow: ≈ 220 ℃
Dark blue: ≈ 300 ℃
Light grey: ≈ 400 ℃
Dark purple black:>500 ℃
It is reasonable when the cutting color is blue or blue purple. If it is silver white or yellow, the efficiency is not fully exerted. If it is blue gray, the cutting amount is too large. If high-speed steel cutter is used, it is better to cut to silver white or yellowish. If blue cutting is used, reduce the speed or feed.
Of course, determining reasonable parameters by color change is only one of the methods or means. Have you learned?