Micro-Engraving Technology for Metals

This provides a practical solution to the problem of thermal deformation of metals during the micromachining process.By optimizing the parameters of the engraving process, selecting an appropriate cooling method, and pre-treating the material, the impact of the heat generated in processing on precision can be effectively reduced.These machines are used for the precision cutting of metal parts and medical devices.

Why does metal engraving easily deform?

Everyone knows that metal conducts heat rapidly, but when it is subjected to high-energy processing like laser or mechanical engraving, a local temperature spike is almost unavoidable.In particular, for the etching of microscopic characters, a bit too much heat and the material will expand or even deform, making the text blurry or even rendering the part useless.

Three steps to solving the problem of heat deformation.

The key is in the pre-treatment.

The first thing to do is give the metal a "warm-up": Clean off the oil and grease from the surface. If you have the means, you can also use low-temperature annealing to relieve internal stress.For example, stainless steel is very difficult to work with, but by coating it with a protective fluid and then engraving the words, the effect is immediate.

The parameters have to be finely tuned.

Don't just stick with the laser's highest power setting; try the "low power, high frequency" option.For example, if one wants to cut a channel 0.5 microns deep, the pulse frequency can be raised to 200 kHz, and the duration of each pulse can be reduced to the nanosecond range, so that there is no time for the heat to spread.When using a diamond cutting head and a small amount of lubricant, the rotational speed can be reduced by 30 % and the feed rate by 50 %, which can reduce the temperature rise by more than 40 %.

The cooling process can't be skipped.

Don ’ t underestimate the importance of cooling! Air cooling is suitable for shallow cutting, but if the depth exceeds 50μm, liquid nitrogen must be sprayed on.The solution was to blow compressed air over the workpiece 5 microns away from the path of the laser beam. This cooled the material without interfering with the area being processed.Remember to blow the air at a 45-degree angle. Tests show that this is twice as efficient as blowing the air straight down.

Choosing the right equipment is half the battle.

There are many devices on the market that claim to prevent thermal deformation, but the key points are these: do they have a real-time temperature monitoring module, and can they automatically compensate for thermal drift?Have you ever seen a closed-loop temperature control system for a particular brand of machine? It has an infrared thermometer built into it, and automatically adjusts the coordinates every 0.1 mm. The error is reduced to under ± 2 μm.

Don't step in the holes.

The old master's lessons: If you carve the same place again and again, it will deform. He suggests using a strategy of jumping around--first outline the contours and then fill in.Also, don't try to continuously engrave thin-walled (less than 1 mm) pieces. Instead, process them in three stages, with a 10-second cooling period between each stage, and you can raise your success rate from 50 % to 90 %.