Laser processing: Avoiding damage to the substrate

If you want to avoid damaging the substrate during laser processing, you have to pay attention to three things: parameter setting, material pre-treatment, and energy control.Sharing practical techniques such as laser power regulation, focus positioning, and the application of protective coatings, this course will help you improve processing accuracy and reduce material waste. It is suitable for use with a variety of materials, including metal and plastics.

Why is the substrate so easy to damage?

Many of my friends have encountered problems with the material burning or the edges of the cut being rough when they use a laser cutter.In fact, this is mostly due to improper control of laser energy, or to improper settings of parameters or materials.For example, metals conduct heat quickly, so if the power is too high, they can heat up locally. And if the focal point is not correct when working with plastic like acrylic, the surface can bubble up.

A golden combination of parameters

Power and speed must be in harmony.

The power is too high, the blade can be burned out.It is recommended that one start with a small test area, such as a 3-millimeter-thick piece of wood. One might start with 30 % power and 10 millimeters per second speed, and then gradually adjust the settings according to the color of the cut (if it turns black, the power is too high).Remember to increase the power output as the speed increases, but don't overdo it. Don't adjust more than 5 % at a time.

Don't be careless about the focal point.

If the focal point is not correct, it's like using a magnifying glass to focus the sun's rays--the energy is too concentrated.For metal processing, it is suggested that you use an automatic focus head. For non-metallic materials, you can do a manual test: drill a few points on scrap material and observe which depth gives the cleanest effect.A little trick is to draw a line on the workpiece with a marker before processing. This makes it easier to see if the focus is off.

The materials are given a protective coating.

You can't afford to skimp on protective coatings.

In particular, for materials such as stainless steel or acrylic that are easily scratched, a layer of high-temperature blue tape or special laser film can be used to prevent scratches and reduce the adhesion of smoke and dust.When removing the film, peel slowly from the edges, and don't use your fingernails to pry it off.

The right auxiliary gas.

The compressed air or nitrogen not only blows away the residue, but also cools the material quickly.When cutting thick boards, increasing the flow of compressed air can effectively prevent carbonization. When processing reflective materials such as copper and aluminum, using nitrogen can reduce energy loss due to reflection.

The condition of the equipment must be closely monitored.

If there is any dust on the lens of the laser head, wipe it off immediately. Even a small spot can cause uneven energy distribution.Check the alignment of the beam each week, especially after moving the equipment.If the lines are too wide or uneven, you should probably replace the lens.

Finally, it should be noted that different batches of materials may have different characteristics, so you should not assume that the parameters you used last time will work this time.It's much more economical to spend five minutes before each run making a test print than to have to redo a job.