What is the relationship between speed, power and frequency in a laser marking machine?

What is the relationship between speed, power and frequency in a laser marking machine?

If you ever owned a laser marking machine or you are familiar with laser marking machine, then you probably know the three most common settings that affect part marking: speed, power and frequency, this article is all but about the three parameters and the relationship between them.

The following knowledge points are listed below:

The speed parameter of a laser marking machine

The power parameter of a laser marking machine

The frequency parameter of a laser marking machine

The relationship between the three parameters

1. The speed parameter of a laser marking machine

This is the speed at which the laser beam passes through the marked part. The control beam system uses a scanning galvanometer with a mirror to move the laser beam through the lens and part surface. Laser marking machines can usually move lasers much faster than laser-marked parts, but rarely run at the maximum speed they can. The problem is that for most materials at this speed, the laser does not have enough time to do work on any part of the part. The effective speed depends on the material and laser power. A speed of 30-35 inches / second may be suitable for removing anodizing on aluminum, but it is better to sculpt deeper on the metal at a speed of 5 inches per second and process the part multiple times.

2. The power parameter of a laser marking machine

The laser can only emit as much power as the design requires. Generally speaking, more power out of the laser will allow more material to be removed or allow parts to be marked at higher speeds. In the marking, the power is calibrated in Watts. A 20 watt laser can only produce 20 watts of energy. You can enter a larger number in the output power setting, but you can only get what laser capabilities.

3. The frequency parameter of a laser marking machine

Unless you have a continuous wave laser, you won't have one. If your laser is used for marking, the laser emits light pulses instead of continuous beams. The duration of each pulse is very short, and the duration of the pulse is measured in nanoseconds.

4. The relationship between the three parameters

As the output pulse frequency decreases, the energy of each laser pulse increases in the laser marking machine . The laser and its associated internal optics have an energy damage threshold, and care is taken to ensure that the output energy does not exceed the damage threshold of the laser or any of its internal components. The damage threshold of a fixed pulse width fiber laser is approximately 1 mj of energy. A 20-watt fixed-pulse-width fiber laser, with a pulse frequency of about 20 kHz and an output power of 20 watts, the energy per pulse will be close to 1 mj. Therefore, a 20 watt fixed pulse width fiber laser is not allowed to operate at pulse frequencies below 20 kHz.

Remember, the output energy increases as the pulse frequency decreases in the laser marking machine. Therefore, a 20-watt fixed-pulse-width fiber laser has a maximum possible energy per pulse at a pulse frequency of 20 kHz. Setting the pulse frequency below 20khz does not cause more energy to be generated per pulse, as the laser is internally limited to pulses at lower frequencies. The typical pulse frequency range of a 20 watt fixed pulse width fiber laser is 20-200khz. A useful pulse frequency range is approximately 20-50 kHz. When the pulse frequency is higher than 50 kHz, the energy produced by each pulse is not enough to do a lot of work. A 50 watt fixed pulse width fiber laser at a pulse frequency of 50 KHz and an output power of 50 watts, each pulse is close to 1 mj, so it is internally limited to work at lower frequencies. The effective pulse frequency range of a 50 watt fixed pulse width fiber laser is approximately 50-80 kHz. Similarly, above 80 kHz, the energy per pulse is not enough to do a lot of work. Variable pulse width fiber lasers allow operation at lower pulse frequencies, although they still have the same 1mj / laser pulse damage threshold.

If a lower pulse frequency is selected on a variable pulse width fiber laser, the output power of the laser will be reduced internally, so the energy per pulse will not exceed the damage threshold. There is no way to bypass the damage threshold. It's physical.

So, material marking is a function of how fast the laser beam moves over the part, the power of the laser output, and the pulse frequency of the laser. Lower speeds, higher laser power, and lower pulse frequencies result in stronger, deeper marks. In contrast, higher speeds, lower laser power, and higher pulse frequencies result in weaker and shallower marks in the laser marking machine.

So, now you know how to adjust the three parameters of the laser marking machine, Laser Engraving Machine, Laser Cutting Machine?