What is difference between Q-switched laser and MOPA laser
Recent years, fiber laser engraving machine is becoming more and more popular. Many spare parts are updating, including the laser source. Many customers ask the difference between Q-switch laser source and Mopa laser source. So today hope we can figure it out.
First, MOPA laser wavelength also is 1064nm, it is belong to fiber laser, so it is just one series of fiber laser. Fiber laser has 2 types: pulse width fixed, we called it Q-switched laser source; pulse width can be adjusted, we called it MOPA laser.
Whatever Raycus laser, IPG laser even Max laser, they all have MOPA series, e.g. we can say Raycus brand MOPA series, IPG brand MOPA series. Several years ago, Q-switched laser source is very popular, and very less people know mopa laser. But recent years mopa laser developed very fast, I think most of people know Mopa laser.
So here is the question: do i need Q-switched laser or MOPA laser? First we check the advantage application of mopa laser.
MOPA laser has some obvious advantages:
# Marking black color on anodized Aluminum, just like Iphone housing.
For such work, Raycus/IPG cannot mark black color, only grey color. If you have to mark black color, then you need choose mopa laser.
# Marking colors on stainless steel
Some people feel only MOPA laser can mark colors on SS. It is a mistake. Raycus laser/IPG laser also can mark colors on SS, just their pulse width is fixed, the parameters are not so easy to get for new beginner.
MOPA laser pulse width can be adjusted, so it is a little easier to get color marking parameters compare with Raycus/IPG laser. As my opinion, it is not necessary to buy one MOPA laser which only for marking colors on SS. Because marking colors speed is low, most of seller only use color marking sample for get customer's attention. But if you have to do such work, then you also can choose MOPA laser. The choices are yours.
# Marking plastic
Somtimes mopa laser can do the plastic more better than Q-switched laser. Plastic is a complex material, I cannot promise you fiber laser can mark plastic, sometimes we need UV or green laser.
So if your 80% work is in same range as above information, then you choose MOPA laser. Or you choose standard Raycus/IPG laser.
Another question, can i use mopa laser make deep engraving or cutting thin metal material?
Mopa laser has 20w 30w 60w 80w 100w. If you choose 20w 30w, it is hard to make deep engraving. But if you choose 60w, it is okay to cut silver gold plate or make some deep engraving. JPT brand updated their model, now Mopa series only have M7. M1 and M6 already stopped production.
Pulse width 2-500ns, frequency: 1-4000khz
If you need more information, pls feel free to contact us. Below are one of our customer’s summary for your information
"A few people have asked what the Q Pulse Width on the MOPA Fiber Laser does. Just jump to practical uses at the bottom if this gets too nerdy.
I will make this as simple as possible, so hopefully people will get it and can at least conceptualize it a bit.
We are comparing short and long pulse widths, on the same machine, all other settings the same.
So both laser pulses will apply roughly the same amount of energy to the material, at the same spot, just over a different time period.
The short pulse width will achieve peak power ( the most the pulse can deliver ) much quicker than the longer pulse width will, and for longer.
Why does this matter?
Material has a vaporization threshold, a melting threshold ( and a few others, depending on material )
If a pulse raises the material above that threshold quickly enough the material will start to vaporize without melting, or transferring energy to the substrate ( surrounding material )
The longer it stays above this threshold the more material will vaporize ( up to a point, physics, longer discussion ), and the more quickly it drops off the less chance that it will melt the material when it crosses into the melting threshold ( briefly )
On the other hand if the temperature is raised slowly, there is a much higher chance of melting the material even if some of it is finally vaporized, and as it drops slowly through the melting threshold it continues to heat the substrate ( surrounding material ) and possibly contributing to melting it as well.
Conceptually the shorter pulse width acts like a blow torch while the longer pulse width acts like a match.
If look at the chart I attached, which is an idealized graph, the bluen line is a longer pulse width, the green line is a shorter pulse width. The bottom axis is time, the left axis is just an idealized representation of the melting and vaporization threshold of some arbitrary material.
Practical Uses
Using a short pulse width will not guarantee you can vaporize the material, but if you can it will do it better than a longer pulse width all other settings being equal.
A longer pulse width on the on other hand can heat things up slower, which for foaming on some plastics will allow you to achieve a finer control and variation all other things being equal.
Carbonization ( changing colors on steel ) is a topic that is still being debated by scientists, pulse widths there contribute more to the finished product vs. the colors available and it's not linear like vaporizing or foaming ( experimentation is required )
If variable pulse widths still don't make sense feel free to ask me a question and I will see if I can make it even simpler.
Of course there is something called a frequency cutoff that we need to take into account, realizing that even though we can set the Q-Pulse to any number it only works in a few ranges, etc. but unless there is some interest I won't bore anyone with that."
