For a project that I was building I wanted to heat fabrics to 70 degree Celsius using lasers.

Since fabric is a very wide term for now I was looking to draw heat patterns on 100% cotton T-shirt and the colour of the T-shirt is black.

The project is similar to many laser engraving projects (on wood and plastic) but the key differences are:

  1. I do not want the fabrics to be cut, engraved or damaged by the laser.
  2. I would want to heat the area under laser dot to 70 degree within minimum possible time.
  3. The laser would go over the entire T-shirt but wherever heat is not needed it would remain off

Could anyone please suggest what power laser would be suitable for such heating project ?

  • $\begingroup$ Not an expert, but look for infrared lasers. Should be a pretty low power needed. Maybe a pulsed CO2 laser? $\endgroup$
    – Eric S
    Commented Dec 15, 2020 at 14:43

2 Answers 2


To expand a bit on the answer of NMech:

I would recommend a pulsed laser, as it allows a way more controlled energy input into the fabric. Some information on how to pick a pulsed laser for a process. A rule of thumb when developing a process with a pulsed laser is:

The pulse makes the process, the power makes the throughput.

What does this mean? When you pick a pulsed laser, they are usually advertised with their average power, which will on top of that be way lower than what you are used to from cw-lasers. While a 1 kW cw-laser is nowadays pretty meager, a 1 kW pulsed laser is already quite the beast.

For a pulsed laser, the way more important value is the maximum pulse energy that hits the material from a single pulse. This value plays a big role on how the light interacts with the material and needs to be carefully picked when developing the process (a good laser should have many different pulseforms with different max pulse energy and pulse energy distribution over the pulse duration, giving you a lot of choices to work with). The average power only decides how often these pulses get fired.

Example: You found a vendor that offers two similar pulsed lasers, one with average power of 50 W and one with 100 W. Which one do you take? The 100 W will fire the exact same pulses as the 50 W, they won't have twice the energy. It will just fire it twice as often and thus allow you to process more material in the same time.

All in all, don't be put off when you see a pulsed laser with seemingly low average power, it might do the job just as well, just slower. Instead, look at the pulse energy. Hope this helps a bit with picking a laser source.


That would very much depend on many factors. IMHO, the most important ones are the following:

  • type of laser you are using (continuous, pulse) and its wavelength
  • the diameter of the laser beam.
  • the speed of laser movement
  • The material properties:
    • thermal capacitance.
    • optical absorbance for the specific wavelength and reflectivity.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.