[AAnzusI]

Hello I'm designing a CNC diode laser machine that can cut 16-Gauge stainless steel to earn my bachelor's at the university.

Since Im new to this enviroment I would like to know how to calculate the power needed to cut that deep, I've searching this forum for answers but all I can find is people estimating 150-500W and not the actual formulas or parameters and the actual research papers that touch this subject are behind hundreds of dollars paywalls which I can't aford.

Any Ideas on how to calculate this are welcomed.

Thank you.

[peteeng]

Hi Anz - Maybe this will help. Peter

https://en.wikipedia.org/wiki/Laser_...er_consumption

I've also attached an article on the melting of steel which gives the enthalpy of melting figures. You maybe able to relate that back to the power requirement of the laser via a process efficiency ratio. You say you are designing a laser cutting machine. If the request is simply what size laser to put on it then 500W commercial machines cut 6mm thick steel. 500W seems to be the smallest commercial laser they do... Small 50-100W hobby table top machines can cut 0.5mm steel. Its just not about the power you throw at the metal its about the power density, heat transfer and the production rate (ie the head velocity) you want to achieve. A smaller laser with better optics that can produce a smaller "dot" will produce the same power density then a bigger poorer optics laser etc. Then you have the issue that you maybe able to melt the metal but you have to clear it. So there is a practical cutting width that under, it just re-welds or clogs and over that width you need excess power... Plus the power required is often about being able to pierce the metal vs cutting the metal. Once the metal is pierced the power required goes down...

If your request is more about the machine vs the laser then ask specific questions about machine design. So with your requests you need to be more specific in your question to get the answer(s) you need. Why design a machine that is available off the shelf at a machine suppliers? Just find a commercial machine and copy it? Is there something different about what your machine is trying to do? As you say you must "earn" your degree so keep at it. Peter

[AAnzusI]

Hi Peter.

I realized my request wasn't specific, what I'm trying to do is to design a laser machine capable of cutting 16-Gauge stainless steel using blue laser diodes, in the order of 450nm. I know the machines you mentioned are capable of doing that but they are either too big or too small and they use either fiber or CO2 laser. As far as I know there are no commercial blue laser machines for metal cutting, I know of engravers like the Atomstack that use blue laser diodes. In my research I found that stainless steel has less refractance at 450nm (about 56%) as opposed to CO2 laser that are in the order of 1064nm (70%), which would mean that less power is wasted and thus less power is requiered to archieve the melting point of stainles steel (about 1400°C).

To earn my degree I have to show this design in a thesis-like document backed up with it's corresponding calculations by the end of my internship around May of this year.

Thank you for your quick response -Anz.

[peteeng]

Hi Anz - There maybe no blue lasers because the wavelength is unsuitable or they can't scale up a blue laser to the power required. Pulsing is used to keep the average power down (so no damage to the laser) yet provides a peak for piercing/cutting. Better find out if blue is going to work otherwise your goose is cooked! Do you mean reflectance vs refractance? Engraving metal usually requires a heat absorbent paint for better results. Peter

[peteeng]

Hi Anz - Seems a laser module puts out about 10W and you would need 50 of these to get to 500W. There are 50W module units that stack the modules, use semi-mirrors to collimate the beam and get 40W out of a 5x10W stack. "Blue" wavelength is used in fibre guided laser for metal cutting so thats not an issue. So I think you are under the limit of current commercial technology if the aim is to use a non fibre laser stack. The attached company can sell you a fibre 500W blue laser module and you can cut your metal.

laser diode | CNIlaser

cheers Peter

May to get a thesis done, better get on your bike!!