by educa » Thu Oct 04, 2012 6:09 am
At 120Mhz they should surely have power enough.
With such controllers the biggest problem is always the same... The want everything parametered to be able to run every where on machine with all kinds of acceleration ramps (mm/s^²), top speeds (mm/s) and different stepper setups (mm/step)
I code for 1 specific machine. My acceleration for normal cutting is 6000mm/s^² with topspeeds between 500 and 700mm/s (where I will probably choose 500) and on X axis for engraving I can shoot 1000mm/s with 30000mm/s^² acceleration.
My machine does a nice 0.02mm / step
Once I write my softwarehardcoded on these parameters, it runs very smooth.
Now I have a another question since this whole "what laser should I buy" bothers me a lot.
I initially wanted to buy a 80 Watt RECI tube from cncoletech on ebay (good seller, allready bought a lot there)
But... since these are quite expensive, I did some research.
These tubes allready produce a 6.9mm diameter beam at the aperture and have 2.4mrad divergence.
My laser has a big size and the biggest distance the beam would have to travel is 2.3 meters. At that point, the beam is calculated to be 12mm diameter.
If I plug all these data into the DOF calculator, then a 12mm beam with 50.8 would have a 0.475mm DOF.
That sounds extremely little distance. I am aware of the V shape (or the X if you set focal point IN the material), but it sounds strange to only have such a small DOF
If I understand right, then this could be a good point for engraving, but a bad point for cutting (which I'll do most)
If I then look at tubes like Lovehappyshopping or coletech 40 Watt, then I see beam diameters of 1.95mm when leaving the tube. I didn't find divergence values for these tubes anywhere so I cannot calculate the spot size at 2.3 meters distance, but I guess that the beam will probably be smaller with these tubes and therefore give me more DOF?
Thats why I am trying to get any technical data about these 40W beams to see if they will be better solution for me.
Another option would be to go for the 80W anyway and use a 100mm focal lens for more DOF (my up down table has 300mm to go up-down)
Or I could abuse the fact that my laser table is so big to selectively put my workpieces where the application is best.
In my upper left corner on the table the beam is smallest (between 8 and 8.5mm) which will give me there a DOF between 4.1 and 3.6mm (I guess this'll shoot veyr nicely on 3mm ply) and in my lower right corner the beam gets upto 12mm giving me 1.8mm DOF there....
Its all calculations and its so hard to find good numbers.
If I could know at least the average divergence on such 40 watt lasers or the spot size of them at a certainl distance, then this comparing would be a lot easier. Thats why I tried to ask on the forum and in other places allready and nobody seems to have these data.
Kind regards,
Bart