Help ! Upgrade chinese 40w laser to 50W

[Mcbride19]

Ok all those numbers make me sick


I Have a DK40 with this laser lens mount:


So to simplify , what is the best distance between the head(I mean the bottom of the head and not the lens) and the material for focal 50,8, 63,5 and 38,1 ??

Or maybe there is somewhere a calculator that can help me ?

EDIT : I've just saw this :

The ideal focal distance is different with each lens. In general, the ideal focal distance is the same as the lens specification; i.e. a 1.5 inch focal length lens will have ideal focal distance at 1.5 inches from the lens.

Is it right ???

[miketola]

All depends what are you doing. This is only what means. You also must have up and down cutting bed. I use only 38.1 mm

[miketola]

Okei.
This one pic explain everything.

If you change 38.1 lens your distance to material is about 35mm - 41 mm. Spot is about same size inside that. So you can use material max 6mm. Because your spot is smaller and more power you can maybe cut 7-8 mm if you have good table and you know your distance.

[Mcbride19]

so with 38.1 you can cut 8mm ?

I think I'm going to buy one of each 38,1 - 50,8 and 63,5
But I must change my lens mount because it only use 12mm diameter lens and it's hard to find those diameter in focal 38,1

your picture is really interresting and show very well how it works, now I understand more clearly.

[miketola]

I have original head , i also have lightobject head in stock. You can use 20mm, 19mm,18mm and 12mm with original head. I have few 12mm lens in stock example 38.1 . You can buy them from ebay or aliexpress about 22 $.

[Mcbride19]

Really, ??
when I unscrew the head to clean the lens it seems that the hole is just 12mm diameter !!

[miketola]

Thats no problem. Hole i just for 12mm lens. 19 or 20mm is ideal.

[Mcbride19]

Really interresting there is much more choice for 19 or 20 mm !
Thanks for this information.
I'm going to wait until March to order that, it's spring hollyday in China so they don't send orders !

[miketola]

Its chinese new year now. Checl also your original lens. Its sometimes upside down.

[Mcbride19]

I tried to put it upside down just to see what's happening, and it was like I didn't have power !!

I made a piece of wood with the good lenght and some weeks ago I bought this

Wholesale Product Snapshot Product name is Lab Jack Aluminum Lab Support Jacks 150x150x250mm Lifting Table Raising Platform 6'' inch

so I can put the table at the good height.

[Mcbride19]

Okei.
This one pic explain everything.

If you change 38.1 lens your distance to material is about 35mm - 41 mm. Spot is about same size inside that. So you can use material max 6mm. Because your spot is smaller and more power you can maybe cut 7-8 mm if you have good table and you know your distance.

So, with a longer focal the d-d distance is longer but you have less power distributed so you must use multipass to cut, with a shorter focal the d-d distance is also shorter but you have more power to cut !

[miketola]

Yes. And spot is smaller with smaller focal lenght. 50.8 lens is compromise.

[Mcbride19]

OK that's why quite all chinese laser have a 50,8 lens !!

It's all clear now the shorter is the focal the smaller is the point and the more concentrated is the beam, of course !!!! it's more clear like that than with the formulas I saw on the web.
I hope the month will finish soon to order the Lens (and the tube) so with all that I will be able to cut 6 mm mdf for futur customers.... great !

[Mcbride19]

How about a lens with focal 41 , what will be the distance(d-d) ?


is there somewhere , a SIMPLE calculator that could help me to know the distance(d-d) ?

[miketola]

I use this , or sometime just calculator.
Few message before you can check how calculate it like manualy.
Laser Optics Calculators

[miketola]

Dot 0.22 and Dof 7.1 if beam before lens is 2.5mm. If its 3mm because you change tube? then Dot 0,18 and Dof 4,9mm

[Mcbride19]

great...

thanks for the informations

[Mcbride19]

Just received the 50w laser tube 1000mm, whouaaa !
6 mm plywood at 12mm/s 45 % of power. Now it cut good !

[rayscott]

The black cable behind the power supply goes to the laser tube.

The 5VDC is used on one end of the potentiometer. Other end of the potentiometer is GND (0 VDC). The wiper of the potentiometer is feed into the laser power supply as "IN" .. the input.

The V- wire should be connected to the Ground wire of the Laser power supply. This gives the command signals (from the motion controller) a reference voltage level. You also need to connect the V- wire to the motion card.. You will need to power that card with 24VDC?

I prefer to pull the L wire to 0VDC when I want the laser power supply to trigger. The H wire should not be wired to anything.

[monkeyfist]

Just received the 50w laser tube 1000mm, whouaaa !
6 mm plywood at 12mm/s 45 % of power. Now it cut good !

This sounds interesting! I'm considering purhasing one of these 40w machines. I think i'll get one without the tube and buy the 1000m tube on it straight away.

Can these laser do something like 3d objects? Some of these 40w models have "lift platform" what does it do, and can it be used to do 3d cuts. Basically to mill wood in to shapes? If i need something like a 4mm wooden board with 2mm edges? Is this possible?