Thread: DIY Laser Cutter Engraver

Hi Sean,
Look forward to seeing this build.
I am totally ignorant on lasers so pardon my question but why do you need to have the table rise and fall - can it be done with a conventional moving Z axis?

I will follow this with great interest.

One thing that has stopped me so far having a go at this is that Mach3 has not been up to the task of operating the laser pulses. So having to get Solustan or similar control software

However there is a bloke in the US who is developing a Mach plugin to do just that.

Have not read the link you gave as yet; but I will.

Greg

No doubt you are on top of this but doing some quick reading I see the laser tube for 80w is 1600mm long and 100w is 1800mm long.
It will be worth considering this earlier in the design.

Originally Posted by rodm

Hi Sean,
Look forward to seeing this build.
I am totally ignorant on lasers so pardon my question but why do you need to have the table rise and fall - can it be done with a conventional moving Z axis?

You ask all the easy questions don't you

Ok so you we need a focal point see pic, its the sweet area that's what we want nothing over nothing under it will change on different thicknesses of material as well so will need to bring it up or down to that focal point.

I also will add a 4th axis so will need plenty of room for this .

Three ways it could be done not sure if they would work as speed is the main aim.

• Put the laser tube on the z axis would be perfect but it will be 1800mm long 50mm dia full of water being glass the forces will smash it in seconds I think.

• Same with putting it on the Y its a glass tube in another glass tube full of water engraving at say 60,000mm a min wouldn't be to good.

• Moving z axis would work for cutting as that's a slow speed easy I think but rasters you need high speeds the Chinese say they can get 60,000mm a min I will be happy with half that and a machine with the extra weight of a Z axis would tear it self apart I would think under those speeds (your thoughts).

You would also be adding another mirror to the arrangement that would also cause some loss to the laser the less mirrors the better.

But I could use shelves to start with as most of my material is the same?

All the above is willy brain theory cant state that its a fact until I try

Willy

Originally Posted by Greolt

I will follow this with great interest.

One thing that has stopped me so far having a go at this is that Mach3 has not been up to the task of operating the laser pulses. So having to get Solustan or similar control software

However there is a bloke in the US who is developing a Mach plugin to do just that.

Have not read the link you gave as yet; but I will.

Greg

Yes been reading that about the software you can apparently also get the LaserCut software as well off the Chinese guys if you get them in a good mood but will have to see how I go.

You and Rod have always been the leaders about time I did some work and got involved again with the group cant always just take take take.

Willy

Originally Posted by rodm

No doubt you are on top of this but doing some quick reading I see the laser tube for 80w is 1600mm long and 100w is 1800mm long.
It will be worth considering this earlier in the design.

Bloody long aren't they got a bit of a shock myself when I was looking at them a few weeks ago I will be leaving the tube in a box hanging out the back like this for easy access.

Hi WillyinBris,
Just a thought but mirrors and lasers and alignment all sounds very complex, would it be possible to mount the laser to the Z axis vertically on a gantry which is fixed. Then have the X & Y axis move the table so the gantry is fixed.

You may have thought of this already and have a valid reason why not but it is just my scratchy brain having a think.

Cheers
Steve

Originally Posted by stevejw

Hi WillyinBris,
Just a thought but mirrors and lasers and alignment all sounds very complex, would it be possible to mount the laser to the Z axis vertically on a gantry which is fixed. Then have the X & Y axis move the table so the gantry is fixed.

You may have thought of this already and have a valid reason why not but it is just my scratchy brain having a think.

Cheers
Steve

Na the 100w unit is approx 1800mm long and it would break it I think even the 400w unit is 700mm long I think and a diameter of about 50mm.
They are then full of water would be like waiving around a fluorescent tube in the air.

Wishe they were able to do this but I think those kind of laser are around the 40k mark that you could mount in place of a router.

Originally Posted by WillyInBris

Y 80/20 Belt driven (need some help on this one) with two joined rails and blocks making it approx1300mm long (will be replaced with one rail after I have proven the build)

.

Sean,

If you want to belt drive then the pulley used to drive the gantry will affect the resolution you get. I found this the hard way.

Eg: say you have a 50mm pulley.

So the maths becomes:

(steps X microstepping X reduction)
---------------------------------------------------
2 x Apple Pie X radius

= 200 x 10 x 4
--------------------------------
2 X 3.142 X 50

= 8000
------------
314.2

=25.46 steps/mm

So looking at this you get a crappy resolution of 1/ 25.46 = 0.039 mm/step

This has been my problem so to solve it i have just bought a harmonic gear reduction 50:1 which combined with my 4:1 reduction gives say 200:1. Just keep this in mind when you do the calcs for the belt drive.

Also keep in mind that the shaft you run between the pulleys to drive it should be about 20mm. So buy bearings this size and support them as close to the pulley as possible. Another lesson learnt.

**Have you considered rack & pinion. Greg has this setup and I think it is really nice. Plus the rack guys are in your state, so cheap freight.


PS: I have always wanted to run a laser. You can do the hard yards for all of us.
Good luck!!

/Michael

Edit: Sorry formatting in this editor is up the creek!!

Oooh I am along for this ride, I hope it works out for you.

What is involved with the pulse train for the laser ? I would think a PWM output of some sort, I MAY be able to help you with that, got a few projects to finish first (2459 to be exact ) but I could possibly do some kind of micro brain that takes some kind of set point via rs 232, 485, MODBus, or whatever you can get easily from Mach and output the PWM to the laser module. I have just ordered some micro's today for another project, 8 bit pics but they have 10bit PWM resolution.

No promises but I am always to happy to try something out of my league...lol

Cheers.

Russell.

What sort of capacity would your planned machine have for cutting? What sort of materials would you be cutting?

Thanks Mike and Russel definitely will need everyone's help on this, PWM sounds the go so far from what I have read but I still have to look into that part but keep it in your thoughts that's for sure.

Russel my main worry about using something like Rack is the weight the Y axis needs to be light as possible so i think belts are the go.

Maybe we shoud call it the The Group Project at Willys Place So GPW lol

Originally Posted by snowyskiesau

What sort of capacity would your planned machine have for cutting? What sort of materials would you be cutting?

Ok to start with it will be a 40w maybe 60w laser main aim is to engrave but also to cut materials up to 6mm like ply etc then an upgrade to 100w and see what it can raelly do.

Lasers are capable of many things but it depends on the setup lens used and its going to be a lot of trial and error to start with but I enjoy a challenge.

Cutting area is going to be about 500x1200 see how I go with that.

Willy.

Ok so I have requested quotes from a couple of ebay shops on the following.
you will see that the actual lens mount is quite small not a lot of weight in it either.

3 x reflection mirrors about $25 US
2 x reflection mounts about $20 US

1 x focus Lens mount about $21 US
1 x focus lens $50 US

Plus shipping......... lets see how bad that is.

I have got another quote coming as well but I think its going to give me a fright when I get it higher quality gear from another supplier.