Has anyone built a 100w+ 4x8 laser?

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Re: Has anyone built a 100w+ 4x8 laser?

Postby Tesla » Wed Sep 19, 2012 8:33 am

k, so for the 2x4 table, ill order the 2x it with extended rails and install the laser on the gantry ? question is do we have any cooling issues ?
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Re: Has anyone built a 100w+ 4x8 laser?

Postby iGull » Wed Sep 19, 2012 9:32 pm

@Tesla
If you are only building a 4x2' laser, why go to all the bother of mounting the laser on the gantry with all it's attendant (DIY unproven so far!) issues?
Don't get too anal about all this expansion/contraction stuff that folks are talking about, it's a non-issue as far as I'm concerned at this size - I've used mine for over a year with zero problems.
You'll want to up the power a bit anyway (I use 60W - purely cost based, 80 to 100W would be better, but it brings in other problems - 60 is a really good compromise) and use half decent quality mirrors and lenses at least 25mm - they are most definitely not expensive - checkout coletech or lightobject's better quality ones. Use a longer focal length lens - I'm using 63.5mm, that way, you can get away with some minor table level/material flatness issues - the beam size is about 0.2mm max (focal depth is around 2.5mm 'ish).
Don't mount your rails on the outer casing, at that size, you are asking for problems - build a seperate inner 'optical table' frame and mount everything on that, then mount that to the casing system. Don't use brackets, screw the frames together using core screws - brackets are MUCH easier, but are just not rigid enough - they're also hugely expensive compared to core screws! Make sure the laser, optics and xy mechanics are all attached to the same 'optical table' NOT to the outer casing - that keeps all errors common mode.
I didn't see the point of having all the peripheral stuff lying around the laser with all the cables, pipes and ducting, so I dumped it underneath - then you don't need to design a skanky wooden 4"x2" pine table to fit under your nice shiny new laser - and all the water and extract is under the same footprint :D All that for the sake of 300 mm of extrusion height and some skins!
If all you are cutting are sheet products, get rid of the rising table and fit a fixed (and really level!) system - simply use the focal tube on the laser head to adjust focus - one less stepper and all the attendant wobbly rise and fall mechanism (and you'd need to get a special long belt made too (I did)! Don't fit a permanent cutting grid - you'll want to fit jigs and stuff to the table frame for standard jobs. By all means, have a removeable grid for those engraving jobs that warrant it - most of the time, it doesn't - all you get is flashback that marks the back of the material - use lengths of mesh plastering 'corner bead' spaced empirically to suit the job - the best thing by far is nothing :lol:
Anyway, I'm ranting now :lol:
That's all MHO, and it's free take it or leave it.

I'd be really interested to see a DIY laser gantry mounted, it has great possibilities for the larger machine - although, I still wouldn't have any flying optics - at that size, you more than likely wouldn't be interested in rastering - lower power vector marking would probably be sufficient.

So, what are you waiting for :lol:

Cheers

Neil
EMOs are a sign of weakness ...
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Re: Has anyone built a 100w+ 4x8 laser?

Postby mikegrundvig » Thu Sep 20, 2012 3:38 pm

Don't mount your rails on the outer casing, at that size, you are asking for problems - build a seperate inner 'optical table' frame and mount everything on that,
Yeah, I learned this in my experimenting initially. Much easier to make a super rigid inner frame that's dead simple and strong vs. trying to work a box onto that same frame.

Don't fit a permanent cutting grid - you'll want to fit jigs and stuff to the table frame for standard jobs. By all means, have a removeable grid for those engraving jobs that warrant it - most of the time, it doesn't - all you get is flashback that marks the back of the material - use lengths of mesh plastering 'corner bead' spaced empirically to suit the job - the best thing by far is nothing

I'd love more details on what to use instead of a grid. Feel free to rant all you want - lots of truths seem to come from frustration :)

I'd be really interested to see a DIY laser gantry mounted, it has great possibilities for the larger machine - although, I still wouldn't have any flying optics - at that size, you more than likely wouldn't be interested in rastering - lower power vector marking would probably be sufficient.
I'm still very interested in a gantry mounted tube but based on a few different people's success with a 2x4 cutter and fixed tube I'm rethinking it a bit as unnecessary. I've got the basics of a design in my head and some of it in CAD. I'm totally set on a 100 watt RECI laser tube which means that I'm at a little less than 5' gantry length. For only 2' of travel, it seems a total waste to go through all the work. If I go more like 4x4, then the gantry-mount makes more sense.

-Mike
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Re: Has anyone built a 100w+ 4x8 laser?

Postby Tesla » Fri Sep 21, 2012 6:20 am

iGull wrote:@Tesla
If you are only building a 4x2' laser, why go to all the bother of mounting the laser on the gantry with all it's attendant (DIY unproven so far!) issues?
Don't get too anal about all this expansion/contraction stuff that folks are talking about, it's a non-issue as far as I'm concerned at this size - I've used mine for over a year with zero problems.
You'll want to up the power a bit anyway (I use 60W - purely cost based, 80 to 100W would be better, but it brings in other problems - 60 is a really good compromise) and use half decent quality mirrors and lenses at least 25mm - they are most definitely not expensive - checkout coletech or lightobject's better quality ones. Use a longer focal length lens - I'm using 63.5mm, that way, you can get away with some minor table level/material flatness issues - the beam size is about 0.2mm max (focal depth is around 2.5mm 'ish).
Don't mount your rails on the outer casing, at that size, you are asking for problems - build a seperate inner 'optical table' frame and mount everything on that, then mount that to the casing system. Don't use brackets, screw the frames together using core screws - brackets are MUCH easier, but are just not rigid enough - they're also hugely expensive compared to core screws! Make sure the laser, optics and xy mechanics are all attached to the same 'optical table' NOT to the outer casing - that keeps all errors common mode.
I didn't see the point of having all the peripheral stuff lying around the laser with all the cables, pipes and ducting, so I dumped it underneath - then you don't need to design a skanky wooden 4"x2" pine table to fit under your nice shiny new laser - and all the water and extract is under the same footprint :D All that for the sake of 300 mm of extrusion height and some skins!
If all you are cutting are sheet products, get rid of the rising table and fit a fixed (and really level!) system - simply use the focal tube on the laser head to adjust focus - one less stepper and all the attendant wobbly rise and fall mechanism (and you'd need to get a special long belt made too (I did)! Don't fit a permanent cutting grid - you'll want to fit jigs and stuff to the table frame for standard jobs. By all means, have a removeable grid for those engraving jobs that warrant it - most of the time, it doesn't - all you get is flashback that marks the back of the material - use lengths of mesh plastering 'corner bead' spaced empirically to suit the job - the best thing by far is nothing :lol:
Anyway, I'm ranting now :lol:
That's all MHO, and it's free take it or leave it.

I'd be really interested to see a DIY laser gantry mounted, it has great possibilities for the larger machine - although, I still wouldn't have any flying optics - at that size, you more than likely wouldn't be interested in rastering - lower power vector marking would probably be sufficient.

So, what are you waiting for :lol:

Cheers

Neil


I concur, im getting started on it !
Tesla
 
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Re: Has anyone built a 100w+ 4x8 laser?

Postby REdington » Fri Sep 21, 2012 8:23 am

I'm going to build a 24" X 48" with a 80 watt RECI tube. The tube was delivered Tuesday damaged and waiting for the claim to be processed. The replacement tube should be shipped by Tuesday. I'm working on a 3D printer now and will start on the laser when that is done. For my Y axis I will use a moving table so I will have 1 less mirror to get aligned and less distance for the beam to travel. The tube will set right behind and parallel to the gantry. The only problem I see will be the weight of the table and will not be as fast as if I had the Y moving gantry. Here is one that my buddy built about 14 years ago that the table is the Y axis. He has a Synrad double tube and it is mounted on the gantry. he doesn't get the speed out of it mainly cause the leadscrew starts whipping.
Image



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Re: Has anyone built a 100w+ 4x8 laser?

Postby autocrib » Sun Oct 21, 2012 9:02 pm

Can some here give more details of the shenhui controller? I've search the forum and Google'd but didn't turn up much.
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Re: Has anyone built a 100w+ 4x8 laser?

Postby Tesla » Fri Jan 17, 2014 6:52 am

Back again, i was going to get started but work got in the way, so i'm interested in a really big laser foot print, would i be dreaming if i wanted something way way bigger like a 4x6 or even a 4x8 ?

What would have to be done, i mean can i buy a small kit and extend the length ? newbie here
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