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 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,
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'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.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.
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 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
Anyway, I'm ranting now
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
Cheers
Neil
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