[bm1984]

Hello all,

I am looking to build or buy a laser engraver for 24"x48" (61cm x 122cm) pieces of plywood, and our budget is $1000. I have found several open source projects that are more suited to smaller formats, but none that suits our needs. I also came across Lasersaur Manual , which is just the right size, but the bill of materials ends up being closer to $8000.

Am I crazy to believe I can build a 40W CO2 laser bed capable of engraving this big for such a small budget? I like Arduino, and am intimately familiar with Linux, just not so much with LinuxCNC.

Does anyone have tips, or a similar path I could follow? I honestly have no idea where to start, what to search for, or even what a good stepper motor specifications would be.

Sorry for the noob question, but I have been searching for a couple days with no luck. Looking at the experts now!

Thanks.

[JustinBell]

Check out the BuildLog.net 2.x Laser.

[Retroplayer]

Hello all,

I am looking to build or buy a laser engraver for 24"x48" (61cm x 122cm) pieces of plywood, and our budget is $1000. I have found several open source projects that are more suited to smaller formats, but none that suits our needs. I also came across Lasersaur Manual , which is just the right size, but the bill of materials ends up being closer to $8000.

Am I crazy to believe I can build a 40W CO2 laser bed capable of engraving this big for such a small budget? I like Arduino, and am intimately familiar with Linux, just not so much with LinuxCNC.

Does anyone have tips, or a similar path I could follow? I honestly have no idea where to start, what to search for, or even what a good stepper motor specifications would be.

Sorry for the noob question, but I have been searching for a couple days with no luck. Looking at the experts now!

Thanks.

I don't know of an existing kit that fits perfectly into that budget. Even the Buildlog laser says $6000 using their materials list and distributors. However, you could probably redesign some of the parts, use different materials, etc.. to get that cost down.

I would offer one suggestion though: At that size, it would makes sense (and you have the room) to mount the laser tube directly on the Y carriage (laser tube moves with the Y axis.) The main reason being that this will shorten the beam path. The longer the beam path, the less power that will be delivered to the material as well focusing issues.

A 40W tube is 700mm which is roughly 27.5 inches. The path you want to avoid is the 48" dimension. So mount the tube perpendicular to this. Should fit on your 24" axis since your actual carriage will be longer than your cutting area due to guide rails, steppers, etc..

[ELaser]

I don't know of an existing kit that fits perfectly into that budget. Even the Buildlog laser says $6000 using their materials list and distributors. However, you could probably redesign some of the parts, use different materials, etc.. to get that cost down.

I would offer one suggestion though: At that size, it would makes sense (and you have the room) to mount the laser tube directly on the Y carriage (laser tube moves with the Y axis.) The main reason being that this will shorten the beam path. The longer the beam path, the less power that will be delivered to the material as well focusing issues.

A 40W tube is 700mm which is roughly 27.5 inches. The path you want to avoid is the 48" dimension. So mount the tube perpendicular to this. Should fit on your 24" axis since your actual carriage will be longer than your cutting area due to guide rails, steppers, etc..

Meh.

Mounting the tube on the Y gantry

Not just a tube is it, EHT DC cabling, coolant lines, lost of extra mass that is going to severely limit acceleration...

I'm going to take the opposite view, maximum beam travel distance on a 48 x 24 inch bed is 84 inches allowing 6 inches each for Z and tube to first mirror, if you have any notable beam divergence in 84 free air axial to the tube no mirrors nothing inches you have a seriously **** tube.

I would approach it this way.

1/ you have a minimum cost to build a 48 x 24 inch gantry with steppers / rails / drive mech etc, we can call this cost A

2/ you have a minimum cost for a half decent 50 watt tube + PSU + coolant loop, we can call this cost B

3/ you have a minimum cost for laptop, USB breakout (parallel port is too slow), mach3, ok, you may already have laptop / PC call this cost C

4/ you have a minimum cost for 3 x good mirrors and 1 x good lens, and a nozzle call this cost D

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Cost C is the cheapest

Cost D is the second cheapest, and one of the worst possible areas to economise on, buy pukka USA or German optics

Cost A is likely to be the thing you change out or upgrade least / last, it is going to be one of the big capital items, and making it not have to carry any great masses (eg no tube etc) is going to cut the cost, as is reducing the maximum expected speed, which ties in with a 50 watt tube anyway, but is HAS to be rigid and is HAS to achieve absolute minimum 0.25 mm REPEATABLE positional accuracy, even a crap beam is going to have a "tool diameter" of this order, and the basic rule of thumb for any such CNC kit is repeatable table accuracy MUST equal or exceed minimum tool diameter.

Cost B is also likely to be a *****, but, this is an element that is upgradeable or swap outable at a later stage, ESPECIALLY if you dissociate the tube itself from the XY table assembly

3 NM nema 23 steppers would run the XY at reasonable speeds on this and have enough power to not miss steps but still give enough microstepping to give good accuracy

Off the top of my head the only way I can see of doing this for even ballpark thousand bucks is buy a failed project / surplus plasma table / kress spindle router kit and refurb / repurpose it to cut down on Cost A

As soon as you start earning money, throw it in a pot to upgrade cost B, better tube and PSU, then throw all the money in the pot to build the MKII machine, which may actually deliver on all the dreams you had for the MKI, and give reliability and productivity too

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To use a mechanical spindle CNC router / vertical mill analogy, cost B is your spindle motor, bearings and collet chuck, and cost D is your solitary end mill cutter

You'd better have a *lot* of "free" hours of labour you can throw at this... then ask yourself, are you better using those "free" hours of labour doing some menial job and earning ten bucks an hour, and increasing your budget so you can go for a solution that requires less "free" hours of labour to implement.

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I don't know where you are on anything else, but, I'm in the UK, I sell "machine time" on my laser, that means I don't want to be a design house or an artist or anything else, I want you to give me a properly dimensioned DXF file and an associated descriptive text file.

For this I charge customers one UK pound sterling per minute for small jobs, or 50 per hour for larger jobs / runs, so you have to figure, assuming of course you can get the work / custom, that every hour of my "free" time is worth 50 quid, if I spend 4 weeks building a machine with "free" time and bugger all cash budget, I just lost 4 weeks potential earnings, assuming of course I can get the work / custom.

The same will apply to down time.

I'll tell you now, 95% of the work I get I get because it is "no bull**** can do service" which means the customer speaks to me, the machine operator, not some sales droid who doesn't know dick, and because I aim for a 24/48 hour turnaround, that's why I get the sale and others don't.

I'm not trying to be a dick or piss on your parade or walk in your shoes or anything else, but you will only be as good as your last job, and you will find it really hard and really expensive in your "free" time to achieve what you want for less than a thousand bucks, I'm sure it COULD be done, but SHOULD it be done, once you tally up all that "free" time if it was charged out at minimum wage...........