[R and G Leather]

Greetings everyone,

Obligatory first sentence - I'm a long time lurker, first time poster.

Now that that is out of the way, lets get down to business. I'm a leather worker by trade, making punk rock gear like studded belts, bracelets, and collars (not my style, but it pays the bills). Like many of you I am a kind of a "jack of all trades" type. I make or modify most of my own tools. This time I'm going to step into the deep end of the pool and try building a Laser cutter/engraver table in a large format (4' x 10' cutting area). I finally found someone who will finance me up to $2500 for the project, and I'm hoping that it can improve the profit margins of my business enough to pay for itself over time.

Enough background for now. On to the plan.

• Optical and related parts
  
  • 80W CO2 tube on ebay ~ $500
  • Matching PSU on ebay ~ $450
  • 4X mirrors on ebay 4x$20 ~ $80
  • Mirror mounts 4x$18 ~ $72
  • Beam combiner off ebay ~ $20
  • focus lens off ebay ~ $65
  • Cooling - full radiator and pump kit off ebay ~ $200
  • SUBTOTAL = $1387
• Motion, Mechanical and related parts (heres where it gets less clear)
  
  • 3 axis kit from stepperword ~ $309
  • Belts not sure, maybe ~ $100
  • Gears maybe ~$100
  • Linear shaft with supported rail (mcmaster) 2 x $78 ~ $156
  • DIY Linear bearings (skate bearing style) - $50
  • SUBTOTAL = $715
• Structural
  
  • Steel square tube and I beam for most of frame (guessing)~ $250
  • SUBTOTAL = $250
• Air
  
  • Air assist for cutting and or keeping lens clear of smoke (guessing) ~ $100
  • SUBTOTAL = $100
• TOTAL = $2452

I know I'm missing tons of little things like shipping charges, software, bolts, etc... I'm planning on paying for all that stuff out of pocket rather that via the loan.
The goal is to build it and get it functional first, then upgrade the parts later as time and money permits.

My goal is to get

• 4' x 10' work area
• max speed of 10" per sec with a single pass cutting through 3/16" leather (slower would be fine initially till I can upgrade componenets
• 2 axis for now, with Z added later
• low or no backlash
• accuracy of .005" or better

So the big questions I have for all you Zoners are

1. Does this look feasable
2. what am I overlooking

Anyway, more info will come later.
Thanks in advance for any help

[Konstantin]

Originally I was into building a 4 by 8 but decided to chill it , and build it on a smaller scale. I have a big table made of T slotted aluminum. For now I am focusing on getting something like 4 by 4 or less.

Where are you going to mount the laser tube?
If stationary then calculate beam travel to the farthest end from OC and calculate the beam diameter. Key term here is "divergence".

If you are making the tube itself movable then some other engineering is necessary, but it will ease beam divergence woes.

Some people say that long tube CO2 laser has low divergence, but it must be taken into account.

Basically beam divergence given in X mRad where you will add X to initial beam diameter every meter. So if beam divergence is 7 mRad and diameter of 3.5mm at the OC (like in Synrad Firestar) then in 3 meters your beam will have a diameter of 3.5+3x7= 24.5mm

What items from your BOM do you have already?

[R and G Leather]

Thank you Konstantin.

This is exactly what I was looking for. Its all the little details that I didn't think about that are likely to trip me up and cause huge problems, expenses, and delays.

I don't have any of the important parts from my rough BOM yet. Obviously some of the random structural stuff may be made out of scrap I have laying around, but that doesn't really count.

The beam divergence thing is hard to say. I just spent a while trying to find specs on generic tubes from China. No luck. I'm going to hazard a guess that the divergence is minimal only because the tubes are ridiculously long compared to most US made RF excited tubes of equivalent power. I will certainly have to do some more research before I buy.

[Konstantin]

Someone post that in long laser tubes divergence is 2.2mRad. It would be a good idea to calculate beam divergence at closest and farthest ends of the table and figure out the focal point shift.

This page cites a 1.7 mRad div http://www.canlaser.com/en/co2.php

[yamingf]

better get a used CNC machine (10 yrs old maybe 20 yrs old) and get a affordable motion controller. that should be a easiest way to build a laser machine. shoot me an email at [email protected] with your #, we can talk more.

[draekar]

Konstantin makes an excellent and often overlooked point on beam divergence. A subject well worth the extra research. The next item is driving the table (imo). Are you planning on vector cutting only or raster as well? Vector cutting can be done with software like mach3 and others but it takes a bit more for rastering (engraving vs cutting). Another thing to consider is how you will set your focus length. the common way is to raise/ lower the cutting surface to change the focal lenght. Another way would be to raise/ lower the "Z" axis. The latter adds weight and mass to the bridge so acceleration/decelleration play a bigger factor.
Just a side note, I have the stepperworld 4 axis board for use on a router table and I am not really impressed with it. It is a unipolar drive board and not a chopper. it will let you do full and 1/2 step. No matter how I tune it, I cant get it to run the motors smoothly for vector, so I got a microstepping, bipolar board.
Keep us updated with your progress,

[MonoNeuron]

Hi Guys,
Don't forget to serialize the build.
I don't think you will get 10" sec out of 80 watts for 3/16 leather, more like 5" sec but someone with an 80 watter may be able to clarify this.
You could always put the laser tube behind the X axis rail as there would be room for it with a 4' table with maybe a bit hanging out and it would solve your divergence problems as the beam would only be going for about 5' max but you may have problems with vibration in the tube if you don't have really smooth rails and fast stops and starts may be a problem also (you could experiment with the acceleration curves.
I also keep asking people to try out photocopier mirrors for wattage's bigger than mine at 30 watt but no one seems to try it and they are free from office scrap so I would give it a go and save $80 if it works.
You really only need a good quality pond pump for the water cooling too. (weipro ?)

I couldn't find out if the stepper drives you want were micro stepping ones, and you will definitely want that, as it makes everything smoother and quieter at 1/8 micro steps.

Try Econobelt for your belt and pulley needs.

You have 1 item missing and it is the heart of the whole machine and ties everything together....... The software !
The cheapest you will get is about $1300 or you could use Mach3 at $150 as others have done and not have engraving capabilities. I could never get it to work very well but that's a refection on me and not the software.
Best of luck.
Rich.

[CncForMe]

I am constructing a 10 x4 and would love someone else to help, work, collaborate on the project. Have the rails and gantry constructed. I would love to put a 400W+ laser on it, thats just a wish but we all have the bug. Funny from Oregon born in Portland but wound up here in Philadelphia PA wish i was still in Portland. Check out the build photos if you like @ PhillyMachineWorks.com . Collecting Mitshubishi AC servo drives, rapids should be in the 2000 ipm range. I wish you luck on your laser project.
:rainfro:

[Konstantin]

Nice soldering skillz Phill.

[protomate]

Your plan looks pretty solid. I work with lasers everyday. I have designed and built many xy systems and co2 lasers. My word of caution is only do some research on the china tubes first. They tend to offer less than expected lifespans and output power. I only use flowing gas in my prototype and production part systems. The other thing to keep not cut corners is on the cooling system. Many newbies buy a windshield washer kit offered buy many Ebay people. They are designed to run for seconds, not hours. Also, if our cooling goes out, our tube can be damaged. I hope this helps.

[Laser Pro]

R&G - you had better have a 1st class air exhaust system or a cast iron stomach. Laser cutting leather is burning flesh.

[iburton]

I have been looking at doing a 4x4 table, and would love to collaborate as well. There are many people doing this DIY, but few if anybody is documenting it well. I agree with others that divergence will be an issue. Are there mid-path lenses that can converge the diameter just slightly, i.e. a 2m focal length lens, or will that scatter the light too much?

[Laser Pro]

I have been looking at doing a 4x4 table, and would love to collaborate as well. There are many people doing this DIY, but few if anybody is documenting it well. I agree with others that divergence will be an issue. Are there mid-path lenses that can converge the diameter just slightly, i.e. a 2m focal length lens, or will that scatter the light too much?

A collimator using 2 lenses could be placed inline just before the beam enters the area of motion in the path along the 1st axis. Avoid using a single long fl lens, that still results in changing beam diameter and thus changing power densities at different places on the bed.

You will also want 2 stationary mirrors (yet adjustable) just prior to each moving axis mirror (on one end of the axis), this allows for proper alignment of the beam along the moving axis so that you keep the beam striking the center of your focusing optic. THis won't be necessary if the mechanical portion of the machine is PERFECTLY orthogonal.

[Laser Pro]

I have been looking at doing a 4x4 table, and would love to collaborate as well. There are many people doing this DIY, but few if anybody is documenting it well. I agree with others that divergence will be an issue. Are there mid-path lenses that can converge the diameter just slightly, i.e. a 2m focal length lens, or will that scatter the light too much?

A collimator using 2 lenses could be placed inline just before the beam enters the area of motion in the path along the 1st axis. Avoid using a single long fl lens, that still results in changing beam diameter and thus changing power densities at different places on the bed.

You will also want 2 stationary mirrors (yet adjustable) just prior to each moving axis mirror (on one end of the axis), this allows for proper alignment of the beam along the moving axis so that you keep the beam striking the center of your focusing optic. THis won't be necessary if the mechanical portion of the machine is PERFECTLY orthogonal.

[bdhubbard]

Hi,

My son, who is majoring in engineering, is eyeing my MaxNC Maxpath and is thinking about a summer project to convert it to a Laser cutter. (Paper, plastic, and wood; adding an O2 feed might enable metal cutting too.) At the moment, I am just lurking, but I am also interested in a possible collaboration. We use commercial 100W CO2 Laser cutters at school; and I have had one bad experience with a low priced Chinese Laser cutter (power supply probably configured for Chinese power, poor service availability). I have also been around Ruby and YAG laser cutters. Because the path of least resistance is to replace the router with the laser head and optics, I'm not sure how far this will get if we use CO2 - they are too large to translate easily. YAG and Ruby lasers may be smaller, but I suspect that they are pricier. The 500W YAG was housed in a teflon package about the size of a pack of cigarettes, with a convenient fiber optic delivery system, but the power supply and chiller were the size of an 8 cuft box. Still, it was amazingly compact for 500W of power. During a brief web search, I have stumbled across http://nilno.com/laser_intro/system.html and http://www.repairfaq.org/sam/lasercc2.htm#cc2toc. On a completely separate line of thought, we live in S. California and there is a lot of sunlight to be collected and concentrated down here: 500W/sqm ?

- Bruce

[protomate]

Ah, another engineer! Good for your son. I have a BSME in engineering. Helps with a lot of the theory. Here is a project update:

Delayed due to boom in business.

Seemingly, many middle aged engineers are retiring or getting laid off. I have been spending a great deal of time consulting and working on CNC system designs. They call this work! HA. Beats corperate America anyday.

With respect to your laser retrofit. Here are my thought's:

CO2 lasers from China are junk. My experience with the power supplies is, 9/10 work when you initially start them up. If they work, they keep going. Very good technology for the money. Anything like their power supplies made in developed nations cost's 10x more. I like them if you are running 50-100w. Over that I have not seen anything. I am a flowing gas man. Actual cost of ownership is far less. Service is a snap, and as long as you don't mis match the part's, they really only consume optics after many, many hours. The sealed China junk is throw away, and if you could get it refilled + optics = 4-5k. I am developing a line of CO2 lasers. 100-500w in power and compact.

YAG vs. CO2 (all approximate)

YAG 100w out
8000W in
7900W of heat. Large capacity/high flow rate cooling pumps
Power supplies switching or not = big, heavy,and bulky
safety glasses = $$$
Fiber delivery = $$$ (they are consumables of sorts)
Optics = $$$
Certain materials, the way to go! Can use KW's less power for some stuff.
Price = not bad if you know the right people

CO2 100w out (slow flow or sealed axial)
2000w in
1900w of heat. low capacity/low flow rate
Power supplies - tiny, 10-40lbs
Safety glasses = Walmart $3
Beam delivery = depends on method
Optics = seem like a real deal compared to YAG
Can work most materials.
Price = not bad if you know the right people
If designed well, you can fit whole 50w system in the size of a trunk. The best way for an arrangement like yours is vertical. Some trade off's, but not bad.
Send the beam up to an articulated arm. Connect output end to the z axis. Add focusing optic, and dry air, or gas to where the beam comes out. ready to cut.
Today I am adding motion to a super precision 3 axis machine. It will run YAG or CO2. I have a 180w CO2 and a 150w YAG to use on it. Will be able to switch lasers on the fly through M code. It is like a very expensive one like the link you posted. Travel 12.5" x 12.5" x 4". Here is the base machine:


Should be running YAG tonight.

Big Table Update:
Due to time constraints, I have opted to order precision flat base plates off the shelf. The machine will now be 60" x 56". At this point I have (3) 750W AC servo motors. (2) For X, (1) for Y. Maybe someone can help. I need for my numerous projects:
YASKAWA or Omron or any other private label of theirs? Anyone know any others?

Step and Direction
drives and motors (have a P in them somewhere I think)
200w
300w
400w
750w

I am willing to offer high powered lasers in a trade or cash
I currently have:
90-250w YAG's,
60-180w CO2's
Argon (3-5w)
25-50 KTP's
You name it, I probably have it if it is laser related.

I have some of my bit's offered on Ebay under my username if you want more info, pics, or lot's of tech data.

Well, back to "work"

Thank you all, and I welcome comments/solution's.

[Konstantin]

Hi protomate.
Well since you are welcoming comments, here it goes, I have seen your Laserland items and actually have sent you some questions about them, and the descriptions tend to be quite vague to be honest.

Like I asked you specifics about your power supply and you copy paste the item description as a response. How about "specifics", "I think it can produce voltages approaching 30kv" is not a specification. Auctions are coming pretty close to heruursciences's it terms of ravings .

And your items are all "AS IS".
So...

[protomate]

I find your post ridiculous. This is not a place for slanderous comments. I am uncertain of your backround. If you think my listings are too vague, then I strongly urge you to avoid them. I can tell you are enthusiastic about lasers, and that is great! One of the great motivation's for my Ebay store is to meet other laser enthusiasts. I try to be as honest and forthright as I can be. If I don't know, I don't make it up. I clearly stated in the listing that I have no personal expertise at the application of that supply. I stated it is suited for the HV wizards. This was/is clearly stated. I do not buy things at flea markets and market them on Ebay. I just clear out my old toys, experiments, and left overs there. As far as "as is condition", I am more than happy to warranty a system I install and integrate, but a $20,000 laser selling on Ebay for a couple of hundred does not command such perks. As many things can render many of the components of a system useless, it is not feasable to offer such garantee's. I have never had a complaint both on and off Ebay about a component I passed along. Please leave the comments to my projects, not your disatifaction.
Thank you,
Ben

[iburton]

Protomate, you did open the door for comments and Konstantin was simply offering an opinion. In as much as the post Konstantin replied to was just a big nonsensical advertisement, his opinions seem to me to be based on opinion and responded to the message. Most of us are smart enough to take opinions with a grain of salt and will often do research on our own. I have had a similarly difficult time getting specifics about your products. I stopped trying because in my opinion, you do not have sufficient knowledge to make me comfortable with a purchase.

[protomate]

Well I apologize to both of you if I did not provide the answers you were seeking. This is not my intention. I offer a truce to you both. One thing I guess I don't understand as I buy quite a bit of things on Ebay is: Most people do not even attempt to answer my technical question's. Is it not a swap site? Anything greater than that is a benefit? Is application's engineering a requirement for such places? I suppose the only laser person who may answer my question's is Heurosciences and HV guy. They are both very knowledgable men. I have talked to both of them. Heuro is a laser engineer I believe, and HV is a high end electrical engineering consultant. Do you think it is fair to complain about the support you received through Ebay? I think you are being unfair. I welcome private emails if you wish to work together to figure something out. Also, please understand that the email volume on certain item's is very high, and it is impossible to spend too much time on one mail. Email me, I am interested to hear what you were looking at.

Thank you,
Ben
PS: I really do need some servo motors. I figured this would be a good place to trade for them?