PROJECT UPDATE - PARTS ORDERED!I'm completely project crazed. I previously said that I was going to retire one of my three other projects before buying parts to start my laser project. I lied.
I've been obsessed the last couple of days with building my own laser cutter/engraver. I've upgraded the design a bit since my earlier musings in this build log. It'll have twice the work area and twice the power of the laser I've been using, and it'll be water cooled instead of air cooled. I'm building an 80W laser with a true 24" X 24" laser area with a slightly larger bed that extends beyond the laser cutting area. I want to be able to load a 24" X 24" sheet and cut to the edges.
With a lot of valuable help from Marco at LightObject.com, I've finally decided to chop down a 36" X 48" XY table to make the 24" X 24" XY table I want. The 3' X 4' table is way more than I need, and I don't have the space for such a large laser, but the typical 11.5" X 20" desktop lasers were going to cramp my style too much. It'll cost more, but I think the 24" X 24" laser will be the best value for my dollar and square feet of precious floor space.
Yes, I'm definitely cheating by purchasing a high quality imported XY table instead of building my own. I'm hoping to earn back some geek points because of the degree of difficulty scoring, given that I'm running a small business and I have three other concurrent geek projects (a large CNC retrofit, my CNC lathe conversion, and a couple of Hadron ORD Bots).
Here's the XY table I'll be chopping down to make my 24" X 24" table.
http://www.lightobject.com/Pro-9001200-X-Y-Stages-for-DIY-CO2-Laser-P708.aspxNote that the XY table includes all of the rails, timing belts, pulleys, stepper motors,etc. Definitely cheating! The part acquisition is probably the least fun part, IMO.
BTW - If you
REALLY want to cheat, LightObject.com also offers an even more complete XY table that can be cut down. It includes the optics mounts and laser head. All that's missing is three 25mm mirrors and a 20mm focusing lens. The cost of either XY stage equally equipped is about the same.
http://www.lightobject.com/XLE-9001200-X-Y-Stages-complete-kit-for-DIY-CO2-Laser-P737.aspxThe next biggest purchase will be the laser tube and matching laser power supply. Probably something like this:
http://www.ebay.com/itm/NEW-RECI-BRAND-80w-80-watt-CO2-LASER-tube-long-life-with-POWER-SUPPLY-/251151358563?pt=LH_DefaultDomain_0&hash=item3a79c99a63I'll hold off on the laser tube and laser power supply purchase until near the end of the project, unless I find a deal I can't refuse. I want to have the infrastructure in place to safely mount the laser tube to minimize handling, and pump coolant through it so I can quickly test the laser tube and power supply once I receive it, in case I need to file a claim for shipping damage or some other problem.
My next task will be collecting a lot of the other components so I can decide what goes where when I design a custom bolt-together extruded aluminum frame. It'll probably have a footprint about 34" deep and 72" long. I want to make sure it'll go through a standard 36" wide door. The rest of the ~72" length will consist of a work surface to the right of the laser table. Part of the reason for the addition of the work area is to allow space along the back of the frame for the 1200 mm (4+ foot long) laser tube. From many all night sessions spent laser cutting parts for my business, I know the work surface will be very handy.
This laser is turning out to be a bit bigger than I originally planned, but it'll be so nice to be able to cut 24"X24" sheets for a few hours as I assemble parts or watch a Netflix movie nearby while keeping an eye on the laser. And every now and then I need to make a laser cut acrylic or poster board spray painting stencil, and the larger cutting area will avoid the hassle of piecing a stencil together from smaller pieces.
The other major laser stuff I still need to buy (in no particular order) includes:
Used PC off Craig's List to control it all, with a big flat screen monitor
MESA Electronics integrated I/O and stepper controllers
Stepper motor drivers
DC power supply for the motors
DC power supply for the control electronics
A large Harbor Fright exhaust fan to remove the nasty smoke from lasing stuff
A large aquarium air pump to push clean air through the laser nozzle to keep the optics from gunking up with smoke
A water pump to circulate the coolant through the laser tube
A large coolant reservoir
Some sort of laser cutting bed and a method to raise and lower it so the material to be cut is at the laser focal point
Misumi extruded aluminum frame with body panels
Lots of small stuff like an emergency stop switch, water flow switch, water float switch, coolant temperature sensor....
I think I'll build the extruded aluminum laser frame and XY table at my friend's business across town. They have large granite surface plates for work tables that will allow me to bolt together very square and flat mechanical subassemblies.
I'll probably spend some time thinking about the possibility of using the clean inlet air for the fume exhaust to cool the coolant. It might also be nice to have a down draft exhaust system that pulled the smoke away from the optics and also functioned as a weak vacuum hold down assist for fixtures or flat sheet stock. Some of the sheet materials I cut are rolled for shipping and they don't want to lie completely flat. I can tape down the edges to keep them flat and prevent the material from moving while it's being cut, but it'd be nice if it was gently pulled flat so the 1/4" thick material is cut with very straight side walls.
I plan on using LinuxCNC as the CNC control system. I've been using LinuxCNC and MESA Electronics for the other CNC projects I've been doing lately, so a lot of that knowledge transfers, and the development and ongoing support should be easier. There are slightly cheaper solutions, but the MESA Electronics hardware is high quality, robust, and very capable. It's not the cheapest, but I consider it to be a very good value.
LinuxCNC won't allow me to draw something and print it to the laser like the Windows software for lasers. CorelDraw has been very handy for quick parts off the laser, like the acrylic Hadron ORD Bot feet I made. I'd want that sort of solution if I was laser engraving trophies or industrial device labels and one-off custom signage all day long, where every job is different, but most of my laser jobs are production jobs that I run a couple of days per month. Using less graphically oriented tools to piece together G code is slower but tolerable for the way I use the laser, and LinuxCNC does generate a nice graphical WYSIWYG interface that shows what will be cut, scaled to the work space, as well as the beam path as the job progresses. Maybe there will be a nice integrated Linux laser controller solution some day.
On the plus side, G code and LinuxCNC allows more direct control of the laser. One of my current laser jobs uses a fixture with a DC gear motor to turn a mandrel to cut rubber tubing. I call it "the rotisserie". It's sort of a poor man's 4th axis. The VersaLaser commercial laser software has a minimum laser speed, so I'm forced to make successive short cuts back and forth to cut the rotating tube. With LinuxCNC and G code, I can move the laser to the position I want and turn on the laser as the tubing rotates underneath, and avoid the back-and-forth cuts on the rotating tube, so I'll have smoother and quicker cuts.
I'm still trying to decide if I want stepper motors for the Z axis. A manual mechanical Z axis adjustment would be all I need, but I'm more of an electrical engineer than a mechanical engineer. It may be easier for me to design a system with two stepper motors wired together (ala 3D printers) to raise and lower the bed by jogging it up and down. Maybe a scissor jack mechanism on each end? Threaded rod in each corner of the bed?
Does anyone know of a good small & cheap integrated PC board that runs LinuxCNC with low jitter? The four year old chock-full-o-viruses Windoze PC on Craig's List is probably the most cost effective solution, but it'd be great to have a small and reliable PC that can be ordered off the internet and known to work with LinuxCNC, preferably with a 64 GB flash drive instead of a hard drive. When I make the Craig's List PC buy, I try to find one with a flat screen monitor for the best bundled price, and I arrange with the seller to allow me to plug in a LinuxCNC Live CD so I can make sure it boots from the CD and can run LinuxCNC with low jitter for acceptable realtime control response before I pay for the PC. It's something of a crap shoot. LinuxCNC doesn't need a fast PC. Most PCs are OK, but onboard video chips that use system memory as video memory and access it via DMA can wreck the realtime Linux kernel response needed for fast CNC control operations.
Here are the parts I bought from LightObject.com tonight.
Qty SKU Item Price
3 LSR-MIR25MO 25 mm Molybdenum (MO) Reflection Mirror $82.50
1 LSR-HD2520LR Pro laser head mount for 25mm mirror & 20mm focus lens. LR Type $69.00
2 LSR-PR25M2D Pro 25mm reflection mirror mount for Co2 laser machine $69.00
2 LSR-TUBEMNT80 Pro Laser Tube Mount 80mm (adjustable) $64.00
1 LSR-PRO90120XY Pro 900*1200 X-Y Stages for DIY CO2 Laser $950.00
1 LSR-EP4 CO2 10600nm Laser Eyes Protection Glasses/Goggle. CE certified $45.00
1 LSR-ZNSE2050HQ High quality 20mm ZnSe Focus lens (F50.8mm) $52.00
1 SHIPPING UPS Ground $78.97
I had a $100 coupon, so I paid $1,310.47. I'll start a spreadsheet to track costs, vendors and part numbers in case anyone wants to follow in my insane path, in whole, or in part.
This was probably the most expensive single order I'll make for this project, and it represents a lot of the hard work done for me, so I expect to be finishing this project instead of becoming mired in designing and redesigning. I should be able to bring this laser project in under $3,500.
Huge thanks to Marco at
http://www.LightObject.com for all of the time he spent helping me. He went way beyond the call of duty. I feel very good about supporting vendors like that, but even if you're ruthlessly self interested, a vendor with low prices and excellent service is an unbeatable deal - way better than maybe saving a few pennies on eBay and regretting it later when it doesn't work out and you're left holding the bag.
The next project is always the best project, but I really do need to start wrapping up some of these projects instead of starting new ones. It's getting crazy around here.