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Message |
    
Gerald_D
Registered
Username: Gerald_d
Post Number: 1324
Registered: 11-2005
| | Posted on Thursday, May 03, 2007 - 06:45 am: | 
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Fabrica, you can start driving this thread . . . . |
fabrica
Registered
Username: Daya
Post Number: 326
Registered: 10-2006
| | Posted on Thursday, May 03, 2007 - 08:30 am: |
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Thanks Gerald, Very true when you say that it is another toolhead. But it's a very sophisticated one, not that straight foward as a Router and Vinyl cutter.
Ok Lets get down to business. I at the moment have purchased a CO2 laser cartridge from Universal laser from U.S.A. (the manufacturer's product link is given below.).
http://www.ulsinc.com/co2laser/english/products/50-60.html
What I have is a 60 Watt version. The reason that I purchased the 60 watt version is because I need this to engrave granite to a depth of 3 mm and cut acrylic sheets having thickness upto 9 mm (without the top or bottom sides getting burnt). The cost of the Cartridge was around US $ 9,000 with the red dot option. The red dot option is required for alighment purposes (the co2 beam is not visible).
As for software I have linkmotion. The reason why I have selected this software is because mach 3 does not support the laser option that much.
The cost of this software is around US $ 1,300. Some of U.S.A. manufacturers of laser machines do use this software.
In addtion to this you would need a beam delivery system. This is to convey the beam from the laser beam genarating device (in my case a stand alone cartridge) to the material to be cut.
When it come to fixing the laser unit to a CNC machines their are two ways of doing it. One is to have a flying optics system the other methord is to mount the laser unit on to the Y car (Z axis). Usually on large tables like mechmate (8'x 4') the laser unit is directly mounted on to the Z axis.If you need to see a exampleof of how it is done follow the link given below.
http://www.graniteart.com/pages/products/mseries/MLS4448-LARGE
If you need to know more about a flying optics system follow the link given below.
http://www.vy-tek.com/pages/our_products/LST
The advantage with a flying optics system is that you could run the machines at speeds in excess of 30 inches per second. For Z axis mounted systems the speed is restricted to around 15 inches per second. This is due to the fact that laser genarators are glass tubes and due to this they are very fragile and heavy. In a flying optics system the laser unit is stationary and the beam is delivered to the cutting/engraving point by using mirrors (beam benders) and lenses. |
fabrica
Registered
Username: Daya
Post Number: 327
Registered: 10-2006
| | Posted on Thursday, May 03, 2007 - 08:36 am: |
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If some Guy could provide me a with a design to mount the laser on to the exisiting mechmate Y car would be really greatfull. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 1327
Registered: 11-2005
| | Posted on Thursday, May 03, 2007 - 09:05 am: |
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The last time we looked at your mounting, we did not know anything about the beam delivery system. Can the suppliers of both the laser and the delivery system supply you with mounting instructions (do's and do not's) and .dxf drawings? |
fabrica
Registered
Username: Daya
Post Number: 328
Registered: 10-2006
| | Posted on Thursday, May 03, 2007 - 09:36 am: |
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The laser manufacturer has sent to us a very comprehensive mounting instructions guide which could be posted to this forum.
Gerald we cannot think of a flying optics system for a large table like mechmate. The laser has to be mounted parallel to x axis. one 90 deg bend mirror has to travel mounted on the gantry to reflex the beam from the laser upwards. For this to happen all along the x axis the v rails have to be accurate to a very high accuracy level. If not a the beam would not hit the centre of the moirror mounted on the Gantry. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 1328
Registered: 11-2005
| | Posted on Thursday, May 03, 2007 - 09:51 am: |
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I was not talking of flying optics, I was talking of the beam delivery system that must be mounted under the laser. Maybe it connects only to the laser, but we still need to know how long it is and how much space it needs.
Don't get too hopeful that I am volunteering to be the "Guy" to do the design, because I am going to be abroad and very busy afterwards when I get back. I am just asking the questions that any other volunteer designer should be asking..... 
Would it help to mount the laser on rubber mountings? If you drop a stone on the table you don't want the shock to get to the glass? |
Bob Cole
Registered
Username: Bob_cole
Post Number: 31
Registered: 10-2006
| | Posted on Thursday, May 03, 2007 - 12:16 pm: |
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Fabrica:
Have you considered the use of fiberoptic cable to deliver the lazer light beam? I do not know if that is a viable option, but I know that the auto industry uses fiber optics to deliver "cold" light to various light sources in an automobile. Perhaps you could ask your laser provider if this might be an option? just trying to think { outside the box} |
Brian_B
Registered
Username: Allegheny
Post Number: 35
Registered: 07-2006
| | Posted on Thursday, May 03, 2007 - 01:34 pm: |
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Bob,
Fiber optics canNOT be used to deliver a CO2 generated laser beam - at least not yet. Fiber optics are used with YAG lasers routinely, but YAG's start at $100,000+ in US dollars!
Brian |
fabrica
Registered
Username: Daya
Post Number: 329
Registered: 10-2006
| | Posted on Thursday, May 03, 2007 - 01:40 pm: |
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Ok The beam delivery system is directly connected to the laser. The beam delivery system has a lenth of around 9 inches and a diameter of around 30 mm.
having rubber mountings would be a good idea.
Bob CO2 laser beam do not travel through Fibreoptic cables. Some lasers such as YAG do. This is due to different lasers having different wavelenths. If am not mistaken CO2 lasers have a wavelnth of around 10.9 Micrometers. |
Bill McGuire
Registered
Username: Johnnydoughey
Post Number: 14
Registered: 12-2006
| | Posted on Thursday, May 03, 2007 - 08:41 pm: |
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RE: Post #328
Fabrica.... just a thought, but would a small parabolic mirror work? That might ensure the beam would end up reflecting in the same direction even if didn't hit the mirror in the exact same spot throught the gantry travel... |
Gerald_D
Registered
Username: Gerald_d
Post Number: 1329
Registered: 11-2005
| | Posted on Thursday, May 03, 2007 - 08:54 pm: |
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Bill, in "flying optics" the mirror needs to deflect the beam by 90o and a flat mirror is placed at 45o. (A parabolic converges a beam at a spot).
Fabrica isn't planning to push new frontiers as regards CNC laser - he has done his homework and is following established practices. For those that don't it yet, Fabrica is in Sri Lanka where he could well be assembling the first CNC laser produced in that country. (They have a tiny number of imported systems) |
fabrica
Registered
Username: Daya
Post Number: 330
Registered: 10-2006
| | Posted on Friday, May 04, 2007 - 08:52 am: |
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My intention is first to start with a Gantry mounted system. The drawbacks with such a system is that the safety of the laser unit is at stake and also the speed would be slow. With lasers neds fast speeds specially when you are doing raster work. The high end machines run at speeds in the region of 100 inches per second by using galvo motors. But in these fast machines the table size is limited to around 24"x 36".
Gerald, we do not have any lasers in Sri lanka at the moment. |
50. Toolheads