Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 23

Thread: Flowing gas CO2 laser conversion from sealed gas

  1. #11
    Join Date
    Jun 2012
    Location
    Mainland China
    Posts
    38

    Default

    What is the necessary equipment needed to make sealed tubes properly? And, is there a test to make sure everything is okay. For example, the room for the laser filling can have a door put on it and be air tight. A hepa filter or filtration system can be used to clean the dust from the air. Is there a dust measuring meter to confirm the dust is not in the air?

    For the gas, how can the gas be tested to know its good. I had read a long time ago that there was a gas company supplying dirty tanks of gas and it caused problems for the laser. The gas company needed to take better care in preparing their gas tanks after being returned from the other shops (something like turning them over and letting them dry out prior to filling). Is there a test to determine if the gas is good? In my area, the suppliers are notorious for bad quality and bad practices.

    Is there a specification for the gas lines and regulators? I have heard that the standard setup for pressurized gas is not so good for a laser.

  2. #12
    Join Date
    May 2007
    Location
    Authentic Asian food area of SoCal
    Posts
    2,473

    Default

    Quote Originally Posted by GregR View Post
    Is there a dust measuring meter to confirm the dust is not in the air?
    Unfortunately, the cost of a decent air quality meter is probably going to run you about the same, if not more than a replacement flowing gas ion tube. If this is just a personal project then, knock yourself out. It is always fun to learn new things. If you are after reliable power from a laser that will last a while, I think this is why Steve (MixedGas) suggested getting a new tube. They really aren't too expensive. As you have seen many people post, lasers are an expensive hobby. Expensive in that, once you buy, you will typically buy again, and you will buy bigger and more expensive. This project might end up costing you more in the long run and you may not get the performance you are looking for. As you may have seen by now, Steve is one of our ion experts. I have yet to see him say "Gee, I have no idea what that is". For what it's worth, good luck on your project!
    Those who fail to grasp art are the ones who criticize it.

  3. #13
    Join Date
    Jun 2012
    Location
    Mainland China
    Posts
    38

    Default

    No shortage of laser tubes at my place.

    The purpose of the project is to "back into" making a CO2 laser. I am not confident in my abilities to follow the instructions from a kit and want a fast and quick way for a small success. Later, I'll do the complete build, but not now.

    If you want to see my collection of RF CO2 lasers, take a look at my profile on this site.

    Click image for larger version. 

Name:	IMG02299-20120612-1000.jpg 
Views:	25 
Size:	18.2 KB 
ID:	33061
    Click image for larger version. 

Name:	IMG02298-20120612-0959.jpg 
Views:	22 
Size:	22.5 KB 
ID:	33062
    Click image for larger version. 

Name:	IMG02297-20120612-0959.jpg 
Views:	21 
Size:	22.0 KB 
ID:	33063
    Click image for larger version. 

Name:	IMG02296-20120612-0959.jpg 
Views:	17 
Size:	16.2 KB 
ID:	33064

  4. #14
    Join Date
    Jul 2008
    Location
    Miami
    Posts
    506

    Default

    I once had a Sharplan flowing gas co2 head with arm in great condition and sold it for peanuts . Sorry I didn't know you then .
    " MANUFACTURER OF HIGH QUALITY MICRO LASER COMPONENTS" !!
    http://www.microlaserlabs.com/

  5. #15
    Join Date
    Jul 2008
    Location
    Miami
    Posts
    506

    Default

    Looked like this

    Click image for larger version. 

Name:	sharplan104001_80.jpg 
Views:	7 
Size:	193.5 KB 
ID:	33074
    " MANUFACTURER OF HIGH QUALITY MICRO LASER COMPONENTS" !!
    http://www.microlaserlabs.com/

  6. #16
    Join Date
    Apr 2012
    Location
    Beaverton, OR
    Posts
    245

    Default

    To build your own sealed tube is no easy job. To copy a chinese tube you will need a glass lathe in the very least. The mirrors are just glued in place. I really don't know how they do an alignment. Mu guess is an autocollimator. With the high gain of a CO2 close may be good enough.

    Then you need to fill. The mix for a sealed CO2 is different than the generic flow through mix. You need equipment to do the filling. This is not cheap. I have a system that can do it. Pfeiffer turbo pump with a 200 AMU residual gas analyzer for checking leaks and contaminants. I can easily pull down to 10^-8 torr with it. You also need a way to bake the tube and not melt the glue on the mirrors.

    But at a little over $100 for a 40 watt tube plus shipping, I would not mess around.

  7. #17
    Join Date
    Jun 2012
    Location
    Mainland China
    Posts
    38

    Default

    Hello Macona,

    Can you give some examples of how the gas analyzer helped you in your work? What is your experience in filling laser tubes? I think it is one thing to know the gas parameters and fill, and perhaps very different to experiment to identify the optimal pressure and gas mixture. Do you agree? How about some photos of your setup?

    GregR

  8. #18
    Join Date
    Apr 2012
    Location
    Beaverton, OR
    Posts
    245

    Default

    RGAs are very nice to have. They will tell you what you have in the tube. It will show you leaks and contamination. The biggest issue in a vacuum is water vapor. It is a nightmare to get rid of side it sticks to everything. That is one of the reasons you bake out the tube. I have a old Leybold 200 AMU unit on my portable vacuum system and a newer 100AMU unit on my big system. They are invaluable for finding leaks. Set it to mass 4 and get a bottle of helium to spray for leaks.

    I don't make or fill tubes. I do plan on using the portable system to try someday, though.

    My portable unit is this guy:


    Hiden HPR-30 with Inficon 200 AMU RGA by macona, on Flickr

    head unit:


    IMGP6084 by macona, on Flickr

    My main system I am setting up for doing coating. The laptop screen shows a trend graph set to mass 18, water. As the system was pumping down I started a 250w ultra high pressure mercury lamp. The lamp emits a massive amount of UV which helps knock the water molecules off the walls of the chamber seen in the spike Where the spike peaked is where I shut off the lamp:


    Vacuum System by macona, on Flickr

    With the lamp on:


    Ushio Mercury Lamp in vacuum chamber by macona, on Flickr

  9. #19
    Join Date
    Apr 2012
    Location
    Beaverton, OR
    Posts
    245

    Default

    Oh, since a RGA is really just a Quadrupole Mass Spectrometer it can show you the purity of the gasses you are using as well. Note these things need to operate at 10^-4 torr or better to sample at higher pressures you need a pressure converter valve or other devices involving differentially pumped orifices and capillary tubing.

  10. #20
    Join Date
    Jun 2012
    Location
    Mainland China
    Posts
    38

    Default

    Wow, that equipment looks very nice and expensive and requires skill to operate. I don't know much about a mass spectrometers but thought that a one standard was required to measure against one sample, or perhaps four in your instrument.

    If you got a CO2 laser tube, how could you determine the gas content with your instrument? For example, the CO2 laser will have the three typical gases, but what about gases that either you do not know if they are used or if you simply do not know the gas. For example, if you know there is a possibility that Xenon is in the mix, can you set the instrument for Xenon. And, will the instrument check for unknown gases?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •