Results 1 to 10 of 10

Thread: Cleaning laser bar front facette

  1. #1
    Join Date
    Jun 2016
    Posts
    6

    Default Cleaning laser bar front facette

    Hi Over there,
    I'm just here trying to repair my old 60Ws YAG laser engraver. A new stack was told to be in the 5000 Bucks range by the manufacturer.
    Quite a lot of money for the bonding of 400 Dollars of Diodes and some grams of brass for the mcp coolers - for a more or less hobby unit.
    The laser source is made by the german manufacturer photon energy. I have s second unit as well, wich was totally filed with water. This laser as well leaked, I just disassembled everything and started to reassemble it in an flowbox.

    Because the Diodes were bad, i've got me some similar diodes from an old foba -Laser and assembled them from two 2 Bar Stacks to a 4 bar stack.

    Unfortunatly I've touched a front facette while mounting.

    Are there any hints to spray clean the front facetes - just to "degrease" them.
    Are ther some expierences and dont`s ?

    On a datasheet from osram they state that the diode facettes can't be cleaned anyway - but maybe cleaning is better than a burning diode.., these diodes are Jenoptik, the old ones were probabky some of a manufacturer from Swizerland.

    Any hint may be helpful

    Best regards

    P.S. If somebody would have some used MCP cooled 808nm Diodes - with two small appx. 4mm dioameter cooling holes in the unterside, smaller than the normal jenoptik MCP cooled diodes - I would be really happy about an offer. Suited protection googles on hand here - also for pumping wavelength.
    Last edited by AuricGoldfinger; 06-03-2017 at 04:51.

  2. #2
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    9,890

    Default

    Let me do some research at work Monday, I work at a university. We'll have something available to us in scholarly journals on semiconductor laser manufacturing. I have to replace an array of sorts next week anyways. So I'm curious. I'm betting on some form of vapor phase cleaning. There's a little section in our charter on aiding the community, so I can take the time to look this up.
    '
    Steve
    Last edited by mixedgas; 06-03-2017 at 10:08.
    Qui habet Christos, habet Vitam!
    I should have rented the space under my name for advertising.
    When I still could have...

  3. #3
    Join Date
    Jun 2016
    Posts
    6

    Default

    Quote Originally Posted by mixedgas View Post
    ...There's a little section in our charter on aiding the community, so I can take the time to look this up.
    '
    Steve
    Sounds great. So I'm going to idle my repair attempt for some days. I anyway will have to reduce the psu's current for the newer diodes witch have less power. So I'm not in a hurry...
    Are you planing to solder and bond the bars in your laser - or to swap the complete modules?

    So I will as well have some time to completely disassemble my qswitch for cleaning - I probably need some practice in celanig optics with Lens cleaning paper...- I don't get it managed to clean the components in a 10mm deep and 15m wide hole in acceptable quality. (Lens cleaner paper, isopropyl (or would acetone be better?),and some kind of a medical arteria clamp for holding the paper..)

    Wishing a nice weekend - Is this monday a holiday day in the US as well?

    Maik




    Maik

  4. #4
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    9,890

    Default

    Auric,


    Looks like blowing dust off with an antistatic can, methanol rinse, then cleaning in a vapor phase cleaner (methanol or isopropanol still) follow by treatment in a plasma cleaner in Argon.
    ~
    I could not find any papers on cleaning post-mount diode arrays.
    ~
    Google "cleaning semiconductor dice" or cleaning photodiode chips.
    ~
    Steve
    Qui habet Christos, habet Vitam!
    I should have rented the space under my name for advertising.
    When I still could have...

  5. #5
    Join Date
    Nov 2008
    Location
    Cleveland Ohio
    Posts
    2,599

    Default

    This just a guess so take it as that. Heat some methanol to vapor and let it cool on the diode array so it condenses. Let it drip off an it should take any oil with the drips. Let dry and done. Since the vapor was distilled there should not be any residue left. Could dip in methanol first.

  6. #6
    Join Date
    Jun 2016
    Posts
    6

    Default

    Quote Originally Posted by kecked View Post
    This just a guess so take it as that. Heat some methanol to vapor and let it cool on the diode array so it condenses. Let it drip off an it should take any oil with the drips. Let dry and done. Since the vapor was distilled there should not be any residue left. Could dip in methanol first.
    While driving on the Autobahn - I just was thinking how to do a vapour phase cleaning...

    But im a litte bit scared about methanol. About 10gramms of that will start being really poisonable. And fume in the air...
    So a closed system with proper ventillation will be necessary.

    Any suggestions - is this a practicable solaution. Better solvents? What about ethanol? Would just make me drunken in the lab

    Regards
    Maik

  7. #7
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    9,890

    Default

    Dispite what they tell you in Europe, methanol is quite safe. Handles just like Vodka, but you should never drink it. Spills on hands or skin is not much of a problem, if you do not do it every day. The vapor is fine at atmospheric pressure, just use it in a space with open windows or a fume hood.

    A cleaning still is a very clean glass boiling flask, with a small vent at the top. The diode array would be hung in the vapor at the top. The boiling is gentle, even a heating mantle without boiling will do. The solvent cond
    enses on the diode array and drips back into the flask. Any "crud" is carried back down into the flask. The diode array has to get warm for this to work, but kept below the melting point of any indium solder in the array.

    You may also use acetone to get started with, by drenching the array in flowing acetone. Then switch to the vapor phase solvent, using ethanol, methanol, or isopropranol. That fluid should be dry as possible, preferably with no water at all.

    If your doing it right, the vapor would push most of the air out of the flask, vent which is good because it makes the chance of any fire go down.

    A professional shop would use a fluorocarbon fluid called Galden, or a very pure propane like substance. but what that costs per liter makes dinner at a five star Resturant look cheap.

    Gloves, lab coat, safety glasses, electric heater, no open flame, platic shield to adsorb any possible explosion is what is required.

    Generally you need very pure lab grade stuff to do this, but only a small amount is needed.

    Steve
    Last edited by mixedgas; 06-08-2017 at 11:49.
    Qui habet Christos, habet Vitam!
    I should have rented the space under my name for advertising.
    When I still could have...

  8. #8
    Join Date
    Jun 2016
    Posts
    6

    Default

    Many thanks for the good ideas.
    Not beeing a chemical lab guy - i will have to go onto a internet shopping tour. Sounds like a small cognag distillery will condensate in my lab as an extra.
    Do you have some sample photos of such a condensing setup? I'm just thinking of some glass with the diode array hanging on the right height and a some kind of funnel typed exhaust. An "iron" will replace the hotplate. Or will I buy one? I'm again afraid of starting my material fetish again. Schott makes so nice lab glass. Now I "have to buy" some...
    (Small vacancy trip: france - city of cognac - distillery tour at remy martin in the old building with tasting - smelling the hundred years old "eau de vie" - after having worked for a week in an other well known distillery as electronics trouble shooter- was a happy week - probably due to the high amount of good alcohol in the air....)

    I will take te paint job exhaust - thats fire and explosion proof. Probably next week i will start that. Finally I will have to check the purity of my isopropanol - and order some methanol and acetone from our pharmacy - checking for the right grade as well. I just remember my first bottle of isop - which had ony 70% purity..

    Ahh - all the time a small repair makes me installing a half factory - and I still find new things to have I'ts not getting boring.



    ....

    BTW: With chemicals of every kind they are going more and more crazy here in germany. Last week i wanted to buy some acid for one of my vintege pre war car batterys. The normal stores got a ban onto selling that sulfuric acid. Probably why some (of our countries new guests) tend to apply it on their wives if they dont want to stay married any longer... . Got it finally on order as a care spare part... . Same with the most common belaching agent - if you want to do some retrobrigt on old equipment housings to get the brome fire retardant colour away - you better leave your house door open for the official team tiding up your home....
    And the enviromental protection is getting harder as well. They banned some types of classic metal anti corrosion platings - let's see what is prohibited next.

    Best regards

  9. #9
    Join Date
    May 2009
    Location
    UCSB
    Posts
    715

    Default

    When I was mounting laser diode bars I just cleaned the front facet with a q-tip dipped in acetone, and used a microscope to inspect the surface to make sure there was no residue. Cleaning the back facet after soldering the top contact was a bit trickier

    I never did a life test, but they seemed to work fine despite the crude processing. The only failures I saw were due to voids in the solder which caused extreme local heating.

    details: http://krazerlasers.com/lasers/diode-mounting/

    Good luck

  10. #10
    Join Date
    Nov 2008
    Location
    Cleveland Ohio
    Posts
    2,599

    Default

    Soxhlet Extractor. Put the diode on the top and clean distilled solvent flows over it in a sealed system.

Posting Permissions

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