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Surfact Mount Soldering Questions — Parallax Forums

Surfact Mount Soldering Questions

UnknownUnknown
edited 2010-05-13 16:44 in General Discussion
On through the hole soldering, I'm told that a 30-40 watt soldering iron is good enough.

When I looked into surface mount soldering, I'm told to use a 50 watt temperature controlled iron.· What temperature should it be at and can you get away with using a 30 watt iron?· What are the pitfalls of not buying a good iron?

I do know there are chizel and 1/32inch tips for regular soldering irons but some are saying that it is only good for weekend hobbyists.

The cheapest SMS iron I've found is a Weller and I haven't done a lot of looking.· If anyone has any suggestions, I will take them.

The more I get into projects, the more reading I end up doing.


·

Comments

  • hover1hover1 Posts: 1,929
    edited 2010-05-10 12:44
    I have found this station to be good for the price.

    ·http://www.radioshack.com/product/index.jsp?productId=3132686

    You will have to check the store for availability though.

    Extra tips can be bought here:

    ·http://www.madelltech.com/Soldertips.html


    Jim
    900M_soldering_tips.jpg
    2080 x 1164 - 759K
  • mctriviamctrivia Posts: 3,772
    edited 2010-05-10 13:14
    you can use a cheap 30W soldering iron for touch ups of surface mount work but since you have no control of the actual temperature it will be very frustrating(and probably damaging to some parts) to do.

    Temperature will depend on your solder type. 63/37 which is the best leaded solder to use but is not ROHS compliant melts at 183 °C so you want your temperature to be slightly above this(250 works really well)

    For Lead Free solder you will have to turn the heat up a little to 250-300C


    The most important thing with surface mount soldering is using the right tip. You want a tip that is small enough to apply the solder where you want it and no were else but big enough to transfer enough heat to the pin and attached traces. For this reason you will likely need a few different sizes of tips and will be constantly switching them out. Having a high wattage temperature controlled iron means that your tips after swapping will heat up to temp faster and even for very large traces will not cool down allowing good solder joints to be made.

    Since you will likely have to swap out tips often it is good to look for an iron that makes this easy. To change the tip on a weller requires you to let the tip cool down first then unthread the end or to carefully unscrew it using a pear of pliers and do a fun dance to get the tip off without burning yourself. I use a JBC AD2700(now discontinued in favour of the AD2950) which has a special setup that allows for easy removal of tips and the tips heat up almost instantly. I beleive there are a few others that have similar quick change methods as JBC but I do not know which. An alternative that many people use is to buy a station that accepts 2 or 3 irons.

    Once you get away from doing 1 offs or want to be able to solder BGA or QFN parts you will need to look into getting stencils made and using a reflow oven. This is the best approach as you can assemble several boards simultaneously(I do 12 propmod-us_ps_sd at a time) but does requiring you purchasing a stencil for every board design you make.

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    Lots of propeller based products in stock at affordable prices.

    propmodule.com will be closed May 1-10th. Orders made in that time will be shipped on the 11th.
  • Peter KG6LSEPeter KG6LSE Posts: 1,383
    edited 2010-05-10 13:58
    After using RS disposable stuff I broke down and spent $240 On Edsyn Loner ..Its going on its 4 th year and 2ed tip .


    It has saved me SO much $$ its great .. It Will do Some SMT BUT no QFPs or small pitch stuff .
    But SOIC stuff It does well WITH solder paste.

    I did IPC SMT assembly certification in college with a PACE PRC2000 system .. it was a Joy to use . But those boxes of love are $900 Plus.
    For any kinda SMT hot air works well IMHO .. But You have to use paste solder ..

    Peter KG6LSE

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "Carpe Ducktum" "seize the tape!!"
    peterthethinker.com/tesla/Venom/Venom.html
    Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway. —Tanenbaum, Andrew S.
    LOL
  • LeonLeon Posts: 7,620
    edited 2010-05-10 15:16
    I use a second-hand Metcal STSS power unit with the newer MX-500 handpiece and cartridges. It only cost me £125. With the appropriate cartridge it's suitable for both through-hole and SMT assembly, including fine-pitch QFP parts.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Leon Heller
    Amateur radio callsign: G1HSM
  • UnknownUnknown
    edited 2010-05-12 00:13
    hover1 said...
    I have found this station to be good for the price.

    ·http://www.radioshack.com/product/index.jsp?productId=3132686

    You will have to check the store for availability though.

    Extra tips can be bought here:

    ·http://www.madelltech.com/Soldertips.html



    Jim
    Are there any replacement parts for the heater element or is there one?· I saw that the Weller has a ceramic heater and I know that can be replaced.· I'm just concerned about being able to fix it in the future.

    Otherwise the Madell Tech AD201D is a lot cheaper.·
  • HollyMinkowskiHollyMinkowski Posts: 1,398
    edited 2010-05-12 01:16
    If you really want to do sm right then get a hot air rework station.
    They have a temp controlled iron as well as the hot air system.

    There are some pretty decent ones from China on ebay for just over $100

    I had an old post somewhere here about ebay hot air stations...maybe search can find
    it? I don't have much luck with the search here though.

    Get a few extra tips for the iron, they are always cheaper when bought with the
    hot air station. The stations usually come with 3 or 4 hot air nozzles...good enough
    for starting out with.

    There are some good video tutorials about hot air station work on youtube and
    also some good ones at sparkfun.com.

    Hot air is the only good way to de-solder a large sm chip.

    You will praise the day you got a hot air station smile.gif
  • LeonLeon Posts: 7,620
    edited 2010-05-12 08:51
    Chip Quik is what I use to remove QFP parts. It works very well.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Leon Heller
    Amateur radio callsign: G1HSM
  • Martin HodgeMartin Hodge Posts: 1,246
    edited 2010-05-12 17:55
    This is my new best friend. Only had it a couple of weeks and it makes SMD work so easy. I bought my Aoyue 852A for $139 from sra-solder.com. It's the "++" version with the integrated vacuum pen. (The two shaped nozzles and tweezers were not included.)
  • HollyMinkowskiHollyMinkowski Posts: 1,398
    edited 2010-05-12 19:22
    That's nice looking Martin! smile.gif

    A vacuum pen is a great accessory.
  • HobbyistHobbyist Posts: 14
    edited 2010-05-12 23:28
    Laugh if you want but I purposely make sure I've got an "extra" copper pad beside each line of pins I need to solder. I secure the board at about a 30+ degree angle, make a big blob of solder on the pad then just "roll" it along the whole line of pins at a fairly quick pace... way, way faster than fooling around with 1 pin at a time...

    I bought a 100 lot of un-named, unlabled, Smile ICs for $8.00 on Ebay to practice on initially. I wasted a few bucks on copper and etch but it didn't take long to get the confidence to do it "for real". ·Works for me : -)

    73 de VA4MGW


    Post Edited (Hobbyist) : 5/13/2010 12:18:57 AM GMT
  • Martin HodgeMartin Hodge Posts: 1,246
    edited 2010-05-13 01:08
    Hobbyist. That's how a lot of pros do it! Watch this clip at about 2:20 on:
  • HollyMinkowskiHollyMinkowski Posts: 1,398
    edited 2010-05-13 04:20
    I like how when you are heating a chip with hot air it
    suddenly just pops into alignment...like magic smile.gif
  • Martin HodgeMartin Hodge Posts: 1,246
    edited 2010-05-13 06:12
    Holly, what solder paste are you using? I'm using Chipquik SMD 291AX (63/37). I think it's the wrong stuff because it boils when heated and slings little 0805 parts all over the board like they were mexican jumping beans. Also it won't stick to the board unless I heat the dispenser needle.
  • HollyMinkowskiHollyMinkowski Posts: 1,398
    edited 2010-05-13 07:36
    I use something called Zephpaste.
    seems to be OK.

    They use something else at work, I'm not sure of the name.
    But they have to keep it in a refrigerator.

    I have had some similar problems with skittering 0805 parts.
    The little devils try to escape when you are not looking smile.gif

    The lead free paste is even worse I think.

    I looked up the paste you are using and it seems pretty much identical to
    the syringes I use. The formulation is the same 63/37.
  • HollyMinkowskiHollyMinkowski Posts: 1,398
    edited 2010-05-13 07:48
    I just called a guy I know and he says you are perhaps heating the paste
    up way to fast..causing it to spit and boil.

    I did a google on boiling solder paste and turned this up..so he may be right.

    "If heated too rapidly the paste deposit can boil and spit. Gentle, indirect heating of solder paste is recommended throughout the soldering process. For this reason hot air heating is a very good method for use with solder pastes."
  • Martin HodgeMartin Hodge Posts: 1,246
    edited 2010-05-13 16:44
    Oh cripes. I just found zeph.com thanks to you. My wallet is getting nervous! tongue.giftongue.gif

    I think you're right about the fast heating. I forget that reflow is the opposite of conventional soldering where you heat, solder and get away quick.
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