SMD Assembly & Rework

Before I spend any $$ on an assembly/rework station, I thought I’d ask what everyone else here is using.

Budget isnt a big problem, but I’m adverse to spending money on junk. I’m very much at the “hobby-level” and the boards I’m doing max-out about 6 or 7 inches on a side, usually 2 layer.

For initial assembly, what are you using and how good are the results? For rework? And maybe a third question: what would you do differently if you had it to do over again?

All opinions are welcome.

Comments

  • Cluso99Cluso99 Posts: 15,531
    edited 2019-09-23 - 21:56:14
    I have a "cheapie" (~$5K) professional IR oven and I use a solder paste screen with 0402 and 0.5mm pitch parts.
    PeterJ has a toaster oven (~$30-50?) and does 0603 and 0.5mm pitch with and without a screen and achieves splendid work. He assembled some P2D2 boards.
    My Prop boards: P8XBlade2 , RamBlade , CpuBlade , TriBlade
    P1 Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    P1: Tools (Index) , Emulators (Index) , ZiCog (Z80)
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  • If you are after a top of line system for rework, look at the Zephtronics product. they are at zeph.com/ if budget is not a problem. But these are not cheap, their air pencil runs about $900.00USD. It can be combined with a air preheater unit and multiple sizes of work frames to hold the boards. If the hobby makes enough bling to keep the other half happy, then go for it. Work took a different direction so my order got chopped a few years back. But there are a lot of lower cost hot air pencils. Depends on what you need to work with. In another post, I mentioned a homebuilt hack I use with a desoldering iron and aquarium pump. At work, a cheap AOUI (Frys bottom feeder). OK for removing say network connectors and not so small stuff, but airflow seems a bit high and not very fine tips.
    Ordnung ist das halbe Leben
    I gave up on that half long ago.........
  • It's like when people want to "get into" photography and they set their sights on only one $5000 brand name on special but not sure if it's right. So I ask them what other cameras have they used and they reply "I don't have a camera". While that tells me they love the idea of being a Insta photographer, I also know that the $5000 camera will end up collecting dust or forever set to "full auto" for its short life. What I tell them to do is get a good but cheap camera, play with it, get to know it and the settings, and then they will have a better idea of what they might want to do. Either way the good cheap camera is handy anyway, and they learn a lot more from that than from something way more complicated.

    Spend a hundred or so dollars and get a toaster oven or a convection oven, some solder paste both in a syringe and in a tub for squeegeeing with a stencil, and flux gel. Don't worry about microscopes and I just use an extra pair of +3.5 glasses or I have a pair with an extra magnifying lens I fitted to swing across. The hobby type magnifiers are useless. Your soldering station needs good flat nosed tips which work way better than a needle tip that can't heat a joint properly and won't hold solder.

    With your small investment you will get to know the 101s of surface mount assembly and soldering and maybe that's all you will ever need. But if you do decide to invest at least you will know what you need and understand the equipment.

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  • This is *excellent* feedback and is exactly what I am looking for. Thanks @Cluso99 @“frank freedman” and @“Peter Jakacki”

    Peter: as luck would have it, I already have a really high-end tri-nocular scope. Overkill for the current use, but still an amazing bit of kit. Your words of wisdom are appreciated. I saw a convection/IR oven at Costco the other day that might make for an interesting starting point.

    Frank: the Zephtronic stuff is a completely new line of product to me. This bears some thought. Pricey stuff but may be worth it.

    Cluso: Remember when I said that money wasnt such a huge issue? I lied. If SWMBO’d (She Who Must Be Obeyed) saw a $5,000 oven sitting on my bench, she’d be demanding a whole new kitchen. (That being said, there is some interesting stuff out there on the second-hand market that has been gently loved. This could get complicated. Heheeh)
  • I built a Controleo3 from Whizoo — great little reflow unit based on Black and Decker (cheap) toaster oven.
    https://whizoo.com

    I love it! And the build was fun too!

    Paul

    Some times my mind seems to wander..... these days I just tag along.
  • WBA ConsultingWBA Consulting Posts: 2,884
    edited 2019-09-24 - 04:14:12
    I second the Controleo3 as it is the only DIY toaster oven system that actually characterizes an oven to ensure good profile execution. About 9 years ago, I had commented on a thread somewhere about toaster oven reflow and stressed the importance of characterizing an oven for a separate controller to be truly effective when mentioning that I was going to design one myself. Since I was only using my oven to build PowerTwigs at the time, which need the most basic reflow profile ever, I never made it past the design requirements stage. I still have the test PCB platform I made with thermocouples attached to properly characterize my little cheapy oven though.

    Apart from that, I agree with Peter on the concept of just trying out the basic setup to get a feel for things. If you wanted a small kt to build a couple PowerTwigs, including some paste and a kapton film stencil, shoot me PM. I made a few DIY kits to sell at an expo few years ago and I think I still have a couple.
  • I bought a hot air rework station on Amazon for like $50 and it works good. I've used it to repair the fpc connector on my IPad.
  • Cluso99Cluso99 Posts: 15,531
    edited 2019-09-24 - 09:57:05
    My story is a little different.
    I ran a contract assembly company for a couple of years. We had multiple pick-n-place robots. Each worth ~$250K, a proper IR oven maybe $50-100K and a thru hole solder line (40 feet in length feed with a nitrogen feed). And staff of well over 100. That was 20 years ago.
    So I’m used to good equipment.
    A few years ago I was asked to design and build a project, and as part payment I was given the IR oven :)
    Otherwise I probably would have built (modified) an IR Toaster oven. I would want to monitor temperature and be able to set a timer.
    To get started, I would start with Peters setup. You can always move up, particularly if you haven’t outlaid much in the first place..

    One word of warning tho, you need to be careful not to overlook you parts. There is a temperature graph and not following that stresses the parts and can result in immediate or later failure. In particular, crystals are particularly sensitive.
    My Prop boards: P8XBlade2 , RamBlade , CpuBlade , TriBlade
    P1 Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    P1: Tools (Index) , Emulators (Index) , ZiCog (Z80)
    P2: Tools & Code , Tricks & Traps
  • @Peter, my first 35mm camera was a Cannon FTb which iirc was a stripped down F1. All manual, only thing electronic was the light meter. Got fantastic images with it. Got slides of nearly all windows in the Glasgow cathedral. Really got to love the Kodak Ektar line of film, not the fastest at ASA 100, but huge enlargements were still fine detail and edges crispy.

    Regarding the optics, you got it nailed. "Hobby visors" are great for breathing in fumes and directing the solder tip with your nose. Minimal clearance or vision for anything from my experience. My bill paying job comes into contact with various medical/dental settings. I have seen many types of lenses some wearable on their own, some embedded in lens frames. My dentist has the ones embedded in the lens, which is fine because it does give him corrected outer field but he has to constantly remove them for some of his work. The card and neurosurgeon types generally seem to wear what look like one form of telescope hinged eyeglass frames. The advantage with these is they can be flipped up out of the way for not so close work or when bringing in the microscopes. This latter is what I prefer to use. I found a U.S. Surgical pair on ebay that a dental student was letting go at a very good price. About a 4x at 14-18". The distance measurement makes all the difference to me. I get the up close view of what I am working with, but the work is about 14" or so away. Lots of room to work and see. Used to wear them over a pair of readers to had good working vision and they flip up out of the way for just the readers. The leap to contact lenses was even better. Does take a bit of getting used to working that far away from the piece. Looking on ebay and other sources, there are lots of these lenses some new, some FSBO, some just shoddy knock-offs. Buyer beware. But there are some great deals. Prices run from sub $100USD to the thousands depending on multiple factors. I am still holding out for the head-lamp one of these days.
    Ordnung ist das halbe Leben
    I gave up on that half long ago.........
  • Cluso99 wrote:
    One word of warning tho, you need to be careful not to overlook you parts.
    Roger that. When your yellow tantalum caps turn brown, you know you've left them in too long! 'Been there. :)

    -Phil
    “Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away. -Antoine de Saint-Exupery
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