Toaster oven reflow soldering

Discussion in 'Electronics & Electrics' started by _zak, Mar 6, 2017.

  1. _zak

    _zak Member

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    As I've been getting further into electronics, I've been starting to hand solder surface-mount PCBs. While that hasn't been too bad at the 0805/0603 level, the smaller-pitch ICs and sockets are close to the edge of what I can reasonably manage (and, of course, are the expensive components when I stuff it up).

    I've started looking at the option of converting a cheap bench top oven into a reflow oven for these sorts of things, which seems to be a pretty popular project. While some people just use the oven as-is, I'd ideally like to use lead-free solder paste, it looks like I'll have to do a little bit of hacking. I'm fine with insulating the oven internally (which shouldn't be too hard), but most projects appear to embrace the US enthusiasm for hacking at mains wiring without a licence. I'm not keen to do that myself, so thought I might ask here to see if anyone has had any experience with this kind of DIY project.

    A couple of more specific questions:

    • Has anyone had any experience with some of the plug-in controllers such as Reflowster or Beta Reflow controller V3? Any other suggestions welcome as well, obviously :)
    • From my reading here, I've often seen people say that you can have your own work signed off by an electrician as being safe. Is there any chance that I could wire up the relays for one of the more elaborate controllers (e.g. ControlLeo2 or X-toaster and have an electrician look over it, or would I need to employ someone more specialised?

    Thanks in advance for any advice!
     
  2. RobRoySyd

    RobRoySyd Member

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    A "toaster oven" is an appliance so depending on which state you reside in you might not need a licence to do work on it. That said the one I have for drying silica gel can be run off an external controller without hacking the internal wiring. Wind the time clock to Max, set thermostat to Max as well. Plug in to external controller.

    The only reason one might want to hack into it is to gain access to the top and bottom elements.
     
  3. mtma

    mtma Member

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    There's a number of ovens out there where they have a 'MAX' setting which actually switches the elements on full time. Thereafter it is simply a matter of setting the timer - get a cheap oven with a mechanical timer - to a suitably long time.

    Then an external plug-in controller would work fine (although if you're DIYing an external controller one must ask if you're not simply hacking up a mains appliance anyway).
     
  4. _zak

    _zak Member

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    I'm in WA, and finding information on modifying appliances has been a bit difficult. There's a fair bit on importing/selling appliances (e.g. Level 1, 2, and 3 equipment), but I haven't found anything on modifying existing approved appliances. Regardless, I'd still like to have someone qualified have a look at it even if I were technically allowed to do it myself.

    The only reason I'm interested in using something like the X-Toaster or ControlLeo2 is because they offer a bit more fine-grained control thanks to the individual relays. From what I've read so far it seems that this helps when using lead-free solder.

    Yep - if I were to go the external controller route, I'd buy one that was ready-made. The oven I've got is this 9L Sunbeam, and it can be set to maximum. I've got a few small boards that need populating - might be a good opportunity to see if it works without any modification?
     
  5. merlin13

    merlin13 Member

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    If you're looking at getting beyond entry-level SMT work then a Yum Cha hot air rework station like this might be worth some pondering. Can be picked up locally at reasonable pricing, it ain't a NASA-grade rework setup but for the coin it does the job quite nicely.

    Been using one of these myself for knock-around contracting work up here in BrizVegas for quite a few years now. Even without the appropriate nozzles mine has handled everything from homebuilds to Production Rework and R&D at more than a few companies.

    Even large BGA to an extent, but I've been doing serious SMT since the 80's so for the novice user I'd tend to advise the toaster oven option on those... :D
     
  6. RobRoySyd

    RobRoySyd Member

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    I really don't have the experience to comment on that however as your oven has a top and bottom element I can see how being able to control where the heat is coming from during the different phases of the process might be handy.

    Only done SMT rework and did some work on a wave soldering system. I do recall the PCB preheaters were ceramic blocks very close to the PCB. So the heating is radiant IR. Same on the rework station.
     
  7. aXLe

    aXLe Member

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    I just received a ControLeo2 kit in the post today (http://www.whizoo.com/reflowoven) and am now on the hunt for a suitable toaster oven to mod :)

    Most of the documented builds are with US model ovens - I need to find a decent local one - recommendation is for around 1600W output.

    The kit it pretty comprehensive, though there are additional items such as external insulation that I will have to source.

    It is supposed to be able to achieve a decent reflow profile with fairly even heat distribution - partially thanks to an additional booster element that is supplied with the kit.

    I've been panelising boards lately on a small panel suitable for the Stencil8 stencil system - using that and an oven should speed up small volume runs even though I will still be manually placing components.

    I'm yet to find a cheap assembly place for small runs (20 boards or so) thus the purchase of this kit. To date I've been hand soldering (including hot air reflow) or using a hot plate which works OK for leaded solder but at some point I'm going to have to go lead free!
     
    Last edited: Mar 8, 2017
  8. aXLe

    aXLe Member

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  9. _zak

    _zak Member

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    This is the same oven I've gone with, though I'm still deciding on a kit to pair with it at the moment. While I like the look of the ControlLeo2, at the moment I think I'm going to insulate it and then see if I can get by with insulation, a digital thermometer and a timer rather than install relays etc.

    Would definitely be keen to see a 'proper' build though - keep us posted!
     
  10. aXLe

    aXLe Member

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    This is the ControLeo2 kit contents - I'm still waiting for the oven to arrive.

    [​IMG]

    Band-Aid is a nice touch - LOL

    The taped roll is the reflecta-gold - now in wider precut lengths rather than the 2 inch roll previously supplied.
     
    Last edited: Mar 10, 2017
  11. dohzer

    dohzer Member

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    Toaster oven was pretty bad for me.
    But that was from one experience with an aluminium PCB and a house that stank for months. #neveragain #solderoutside

    Picked up a cheap T862 Infrared Rework Station for ~$100 on eBay and haven't looked back. For extra credit, get a cheap solder paste stencil of your PCB for ~$50 and pump out multiple PCBs in rapid succession.
     
  12. bleckers

    bleckers Member

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    I'm looking at doing this exact build, I would definitely be keen for a thread (and would be happy to add to it once I run my build). At the very least some opinions of the oven/controller combo performance.

    Edit: I've ordered the ControlLeo board/enclosure only as I found a couple of old and used Crydom d2440d Dual SSRs sitting in a junk bin at work. These will help me reduce space and I was also concerned about the quality of the SSRs that the build kit comes with. I have sourced all the other parts as well from my misc bins and online (the legit thermal tape being the most expensive).

    The kit seems to be pretty good in terms of pricing, I've only saved a little by using existing/ordering the parts. If their shipping was cheaper on the build kit, it would totally be worth it provided their SSRs are to spec (I noticed the ones in your post aXLe are branded differently, so these might be fine).

    I'm still tossing up over the Sunbeam BT2600, the sizing is right. All the convection ovens are all much larger and quite pricey. I will check it out and see if I can install an convection fan later.

    I also considered building a software compatible controller myself from here - http://brianmakesit.com/reflow-oven-controller-controlleo-2-compatible/?v=6cc98ba2045f
    However, with OSHPark it would be $42.60USD for three boards and the rest of the components would make it almost the same price. If I was building more of these or decided to flog the other boards off then that's a more economical solution (it would work out about half the cost), however you do get official support if you buy from whizoo.
     
    Last edited: Mar 16, 2017
  13. _zak

    _zak Member

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    So I've got the oven ready to go, and next up is adding insulation. I've looked at Reflect-A-Gold which Whizoo state is the standard, but it's definitely pricey - even more so with the lower AUD and relatively low demand here. I'm debating trying the EPMAN clone, though it seems pretty likely that this is the stuff that peels away from the adhesive when heated. Probably worth a shot for AU$13 though...

    I'd be interested in sharing the cost of boards/components if that makes it more viable; most electronics stuff fits in an Express Post envelope (as opposed to satchel), making it pretty cheap to ship across Aus too. Let me know via PM if this is viable.
     
  14. bleckers

    bleckers Member

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    Damn I would have, but I decided to go with the ControLeo and have already ordered it. I don't mind the extra cost as the support they offer is pretty good. Plus for the work they put into the build guides, it's worth it to donate a little to the project for their time.

    I'm planning to use this for small scale production of a project I'm working on, so I'm more than happy to spend a little more if I run into issues. Plus the ControLeo comes with a $10 OSHPark voucher, so the cost really doesn't end up being that bad. Their OS shipping is what kills it really.
     
  15. aXLe

    aXLe Member

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    I received the oven this week so hope to be starting the build soon - will set up a new thread when I start on it :)
     
  16. _zak

    _zak Member

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    No problems - completely understand going with the Whizoo kit, particularly for stuff that you're planning to scale up.

    Looking forward to seeing the builds!
     
  17. bleckers

    bleckers Member

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    I ended up getting the official stuff off Amazon - https://www.amazon.com/010396-Refle...qid=1490340359&sr=8-2&keywords=reflect+a+gold

    For the price difference, time and cleanup possibly required, I wouldn't bother with the cheap stuff. You could end up going through 3-5 rolls of cheaper tape and still not find something suitable. All the reviews I've seen have said, cheap means melting adhesive and smoke.

    I got the oven today too (Sunbeam BT2600):

    [​IMG]

    I was tossing up between this and the Russell Hobbs RHTOV20 with convection. I compared both in the store and I figured the 9L size of the Sunbeam will really help with getting a nice steep profile, especially with a boost element which I'll be adding in as well (I have some thicker gauge power cable for the mains connector to cope with the extra wattage just in case). The RHTOV20 was a fair bit taller and much deeper, so it had a lot more empty thermal mass to deal with. I would have liked the depth, but the height wasn't worth it. Both units had similar manufacturing issues in terms of sealing (the curved door of the Sunbeam does not sit flush with the case at all), but I'll sort that out with thermal insulation. The Sunbeam however has a "crumb tray" (in addition to a baking dish and wire tray) which normally goes into a slot in the bottom of the unit. It however, fits perfectly in the tray guides, so I'll be using that to put my PCBs on instead of getting some sheet metal cut. This tray has some slightly raised moulding on it to make it more rigid, but I'll flatten that out. The RHTOV looks like it has Quartz elements versus the resistive elements on the Sunbeam, however this shouldn't be too big a deal given the size.

    I plan on adding a small convection fan to this unit at some stage, probably through the roof of the chassis and just leave it dangling there stirring the air without any guard to protect it.

    I have most of the parts, I'm just still waiting on the controller which took two days to be shipped and leave the US, and has been sitting for a week in an Australian depot somewhere. I did a test run to heat it up and it took about 60 seconds to reach 230 degrees on the built in thermostat, so it's looking quite promising. The first time you power the unit up, it will give off all sorts of smoke and fumes, so run it in a ventilated area.

    All in all, I'm pretty happy with the Sunbeam so far.

    After gathering everything required, my pricing so far (in AUD):

    $67 - thermal tape and mat - https://www.amazon.com/gp/product/B0039Z5TYU/ref=od_aui_detailpages01?ie=UTF8&psc=1 https://www.amazon.com/gp/product/B00029KC2K/ref=od_aui_detailpages01?ie=UTF8&psc=1
    $59 - Sunbeam oven from JB - https://www.jbhifi.com.au/whitegood...s/sunbeam/sunbeam-mini-bake-grill-oven/34577/
    $105 - Controleo controller
    $7 - Boost cartridge heating element - http://www.ebay.com.au/itm/191687060719
    Total - $238AUD
    Optional $33 - Convection motor (with a custom made fan) - http://www.ebay.com.au/itm/WESTINGH...680184?hash=item3d3562eaf8:g:afYAAOSwSlBYwfiY

    The rest of the kit items I've managed to source elsewhere. You can also source the "boom mat" they use in the build guide from Amazon, but they charge a lot for shipping on that item ($35). I went with something slightly cheaper and didn't cost as much for shipping. I'll try it out and if I find it isn't a suitable replacement, I'll go with the recommended version.
     
    Last edited: Mar 28, 2017
  18. bleckers

    bleckers Member

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  19. _zak

    _zak Member

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    Thanks for all the info! Given that the stuff from Amazon isn't actually that much more, I think I'll probably go with that.

    Meanwhile, I decided I had nothing to lose by just using the oven and seeing what happened. I also have the Sunbeam BT2600, and after a quick trial with a thermocouple (pro tip: while your thermocouple might be good to 300 degrees and up, check that the insulation is too) realised that even without insulation I was able to hit the right temperatures for lead-free soldering.

    Reflow 'profile': turn on the oven with the thermostat set to ~ 170. When the 'heating' light turns off, count to 20 (soak), then turn the oven to maximum ('Toast') until the solder reflows, count to 15 and then turn off.

    The results look a bit like this:


    Click to view full size!
     

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