Some questions regarding SMD soldering - Page 1
Forum section: electronics / beginners

author: T_guttata
author_rank: Regular Contributor
timestamp: July 31, 2021, 04:47:46 pm
content: HiI would like to start using SMD components. So far, I have tested if I can solder items in SOT23 package. That works without any problems with my Weller WE 1010 with the standard tip.However, I would also like to use components in other packages. Maybe someone could help me with the following questions:1) Which soldering tip is suitable for SMD work? What do you think about the 4ETHL-1:https://www.weller-tools.com/professional/EUR/de/Professional/Loettechnik/Loetspitzen+_+Duesen/Loetspitzen/ET/4ETHL-12) Are there any SMD packages which can not be soldered with a regular soldering iron? I'm not going to try the smallest SMD resistors. I'm particularly interested in some of the newer infineon mosfets which come in a PG-TSDSON-8 package.3) If the components can not be hand soldered with a soldering iron, what is the best bet? There are many ideas around like hot air, kitchen hot plate, specialized ovens etc. I will only complete PCBs for prototyping, not for serial work. So I'm interested in solutions which work safely, speed is less important.Thanks for your advice.

author: fourfathom
author_rank: Super Contributor
timestamp: July 31, 2021, 05:53:40 pm
content: Check out the EEVblog video on soldering SMT components:I so some hand-soldering, and have used a hotplate, but for anything with more than a dozen components I use my toaster-oven (with custom controller).

author: T_guttata
author_rank: Regular Contributor
timestamp: August 01, 2021, 06:49:12 am
content: Thanks for the video. I watched it, as well as some other videos on the topic. However, it does not answer my questions. The components beeing soldered in the video are quite large...

author: fourfathom
author_rank: Super Contributor
timestamp: August 01, 2021, 03:23:24 pm
content: FWIW, I've soldered a few 0402 components using a sharp-tipped iron. I melt a drop of solder on one pad, then with tweezers (and a microscope) hold the 0402 in place while I re-melt the solder. I then solder the 0402 to the other pad. It's a bit hit-and-miss but I usually get it right on the first try. I don't know exactly which tip I used, I've got a few different irons, but it's fairly small.

author: Jwillis
author_rank: Super Contributor
timestamp: August 02, 2021, 02:55:38 am
content: Quote from: T_guttata on July 31, 2021, 04:47:46 pmFor most smd components you can get away with the soldering iron. This includes gullwing and J hook leads .Surface Mount Components without leads require a different approach to assembly . In the case of the PG-DSO , PG-TDSO , PG-TSDSO packages your placement process will require solder paste stencils and a re-flow skillet or other comparable device. In most cases for small projects you could get away with just a hot air soldering station . Infineron has recommendations for board assembleHere. Page 11 figure 10 shows an example of foot print design and stencil apertures.There are also plenty of tutorials on solder pastes stencilling and re-flowing . You can purchase stencils for the particular package your using from any of the popular distributors . Or if you into more self abuse there are DIY tutorials online as well.Other Non leaded components include BGA ,FLGA and W-CSP which require their own procedures for placement . You should be able to find assembly recommendations from the manufacturer .

author: JustMeHere
author_rank: Frequent Contributor
timestamp: August 02, 2021, 04:39:28 am
content: You really should look into a hot air source. It will save you countless headaches. It will help with all soldering.My diaphram pump one (Aoyue 852a++) works well enough. It's a bit buggy. I found the pickup tool useless and removed it. This yields better airflow.I still use my regular iron for touch up work. I use the largest bevel tip that I can fit between the components.Flux will be your best friend. I have some paste flux I use to "glue" components in place until I solder them. I also use some more liquid flux to clean broad areas.Don't be intimidated by no lead packages. I actually find them very easy to use hot air to place them. Then touch up with the aforementioned bevel tip.Make your footprints a little longer. This will help with hand soldering. Many package libraries will have options for this.An inspection microscope will be useful. I don't have a good one. I've used a jeweler's loupe a good bit. This will help with inspecting joints.Find an old board and pratice. I find 0402 a bit tedious, but 0603 are easy. 0805 is very easy.

author: T_guttata
author_rank: Regular Contributor
timestamp: August 02, 2021, 07:04:51 pm
content: As mentioned, I would like to use some of the newer MOSFETs from infineon, which don't have any legs.Getting a stencil is no big deal, it's cheap on easyeda, you just order it for your custom pcb.I googled for hot plates such as this:https://www.youtube.com/watch?v=g51xTKOXkk0,but there are not many around. Hot air stations seem more common.I don't know what is better, I just don't have the time to build my own device, so I would like to buy something in the $ 100-200 range. Any suggestions?

author: Jwillis
author_rank: Super Contributor
timestamp: August 02, 2021, 10:16:14 pm
content: Quote from: T_guttata on August 02, 2021, 07:04:51 pmEach would have it's advantages and disadvantages . Hot air stations are certainly the least expensive method but you also need to consider the time factor of assembly . Another problem is with larger designs is the unequal distribution of heat from one component to the next during assembly. This can cause stress fractures to occur through out the board . This of course can be mitigated some what using a pre-heater board but is not entirely effective . Then you've spent just as much as a hot plate or oven in some cases and the work area isn't much different. Another advantage of the hot plate oven method is there is less risk of component misalignment because theirs no air blowing things around .This all depends on the scale of production .For small hobby jobs the hot air work station would the best least expensive approach . For small scale assembly line production the hot plate or reflow oven might work better.Hot air work stations are indispensable in either case because of the ability to do small projects and repair . But be prepared for increased difficulty when working with very small packages.

author: T_guttata
author_rank: Regular Contributor
timestamp: August 03, 2021, 04:48:47 am
content: Ok, so the hot air station is better for repair work. That seems logical as you can not heat single components with an oven/plate.Actually I would like to have both options, but it will obviously depend on the price. I will not spend $1000 for an oven…I don‘t understand why there are not many options around? A hot plate + controller would not be too complex? Anyone tried the hot plate from banggood?https://m.banggood.com/de/200x200mm-946C-110-220V-850W-Hot-Plate-Preheat-Preheating-Desoldering-Station-for-PCB-SMD-Heating-p-1348275.html?gmcCountry=CH&currency=CHF&cur_warehouse=CN&createTmp=1&ID=515155&gbraid=0AAAAADshcaUV1AL4hpd1SKoIfkFhw0eVB&utm_source=googleshopping&utm_medium=cpc_bgs&utm_content=sandra&utm_campaign=sandra-pla-ch-la01-all-mb&ad_id=326293551530&gclid=CjwKCAjwr56IBhAvEiwA1fuqGhC_Tlu8T-2mbLR-bjjm6Qo_DNAL2BGANUvotXFh2HfAV2fF0CWZthoCwWQQAvD_BwE

author: fourfathom
author_rank: Super Contributor
timestamp: August 03, 2021, 06:09:39 am
content: I tried a hot plate and while some people seem comfortable with it, I wasn't happy with the achievable thermal profile, or the non-uniformity of heating. I ended up buying a small toaster-oven and built a controller for it -- it works quite well for my modest needs and total cost was under $100. There are several threads about toaster-oven soldering, and some people even skip the controller and just do it by eye.Here's a recent thread:https://www.eevblog.com/forum/projects/finally-starting-on-this-convection-oven-gt-reflow-oven-conversion-project/

author: T_guttata
author_rank: Regular Contributor
timestamp: August 03, 2021, 07:22:06 pm
content: Unfortunately I currently have no time messing arround with a DIY reflow oven.But I found an interesting solution:Reflow Controller V3 Pro, which can be used with any oven. It's not cheap, but still affordable.https://de.beta-layout.com/elektronik-shop/reflow-loeten/10579-reflow-controller-v3-pro/Does anybody have experience with this device?

author: rstofer
author_rank: Super Contributor
timestamp: August 05, 2021, 08:04:05 pm
content: I use a hot plate from Target like this:https://www.target.com/p/oster-single-burner-hot-plate-ckstsb100/-/A-13773420#lnk=sametabI would prefer one where the center is not depressed. My boards are always pretty small because I use ExpressPCB so a hot plate works well.I modified a Black & Decker InfraWave Toaster Oven (out of production) by stuffing the wall cavities with insulation (McMaster Carr) and a controller like this:https://www.rocketscream.com/blog/product/tiny-reflow-controller-v2/Actually, mine is V1 and considerably different. Google for 'Arduino Reflow Controller' for other options.For the hot plate, I put the board on the plate and turn the plate fully on. I watch until the solder flows and then remove the board using tweezers. I place it on some surface to cool and then turn off the plate.Toaster ovens don't usually have the cavities filled with high temperature insulation and they won't come up to temperature fast enough. My insulation came in sheets and it was pretty easy to stuff the cavities.

author: fourfathom
author_rank: Super Contributor
timestamp: August 05, 2021, 09:05:10 pm
content: Quote from: rstofer on August 05, 2021, 08:04:05 pmMy toaster-oven I described in that thread I referenced above (https://www.eevblog.com/forum/projects/finally-starting-on-this-convection-oven-gt-reflow-oven-conversion-project/msg3559017/#msg3559017) has no added insulation, and it gives me a pretty good temperature profile. The unassisted cool-down is a bit slow (door opened, but no fan), but it's not bad enough that I worry about it.

author: T_guttata
author_rank: Regular Contributor
timestamp: August 06, 2021, 07:22:00 am
content: This controller looks interesting, but it still says "re stock date" may 2021...The reflow controller V3 which I linked is much more expensive, but you don't have to do anything by yourself. Just buy a thermocouple and an oven and connect everything.