With so many projects containing SMD components now I feel compelled to try and gain the skills to do some basic stuff.
The (I'm an accomplished solderer with normal THT stuff) only problem I have is I'm joining the game a bit late (64 years)
and the vision is fading a bid. After reading an article I'm wondering is something from AmScope might be the answer?
AmScope
Regards,
Dan
The (I'm an accomplished solderer with normal THT stuff) only problem I have is I'm joining the game a bit late (64 years)
and the vision is fading a bid. After reading an article I'm wondering is something from AmScope might be the answer?
AmScope
Regards,
Dan
SMT wasn't ever intended to be done by hand, so whatever works for you is the right thing.
Everyone has different limitations in eyesight, dexterity, patience, etc. But use lots of flux.
Everyone has different limitations in eyesight, dexterity, patience, etc. But use lots of flux.
I think I'm good with everything except eyesight. I have a board with 100 THT components on it and four SMD components.
I'm reluctant to keep sending stuff to friends.
I'm reluctant to keep sending stuff to friends.
Get some practice in. Buy some cheap smt boards and cheap smt parts, a flux pen, and start soldering.
You'll soon know if you need a stereo microscope. But stay with the larger smt parts for a while.
You may just need good single vision reading glasses (not progressives) and a proper vise.
I actually see better without reading glasses.
You'll soon know if you need a stereo microscope. But stay with the larger smt parts for a while.
You may just need good single vision reading glasses (not progressives) and a proper vise.
I actually see better without reading glasses.
I use 4x reading glasses to do my surface mount soldering. I use parts that have a 50 mil or greater pin spacing. You need a steady hand, a pair of good tweezers, some very thin solder, and a sharp tip solder iron of 15W or so. I recommend using a solder tip tinner often to keep your solder tip tinned. I find that the fine tips damage easily and need re-tinning often. Some people use solder paste with hot plates or heat guns to attach many SMT parts at a time. Youtube should have some useful videos on SMT soldering.
I'm older than you, and use a pair of Optivisors with 10x lens in them. Stainless steel tweezers (sharp point), liquid flux and a flux pen to dab pads, and a Hakko 936 with various tips. Normally a 1.6mm chisel tip, but have others both smaller and larger. I do have a cheap USB microscope which I did use once for a 100 pin uP chip.
Buy extra parts (i normally order min of 10) as you will lose some never to be found again. Work on a level surface, and don't sneeze! I have gone down as small as 0402 or 0603, but try to stay at 0805 and above. I normally do not pre-tin the pad, but apply a dab of flux, a bit of solder on the tip, and hold the part in place and tack down one pad. I don't pre-tin the pad because the part won't sit flat IME, and I prefer that.
Buy extra parts (i normally order min of 10) as you will lose some never to be found again. Work on a level surface, and don't sneeze! I have gone down as small as 0402 or 0603, but try to stay at 0805 and above. I normally do not pre-tin the pad, but apply a dab of flux, a bit of solder on the tip, and hold the part in place and tack down one pad. I don't pre-tin the pad because the part won't sit flat IME, and I prefer that.
I'm new to SMT as well and this is a great thread. Is there such thing as temporary/low strength adhesive to hold a part in place? Something that loses adhesion when heated up, so that a part can be replaced later?
Ceramic tweezers are another option (some stainless steel is magnetic). Make sure everything is drenched in flux so no oxide films can form. Surface tension works for you if the PCB has solder mask (solder mask is important for SMT work at fine pitches).
Hot air rework station or a temperature controlled oven are the most reliable ways (many PCB fab houses will have the option of creating solder stencils for a board).
Hand soldering with an iron runs the risk of shorting pads together if you use too much solder (use far less solder than for THT soldering, the bare minimum to wet pads will do, so long as you drench in flux as mentioned).
Hot air rework station or a temperature controlled oven are the most reliable ways (many PCB fab houses will have the option of creating solder stencils for a board).
Hand soldering with an iron runs the risk of shorting pads together if you use too much solder (use far less solder than for THT soldering, the bare minimum to wet pads will do, so long as you drench in flux as mentioned).
Solder paste and hot air works if you're careful. Likewise fry pan on stove top. It helps to do some practice runs first, though.
The 'helping hands' magnifiers can be useful. Some have a smaller window within them, for real close up. I have found my phone useful to. It's not a good phone, or even from this decade, but the zoom is useful. The soldering iron enters stage looking like a baseball bat, but if you're good, you're good 🙂
What I used to practice until I felt confident enough to tackle real projects.
https://www.amazon.com/gp/product/B01HPSRXJ0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Method I found worked best for me was taping the component down, snip a small piece of solder and place on pad, dab with flux, apply iron tip. There are other methods and recommend experimenting to find what works best. If I have to do SMD again at any large quantity, will investigate one of the hot air stations.
https://www.amazon.com/gp/product/B01HPSRXJ0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Method I found worked best for me was taping the component down, snip a small piece of solder and place on pad, dab with flux, apply iron tip. There are other methods and recommend experimenting to find what works best. If I have to do SMD again at any large quantity, will investigate one of the hot air stations.
Make sure to have narrow solder wick available and don't solder thin-film resistors hotter than necessary.
I went for a trinocular microscope from AmScope (SM-4 series) and am glad I did. I went with a trinocular scope so I can attach a camera for YouTube videos and such. If you don't have this need, save yourself some money and get a binocular one instead, like the SM-4B. Get the 144 LED ring light.
The 3.5-45X magnification is perfect. It would be nice if it went a bit wider (i.e., lower magnification). 2.5-10X would probably be good. All that really means is that it might take you a bit longer to find the component that you need. Or you need to find the component without magnification first and then place it under the lens so you can find it with magnification applied.
The optical quality is not up to the standards of Zeiss, Leica, Hoya, et al. but neither is the price. I find the contrast to be a bit on the low side, but the scope works just fine for the job. The stand, boom arm, etc. are super sturdy and very smooth in operation. There are some nice linear bearings in there. It's good hardware!
With the boom arm I can place the scope by the back edge of my workbench and maneuver it such that it's basically parallel to the wall and out of the way when I don't need it. Then I just swing it in when I need it. That's brilliant.
I would definitely get a binocular optical microscope rather than a one-eyed digital one. Having depth perception is a must for soldering and that requires the use of both eyes.
I solder 0603 with ease using this microscope. I would probably attempt 0402 if I needed anything that small.
For the actual soldering, I much prefer to deposit solder paste through a stencil, place the components, and bake the board in a toaster oven. That works very, very well for prototypes and DIY work. Just don't use the oven for toast after.
Tom
I don't see the recommendation in this thread, so here it is. To remove SMT components I use SMT removal alloy. It is an alloy with an extremely low melting point. You melt and mix it with the solder on the component. It stays liquid long enough so you can liquify all pads en lift off the component.
DO however remove all the removal alloy with solder, flux and wick and thoroughly clean the pads. The alloy is definitely not to solder.
Instruction videos on Youtube, for example
. You don't have to use exactly this brand.
DO however remove all the removal alloy with solder, flux and wick and thoroughly clean the pads. The alloy is definitely not to solder.
Instruction videos on Youtube, for example
I find that solder paste holds the components well enough that I can carry the board from the lab to the kitchen where I have my reflow toaster oven set up under the vent hood.
I may try double-sided assembly next. That could be fun. 🙂
Tom
I modified a toaster oven and use an Arduino to control the temperature profile. I use the Rocket Scream software, which incorporates PID algorythms, in the Arduino controller and it does a very good job of adhering to the recommended temperature profile.
I only had to buy the thermocouple and its interface module and a few small items so it didn't cost me much at all. I'm lucky that I had an old toaster oven which I hadn't used for years and I've some Arduinos hanging around and other odds and ends.
The operation is very simple. Load the oven and press a button. The only manual intervention needed is to open the oven door when the controller cycle has completed to help maintain the cooling profile.
If you intend to pursue SMD work, building a toaster reflow oven is a great idea. One thing to look out for, though, is to find a high power oven. I was lucky that my oven had great heat capacity, so it was able to get up to temperature properly. Goodwill stores are great places to find candidates for conversion.
I only had to buy the thermocouple and its interface module and a few small items so it didn't cost me much at all. I'm lucky that I had an old toaster oven which I hadn't used for years and I've some Arduinos hanging around and other odds and ends.
The operation is very simple. Load the oven and press a button. The only manual intervention needed is to open the oven door when the controller cycle has completed to help maintain the cooling profile.
If you intend to pursue SMD work, building a toaster reflow oven is a great idea. One thing to look out for, though, is to find a high power oven. I was lucky that my oven had great heat capacity, so it was able to get up to temperature properly. Goodwill stores are great places to find candidates for conversion.
All good suggestions above.
I use a Stereo Zoom microscope bought from Ebay, mimicking what I used at work. It's hard to overstate the benefits of good magnification and good lighting--- it's astonishing how much it reduces the shakes and fatigue. 0402 parts are manageable, 0201 are a challenge, though audio work seldom needs these small parts. I use an Hako iron and hand solder with 60/40 rosin core solder. Solder wick and liquid flux are indispensable.
Make sure board is scrubbed clean before beginning. To install a two-lead part, I typically flow a small amount of solder onto one pad to "wet" the site. Then position the part beneath the scope and keep the part in position by pressing gently with a small tool while you melt the first joint with your iron. This anchors the first joint. Then apply iron and solder to the other joint. Touchup the first joint with additional solder, if necessary.
To mount a SOIC, apply similar technique to anchor a corner pin. Then solder the diagonally opposite pin. If it's not perfectly alligned, you can rotate into proper position while you solder. Then go back and reflow the initial joint to relieve any misalignment stress. The remaining pins are easy.
These are methods I typically use, but you have to find techniques that work for you. Be patient with yourself and the task in front. Take breaks when tired or frustrated.
Good luck!
I use a Stereo Zoom microscope bought from Ebay, mimicking what I used at work. It's hard to overstate the benefits of good magnification and good lighting--- it's astonishing how much it reduces the shakes and fatigue. 0402 parts are manageable, 0201 are a challenge, though audio work seldom needs these small parts. I use an Hako iron and hand solder with 60/40 rosin core solder. Solder wick and liquid flux are indispensable.
Make sure board is scrubbed clean before beginning. To install a two-lead part, I typically flow a small amount of solder onto one pad to "wet" the site. Then position the part beneath the scope and keep the part in position by pressing gently with a small tool while you melt the first joint with your iron. This anchors the first joint. Then apply iron and solder to the other joint. Touchup the first joint with additional solder, if necessary.
To mount a SOIC, apply similar technique to anchor a corner pin. Then solder the diagonally opposite pin. If it's not perfectly alligned, you can rotate into proper position while you solder. Then go back and reflow the initial joint to relieve any misalignment stress. The remaining pins are easy.
These are methods I typically use, but you have to find techniques that work for you. Be patient with yourself and the task in front. Take breaks when tired or frustrated.
Good luck!