A kit with surface mount ICs, would you be wary of building it?

[mvs sarma]

I've avoided using surface mount parts in my kits because I'm concerned my customers may not want to tackle the difficulty.

That said I'd like to use a few surface mount ICs in the next kit. It's trivial to solder an 8 pin SOIC, very simple actually just a little tape and patience works great.

As for larger SOIC not too bad as long as you tack down one corner and tape the IC in place. Solderwick is handy for soaking up excess solder.

But TQFP is another story, you have to get it lined up perfectly and you will need solderwick. They are also very difficult to reposition once you solder them to the PCB. 64 & 80 pin TQFP can be a chore.

Comments?

It is not that difficult if you have a Hot-air gun and SMD rework station
i see guys easily lifting off the TQFP chips just with Hot-air gun and a thin knife.
even i could solder , remove and re-solder one CY27EE16 chip y-day. without any of hose things
of course it is SSOP 20. what all i had is only a mini soldering station.

 

[be80be]

Get the reading glasses. Something like 2.75x or even 3.00x if they are available. It helps tremendously and are easier to work with then those large bench magnifying glasses.

I started with 1.25 now up to 2.5x reading glasses are the way to go DL

 

[whiz115]

no problem doing smds i can do SSOP28, SOT-8, 0805, 1206, etc but my limited knowledge on electronics is indeed a big difficulty!

 

[be80be]

where you live whiz115 if in the US I'll tell you a good book But you can't beat this site Learning Electronics : Free Electric Circuits Textbooks

 

[whiz115]

But you can't beat this site Learning Electronics : Free Electric Circuits Textbooks

i think i've seen this site before! thanks though!

 

[Mr RB]

Hi Blueroom, I'd say go for it at least with SOIC parts, builders of more complex microcontroller kits (like the cricket and ladybug) are not the typical electronics beginners learning which end of a soldering iron to hold, they are a lot more competent than in years past. They expect a complex project that will take a little time and effort to assemble and program.

You write good comprehensive instructions (based on your Junebug instructions that I have read), so it won't be hard to add some SMD instructions to your kit, or even say a 2 page dedicated SMD leaflet you could re-use in each of your kits.

I would REALLY try to avoid anything smaller pitch than a SOIC. Even 0805 will make a kit painful to assemble if there are more than a few or if they are close together. It will be easy enough for the kit builder to solder a couple of SOIC chips but if they are required to solder 3 SOIC plus a heap of 0805's I would look at just getting the whole lot soldered by a SMD house. It only costs a few dollars per PCB for the SMD soldering of 30 parts, and it goes right on the added value of the kit you are selling so you can just bump the price a few dollars, it might even add a couple dollars per kit to your pocket.

There is also an added value to making your product small, people will pay MORE for a tiny neat SMD PCB that does a task, quite funny since the tiny PCB saves you a few dollars in PCB area and drilling costs too. The large high quality through hole PCB's you have been making so far can't be cheap.

 

[VISN]

https://www.electro-tech-online.com/threads/would-you-want-to-solder-a-tqfp-ic.37975/

Been waiting to see the ladybug design for some time now ... I checked early this month - there was no update - is it coming out soon?

 

[bryan1]

Hi Bill,
When I first thought about smd I thought noway could I solder them but after trying some old chips I got off old boards I found it isnt that hard. I got an email off TI this week and their new microstepper driver chips Special Function Amplifiers - PWM Power Drivers - DRV8811 - TI.com

My next fun trial will be soldering the thermal pad under the soic chip. I reckon the easiest way will be tinning the pad and copper then heating the underside with a micro blowtorch quickly to get the bond.

I reckon you might like this chip for a future product as off my first looks it's one good chip for steppers and perfect for robotics especially with the microstepping.

Cheers Bryan

 

[ronp849]

One thing I would suggest is to have a 9x eyepiece magnifier - this can pick up solder whiskers that cannot be seen with a lower power magnifying glass.

Ron

 

[vsmGuy]

I too am thinking about this a lot.

Care to contribute : **broken link removed**

 

[bountyhunter]

I just soldered about 120 0805 caps & resistors. Not bad but give me through hole anyday.

I recall there are an assortment of SM sizes: I think 1206 is more manageable, I think it was 0805 that made me grind my teeth if those are the super tinys. The space savings are not worth the grief. You also can't read the values even with a mag glass.

A tip on soldering SM resistors and caps: use a piece of scotch tape laid exactly across the center of the part so one end of the part hangs out. That lets you steer the part into place on the board and will hold it there while you tack down one end. Then lift the tape and solder the other end.

 

[3v0]

A tip on soldering SM resistors and caps: use a piece of scotch tape laid exactly across the center of the part so one end of the part hangs out. That lets you steer the part into place on the board and will hold it there while you tack down one end. Then lift the tape and solder the other end.

If my 3rd arm would grow a bit more it would be easy.

I use 805. A bit of solder on one pad. Liquid flux on component and pad. Hold component in tweezer (or hemostat) and set it in place using soldering iron to heat the solder already on the one pad.

If you do this for a while it is faster then through hole work. But I do most of my projects in a fry pan.

3v0

 

[bountyhunter]

If my 3rd arm would grow a bit more it would be easy.

I use 805. A bit of solder on one pad. Liquid flux on component and pad. Hold component in tweezer (or hemostat) and set it in place using soldering iron to heat the solder already on the one pad.

If you do this for a while it is faster then through hole work. But I do most of my projects in a fry pan.

3v0

Never had good luck with tweezers. Parts keep flying across the floor.

 

[be80be]

Never had good luck with tweezers. Parts keep flying across the floor.

A little shaky are we. I couldn't use them myself till I got me some 2x glasses

 

[Hero999]

Personally I'm used to working with SMD parts and I actually show a preference for them with my own projects because it means I can produce my own PCBs without having to concern myself with drilling lots of holes.

I wouldn't be put off by a kit that had SMD parts.

Brian

I agree, I prefer SMTs because I don't have to bother drilling the holes.

805 and 1206 are also good for mounting in between tracks on veroboard.

Soldering 805s is easy, it's when you get to 603 and below things start getting a little tricky.

Unfortunately I don't have that many SMT parts in stock and lack many resistor and capacitor values.

If anyone knows where I can buy a cheap E12 SMT resistor kit and cheap E3 SMT capacitor kit in the UK, I'd be interested.

 

[3v0]

Never had good luck with tweezers. Parts keep flying across the floor.

It is like most anything else. Seems nearly impossible till you get used to it, then it is routine.

3v0

 

[chuck]

I just salvaged my Sony sw7600 radio by replacing all the surface mount elect. caps. I didn't expect it to ever work again. It was like trying to solder a pill bugs on the board. I used magnification-- a must for older eyes. The radio didn't work at first, but upon a close look a small piece of solder had bridged two points on the board. I sure was happy. I saw a kit I would like to have but it is a surface mount. My little soldering iron is from a 'early '70 Heathkit stereo. Solder-wick--I'd love to have some. I probably should leave sm stuff to the younger folks.