Newbie wanting to build boards

[greencardigan]

Hi,
I want to build the following two boards.
 
https://github.com/greencardigan/TC4-shield/blob/master/hardware/TC4/TC4%20V600/tc4-controller-0600-brd.pdf

https://github.com/greencardigan/TC4-shield/blob/master/hardware/ZCD/V006/zcd-brd-006.pdf

Will I be able to build these using an iron and/or hot air reflow? Or will I need a reflow oven?  I’d probably use larger SMD diodes on the ZCD board.

I’ve not done any SMD parts or boards before but have reasonable soldering iron skills.

Depending on how I go, I may make boards to sell in limited quantities.  Would that change the ideal method for populating the boards?

Background: These boards used to be available for purchase and used in DIY coffee roasting setups.  They are currently not available for purchase and I want to make them available again to the community.  I am currently ‘responsible’ for the open source code repository developed in conjunction with these boards.

I’m open to building a reflow oven if definitely needed.  I should be able to use my coffee roaster controller (using the TC4 board) to do reflow profiling.

Cheers,
Brad

[Wimberleytech]

With transfer paper, good laser printer, an iron...a steady hand--yes.  There is one part on the first board that would be hard for me (RN1), but since I use coffee as an upper and wine as a downer, it is hard to find the precise time for me to apply a steady hand.

[greencardigan]

Thanks, I should have mentioned I would likely get the boards made at elecrow or similar.

[greencardigan]

So I understand you are saying I don't need a reflow oven and I can solder it all with a hot air reflow station?

[Vic20]

Will I be able to build these using an iron and/or hot air reflow? Or will I need a reflow oven?  I’d probably use larger SMD diodes on the ZCD board.

I don't think an oven is really needed for that.
You can probably solder all components using a hand solder and a lot of flux.
O have done that up to TSSOP pitches with no problem.
For SOIC pitches there is no problem at all.

You can use hot air, but I don't think it is really needed for exposed lead components. I only really need hot air for unleaded components like QFNs.

Having soldermask on the board helps a lot as also helps using custom footprints that take into account that the board will be hand soldered.

It all depends on volume. Reflow is good for high volume as you solder all components at once.

One problem with oven reflow is that it requires solder paste and when it expires after some storage time it can give unreliable soldering.

I’ve not done any SMD parts or boards before but have reasonable soldering iron skills.

It is not that difficult, really.
You just need to use the proper thecniques.

Depending on how I go, I may make boards to sell in limited quantities.  Would that change the ideal method for populating the boards?

Yes, because the soldering method affects the time needed to assembly each board.
For medium volumes, having a solderpaste stencil and a reflow oven can come handy for boards with a lot of SMDs.

[Shock]

You can do test runs of that board with a suitable soldering iron and tip.
Solder paste will speed up the job. Hot air will do the same with practice.

If going into small scale production a solder paste dispenser/stencil, pick and place tool, reflow oven will speed things up further. It's up to you how you want to do it.

This video shows a suitable hand soldering technique.

[Buriedcode]

A temperature controlled soldering iron, with a reasonably small tip (2-4mm chisel bit) and flux is all you need to populate those boards.  There aren't any large copper pours that require a high wattage iron, or any "awkward" packages like QFN or BGA that would really warrant hot air.  You could use hot air for the SMD's, but by the time you've put on paste and placed the parts you could have soldered them by hand - it doesn't really speed things up or help in any way.

A reflow oven is nice, but it all depends on how many boards you're making.  Also, reflow ovens tend to be for just SMD devices - TH devices especially R/A connectors can't be held in place, and most likely won't take the heat of the oven anyway (the JST 0.1" types tend to just melt).

Those boards actually look quite good for practicing SMD - after 3 or 4 you should be laughing.  Once you're confident, then batches of 5 (for say total volume of 25 max) seems to be the sweet spot for me.

[greencardigan]

Thanks for the advice all.

I will try using both an iron and hot air reflow.  Looking at some videos, it appears that the hot air reflow will give a more 'professional' looking board.

But maybe I'll build a reflow oven at a later stage if I need to produce more than a few boards at a time.

[greencardigan]

Just an update on this.  I ended up using a cheap hot air reflow replacement handle from ebay connected to a Arduino based phase angle dimmer (which amusingly uses the same shield that I am building).

I was surprised how easy the process was.  I did minimal practice removing parts from a junk board, then went for it on my board.

End result attached.

[Old Printer]

Just an update on this.  I ended up using a cheap hot air reflow replacement handle from ebay connected to a Arduino based phase angle dimmer (which amusingly uses the same shield that I am building).

I was surprised how easy the process was.  I did minimal practice removing parts from a junk board, then went for it on my board.

End result attached.

Very good to hear. Could you post a link to a video or two that you found particularly helpful. I would like to try this.

[greencardigan]

I didn’t really watch any tutorial videos other than Dave’s one where he built the LED ring.

However, I subscribe to Louis Rossmann’s youtube channel so I’ve watched him do plenty of rework.

I think having good lighting, good eyesight, and a reasonably steady hand would help a lot. I’ve done another board with a few 0402 caps and it was definitely a challenge in the placement stage with my slightly unsteady hands.

[tggzzz]

I’ve not done any SMD parts or boards before but have reasonable soldering iron skills.

SMD isn't as difficult as you might think, but it helps to have minimal equipment: head-mounted visor to see things, tweezers, solder paste, and a saucepan.

For my experiences, see: https://entertaininghacks.wordpress.com/category/homebrew-pcbs/

[Jwillis]

The backing for adhesive vinyl like Endura or Oracal works really well for transferring toner to your copper clad.I get it free from a local sign maker .I found some photo paper won't transfer at all .The cheap stuff works best .I found that these methods don't work well with very fine detail.

Another idea is Negative Dry Film Photoresist .You can get kits or Get a roll of Dry Film and use off the shelf sodium carbonate for developing and sodium hydroxide for stripping after etching.You can use sunlight or florescent light but a good UV(Black light) works faster.The whole process should only take around 20 minutes.

[james_s]

I hand solder stuff like that all the time, it's pretty trivial. If you wanted to build 10 of them I'd say get a stencil and use a hotplate or reflow oven, but if you just one one or two? Just solder them by hand with a temperature controlled iron with a chisel tip. Tack one corner pin of the IC, adjust it as needed to get it perfectly straight then double check it's not flipped around backwards. Then solder the rest of the pins, piece of cake.

[jmelson]

Another idea is Negative Dry Film Photoresist .

I currently buy my dry film from Think N Tinker in the US.  I highly recommend dry film resist, it is very durable and provides excellent etching.  I built my own exposure setup with a box with 4 each 24" black light bulbs with ballasts and starters, and crumpled aluminum foil as a reflector.  One minute exposure per side is all it takes.  I  have an old Kepro spray etcher, and it usually etches completely in less than 2 minutes.

The dry film has to be applied with a heated roll laminator.  I roughen the copper first with fine sandpaper, and then water wash and acetone wipe before laminating.

Jon

[t1d]

The Chinese board houses are great for producing boards. Cheap, descent quality, etc... The only issue is the typical three week delivery time and high shipping cost. But, the boards are so-o-o cheap, that it offsets shipping. I like Seeed.cc They offer assembly, too. So, it depends on whether you are in it for fun, or profit...

[james_s]

Yeah the only time I etch my own boards anymore is when it's single sided and I only need one, or I really want one without waiting.