PCB Prototyping and Fabrication

Question

I have been working on a project for the past four months. Most of my development have been on breadboards and prototyping boards. I am now in the stage where I want to get a PCB printed and fabricated so that I can miniaturize my device.

I am new to the process of sending designs and schematics in for fabrication, and wondered if someone knew how I can get started?

I am at a loss as to where I should go and what software to use (preferably something free). I have worked with Eagle to do very basic things before.

Also, what would be the best way to solder the surface mount components after assembly?

The packages for soldering are VQFN for all IC's and regular surface mount resistors and capacitors for the rest.

Answer 1

Here is what I do:

• use Eagle to design my schematics and PCBs,

• order PCBs from iteadstudio (google them), I typically get them in about two weeks, and the prices are unbeatable (I end up with PCBs costing about $1.40 each). Follow their instructions, pay special attention to downloading their DRC rules (so that Eagle can check your board) and their CAM job (so that you can export Gerber files),

• apply solder paste (leaded) with a syringe (stencils are too expensive),

• manually place components using tweezers,

• either use a home-made reflow oven or simply heat the board with my hot air soldering station if the board is really tiny (no nozzle, I use a timer, and I preheat slowly).

I routinely use QFN packages and 0603 components, no serious issues. Easy to do with a loupe and a steady hand. Sometimes if you apply too much solder paste you'll short two QFN pins together, but that is easily detected and corrected with a hot air station.

I find the above process much easier and more pleasant than trying to manually solder SMD components.

All in all, I'm quite happy with the process. The only downside is the ~2 week waiting time for PCBs, but you can mitigate that by staging projects, so that you always work on 2-3 at a time.

Also, I found that you can really do a lot with a hot-air station. Boards up to 3x3cm can be reflowed using hot air with no serious problems for amateur purposes. I use the oven for larger 5x5 or 5x10 boards only.

For very quick one-off breakouts I'll often whip up a 2.5cm x 2.5cm one-sided board in Eagle, print it on photo paper, transfer to a PCB using an iron and etch. It's about an hour of hard work (peeling away the paper is especially troublesome), but I can experiment with that I2C accelerometer in one hour, instead of two weeks :-)

Answer 2

One option is Advanced Circuits. They have their own free capture and layout software available in house. You order the board from inside the software. I've used it several times with success. There are several people out there that collect Gerber files from people, and put their boards together into a single bigger board for fabrication. These boards are significantly cheaper (like $10-15), but lead time varies and someone else is in control of your files.

Edit: Also, in reference to soldering SMT components. First, like Phil, 1205 is about as small as I can go. Heat up one pad, and put a small blob of solder on it, and let it cool. Then use tweezers to hold the component and center it over the pads. I apply a slight down pressure as I reflow my small solder blob, taking care to heat the component and pad. This will hold the component and make soldering the other side a breeze. A word of caution, L and some R components will melt the solder joint on the side you just completed if you aren't fast enough. It's important to use lots of heat, and a short amount of time.

Answer 3

See the question Schematic capture/PCB layout program recommendations for information on software selection.

Since you are asking how to solder the components, I'm assuming you don't have a production reflow oven. I design my hobby boards to use the biggest surface-mount components I can find (1206, etc), and I solder them with a good soldering iron with a fine tip, fine solder, and tweezers. It's easier than you'd think. Some people try to do a reflow process with electric hotplates, rigged toaster ovens, heat guns, etc, but I've never found these to be easier than just soldering with an iron.

Answer 4

Eagle is good and easy to use and has good libraries from Sparkfun etc.

As others have mentioned you can hand solder the boards without any reflow methods as i do some as small as 0402.

If the board is just a two layer board and you are looking at manufacturing 1 or 2 boards for personal purposes, you could also try etching the board yourself. I have trieds traces as small as 5 mil without any difficulties. But i would say that this requires some practice

Answer 5

Check out this:

• PCB Design For Manufacture - Part 1
• PCB Design For Manufacture - Part 2

I think that this is not the direct answer for your question, but there is outlined most important considerations you may want to think of prior to design PCB for manufacture.

Answer 6

If you have enough time to make the boards and assembly by yourselves, then take the suggestions above ,but when it is a project that would be done at planned date and work into funtional test in sample stage,then work into production run after test, You would better choose a source take it from prototype stages to small run and finally volume production.

You can find many sources in google,Some prototypes companies can offer you super low price but need at least 2 weeks to make a simple 1-2 layer board,while you are free to choose other source take these prototypes finished in 1 weeks at the reasonable price.

It will take a long time if you buy the PCBs and send to your assembly jobs ,You can also ask the fab house take the assembly job for you ,you can buy the components by youselves and ask them buy the components for you.

Answer 7

As said by many, Eagle is a good place to start for the software choice. With Eagle you will be able to make a schematic and PCB.

You seem to be new to all this and VQFN is not a package used by a newbies, therefore expect you will make mistakes and several runs of the board to get it right ... I suggest you have the board checked by someone experienced or post the project in a forum to detect possible flaws...

what you are doing is good for learning though :)

Answer 8

While the OP's original project must be long finished by now, let me write an answer from the perspective of a similarly beginning hobbyist who's just been through the learning curve (also, I think some things have changed in just the few years since the original question):

First, there are now several cheap PCB prototype manufacturers, a list of which you can find at pcbshopper.com, and in addition to those I'd mention Hackvana, which I've tried once and had a good experience with. Up to 4 layers is not ridiculously expensive anymore, and also delivery times a bit less than two weeks are affordable (although the cheapest is still 2 layers and a month for delivery).

For software, you can use anything which exports gerbers. I personally recommend KiCad, which has a slightly idiosyncratic UI but perfectly usable once you get used to it, and most importantly, since it's free and open source, there is no danger of vendor lock-in. For comparison, I find the interface more logical than Eagle.

As far as soldering goes, a temperature controlled iron with a good tip, and a lot of flux for multi-pin packages, goes a long way. A beginner hobbyist, I've now built five boards (with the last two self-designed), going from through-hole to 0.5mm pitch LQFP SMD's and 0603 passives in that time, and I seem to be doing fine enough. Watch the various soldering tutorials, practice on some kits, and you should be fine. Just to point out that to start with I was the most hopeless case you can have: back in school I was the kid whose any product in woodworking class was just a piece of wood inside a blob of glue (and metalwork just resulted in me burning myself...), so you don't need to have special craftsman skills to learn SMD soldering to a usable level.

However, I don't have experience with the QFP's the OP mentions, although I expect that with a hot air station it should be doable. Those are not too expensive these days, although watch out for the very cheapest ones.

To summarize: for a hobbyist, the process these days is:

1. choose an EDA software that suits you, as long as it exports Gerbers, and learn to use it.
2. draw your schematic and route your PCB
3. pick a cheap PCB prototyping service you like, and send the Gerbers to them
4. Solder the board. Don't be too afraid, it's easier than it looks, you'll just need to be careful and concentrate.

Answer 9

I am fairly new to this myself.

Generally when I want to prototype, I draw a rough schematic on paper. Once I am happy, I use a solderless breadboard to test it out. (makes things so much easier). Once I like the functionality, I transfer it over to a perforated prototyping board and use it for a little while. If I am happy with the design and use, I then use KiCad to create the schematic and PCD. (It's free and open source, also gives better free stuff than Eagle).

I also buy the biggest through-hole components I can find.