does anyone know an easy way that's CHEAP to make or purchase custom PCBs
?
I make my PCB's with the Toner Transfer Method.
It's cheap and easy.
Instead of using Ferric Chloride which is nasty stuff for the environment,
and your legally not allowed to pour it down the sink.
Try using equal parts Hydrochloric Acid (Muratic Acid) and Hydrogen Peroxide.
The Hydrochloric acid you can get at hardware stores, it's used for pool acid (muratic acid).
And Peroxide you can get at pharmacists, it's used for cleaning cuts and bleaching hair.
Only mix the chemicals you need and store in plastic or glass containers, as it will eat through most Metals!
Always wear large chemical gloves and goggles. just basic chemistry safety, you don't want to get this stuff on you or in your eye!
Be careful when mixing the chemicals as there is a slight thermal reaction, just pour slowly.
and as always work in a really well ventilated area as they give off a fair amount of chlorine gas, which is toxic!
once mixed in glass or plastic container, throw in your PCB with toner print, and watch the uncovered copper disappear in no time!!..
Hope that helps!
A quick Google search turned up this thread at element14:
http://www.element14.com/community/thread/5197/l/cheapest-pcb-makers-low-volume
unfortunatly, the prototyping link is down at the moment.
if you want a small board, can fit 4 on a 5cm sq board, they sell in lots of 10, so 40 boards would be really low cost.
alas, you did not offer how many or what size.
I highly suggest you divide your work into stages
#1) a board with traces - easy to do at home
#2) a board with traces and holes - relatively easy, needs drill bits
#2A) a board with traces and accurately located holes - relatively easy, needs drill bits and a way to locate holes
#3) dual sided.
#4) traces, holes, solder resist
#4a) traces, holes, solder resist and silk screen
I highly suggest you buy perf board, lay up your circuit and verify everything works before making lots and lots of boards.
unless dropping $25 a couple times and 2-3 weeks wait each time will work withing your project.
far and away, a lot of 10 boards for $25, to toss 9, but have one perfect board with solder resist and silk screen is much more professional than home making a board.
@cminke,
I use iteadstudio all the time, you can see examples here:
www.crossroadsfencing.com/BobuinoRev17
All the green cards in all the different sizes are from them, from 25x50mm up to 100mmx100mm (10cm x 10cm). I try to stay under 10 cm x 10cm to keep the 10-lot cost down. Bigger cards, like the Mega screwshields, are 12.5cm long and cost more.
5cm x 5 cm, 10 boards for $9.90
5 cm x 10cm, 10 boards for $19.90
10cm x 10cm, 10 boards for $24.90
larger than 10cm x 10cm, 5-lot pricing starts.
http://imall.iteadstudio.com/open-pcb/pcb-prototyping.html
You can pack quite a lot onto a 10cm x 10cm card, and if surface mount you can stuff even more! With too much, you can run into problems getting every grounded. Good placement is a must! I've ben able to complete every design so far helping out the Eagle autorouter for the final grounds and occasional signal.
Solder paste stencil for surface mount parts is required if you have more than a few components - I've been getting mine from pololu.com, laser cut 4mil thick material. Used one for the Bobuino2 boards and the 1284OnTop (Bobweeny) cards we made the last 2 weekends. Stiff 1" plastic putty knife from local hardware store for smearing Kester EP256 lead solder paste across the stencil.
http://www.kester.com/download/EP256%20Data%20Sheet.pdf
R276 looks like it will work well also, and its findable in 35gram syringe, which will do quite a few boards.
Buy it in a syringe. Squeeze some across one edge of the stencil, smear it across. Remove stencil, place components with tweezers, then reflow in a 4-element toaster oven: full on to get to 125-150C for 1 minute heat soak, back off & hold the temp, then full on again to ramp up for 1 minute at 183-210C, back off & hold the temp, should see the paste turn from grey to metallic silver right at the end of that. DO NOT EXCEED 225! Heat full off, let oven temp drop down to under 200C, open door slowly to let cool down start. I use a J-K thermocouple with a multimeter and tweak the temperature knob manually while monitoring/controlling the temp.
Better price $15.23 for 35g
http://www.techni-tool.com/488SO540
Even better - EP256, 35g, $12.99, two for $10.75 each:
http://www.cmlsupply.com/electronics-materials/solder-paste/kester-ep-256-syringe.html
CR,
I'm interested in stencils. Are they made for the entire board or can I get some small ones, each for a standard components so I can use them on separate boards? I'm still prototyping.
OP,
What's your location? There are cheaper services in US such as OSH park, not as cheap as iteadstudio but still worth considering, when you are doing pretty small boards. They charge per area, unlike iteadstudio that charges per maximal allowed area. You get 3 boards from OSH, not 5,10,20 boards. Everything is lead-free, compared to extra charge at iteadstudio.
Besides what CrossRoads said already about solder paste and surface mount, you can also use soldering iron for surface mount parts. I've just started doing that. A lot of "fun" but you need good iron and thin solder.
liudr,
I've purchased individual chip stencils from proto-advantage.com
Proto Advantage - Stencils
Pololu will make a stencil for whatever the gerber you send to them is for - board, or chip, or some combination.
We made 21 1284OnTop cards over the weekend, I used a pololu stencil for those. The board uses 1206 components to be able to hand solder - using the stencil took all the aggravation out of it. I just layed the stencil on the board, held it in place be hand, squirted some solder paste along one edge, and wiped across the board with plastic putty knife. Had to wipe 1 or 2 off and start over, I cleaned off the stencil halfway thru (vs after every pass like bigger boards need), but overall i was very smooth. I did all 21 boards, Kathy placed all the components, we reflowed all 21 in one shot.
Small 0803 Rs & Cs are hard to do by hand - the surface tension of the solder makes them stand up on one end as you heat it up. Really need 3 hands - one to hold the part, one for the iron, and one for solder. Lot cleaner to reflow them when possible.
Some advice for the "tombstoning"... (By the way, I assume you meant 0603, or 0805, not 0803). Are you sure you are putting down the right amount of paste? Too little can cause problems. Are you putting down paste unevenly --meaning 1 pad has way more paste than the other pad? That's where most of my tombstoning happens. I personally don't use an oven - I do all my surface mounts with a hot air reworking station. Uneven heating can lead to tombstoning too, so maybe take a look at how your oven is heating the boards? Finally... there is a glue you can use to hold the parts in place. I forget what it's called, but it's usually reddish in color. I've never used it, but one little tiny tab of that between the pads will hold your resistors and caps in place and prevent the tombstoning during reflow.
Yes, 0805.
The tombstoning occurred on a part where I missed the paste, and we didn't notice that part was not placed before the reflow. I attempted to dab a little paste on the pads and then heat with fine tip soldering iron (due to several SMD and thru hole parts very close I did not try hot air).
1 part out of 45 on 20 boards, not too bad. I think it was on the very first board we did too, I think it was C9 next to 1284P pin 31 on one of these boards, noticed it as I was installing the female headers:
im looking for a board to fit rbg 5 mm leds, 5 m red leds, my MOSFETS, and my resistors in a 9cm x5 cm area
what EXACTLY does the paste do?
and does the self etching with a permanent marker work? saw it on youtube and it looks like it works but it could be a trick to the eye.
@ CrossRoads,
OK, as an elecrow member, here i intruduce you the elecrow PCB service:
-
if you care about the price:
the 5cmx5 cm max , 10 pcs , color free--> 9.9$
the 5cm x 10 cm max, 10 pcs , color free--> 12.9$
the 10 cm x 10 cm max , 10 pcs , color free --> 15.9$,
and also special for green board: 10cm x10 cm, 10 pcs, green, only 12.9$
so, as the price, elecrow is good! -
as the Stencil service:
the Laser Cut PCB Stencil service 20$, and the Stencil service without frame 20$ too, which would reduce the shipping fee greatly for customers. -
as the other kinds of PCB service?
?Provide the 4 layer PCB, FPC, and high-quality PCB service.
Elecrow:
@ CrossRoads,
OK, as an elecrow member, here i intruduce you the elecrow PCB service:
if you care about the price:
the 5cmx5 cm max , 10 pcs , color free--> 9.9$
the 5cm x 10 cm max, 10 pcs , color free--> 12.9$
the 10 cm x 10 cm max , 10 pcs , color free --> 15.9$,
and also special for green board: 10cm x10 cm, 10 pcs, green, only 12.9$
so, as the price, elecrow is good!as the Stencil service:
the Laser Cut PCB Stencil service 20$, and the Stencil service without frame 20$ too, which would reduce the shipping fee greatly for customers.as the other kinds of PCB service?
?Provide the 4 layer PCB, FPC, and high-quality PCB service.
You guys seem new to me. I'll give you a try sometimes.
You guys seem new to me. I'll give you a try sometimes.
I'm happy with their service.
China shops underpricing each other, interesting.
@cminke,
What do you need such a big board for? Those components would fit on a 5cm x 5cm board easily.
The solder paste is for surface mount parts.
You use a stencil, squeegee the paste onto the board, place the parts, and then run the board thru a toaster oven (reflow oven) at two temperatures - ~125C to activate the flux in the solder, and then ~200C to actually melt the solder. Only needs 75 seconds or so at each temperature.
I have a thermocouple and multimeter, I just crank the temperature knob on my old 4 element Sears toaster oven up & down to hit the temps as needed. I really need to assemble all the bits I purchased to make an oven controller - one of these weekends!
See the chart here for the solder profile.
Kester_EP256_Data_Sheet.pdf (54.9 KB)
CrossRoads:
China shops underpricing each other, interesting.
Want the real price? I kind of know it but there is no way you or me can get it.