Cam

Ordering PCBs cheaply?!
« on: March 06, 2017, 11:58:25 AM »
Hi all, hope this is in the correct forum..

I've designed some PCBs for a small project. They work together to form a bigger circuit, but because I know I'll have made plenty of mistakes, I've designed it across multiple boards, connected with ribbon cables (11 boards in total). This way it'll be far easier for me to repair/replace/modify certain parts without worrying about ordering the full PCB again (and the whole desoldering process that would involve). My eventual aim would be to redesign it as one PCB, once I've ironed out the various faults.

Anyway, I'm trying to find a way to get these 11 PCBs printed cheaply, but I'm failing miserably! I've only talked to a couple of places, but I've been told they would treat it as 11 separate circuits, regardless of whether I placed all the circuits on one PCB (that I could cut up myself), or on separate PCBs (that the PCB manufacturers would cut up). Is this really correct? I'm slightly baffled by the idea to be honest... And if this is normal, is there a trick I'm missing about getting this done more affordably?

Roughly speaking, the cost seems to triple, simply because I'm using ribbon cables to connect parts of the circuit together!?

Any advice would be much appreciated - I've no idea what I'm doing, but I'm always wary!

C


Andy Peters

Re: Ordering PCBs cheaply?!
« Reply #1 on: March 06, 2017, 01:01:42 PM »
Anyway, I'm trying to find a way to get these 11 PCBs printed cheaply, but I'm failing miserably! I've only talked to a couple of places, but I've been told they would treat it as 11 separate circuits, regardless of whether I placed all the circuits on one PCB (that I could cut up myself), or on separate PCBs (that the PCB manufacturers would cut up). Is this really correct? I'm slightly baffled by the idea to be honest... And if this is normal, is there a trick I'm missing about getting this done more affordably?

If the designs are different, they are different, and the fab houses will treat them as such.

If you are willing to engage with a fab house (say, Advanced Circuits) that caters to professionals, they will be glad to build your pre-panelized boards for you. You have to provide the panelized berbers, with the v-scoring indicated and all of that.

And you will pay for this. It may end up being less expensive if you use one of the offshore places (Seeed Studio has been good for me) and order up ten each of the individual boards. Seeed will do ten two-sided boards for ten bucks total, so your eleven boards will cost $110 plus shipping.
"On the Internet, nobody can hear you mix a band"

JohnRoberts

Re: Ordering PCBs cheaply?!
« Reply #2 on: March 06, 2017, 01:36:33 PM »
Why not put all the circuits into a single PCB design, like you want to end up with. The PCB house does not need to know how you plan to chop up that larger PCB for prototype/debugging...

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

john12ax7

Re: Ordering PCBs cheaply?!
« Reply #3 on: March 06, 2017, 02:43:01 PM »
Pcbshopper. com is a good place to get multiple quotes at once.

Cam

Re: Ordering PCBs cheaply?!
« Reply #4 on: March 06, 2017, 05:03:08 PM »
Why not put all the circuits into a single PCB design, like you want to end up with. The PCB house does not need to know how you plan to chop up that larger PCB for prototype/debugging...

JR

This is kind of where my understanding fails - at what point does it become "one circuit"? For all intents and purposes, my individual boards are one circuit - just a circuit where the different sections are connected with ribbon cables.

Say for example I copy each of my circuits onto a single PCB layout, so everything is contained on one PCB, but they are electrically isolated from each other - this is NOT a single circuit in the eyes of the PCB fabrication houses? But if I remove the connectors I would've used to connect each section together, and run traces, it becomes one circuit and can be treated as such? And if that's the case, at what point is the "changeover" from multiple circuits to a single circuit?

C

[silent:arts]

Re: Ordering PCBs cheaply?!
« Reply #5 on: March 06, 2017, 05:36:42 PM »
If you provide one single Gerber package without v-scoring layers (or any other extras like cutouts etc) it is one single PCB

Cam

Re: Ordering PCBs cheaply?!
« Reply #6 on: March 07, 2017, 11:51:39 AM »
I realise this is like explaining the world economy to a 3 year old, but please bear with me a little longer!!

Can I give an example, and perhaps someone can explain in idiot English why this doesn't work in the eyes of the PCB houses?

Say I was making a single PCB for an 8 channel mic amp. For this design I have (for discussions sake) 8 completely different mic amp designs: one Neve based, one SSL based, one API based etc... They all exist together on a single PCB in my PCB design software. Everything, including power and earth, is wire to board - no common traces exist between the different mic amps.

How will the PCB fabrication places treat this design? Is it 8 single circuits in their eyes? And if it is, why is it? Why does it matter? 

If I added a common ground and power rail traces to this board, powering and earthing all the mic amps, does it become one circuit? At what point can it become one circuit?

I'm really just trying to establish what the deal is here, so I can design my little irrelevancies efficiently and cost effectively.. I've talked to a few PCB places now, but I haven't had a clear answer... Presumably my question is so stupid they can't fathom it!!

Thanks,

C

JohnRoberts

Re: Ordering PCBs cheaply?!
« Reply #7 on: March 07, 2017, 02:56:48 PM »
In general a single gerber is a single PCB,,, The PCB house is fairly automated so handles a single consolidated design as one.  If they have to handle multiple different gerbers, it is by definition multiple PCBs.

The PCB house cares first about their labor and second square inches of PCB stock...  What you do with it after you get it is not their concern.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

Andy Peters

Re: Ordering PCBs cheaply?!
« Reply #8 on: March 07, 2017, 05:42:03 PM »
Say I was making a single PCB for an 8 channel mic amp. For this design I have (for discussions sake) 8 completely different mic amp designs: one Neve based, one SSL based, one API based etc... They all exist together on a single PCB in my PCB design software. Everything, including power and earth, is wire to board - no common traces exist between the different mic amps.

How will the PCB fabrication places treat this design? Is it 8 single circuits in their eyes? And if it is, why is it? Why does it matter?

If you generate one set of Gerbers which encompasses all of your eight single circuits, then it is, in the eyes of the fab house, one single design. This should not be a problem.

If you add V-scoring to the design, the cheap off-shore fabs may reject it. It might not really be worth adding the V-scoring for such a test board. Do you need them physically separate?

The better board houses won't care about your scoring indicators, but they are also charging you more in the first place. We (day job) recently did just this: we needed four different boards for testing, and we needed only three or four of each, so we did it all up as one large design, with V-scoring indicated. The main reason for doing this was to avoid paying multiple NRE charges.

All that said: if you are doing truly isolated designs that all end up on one "board," you must take care to keep things like power supply nets separate. You can't just use +15V for op-amp power, as the layout software will want that net to be connected on all of your "boards." You need to name the nets +15VA, +15VB, GNDA, GNDB, GNDC, etc etc, one for each little board.
"On the Internet, nobody can hear you mix a band"

mattamatta

Re: Ordering PCBs cheaply?!
« Reply #9 on: March 07, 2017, 07:54:51 PM »
One issue, and one of the reasons why you are getting inconsistent answers is that, while a "typical" fab house will care about overall size (As well as any special operations like V scoring, etc)  and not what you're planning on doing with it, some of these modern proto houses have "per board" type deals. 

If they're running something like a "10 boards for $20 up to a certain size" deal, then they may take issue with multiple smaller boards in a single design.  And in that case, whether they notice or not may depend on how much it looks like a panelized design of smaller pieces.


Gene Pink

Re: Ordering PCBs cheaply?!
« Reply #10 on: March 08, 2017, 02:35:01 AM »
  And in that case, whether they notice or not may depend on how much it looks like a panelized design of smaller pieces.
Perhaps a sneaky way around that would be to include some fake traces that run between the various circuits making it look like one giant circuit, and then once cut up, it leaves placebo traces that start from an unused solder pad, and go to the edge and stop.  ;D

Gene

iampoor1

Re: Ordering PCBs cheaply?!
« Reply #11 on: March 08, 2017, 04:18:48 AM »
If they're running something like a "10 boards for $20 up to a certain size" deal, then they may take issue with multiple smaller boards in a single design.  And in that case, whether they notice or not may depend on how much it looks like a panelized design of smaller pieces.

I have ordered 5-10 seperate designs on 1 board with silkscreen lines inbetween them from elecrow.com without any problems multiple times.  Not sure how the other cheap fab houses deal with this.

Cam

Re: Ordering PCBs cheaply?!
« Reply #12 on: March 08, 2017, 05:18:25 AM »
I'm glad I'm not going mad here!

I would've agreed - who cares how many individual circuits are on a board, as long as they're all on the same gerber files... My confusion came when a couple of PCB manufacturing places said something along the lines of:

"each circuit has unique job ticket no matter single board or combined on the panel. As long as they are isolated/separated circuits, more manufacturing process will be applied"


I'll just keep searching for companies I guess..

iampoor1

Re: Ordering PCBs cheaply?!
« Reply #13 on: March 08, 2017, 03:26:23 PM »


I'll just keep searching for companies I guess..

www.elecrow.com

Right now they are running a 10x10cm specialfor under 10$ for the "PCB Prototyping" service. Doesnt get any cheaper than that!

gyraf

Re: Ordering PCBs cheaply?!
« Reply #14 on: March 11, 2017, 11:24:03 AM »
"Jetek PCB" did not charge me extra for idc-attached break-away subboards - http://www.jetek-pcb.com/

They do quick and very, very high quality. Yes, I'm a fan.

Not sure about pricing for one-off's though

Jakob E.
..note to self: don't let Harman run your company..

john12ax7

Re: Ordering PCBs cheaply?!
« Reply #15 on: March 11, 2017, 09:25:07 PM »
"Jetek PCB" did not charge me extra for idc-attached break-away subboards - http://www.jetek-pcb.com/

They do quick and very, very high quality. Yes, I'm a fan.

Not sure about pricing for one-off's though

Jakob E.

The pricing seems rather good.  How do you actually order from them? Send an email?

gyraf

Re: Ordering PCBs cheaply?!
« Reply #16 on: March 12, 2017, 01:15:33 AM »
Yes, I just sent an email.

They were quite quick at answering, in perfectly usable  English.

Then sent the Gerber collection and got a quote within a day. Accepted, then some ~8h later I got a notification of a potential problem (some secondary-side pads were missing): I already knew the potential problem was there, and it was of no consequence - but its detection showed that they actually have someone sitting there and closely DRC-re-checking your work. and THAT I find to be good service..!

PCB quality (specially alignment precision and plating) turned out way over expectations. And was delivered to my workshop in just under a week (!)

Jakob E.
« Last Edit: March 12, 2017, 01:18:34 AM by gyraf »
..note to self: don't let Harman run your company..

john12ax7

Re: Ordering PCBs cheaply?!
« Reply #17 on: March 12, 2017, 01:48:17 AM »
Very nice.  Will give them a try with my next order.

joaquins

Re: Ordering PCBs cheaply?!
« Reply #18 on: March 12, 2017, 11:49:46 AM »
...
All that said: if you are doing truly isolated designs that all end up on one "board," you must take care to keep things like power supply nets separate. You can't just use +15V for op-amp power, as the layout software will want that net to be connected on all of your "boards." You need to name the nets +15VA, +15VB, GNDA, GNDB, GNDC, etc etc, one for each little board.

  I usually draw the circuits independently and then put them together in the gerber, so they don't care the signal name. In the gerber edit the panelization and even add the extra mechanical stuff as V grooving and panel holes.

JS
If I don't know how it works, I prefer don't turn it on.

Re: Ordering PCBs cheaply?!
« Reply #19 on: April 18, 2017, 03:21:18 AM »
For Cheap PCBs, I absolutely recommend PCBWay.com (  Only $5 for 10 boards ), and you will get a $5 coupon when becoming a new member. So, my first order is free. 8) 8) 8) Best company for PCB prototype !!
« Last Edit: April 18, 2017, 03:27:48 AM by Oliver B »