Why do people outsource PCBs to other people/organizations when they do the design

[matrixofdynamism]

I have been wondering about this for a while now. I can see that there are many people that specialize in PCB design and there are even whole companies that only do PCB design. Now what I am wondering is that when an electronic engineer is going to be designing the whole system why not the PCB as well? Usually the person that designed the system will have a good idea about how the PCB is supposed to be as well right?

I understand that often engineers shall be working in teams and in this case they will only get a part of the whole design, but having 1 guy who only designs PCBs looks wierd to me. Having to outsource the PCB design to another firm looks even more wierd. Why do people do things this way?

 

[andre_luis]

I agree with you, and due some designs I develop have some critical issues, I prefer do it myself instead recursively ask to the partner make revision.


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[Mattylad]

Because often an electronic designer does not have the necessary skillset to be able to design the PCB layout itself.

There are a lot of issues to consider, getting it to work, EMC, DFM,DFT, assembly, repair etc and often (in my experience) a design engineer just does not consider these factors well enough. Also the actual layout is a specialized skill in itself - you do not just chuck them on the board and autoroute it (not if you want a decent board).

I have seen boards that design engineers have laid out and they have been awful, unlikely to work well, really bad for manufacturing the PCB, as bad for assembling the board etc.

So rather than employ a specialized PCB layout person design companies can save money by designing the circuit and passing it onto the companies that specialise in the layout.
They pay on a per board basis (allowing the actual cost of the board layout to be included in the designs costs) rather than pay £xx P.A. for a PCB engineer which also carries many overhead costs.

If you have never designed a board that has DDR3 on before, would you be sure that you can route it correctly & according to the DDR spec?
Its a big job to learn, time consuming etc and can be far cheaper to sub the job out to someone that does this often.

As for asking the PCB people to make revisions, perhaps if enough information was given to them in the first place they would be able to do it right first time.
The designer turning around and saying they want it different, changing the circuit or only coming up with a specification after the design has been placed/routed is very common.

I.E. "But I wanted the connector in the top left corner on the underside".

PCB guy thinks "well why didn't you blooming well say so then!!" grrr... and moves it all.

I can design a kitchen, all the units and make some pretty pictures of them. nice thick oak doors, worktops etc.
I would however get a joiner to actually make them if I wanted them to be any good.

 

[babbit12]

Totally agree Mattylad , in my 25 years experiance as "only" a PCB designer I have found that many engineers want the challange of laying out PCB's but they get 3/4's of the way through, can't finish the job due to bad placement and design constraints and then pass the job over to their in house PCB designer to finish off !!!! lol . I have always thought that it would be more cost effective for a design engineer to design and a PCB designer to layout the boards, but that's just me !!!

 

[marce]

Engineers do not generally do good layouts, but then again a lot of so called PCB designers don't either. PCB design is a field of engineering that needs to be studied and learned these days, to cover all the aspects, digital analogue, RF, high speed, EMC etc etc. To get the best layout you need a good PCB layout engineer...

 

[andre_luis]

...to cover all the aspects, digital analogue, RF, high speed, EMC etc etc. To get the best layout you need a good PCB layout engineer...

I totally agree with you, not just because I'm an electronic engineer ( :grin: ) but as you said, there are a lot of phisical phenomens we have good knowledgements so that we can predict its influence on board, avoiding them.


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[hareeshravi]

I would like to share my experience with you.

I was an FPGA design engineer with some experience of board design. Recently I have taken up a slightly complex 'hobby' project for one of my research project which includes board design. My intention was to understand the full design flow (alternate arrangement is also in place). This has thrown me up to many many issues and I could really appreciate the art of Board Design. Being a self-financed project, my aim is for first time success (***, help me).
This is a Standalone Portable Data acquisition device, with 8 channel 20ksps Analog Data aquisition, some digital inputs from accelerometers, basic I/O, 8GB NAND Flash memory , communicating to add on board (kit) for extracting the data to an external pendrive.

These are the things I am/was really worried of..

Component selection

- Cost, features,supply voltage, compatibility, availability ....
- Can I give this for soldering with reasonable cost?
- Does placing this component affect others? (Interference? Heat ? Accessibility ?)
- Does it require special tools during soldering (Some tiny packages like uMAX-10 (Maxim) seems to be too small)
- Can I get footprints of the package for my design tool? How accurate are they ?
- Is the pin-orientation is inline with my overall architecture?​

PCB Design

- PCB Stack :: So i had to fix whom I am going to give PCB manuf.
- After a few trials with the tool, I went back to paper and pencil, and identified suitable placement location. This really helped me later
- Auto route?? ( I really laughed at the results ) - Yes, it is not tools fault, I could not constraint the routing algorithm properly..
- Most IC's have strict layout constraints..
- I am using an FPGA, so had to deal with many decoupling capacitors, with strict constraints. !!!
RTL is not ready. So what power should I desgn for?
- Which pins should be taken out as test pins?
- How far the design is friendly for PCB manuf., placing & Soldering?​

Power Supply

- Still in dark ! ( Yet to learn many things)
- Power supply architecture.. Where to put the heat? can i use Switching regulators?
- Isolating analog part..
- How much heat is expected? Should I keep heatsinks? How much?
- Will the routing be sufficient? grounding problems? EMI/EMC ???​

Tool:

- I tried many tools. Its my luck that I got access to Altium Designer tool to work with
May be after my first experience, i can do the same in open source tools also...​

PCB Fab: (Milestone not reached till now)

- Manufacturer wants so many data than I had initially thought of. Gerber files, tool list ( some tools not to be used ), drill and hole sizes etc.etc.
- Manufacturer has his own set of PCB design rules.
​

Googling and understanding possible side effects of each decision you make when fixing the architecture is really difficult (Eg: Should I isolate? then I am adding another major component ! big rework.. Why did I not think of it before? ...), but enjoyable. A snapshort of the design is attached below (Many more changes are to be implemented).



Considering the complexity and risks involved, in a commercial scenario, I would definitely outsource it.


Regards,
Hareesh

 

[Mattylad]

As Hareeshravi also says in his reply, PCB layout is part of the process. A good PCB design also includes picking the right components, not just for the circuits but for the layout and assembly too.