Good ideas, if you're paying for whole panels. However, if you're going through a prototype PCB house (Sierra Proto Express, Advanced Circuits, or any of the 100 others), they panelize it and you just get the PCB so none of these tricks work.
We love proto PCBs houses, because we can just buy what we need (or as many we we can get for the same price as what we need -- proto PCBs are like sheet metal parts: for small volumes the cost is all in the setup, so the cost difference between say buying 1 or buying 10 is minor), instead of ending up with a large volume of unused boards, which always happened in the past (when we had to buy ~100 boards).
However, if you're going through a prototype PCB house (Sierra Proto Express, Advanced Circuits, or any of the 100 others), they panelize it and you just get the PCB so none of these tricks work.
I would hope that if you were submitting your own panel that the board shop would treat it as a single board. I have no doubt that the board shop would further panelize the panel anyway. You just have to be able to persuade your layout tool to allow you to mix boards on the panel- it is then simply one PCB.
Also the test techniques described are actually on production panels.
I do hope that if you need them you can get the tips to work for you.
The pricing of PCB manufacturing is sometimes a little obscure, but it was always my impression that one major part consists of the area the board takes on the panel ... including the unused area. It became a habit to use such areas as cooling "wings" for power chips that use copper areas as part of their cooling. I leave them with more or less full copper on both side and little solder areas. On the major board I leave adjacent lanes without screen. In the end the otherwise useless pieces of board get soldered vertically between these lanes and provide additional cooling at (almost) no additional cost.
It looks good if you are so concerend about saving $300 and delaying work. However, time to market for everyone is so great and no one wants to wait for even half a day. In general we pay premium for two three days delivery. I am not sure, this is practical in bigger organization.
It looks good if you are so concerend about saving $300 and delaying work.
We appear to wok in completely different markets. It's not $300, it's $300 per board. We produce probably more than 50 boards a year, but let's take that as a round number. Making each individually would cost $15K. If we spread it over 7 panels that works out to $5K6. Although we make quite a number of boards, we are a small company so the $10K saved is important.
And yes, we have the luxury of not being pressed to get a product to market ASAP most of the time. Because each of the engineers have at least 2-3 projects going on simultaneously (and I am NOT advocating this as a great way to work) the board delays are not normally an issue.
Yes, I agree with you. But for us, sometime we ask next day 9:00 am delivery or if they make mistake in delivery, we ask them to send it in person or by taxi. Yes, it is expensive, but you must follow management instructions. I wish I get that much money for my test and measurement equipments or like that. But that is difficult.
While I have not had the need to do this, it's my understanding that some of the proto houses (Advanced Ciruits was specifically mentioned in this regard) will send you the uncut/unbroken panel. This can be a real moneysaver if you are making a fair number of small boards and the PCB house charges by the individual board. Of course, some PCB houses won't cooperate here.
Thank you for taking the time to write these ideas up and share them. I have never considered the efficiencies that might be possible with mulitple units on a panel and a common test connector. This type of setup may be well suited to some of the prototype work we do.
Hmm running the tracks in from the edge for testing is a neat idea!
Those tiny PCB's look like the "fuse blown" indicators , do you use those little spongy EMI pads to get a good contact , e.g. Gore 25SMT-4442-01 ? or a little metal spring finger like the Harwin S1741-46R?
I also usually send my PCB's in as full panels , was 10.5 x 16.5 " , but changed supplier now 15.74 x 10.23" , I get it a cheaper rate, the so called "plot and go"
I also discovered that if you are making 10" x 8" panels , it is cheaper to ask for "5 full panels, each with two of the attached halfpanel.pcb files" than to ask for "10 panels of halfpanel.pcb"
It helps to put a dividing line somewhere near the middle to make shipping easier.
I can have upto 20 designs/panel.
The other thing is with say a production run of 3" x 4" PCB's , you get about a 2" margin left all around the panel, so you fill this up with prototypes. So with a run of 10 panels, you get 120 production boards and as a bonus get at least 10 of each proto board for free. (The stencils are just made to cover the area of the "production boards") , the proto boards are hand pasted or maybe mylar stencils.
Next production run, you make minor tweaks to the "production boards", but run a completely different set of proto boards around the edge.
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