Engineer's playgroung - Page 1
Forum section: electronics / projects

author: tszaboo
author_rank: Super Contributor
timestamp: March 20, 2015, 04:20:20 pm
content: So I've just released a project, where due to the mechanical layout, I had some 15mm x 200mm panel edge. On other projects sometimes there are huge areas left blank just because the board size is contained by other factors than the size and number of components.This time, I've placed some SMD breakout SO8, SO16 SOT-23 and so on and resistors to all the pins.What do you usually do with this playgrounds?Do you use them or is it left blank?Am I the only one who does this?On an unrelated topic: Looks like I cannot spell playground properly.

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: March 20, 2015, 04:22:58 pm
content: You're not alone

author: Falcon69
author_rank: Super Contributor
timestamp: March 20, 2015, 06:16:44 pm
content: I sometimes have large areas left over as well, do to layout. But, If I place any type of pad on them, I get charged extra. They say it's another design on the board, and I get charged for that. So, I often just leave them off, unless I have a large run, then it is worthwhile.You can always sell them on eBay or something. I know I've been guilty of buying boards to use for my SMD components that I need to breadboard.

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: March 20, 2015, 06:21:32 pm
content: I use the extra space mostly to do experimenting with stuff where the pcb is integral part of design.

author: georges80
author_rank: Frequent Contributor
timestamp: March 20, 2015, 07:44:10 pm
content: Quote from: Falcon69 on March 20, 2015, 06:16:44 pmI refuse to use any PCB house that tries to charge extra for multiple boards/layouts on a single 'pcb'. You're paying for the sq in of PCB already, why should it matter to them if it contains several designs?cheers,george.

author: Falcon69
author_rank: Super Contributor
timestamp: March 20, 2015, 08:25:24 pm
content: I agree completely, however, I have not found any that DO NOT do that. And the ones I have found that don't care either way, are like 4 times the cost.Even Elecrow charges for multiple designs on one board.

author: tonyarkles
author_rank: Regular Contributor
timestamp: March 20, 2015, 09:07:06 pm
content: Laen from OshPark had a good story about this on the Embedded podcast a week or two ago:http://embedded.fm/episodes/2015/3/11/92-everybody-behave-pleaseWhen he was first starting his panel-sharing service, he'd fill the extra space on the panel with perfboard. After he'd been doing it for a while, he was informed that his board house "hated making his boards". After the podcast, he posted this to twitter:https://twitter.com/laen/status/57613075936842137614,000 drill hits!I'm guessing things like that are the reason that board houses charge extra for additional designs

author: Falcon69
author_rank: Super Contributor
timestamp: March 20, 2015, 09:15:08 pm
content: That's what i think too. But, then again, if I had a board say 100mm x 100mm that the single design filled the whole thing, vs. the same size with multiple designs, and BOTH equal same amount of holes and pads, why should it matter what it costs? But, they charge for the multiple designs anyway. Bad business in my opinion. Just another way for them to justify making a buck or two off you.Wow, look at all that deadspace he has on that board of 14,000 holes. I would never let one of my boards go out with THAT much dead space.

author: ajb
author_rank: Super Contributor
timestamp: March 20, 2015, 09:48:35 pm
content: I've started ordering larger panels for prototypes when I can. Above ~100 sq inches, you can get tab routing, non-plated holes, tighter traces, and smaller drills, for about the same price per area as lower spec domestic prototype options. Works out to be a pretty good deal if you can save up a few designs to get made as a batch. Anyway, at that size extra area is dirt cheap, so it's easy to stretch the dimensions a bit to fit in some breakout boards or side project PCBs. I've been building up a little library of SMD adapters and switching converters that I can usually tuck into spare corners which are handy for projects.

author: georges80
author_rank: Frequent Contributor
timestamp: March 20, 2015, 10:07:30 pm
content: Quote from: Falcon69 on March 20, 2015, 08:25:24 pmI've used Silver Circuits (fabbed in Malaysia and about 1 week delivery from ordering). Reasonable cost for 5 copies of your board (comes to around $70 with Fedex shipping typically) - and no restrictions on multiple different designs on a board. Soldermask and silkscreened. Using their proto service they do have some geometry and drill hole minimum restrictions, but still more than adequate for prototyping various designs that I do.Not being restricted to a 'single' design, I typically put 5 or more different designs on a single panel and that gives my 5 copies if I need more than one. I consider that a cheap way to evaluate several designs/layouts. I added designs to the panel as I dream them up and when I have enough to justify a run or I have an urgent need for a new design to be prototyped I kick the whole panel off to fab.cheers,george.

author: tszaboo
author_rank: Super Contributor
timestamp: March 20, 2015, 11:00:05 pm
content: Quote from: tonyarkles on March 20, 2015, 09:07:06 pmWell, that is a lot of holes. I totally agree, I wold hate that board, probably braked the drills all the time. Although I usually avoid TH components, so I guess it means less holes. Except thermal designs, then I place as much 0,3mm holes as necessary, have fun replacing the drills.Merging different designs is not really an option, as is does make more sense to order the exact number of boards as you need, especially if that number ends up 1000+ boards.

author: Siwastaja
author_rank: Super Contributor
timestamp: March 21, 2015, 09:57:17 am
content: I would never use a PCB manufacturer that is so totally and absurdly unprofessional that they think having a lot of drill holes is anything special, and are unable to have a pricing model which takes this into account. (Take a look at any high-density modern digital board and the absurd number of vias they may have, for example.)Drilling doesn't cost much, but it does costsomething; they just need to include the number of the holes in their pricing scheme, like many companies do -- then there's no complaining.Drill changes are automatic - once the drill bit it near its end-of-life, the machine replaces it before it breaks. Of course, unprofessional fabs might want to give people a wrong impression about this, but really, drilling 10000 holes is nothing special. How do I know? Our electronics club has a lot of used, end-of-life drill bits we got for free from a professional PCB fab; they are good for thousands and thousands of holes in our CNC drill. Heck, there even is a business around sharpening (re-tipping) and re-selling used PCB fab drill bits (take a look at Ebay).Giving out "free" service and subsidizing it from other customers and then publicly complaining how they "hate" the freeloaders is completely unprofessional. Why use such a company?I have never used OSHpark anyway because I always hate it when everybody on the internets go nuts that this is the greatest thing and so cheap OMGand when I actually check the prices, it's one of the most expensive.So instead of this amateur crap, I either DIY my boards so I have TOTAL freedom with almost zero cost and no stupid politics, or use a proper professional PCB house with professional specs, and some of them are not much more expensive than the "hobbyist" ones - and sometimes, the professional one is even cheaper.How can a PCB house that forbids "multiple designs" even know you have multiple designs??? Is there a risk that if my design, by accident, happens to look a bit like a multiple design board, some manufacturers start crying about it? Recently I ordered a board that had 56 small modules, routed to be separated after programming, calibration and testing. I used a real professional PCB house and the price was about half of the OSHpark price; but now I can see that the OSHpark price would have gone through the roofs have they noticed I have 56 "designs"!The professional house naturally never questioned my design intent - they did what I paid them to do - their job. Professional houses take pride in that, I guess.

author: tonyarkles
author_rank: Regular Contributor
timestamp: March 22, 2015, 08:41:36 pm
content: Quote from: Siwastaja on March 21, 2015, 09:57:17 amThe 14,000 drill hits resulted in a panel that took over 8 hours to drill. If I recall the details, they did eventually quote him a price and it was somewhere around 10x the initial panel cost. He quit putting perfboard on the spare parts of the panel instead

author: tszaboo
author_rank: Super Contributor
timestamp: March 23, 2015, 09:05:50 am
content: Quote from: tonyarkles on March 22, 2015, 08:41:36 pmWhen I create demo boards, I use SMD pads. I'm not sure why would anyone include space for 5-6 TH components on every pin. It is not like we are in the 90s and SMD for hobby or prototype is a new thing.The other thing is the manufacturer. At other proper manufacturers you pay by the area of the PCB or the size of the panel you want. They specify the number of drills you could do without extra cost. If you dont exceed that, they should shut up and do the board. 8 hours sounds like a lot BTW.It is usually specified like 1000 drills/dm2. I really think that the proper way of dealing with manufacturers is to stay away from those, who do doggy things.

author: Siwastaja
author_rank: Super Contributor
timestamp: March 26, 2015, 02:00:13 am
content: Quote from: tonyarkles on March 22, 2015, 08:41:36 pmTotal and utter bullshit.14000 drill hits in 8 hours is 1750 hits per hour, or 29 hits per minute, or 2 seconds per hit. This is twice as slow as our extra-slow half-DIY machine. ANY PCB production NC drill of any quality and price is at least an order of magnitude faster. The really good ones sound like machine gun.A typical real (professional) panel of that size might have something like half the number of holes, and maybe those 14000 hits would increase the cost a bit, like 10-20% maybe, due to something like extra fifteen minutes of machine time. But as said before, any professional fab includes drilling in their pricing system, because the number of holes varies wildly between the customers, and believe it or not, it's completely normal to order a lot of holes for a number of reasons.This is simply the worst level of PCB service imaginable, but with the right marketing (mostly topical buzzwords, like "open source"), people will not only suck it up, but even love it and defend it on the internets, repeating all of their lies as-is.But hey, it's important to always have a story! Even if it's fake.I understand this may be hard to grasp if you don't know the process. -- But really, this is similar to ordering double cheese on your pizza, and the pizza place then going crazy that it will take 8 hours to do it and will cost you ten times more and tweeting about your crazy order.