Questions about hobby PCB fabrication
Ray0665
Posts: 231
I have never had a PCB made before and have some questions. I am currently using DiPTrace to layout and route the board and am at the point where I want to send it out for fabrication. The board I am building is through hole two sided. I used schematic to draw the circuit and PCB to autoroute the board. I did the board outline, parts placement, and mounting holes manually and just used all the defaults and have no errors or warnings.
1: Does fabrication include drilling the holes and plating them or just etching?
2: Does the gerber file include drilling and board cutout information etc.
or do I need to produce seperate ncdrill files?
3: I did not specify any drill sizes are the defaults for vias and components OK?
4. What company would you reccomend for say 5 boards?
1: Does fabrication include drilling the holes and plating them or just etching?
2: Does the gerber file include drilling and board cutout information etc.
or do I need to produce seperate ncdrill files?
3: I did not specify any drill sizes are the defaults for vias and components OK?
4. What company would you reccomend for say 5 boards?
Comments
You need to supply a drill file as well as the Gerbers. Some suppliers accept PCB files produced with the more popular packages.
You need to check your track sizes and clearances, drill sizes and annular ring sizes against the supplier's requirements.
PCB Pool provides an excellent service, and their boards are very high-quality:
http://www.pcb-pool.com/
They accept PCB files from most packages.
Have a look at oshpark.com. Only 5 dollars per square inch and you get three copies of your board for that! oshpark is very easy to use, just upload a zip of your gerbers and it immediately tells you how much it will cost and generates images of what the boards will come out like.
1) Yes fabrication gets you the holes, plated through, and the solder mask layers and the silk screen layers. And the "gold" plated exposed copper. Also any cut outs and slots etc.
2) You need a separate gerber file for each layer and a drill file for the holes. You should be able to get your PCB software to export all of those.
3) Drill sizes are normally specified in the hole size for the pads on footprints and vias.
4) For five boards, especially prototypes, I would suggest oshpark.com. I don't think those prices can be beat, the service is good, and by all accounts the quality is good to. I'm about to try oshpark out myself.
oshpark might be a problem for production items if you want any colour other than purple!
Finally here is a tip:
When you have completed the design and exported the gerbers and drill file you can check how they will come out with a 3d gerber file viewer http://mayhewlabs.com/3dpcb.
Spin them around in space, flip them over, look through all the holes. Magic?
Check your component pins and be sure your drill sizes will work with them. You want to keep the hole size close but leave several thou clearance. Nothing sucks so bad as paying $20 -$50 and then you can't get the @#$% component into the holes. There are 1.1 million items to check and double-check and you're still likely to make a goof. Just try to layout a process to stick with as you revise and recheck. Also make sure the vendor can handle your via size. You can set that in Diptrace and apply to all vias. As Leon mentioned. Be sure the ring created between the hole and the outside of the pad is in spec. That's easy to overlook as you adjust hole sizes.
USE DRC! (Design Rule Check). You select your vendor and then setup DRC to something above their minimums. Then you can run DRC and verify you have no violations like traces too close to pads or traces that are too thin, too close together, ect.
Diptrace will produce all the required files but pay careful attention to naming requirements. Different places want the files named different things and some may delay you or cancel the order if it's not to their liking. I've pretty much always just taken the defaults from the Diptrace export dialogs unless the production house specifies something different.
If your board gets big then OSHPark starts to get expensive in a hurry but is still worth it if you need it soon. If you have a larger board and can wait for 4-6 weeks then you can get it cheaper from Seeed Studio Fusion PCB service. They don't have the nice preview that OSH has but they do have a nice guide for submission. The quality is good but a notch below OSH I think, and you get 5 boards for the price. I've used them for a large board designed for a BeagleBoneBlack in my robot and the results were really nice. It just seems to take FORRREEEVVVVEEERRRR for them to arrive when you are waiting to do something. Difference in price for the main boards from OSH to Fusion was about $30.
OSH Examples:
Fusion PCB Examples:
What to you mean by "Tinning the pads would be nice"?
I thought oshpark boards came with ENIG plating on exposed copper. Isn't ENIG a superior alternative to the old tinning with solder technique? Certainly looks nice:)
I didn't realize how easy it is to get a price and upload your design there. Basically you can just visit the site, upload a .brd file or zip file of gerbers. It processes the thing and comes back with a ton of pictures of all the layers it thinks you have. You can check that looks OK and then hit the "buy" button. Brilliant!
So much easier than other PCB vendors with their complex pricing schemes and options and having to register first and bla, bla, bletch.
I have to throw a few dollars to the young guy that created oshpark, I forget his name, for coming up with such a simple idea for an interface and actually creating it.
Sure it does not cover all the requirements professional board builders may want but it seems to cover 90% of what hobbyists will ever need.
Top marks to the oshpark guy.
Here's a tip: they seem to do pricing based on square inches. Put in your quantity and the shipping days to get a price. Then bump the quantity until the price changes. For small boards, you'll often get far more boards for the same $ as your initial quantity.
If you're going to use an outside service (like Oshpark), you may want to ZIP your Gerbers and send them through an online DFM first (I use freedfm.com).
For my bigger orders I used GoldPhoenixPCB.com. My latest project with them was the IronMac shield for the DEFCON 22 badge. I've also used them for some custom QuickStart shields used in projects I worked on for Steve Wang.
Ray last logged in June of this year so he's still around.
Lot's of good info though.
Weird. I have no idea how I came to be replying to that old thread. Must of stumbled across it while searching the forums for something else. For sure I'm not in the habit of checking the dates on posts.
Still, 4 years is but the blink of an eye. Probably I could still use answers to questions I asked many years ago.
But whilst we are here. They do still have crazy prices at pcb-pool and the same old web interface. Despite people like oshpark showing how it should be done today.
Like you say, lot's of good info. No harm in dredging up an old thread to show how things have changed.