So, printed circuit boards - or PCBs to most of the electronics COMMUNITY. My friend and one-time business partner has been designing them for around 35 years so he has been through just about every way of laying out a circuit that there is. This means that he started out with a pencil and a large piece of paper, surrounded by integrated circuit manufacturers data books and an idea. Once the circuit had been designed and a prototype built and debugged, then a couple of sheets of transparent film were taped together and rolls of red and blue tape used to lay down the pcb tracks.
These films were then separated, photographed and sent off to a manufacturer to produce a copper-only prototype, i.e. no solder resist or component legend, typically costing around 300 British pounds after a wait of about 3 weeks.
Then along came the German company Cadsoft and their revolutionary and cheap product known as Eagle PCB. Aidan and I bought version one for about £500 and what a winner it turned out to be. Of course, it was full of bugs and had many essential facilities missing, but we beta tested it and wrote reports for one of the Cadsoft developers, Rudi, until it ended up in pretty much the form we have today 25+ years later. Bearing in mind that this wasn’t originally a Windows product, but ran under CP/M initially and was pre mass email meaning that we had to send our bug lists by fax, download updates on a 9600 baud modem direct from their computer in Germany and you can imagine that it wasn’t the fastest process.
However, here we are today and you can download a free version of Eagle which is limited to 50mm x 50mm pcbs or pay a bit for the version that will do 100mm x 100mm – this is more than adequate for the majority of small or hobbyists requirements.
What about getting those prototypes made though? Well, you can go down the messy route with chemical etching and the rest if you have masochistic tendencies, however there are several Chinese companies offering great services for limited quantity production runs of typically 10 boards. I have tried a number of them over the last 7 years and they all seem to have cracked reasonable quality production, but their service and delivery times vary.
One of the first was Sitopway who were great and for around forty pounds, you got 5 full production standard boards delivered in 3 weeks. This was a huge advance in terms of both costs and quality.
Times have moved on though and I have used dangerousprotopes.com, Itead, dirtypcbs.com, seedstudios.com and several others. However, we regularly try out the services of different companies and came across an outfit called jlcpcb.com early last year and decided to give them a try.
In the past, Aidan normally just paid for China post shipping as it is the cheapest method and Jlcpcb.com do offer this at a slightly higher cost than others, but they also offer DHL as an alternative. The first order was a nightmare! he uploaded the files to the order section of their website and paid his pennies. There was no order acknowledgment or indication that the order had been accepted and did start to wonder if he’d been ripped off. Over the following 3 weeks, he sent increasingly snotty emails to their customer support without reply and I was just about to apply to PayPal for a refund when the pcbs arrived. As it turns out, they were excellent.
So, he sent them a critique of their website and detailed what he expected to see. These were, email acknowledgment of order, a Gerber view of the uploaded files so that he could be happy that what they think he wants to be manufactured is the same as what he actually wants, plus a tracking facility so that he can see at what stage of manufacture or shipping his boards are at.
Well, that did the trick and we had a very helpful and useful exchange of emails until the system was bang on perfect. The rest is – recent – history! JLC PCB have one of the best services going.
Aidan now opts for the DHL shipping system as, like me, he’s just plain impatient. In the last year, he has designed about 15 new boards and had made several iterations of each totalling 39 PCB designs as we no longer bother hand building prototypes – it’s so cheap to make a PCB, so why bother? He generally bundles up several designs to save on the shipping cost. They charge $2 for the first design and $5 for subsequent ones.
So, generally Aidan saves up his orders until he has 3 designs to make. So, to make 3 sets of 10 pcbs and have them shipped to the UK costs about $38 or £27 in UK money.
Best delivery time from uploading the Gerber files to receiving the finished product was 4 days and typically it’s 5, worst case it’s 6 days. This is just a stunning service and has transformed the way in which Aidan designs boards.
The GERBER Files
If you want a seamless and quick service then you have to send your designs in the correct format. JLC will accept an Eagle file, but we’ve discovered that there are some minor inconsistences in format, mainly to do with text size. For text on your board, select “vector font” with something like a 14% proportion setting. When you’ve uploaded your design, use their Gerber viewer service to check that your text is the correct size as it can be irritating if your neatly designed labels are smeared right across some components.
Aidan has uploaded his Gerber generation script HERE to help you out. https://www.dropbox.com/s/3cgbgunqltjxr7e/Aidans%20Complete%20PCB.cam?dl=0 This is based upon his own combined with one from Itead. In your Eagle program directory, create a sub folder called GERBER before you start. Then simply click the blue process button and then click “process all”. The script will generate 13 files which represent the top and bottom copper layers, the solder masks to stop you shorting stuff out as you solder, the solder legend for labels, component numbers and values, the drilling information and finally the routing info for the profile of your board.
Please note that most of these companies don’t let you do internal cut-outs on your designs, but they can drill some pretty big holes. Aidan also has a version of the script that generates multiple copies on a panel, but you don’t really need that for prototypes, just for production.
So, in your Gerber folder, you should now see 13 files named as per your PCB design file, but with differing file suffixes such as .sts, .drl etc.
This next bit is important!
Proper Labelling is Vital
On your PCB layout, somewhere on each of the 4 main layers – top and bottom copper plus top and bottom legend (tplace and bplace), put a pcb reference, such as “PCB REF-My PCB V1.0”. This will ensure that both they and you know which board you are referring to if there are any problems or just if you want to order some more.
Go into the GERBER folder and block-select the 13 files, then right click them and left click “Rename”. Rename them as “PCB REF-My PCB V1.0”, or whatever. Then block-select the newly renamed 13 files and then right click and select “Send to Compressed Folder”. The new, zipped, file will have the default name of your PCB REF.
You can now upload this zipped file to jlcpcb.com, pay your cash and off you go!