Ordering PCBs for rhococo
|Project How to order PCBs from China|
|For RhoCoCo I needed two PCBs, a 10 x 10cm dual sided "motherboard" PCB, and a 18.5 cm x 10 cm single sided keyboard PCB. These are my experiences with the ordering process.|
I was given an offer that I could get free PCBs if I would write a "HOWTO" about ordering PCBs from the Chinese PCB manufacturer PCBWay. So here are my experiences.
Firstly, you have to realize that the Chinese live in a timezone eight hours later than a Dutch person, so its not a good idea to order PCBs at 19:00 hour, especially not on a Sunday, as stupidly I did, I had to wait until far after midnight before my designs were checked (my fault, it normally takes just a few minutes). The ordering process, although largely automated, still means the PCB must be checked manually, and that takes longer when its four o-clock on Monday morning :-). So first tip, do your ordering in the morning.
Secondly, you need to know the details of your PCB, at a minimum you need the X/Y size of your PCBs, in my case 100mm x 100mm, and 185mm x 100mm. Sure these information is also contained in the gerber files, but almost all PCB manufacturers also want you to state the sizes, if only for determining the price.
PCBWay always produces PCBs in multiples of 5, so the minimum order is 5 pcs, and more in increments of 5 pcs, so 5 - 10 - 15 -20 etc.
I assume this is because they stack 5 PCB Panels, so they always create 5 of each they make.
all modern PCB manufacturers pool all orders until they have enough orders so that they can fill a whole panel, where they will make a "jigsaw" puzzle of all the designs, trying to cram as much designs on the panel as possible. If your designs are large or have unusual shapes, this process becomes more complex. Small square PCBs are easiest to combine to fill a panel, so PCBs smaller than 100mm x 100mm are cheaper, as its easier to find unused space in the panel where they can fit it in. The larger, and less square your PCB is, the more difficult it will be to fit it with all other designs on a panel, and so the cheaper it will be.
The stack of five panels will be drilled as if its one PCB, so all 5 designs in the stack will be the same type, for example they will all be dual sided (or single sided, if the panels are single sided) probably with the same color of lacquer, and the same color of silk screen (printing). the same thickness PCB, the same material, and probably the same precision grade.
This explains why ordering standard PCBs (with standard lacquer and silk screen colors, same PCB material (FR-4) and thickness (1.6mm) ) will always be cheaper, as its easier for the manufacturer to pool designs with these parameters.
Ordering the main PCB
This is the page where you can choose from all the available options, in this case Iḿ ordering the 100mm x 100mm dual sided main green PCB, with white silkscreen, and standard thickness (1.6mm) and default PCB material. Where possible always choose the default options.
Ordering the keyboard PCB
This is the screenshot of the options for the single sided keyboard PCB, measuring 185 x 100mm. Note that I opted to give the PCB manufacturer the choice over the type of surface finish, this makes pooling these PCBs easier, as the manufacturer can choose in which panel-stack with a specific finish he can pool these PCBs.