Well, the first of two orders of PCBs came back just before I went away on vacation. The first lot I had discussed in my previous blog entry, and was a remake of my stepper gauge project that I sell on Tindie. As my previous experience with OSHPARK, the service is superb. About a 18 day turnaround including crossing the border, free shipping to Canada (not many include that), plus a nice “PERFECT PURPLE PCBS” sticker, which I’ve adorned to my electronics toolbox. If you need a quick(ish) PCB service for a prototype, OSHPARK is pretty close to perfect.
Apparently I did my homework well, because the X27.168 stepper package outline (I found one on the net, but tweaked it further) fits like a glove, unlike my previous revision where I had relied on someone else’s package file and every board required some drilling to fix layout holes. It all looks very nice, and I love the purple, but sadly I didn’t get a chance to assemble one before I left on 3 weeks holiday, all I managed to do is file off the mouse-bites that they used to panelize it.
Once I had become familiar with KiCad, there was no stopping me, so I had also slapped together a little hybrid surface-mount/through-hole project that I’ll use for an electronics class I’ll be teaching in the near future, and ordered them from a company I had read about on EEVBLOG called DIRTYPCBS. When I return, I’m hoping my other PCBs will be sitting waiting for me. I read about this service on EEVBLOG, and it has a few advantages over OSHPARK. Firstly the price; as they’re in Asia (Hong Kong), the price is amazing (US$24 incl shipping for 10 boards 10cm x 5cm). Secondly you have a lot more options such as PCB thickness, soldermask colour, etc etc. I’m quite excited that DIRTYPCBs might become my go-to circuit board provider for anything more than a couple of small samples. Also this board will be my first real foray into SMD (just some 0805s, SOT23 and small LEDs). I’ve avoided SMD as I lack the tools (and eyesight), but wow are the parts ever cheap, one dollar will buy you 300 resistors, or 100 capacitors, or 100 FETs; just incredible. I’ll still try assembling with the old weller iron, but I’m curious to try paste and and a hot air gun.
Also, I did some reading (and viewing on YouTube) of people doing hybrid hot/cold transfer for laser printer transfers. I have made single sided PCBs using the laser printer transfer method and an iron, but it took a fair bit of experimenting to discover that with my brother laser printer that only glossy magazine paper really worked for laser printer transfers. Two things have changed; one I discovered people are using a mixture of acetone/isopropyl alcohol on the PCB surface prior to transfer to slightly disolve the toner, and secondly Misses Boffin has purchased a heat press (for doing vinyl transfer), so I have a better heat press with likely more even heating/pressure.
Hmm, I wonder if I can just cut a PCB mask using a silhouette vinyl cutter. Must look into that, that might work too.