This is a multipart series on how to design an efficient and modern high voltage nixie power supply, from the idea to shipping it to customers worldwide.
- Part 1: Idea
- Part 2: Design & Simulation
- Part 3: Making a prototype
- Part 4: More prototypes!
- Part 5: Sending for Assembly
- Part 6: Efficiency
- Part 7: Production Run
- Part 8: Selling & Conclusion
The Coilcraft Rant
Production run is all about making your product the most cost effective. In the world of electronics, volume is king. As I am an independent designer with limited resources, I unfortunately cannot order 1000 pieces upfront. Nixie enthusiasts is a niche market anyway so a 1000 units would take years to sell. I decided to go with 200 pieces.
200 stems from the fact that the most expensive component on the power supply -the power transformer- comes in full reel of 200. Ordering a complete reel of components is typically the most cost effective.
On a turnkey basis, PCBWay quoted US$2270 for 200 boards. That is $11 per board and it doesn’t even include the cost of assembly and PCBs! Needless to say, this was way more than I first anticipated.
The biggest offender, again, is the Coilcraft transformer, at a quoted US$4.40 a piece, despite the volume. For reference, Mouser quotes US$2.84 a piece for a full reel.
I did the sensible thing and decided to source most of the components myself, but first of all I called the Chinese Coilcraft representative to explain my situation; who sent me over to a local counterpart in Singapore. This is how this conversation went:
And so I ordered the complete reel (and an additional 2 pieces to allow for mishaps at the assembly line) from Coilcraft.com.
To that they added $26.77 worth of export US tariffs and $48(!) of shipping for a grand total of US$610.06. Once the parcel reached China, I was slapped with 25% import tariff thanks to the Sino-American economic war; which added US$147 ($140 + $7 paypal fees paid to PCBWay). Total of the operation: US$757.06 or US$3.79 a piece. Still cheaper than Turnkey service but certainly a lot more than what I thought.
Moral of the story: don’t work with Coilcraft if your assembly line is in China. Addendum: I used to love all their quality components; I will now go out of my way to avoid them. Rant over.
Getting products home
Since I had already ordered 10 boards with the exact same Gerber file, this time production went extremely smoothly. In line with what happened the first time, the PCBWay representative will order the production of a single board (or panel in that case), ask me to confirm everything looks good, and from that point it’ll only take a day to do the rest of the production run.
To give you a sense of timeline, from the moment they acknowledged receiving all the components to Fedex picking up the shipment, only 5 working days had passed. The lost time is mostly in the logistic of sourcing the components.
Fedex being Fedex, they claimed “Office closed or customer not available” on the day of the scheduled delivery, at 5:40pm, when there is a receptionist and I was there waiting. No one ever turned up on the day of the delivery. And the update was “Collect at the Fedex location”. You pay so much for courrier delivery and that’s how they treat you. After discussing with an agent and threatening that I could pull the CCTV clearly showing no one ever came; they rescheduled the delivery on the next day.
After all of this, I am now the proud owner of 200 nixie power supplies.