Dangerous Prototypes

A few months ago we started a private PCB website so our team can get cheap PCBs from a fab in China. Someone spilled the beans, and it hit Hack a Day, Hacker News, etc. We almost shut it down, but it was too much fun to hack and refine the process. Dirty Tuesday is a weekly post about our misadventures accidentally starting a PCB service. As a design shop with Seeed Studio doing fulfillment, we’ve never been on this side of the fence and want to share the terrifying experience.

DirtyPCBs. A site named to manage expectations. We’re not a PCB company, we’re a couple hackers with access to a cheap board house in China helping out other geeks. The cheapest board house, really. It’s no secret, rank Taobao results by price and you have our supplier list. Despite our flippant attitude and dirty board house, we do our best to offer extremely good service. Here’s some highlight of our comedic attempts to overlay first class service on top of China’s cheapest PCB manufacturer.

Sorting orders

Briefly mentioned last week, our original goal was to make cheap prototype PCBs without adding annoying little numbers to the silkscreen. Our solution: stickers! The board house must already have a way of tracking boards through production, so we’d have them put an order number sticker on each pack.

The factory agreed to do this, no problem. We printed shiny metallic stickers on a trusty Postek C168 (far superior to the G3106) acetate transfer label printer and sent them to the factory via SF (UPS of China). The first batch of boards with labels arrived a few days later and we mailed them out.

A week after we start getting emails with variations of “not my PCBs”. Apparently the factory applied the labels randomly to any board of similar size and color. At the time we didn’t have an image of each board to reference before shipping, and we placed all our trust in color and size. We ended up replacing a few dozen boards at our own expense.

Solution: we gave up and added the PCB ID to the silkscreen of each board.

Colors and Quantity

Dirty board house doesn’t charge for colors, and neither do we. However, sometimes the board house sends boards in the wrong color. From their perspective it’s a cheap PCB for the Chinese market, it works (100% e-test), it didn’t cost more, better luck next time.

The board house is supposed to send 10 of each board, as advertised on their Taobao page. Most of the time they send 12 or more PCBs. We’ve even seen 50 of a medium board, and 200 of a tiny board panelized for free into a 10x10cm order. About 1-2% of the time, they send only 8 or 9 PCBs. Once or twice we’ve even seen just 7. As with colors the board house doesn’t care or want to replace them. Our sales rep argued extensively that most people only want one or two anyways, and they gave us extra PCBs in other orders. We mostly agree, but that doesn’t fly with buyers outside China.

Dirty customers are awesome. We email explaining the situation, and most people have no problem with fewer PCBs. Getting the wrong color is more disappointing but not the end of the world. As the volume of boards going through DirtyPCBs increased this because a huge time sink. Counting each order, writing emails, and tracking replies was so frustrating that we shut the site on several occasions.

Solution: the “protopack”. Instead of selling quantity 10, we market the service as a prototype PCB package with + or – 10 boards. Usually you get more, sometimes you get a few less. If you really need ten, you can choose quantity 10 for 25% more money to pay for the increased hassle. To date nobody has paid extra to guarantee 10, and there have been no more emails about too few boards.

Rush orders

Most board houses in China offer 48 hour and 24 hour board processing options. Usually this works pretty well, but it isn’t guaranteed. It just means your boards won’t be held in queue until they can be done with a huge batch of other boards. This is great if you’re doing prototypes in China as a board really can be delivered the next day if you time it right.

Depending on the board house load, rush service can cut a week or more off normal processing time. It really can speed development at a cost way less than having a rush order made and shipped from a US-based board house. However, we’re not actually the manufacturer – boards still have to ship to us, we have to pack them, and then hand them off to logistics. This led to some angry emails early on when buyers thought their boards would ship in 24 hours or less.

Solution: we label the 48 hour service “rush (2-3 days)”, and the 24 hour service “emergency (1-2 days)”. The extra day is absolutely needed for the boards to be delivered to us (same or next day).

4 layer board house

4 layer boards are not so dirty and come from a different cheap board house found on Taobao. While the 2 layer house loves working with us, the 4 layer board house is completely indifferent.

Each order has to be uploaded to the 4 layer board house website. The zip file cannot have the same name as anyone’s previous order. Once you tackle that lovely bit of poorly thought out code, you fill in all the specs and wait.

Within a day an engineer verifies the board and then calls to confirm it. Each and every one. If there’s an error, upload new gerbers (can’t be named the same!) and start over. When all is good, login again and pay via Alipay.

This process drives everyone nuts. We’re fully integrated with the 2 layer board house. We send an email with attachments and a spreadsheet in their internal factory format. From there boards pop out on the other end with minimal handling. We asked the 4 layer board house about better integration. The sales guy said “it only takes 10 minutes a board”, and “our big clients just hire someone to enter boards all day”. Lovely.

While the 2 layer board house allows panelizing, the 4 layer board house doesn’t. In fact, they charge more to process a panelized board than it costs to do the panelized designs separately in individual orders.

The 4 layer board house has rush (72 hour) and emergency processing (48 hours) for 4 layer boards. However, you can’t combine that with a color or ENIG coating.  Gottcha!

Solution: future tour to get around sales reps and talk to an actual manager about production line integration. Apply cognac or tea liberally and see what happens. We’ll post pics, promise!

Missing boards

Sometimes boards just don’t show up. Our dirty backend system shows the age of each order and we nag about it as needed. Many times the board house simply forgot about them, sometime their system says they’ve shipped already.

Our system is simple and redundant. For each batch of boards we print a packing list and keep them in dated files. When boards arrive we scan a barcode on the packing list to load images of the order. We we compare the boards for design, color and coating, then scan the barcode again to mark it shipped. At this point the shipping label is printed and placed on the box. If the database says a board has not been shipped, and the packing label is still on file, its highly likely we didn’t receive it.

Solution: if DirtyPCBs gets another update before we pull it offline, it will auto-nag the board house about all orders past 7 days. The auto-nag will include the missing boards as attachments so they can skip asking for the files again if they were lost.

Queued shipping

Very recently we noticed that boards started coming only once or twice a week. Usually Tuesday and Friday. Three or four giant boxes would show up, so heavy that I felt genuinely bad that Xiao Tang had to drag them up seven flights of stairs (and then back down for shipping).

The Tang had to process half a week of boards in a few hours and then lug them up to espeed logistics in giant bags. The rest of the time he was bored. There’s nothing worse than a bored Tang.

A quick call to the board house confirmed that they were holding our orders for a few days so that we could save $1-$2USD per batch on shipping. They seemed rather proud to have given us this excellent money saving opportunity, but we explained that people want their boards fast and we’d rather pay more.

Boards started arriving more frequently again but not every day. Including rush orders, we should get 2-3 parcels every day. After some digging we found out the cheap delivery company was batching up our deliveries so they didn’t have to come every day.

Solution: all orders, stencils, etc are now shipped by SF. In China SF is like UPS or Fedex, but much cheaper and faster. It costs twice as much to have boards delivered now, but the service is much more reliable.

Conclusions

Running DirtyPCBs has been a first hand look at dealing with suppliers, customers, and logistics. Each bump in the road was a traumatic yet fun chance to hack a system. It’s been a great experience to get a taste of this side of the industry, but it also reenforces our desire to have Seeed Studio and our fantastic distributors handle all this stuff for our projects.

The cover image is PCB etching and drilling equipment. In a pile. In a parking lot. In the rain. Just chilling. Photos from our factory tour soon.