Jeremy Rubin's Blog

Flex PCB Factory Tour at King Kredie

Shenzhen Adventure Day 12

While we were doing the Engineering Query at King Kredie, we also got a special bonus tour: Flex PCB Manufacturing.

Flex PCB is kind of the future – as devices get smaller, a thick-old-green PCB is no longer practical unless it is also a structural element. Flex PCB’s, traditionally used more often as a custom connector, can be populated with components as well so are a really cool technique to experiment with.

The process is pretty different from traditional PCB etching.

You start with a big roll of copper foil.

Punch out a pattern using a big press.

The die looks like this:

Then you laminate it. The laminate sheet has also been punch cut appropriately.

An iron is used to bond the plastic laminate to the copper/backing laminate.

Then you (optionally) silkscreen print on

Alignment is not critical here.

Finished product:

This flexpcb has a stiff copper trace inside of it as well for rigidity on that axis

Later on, these will need to be cut out/depanelized.

Tea Ceremony

Shenzhen Adventure Day 11

The printing press guys were really the best – so good, they get three posts for one day!

Following our visit, they taught us how to do – and appreciate – the traditional tea ceremony.

To make the tea ceremony, first you use hot water in a little basin to wash out all of the tea cups. Then, you fill the teapot with tealeaves, and use the basin (with fresh water) to pour hot water over the leaves. You stir by gently shaking the tea for 30 seconds, and then pour out the water. The first wash is thrown out traditionally to make sure the leaves are clean. Then, you repeat and let steep for a few minutes. You drink all the tea, and then repeat over multiple washes of the tea.

The tea they were using was incredibly good; probably the best I’ve ever had. When we asked where it came from, they told us their friend grew it!

A parting gift

The week we were set to leave Shenzhen, the guys from the printing press sent us a big box of the tea we made the ceremony with. I’ve shared my stash of the tea with friends and family, sharing my stories from Shenzhen, especially the generosity of everyone who made us so welcome there!

Seaside Lunch and Opium War Museum

Shenzhen Adventure Day 11

With the guys from the printing press we got lunch in the middle of our tour.

We went to this lovely restuarant by the sea that had really fantastic seafood.

The sea is that color from sediment

After lunch, we went to Shenzhen’s Opium war musuem and saw some of the exhibits. It was really interesting to see the Chinese perspective on this era, and the museum itself was interesting architecturally.

The MIT Crew entering the museum

Printing Press Tour

Shenzhen Adventure Day 11

Today we got to see a printing press. Printing presses are pretty cool; they’re a pretty old technology which one might argue was the driving force behind the renaissance.

Printing

Printing presses are fast. If you’re looking to get something made at one of these factories, you need to order at least something like 10,000 copies because it prints that many in about the time they can turn the machine on and off.

Gold Leafing

One of the coolest processes we got to see at the factory was how they gold-leaf page edges.

Basically, they sand down the edges of a block of paper to be super smooth.

And then they press a piece of foil onto it.

The result is very shiny!

Paper Cutter

Imagine cutting a piece of paper. Now two pieces. Four? 16? 32? At a certain point, the paper becomes too thick to easily cut.

Now imagine you aren’t just trying to cut it, but you’re try to make a perfect edge, uniformly.

At a printing press, they cut thousands of sheets simultaneously. That requires a really sharp knife, a lot of pressure, and a highly attentive worker.

At the factory, pages are typically cut twice. The first time is to cut to the general size of the job and the second time is done as a trim on the finished product to remove the edges.

Binding

These big rotary machines are used to bind pages

Special Requests

Printing presses – or at least this very awesome one – can accommodate a lot of special requests.

Here are a few examples of special processes

Adding a bookmark

Plastic window

Bootcamp Project Update

Shenzhen Adventure Day 9

Today we wrapped up our electrical changes to the orchard board. At the end of the day, we submitted our boards for Engineering Queries and price quotes.

I also added some sweet graphics to my board, this is what is will look like:

One thing people often ask is how bad the pollution is… Actually Shenzhen is basically a physically greener city than any other I’ve been to and the air is very clear. Of course, some days are better than others, today was particularly clear. What does suck is that everyone is smoking everywhere; that is probably worse for the air quality than other factors.

Bonus office selfie from Hax:

After work, we went out to dinner at Coco Park, the notorious clubbing part of Shenzhen. We didn’t go clubbing, but we went to a pretty western-menued bar & grill for beers and dinner.