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Scotty Allen
Scotty Allen

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Inside a Flexible PCB factory - in China

This is the first of the five factory tour videos we shot in China in June and July.  JLC took us to their flexible circuit board factory in Shaoguan, and then to their PCBA factory in Zhuhai, to see how flexible printed circuit boards (FPCs) are made from start to finish.  I'm SO excited to be going to China again, as well as to be back making these kinds of videos.

This is one of our earlier rough cuts, so it doesn't have things like color correction yet, and it's longer than the final version will be.

Comments

I loved this video!! This was so much more in-depth and technical than most factory tours, and I loved every second of it. Thank you so much for putting in the work to bring this experience to us!

Suchipi

Yes, the final version will have better subtitles! Because it’s so technical, I’ve had to end up doing the translation of that scene myself, with tons of help from Google translate and chatgpt

Scotty Allen

I was wrong on my guess about the black holes, I found an article/blog that explains what a black hole is a bit better. https://www.pcbelec.com/flexible-pcb-manufacturing-process.html "STEP 4: Shadow / Black Hole -Purpose: Deposit a layer of carbon powder on the glue of the hole wall of the electrochemical hole, which will play a conductive role during electroplating. -The black hole line uses the principle of carbon powder to be conductive,and positive and negative to attract, and the carbon layer is evenly attached to all the hole walls." It seems that they have to do the cleaning due to not only the oils but also from the drilling. They need the holes to be very clean so that they can carbon/graphite toner will stick to the inside surface of the drill holes. One thing that I had not considered is that they are trying to the holes are not just thru copper. They are a sandwich of copper, adhesive, polyamide,adhesive,copper. So getting a cabon/grahpite toner mix to evenly coat the inside surface of the hole is complicated and then stay there until they can electroplate it is why that machine was so long. To add another layer complexity whatever that toner mix is has to be something that will stay in the holes when washed off the surface of the copper layer, be sticky enough to bond to sides sides of the adhesive and polyamide layers inside the hole and then still be conductive enough to allow electroplating from a copper on top of the carbon to bridge the gap between the two copper layers of the flex pcb.

Kyle Ronan

Over all a cool video. The only thing that I thing I think that needs work is mainly the translation/Subtitles for the parts where "installing the holes" on the black hole line. At first I was confused and was thinking the space singularity type black hole. It was only after it was section of the video was over that I realized what t Mr. Chen was talking about. I think the simpler explanation is that they doing a lot of cleaning, then are filling the vias and dilled holes with black toner, by coating the entire board with toner and then carefully washing/etching/scrubbing away the toner off the surface. And this is where the translation might be a bit confusing as they are filling the holes in the boards with black toner to fill and temporarily plug the holes. I think the purposed of this is so that it prevents issues when later doing the electroplating step, the holes are not accidentally plated over. I am guessing this is a very delicate balance as if the holes are to well coated/filled with toner that then the plating will never go through forms one side of the copper to the other. But if the toner plug/coating in hole is to thin it will wash out and electroplating might close over the holes entirely, especially if they are very small. Again I might be completely missing the concept and it could be just where they put in the magic electrical smoke that everything runs on. ;) TLdr; the black hole assembly line section of vid is confusing and might need help before youtube.

Kyle Ronan


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