Making 2mil/50µm PCBs at home - Page 1
Forum section: electronics / general

author: Leonhard Bandilla
author_rank: Contributor
timestamp: February 29, 2020, 10:30:53 am
content: Hello,I thought I could post my project here as it might be an interesting alternative to the common china PCBs. I've build a machine that uses a laserhead out of an DVD player to expose PCBs. The laser is automaticly focused and has a focused spot size of 50µm. You could in theory make 2mil/50µm PCBs. I usually go bigger anyway, but it definitly could. Etching is a different story, you need to etch very precise and have only a thin copper layer. But it easily outperforms other methods like toner transfer or printing on a transparancy and even some chinese PCB manufacturers. I present this project at Jugend Forscht, a german talent/science (don't know what to call it) show/exposition. If you are interested I have results and a 11 page paper.

author: artag
author_rank: Super Contributor
timestamp: February 29, 2020, 01:52:46 pm
content: Yes, interested.

author: Rerouter
author_rank: Super Contributor
timestamp: February 29, 2020, 02:07:52 pm
content: seems to not be the first time its been attempted, in the past people have just used "lightscribe" to cheat it, as that way the laser is not focusing inside the disk, but on its surface,I suspect you could punch out PCB blanks with the correct shape if your design was small enough to just burn conventionally.e.g.https://www.jstage.jst.go.jp/article/photopolymer/28/1/28_99/_pdf

author: Leonhard Bandilla
author_rank: Contributor
timestamp: February 29, 2020, 03:22:09 pm
content: Thats kinda nice, but I can trace the traces, not just raster them and I have a rectangular working area of 210x170 mm. That way I can actually make usable PCBs, maybe also panels of smaller PCBs. With Jugend Forscht I have already gotten in a second round. The onyl disadvantage is that currently it still takes forever if you want to fill in larger areas. I had a PCB smaller than my palm take over night. But the quality is just so much better

author: Leonhard Bandilla
author_rank: Contributor
timestamp: February 29, 2020, 03:33:13 pm
content: This is my machine. It uses an XY system. I Can onyl show the result of a cyanotype run which was horribly overexposed and only had 0.25 traces with 0.2 spaces. I have exposed and developed a PCB, not etched, but you can only see the traces under the microscope. (cannot even show that one, over 5 MB)

author: Leonhard Bandilla
author_rank: Contributor
timestamp: February 29, 2020, 03:37:04 pm
content: Here is the cyanotype paper, had to upload in different post

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 01, 2020, 06:02:19 am
content: Quote from: Leonhard Bandilla on February 29, 2020, 03:33:13 pmnow you are posting!Quote from: Leonhard Bandilla on February 29, 2020, 10:30:53 amnice try! but be aware there are few steps before we can match with common china PCBs, and any other fab houses in the world actually for this matter...1) pcb etch/making... like many of us and you try to do diy...2) pcb drill3) via connecting (we can see some youtuber mess with chemicals, rivets also sold in ebay (from china too)... for some, we just do manual jumper wire soldering albeit not neat)4) solder masking5) pads plating (should not be that difficult)6) silk screening anyone? (although not functional beneficial, just for aesthetics and easy referencing)good luck!

author: jeremy
author_rank: Super Contributor
timestamp: March 01, 2020, 08:15:08 am
content: I assume that you mean a blu-Ray player and not a DVD (dvd is red)?See alsohttp://www.ippt.pan.pl/~bulletin/(56-1)17.pdfI would be interested in reading your paper (assuming it is in English). How do you do the autofocus?Also you may be interested in looking at a galvanometer, would speed things up a lot (although an f-theta lens rated for 405nm is probably pretty expensive).

author: Leonhard Bandilla
author_rank: Contributor
timestamp: March 01, 2020, 10:05:39 am
content: Yes a galvanometer would be faster, but I might not get the best focus out of it. 50µm is really course for this laser head and I'm improving it to get finer. It is HD-DVD, similar to Bluray. I can etch, but can't drill or plate fine via, let alone microvias or generally multilayer boards. But the quality of the machine is still stunning. Sorry, but my paper is written in german, if you want it anyways? I focus using the autofocus method used the the HD-DVD players. It uses the optical distortions at a cylindrical lens and a pattern of photodiodes to judge if the laser is in focus.

author: jeremy
author_rank: Super Contributor
timestamp: March 01, 2020, 11:05:10 am
content: Ah right. Yes, I think you should post your paper here anyway as it sounds interesting.LPKF gets their spot to something like 20-30um with their F-Theta lens in the protolaser, and you are still far from the diffraction limit at 405nm anyway. So it is definitely possible with a nice round beam shape.

author: Ranayna
author_rank: Super Contributor
timestamp: March 01, 2020, 11:10:05 am
content: I would be interested to read that, is it online somewhere already? I may be able to assist with translating at least parts of it, but i likely do not have the time to fully translate 11 pages.And, if you don't mind my asking, at what stage of Jugend Forscht are you? I do not closely follow them anymore, but i think at the moment the regional competitions are running?

author: Leonhard Bandilla
author_rank: Contributor
timestamp: March 01, 2020, 12:12:56 pm
content: I can send it to you right here in the forum, it's actually the paper I've made for Jugend Forscht. I have passed the regional stage with a 1st price and am now going to compete against people all over bavaria.