terjeio 134 Posted May 18, 2016 Share Posted May 18, 2016 Here are the files for my PCB Exposer/Printer, it is the complete package including mechanical design files. The printer itself. Example - a power control PCB for Raspberry Pi - 40 x 40 mm. Code includes driver for MCP4725 DAC, buffered serial port driver, stepper motor control and command parsing for the MSP430G2553 used as the main controller. Code and design files: PCB Exposer - controller code for MSP430G2553.zip PCB Exposer - desktop application.zip PCB Exposer - mechanical design files in Vectric format.zip PCB Exposer - schematics and PCBs.zip Desktop application is coded in C#, schematics and PCBs in KiCad format. There is some more information to be found in this tread: http://forum.43oh.com/topic/4990-what-are-you-doing-right-now/page-5 Terje dubnet, Rickta59, timotet and 8 others 11 Quote Link to post Share on other sites
colotron 5 Posted May 18, 2016 Share Posted May 18, 2016 Downloading... this could be the more precise way of doing PCBs in home. So how precise is the machine?, are you able to work with 0.5mm pitch packages? (8 thou/0.2mm tracks, 0.3mm pad's width) . Those pesky QFN accelerometers are a pain to do manually, and fine pitch microcontrollers too. I saw other people doing it with toner transfer, but my skills are not that good. Another advantage over toner transfer it's that it should be easier to etch and solder after, because less oxide is formed if no heat is used. Have you noted a better etching/soldering?. Congrats!!! Quote Link to post Share on other sites
terjeio 134 Posted May 18, 2016 Author Share Posted May 18, 2016 @@colotron The machine has an inherent resolution of 1200 dpi (~0.02mm) so I am able to work with 0.2mm tracks - however I use 0.25mm as default for most designs. The PCB outline (fom Edge.Cuts i KiCad) in the example board above is ~0.1mm. For consistent results I think presensitized boards will be the best choice. I am using Riston which is not always easy to attach perfectly - sometimes I have to touch up some tracks due to dust under the film causing breaks. So I think the practical limit is not what the machine is capable of but rather the properties of the emulsion used. Etching is definitely a lot better than what I could achieve with toner transfer, and soldering is easier but could be due to the fact that I now add a solder mask which I also expose in the printer. The solder mask is cured at 140 deg. C for about 1 hour. I have found that it is important to vigorously rinse the mask in running water after development to reduce/avoid oxidation during curing. I have also tried tinning solution, when fresh it gives a nice shiny finish that is easy to solder, but it does not store well... All in all I find it a lot easier to make my own boards now - no more frustration from toner transfer failures and it is great to be able to add a solder mask. You will find more photos and details in the referred tread. Terje colotron 1 Quote Link to post Share on other sites
timotet 44 Posted May 20, 2016 Share Posted May 20, 2016 Great work thanks for sharing!!! Quote Link to post Share on other sites
terjeio 134 Posted June 20, 2016 Author Share Posted June 20, 2016 Improved homing cycle has led to (near) perfect registration of solder mask. Layer registration mark, lines are ~0.1mm wide. Part of TSSOP 20 footprint, mask is way past "use before" date so some problems with spots appearing. I have started to apply the Riston film on wet PCBs, dust problem nearly gone - easier to handle. Terje Fred, zeke, agaelema and 1 other 4 Quote Link to post Share on other sites
terjeio 134 Posted November 25, 2018 Author Share Posted November 25, 2018 A new design is now up on my Github account, cheaper laser cut acrylic case and 3D printed "laser head". Some info on Hackaday as well. zeke and timotet 2 Quote Link to post Share on other sites
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