terjeio

PCB Laser Exposer/Printer

5 posts in this topic

Here are the files for my PCB Exposer/Printer, it is the complete package including mechanical design files.

 

post-45966-0-60966600-1463563791_thumb.jpg

The printer itself.

 

post-45966-0-19242500-1463563111_thumb.jpg

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

 

 

jazz, dubnet, zeke and 8 others like this

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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!!!

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@@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 likes this

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Improved homing cycle has led to (near) perfect registration of solder mask. :)

 

post-45966-0-36412900-1466428038_thumb.jpg

 

Layer registration mark, lines are ~0.1mm wide.

 

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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

 

agaelema, Fmilburn and Fred like this

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