PCB exposure device with Chinese resin printer tech?

#1

I’ve done some research on how those cheap Chinese resin printers work and it seems like they all use similar off the shelf parts and common design: at the bottom of the resin tank there’s a high resolution LCD screen illuminated from behind by a fairly powerful UV LED array. In the printer application this cures the resin at the point of contact with the screen, causing a layer to form, and a motor then pulls the print away one layer.

But exposing PCBs is another application that might benefit from this process. At least in theory it does away with the separate step of printing transparencies of your Gerber files, and aids the process of exposing the photoresist. I’d say it’s a good enough reason to try.

There are drawbacks - as always - to this approach. The screens used in these printers are rather small, comparable to those of smartphones. This still should be enough for smaller PCBs though.

Does anyone know of something similar? Or have any information that I could use to decide whether to make this thing?

#2

have you seen this

#3

No, but I’ve seen a similar project using a filament 3D printer mod. It’s still putting lasers on what’s ultimately fiberglass though, and I think with the LCD exposure mask I can do the same if not better.

#4

I’ve got an Anycubic Photon at home, and this thought had occurred to me too (although I’d be more interested in photo-etching metal parts for model making rather than PCBs).

There are is a really strong community of “Photonsters” hacking and modding that machine, both in terms of hardware and software. I’m not sure I’ve seen anyone adapt it for this purpose, but there are a whole team of users completely tearing down and rebuilding their machines (with upgraded slide rails etc) and also working on open source firmware etc. The “Anycubic Photon Users Group” on Facebook seems to be the best place to find them. Would be the place to start for advice on what mods work and what might be a “gotcha”.

I would have thought you could achieve what you’re aiming to do purely by customising the gcode/ slicer files that the machine accepts, to create longer exposures without moving the Z axis. You might have to think about cooling and/or lifetime of the UV LED array, which is only designed for intermittent use?

You can get almost all of the parts for the Photon as spares, which might be a better solution for you, considering you wouldn’t need the Z axis or resin vat, etc. https://www.fepshop.com/product/anycubic-photon/ is a great place to start - based in the Netherlands - but the same parts are also available cheaper on eBay or ALiExpress from Chinese sellers.

#5

You can request to have the backlight removed from screens when ordering one, from China, as people make DIY projectors as well as 3d printers with them. Usually high resolution phone screens. Myself and Howard are always chatting about such things (pcb manufacture) ,that said it’s so cheap to order high quality pcbs now that there isn’t a lot of incentive to make our own.

#7

Found a video showing how you could also use the 3d resin itself to form etch resist. Standard exposure time for a DLP layer by the looks of it, then UV-cure. Comments also raised a point that this could be a good way of producing a soldermask. The downside is that it’s a little annoying to clean off the etch resist after etching…

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