This topic contains 26 replies, has 12 voices, and was last updated by 
click 4 months, 3 weeks ago.
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Normally when I make my pcb, I use really expensive toner transfer paper (press n peel) to mask over my copper board. The results are much better than the cheap magazine method, but far from flawless.
Moreover, if it is a double sided design , I have to first etch one side and then drill alignment holes before positioning/ironing the second layer mask.
I can’t help thinking that the Robox might provide a simpler option right out of the box.
So my questions are:
1. Is it possible to have the print head recognize the added height of a copper board on the pei bed?
2. Is it possible to specify an alignment regime so that Via’s in a two layer board can line up? If I drill a hole, can the print begin in reference to that?
3. Will a really thin layer of abs on freshly scrubbed copper adhere well? Will it be airtight as in resist etching liquid( or would I need to include an acetone chamber to processing)
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This topic was modified 1 year, 11 months ago by
Mark Dee.
A milling head is the answer and it is almost definitely on CEL’s roadmap for additional Robox heads.
Or a etch resist pen mounted in the plotter head… e.g. http://www.rapidonline.com/Tools-Equipment/Permanent-Etch-Resist-Pen-34-0300/ - much simpler…
Or attacking it another way, a tiny little UV laser?
Tom Gidden -- Bristol, UK
Your best bet for doing both sides will probably be to construct a positioning holder for the PCB so that it will index two sides. Another option is to create a holder the same thickness as the PCB that will go all around your board and hold the PCB. Then with the holder and PCB in place, print your design on the PCB. The holder will allow the Robox to autosense the position of the bed before the print.
I am not sure that ABS is the best material, you may need to try nylon or something that will stick to a cold bed. The issue is that when the ABS cools it will shrink and pull itself off the surface.
If you get a chance to try this, please update as I am looking for a good solution also.
I operate two Betas and one Production Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/benThanks for the many excellent responses.
@dr-woo, I think your idea might be the best because this eliminates the use of harmful chemicals, allows for vias to be drilled, and prevents the overhangs that occur because the etching liquid has begun attacking the exposed copper under the resist layer. My only issue would be related to the large amount of dust that will be generated.
@chrisyt, I use the etch resist pens to touch up areas when the press n peel fails. The results are always the same: grainy edges and tracks with holes in them. I’ve tried the lumocolor series, sharpies and their industrial strength equivalents too. The laser toner transfer method is by far the BEST! If only the head could incorporate a hack for a toner cartridge.
@gid, I like the tiny UV laser idea. Obviously, that means using the photo sensitive PCB masks, which are tres tres expensive. Following on from this, someone mentioned that the L-Cheapo laser module(2W) might be a good addition, and this might do the trick.
@bhudson, your method sounds doable, albeit complex and non scalable. CEL might be able to give us an idea if a positioning holder hack can give the head some feedback. Thanks for the info about the materials. When I get my machine, I shall experiment with Nylon. Speaking of, shouldn’t it be possible to get some conductive filament that adheres well to a flat substrate? That might be the best thing by far.
Will generate a tutorial if I manage to determine the correct protocol and post it on this forum.
You have a 3D printer, use it to print the holder for your PCB. I would just leave it on the bed and put your PCB in the opening after it finishes printing. Then do a new print with your PCB design. Use the default centering in AutoMaker and it should pop right into the correct place.
I operate two Betas and one Production Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/benDid anybody experimented with PCB etching for prototyping? I was looking for the flexible PCB that is used in all kinds of equipment. I saw some videos on youtube that had succes with a material from Dupont called Pyralux and a etch pen. You can buy it at Adafruit or tech-place.
https://www.adafruit.com/products/1894
http://www.tech-place.com/en/5-pyralux
For single sided flexible PCB’s.
idea 1:
- stick the pyralux to the print board, it has a 150 um thickness
- plot schematic with an etch pen
- dissolve unwanted copper
idea 2:
- stick the pyralux to the print board
- print schematic with a thin layer of filament
- dissolve unwanted copper
- remove the filament from the flexible PCB by bending
Will this work? Any suggestions.
It seems that nobody answered question about additional height: Robox will recognise it, but you would need copper board that covers whole board!
I can already see another alternative: print a ‘template’ size of the whole bed and of thickness of copper board with cutout of exact size of the PCB. Slot the board in and then you have ensured that each time copper board is at exactly same position and you can then repeat the process many times knowing that absolute positioning Robox uses will result in same position (you won’t need to worry that you didn’t place copper board at the right position).
As for ‘relative’ positioning - I am not aware that current software is going to handle it. You would need to work outside of AM, etc…
Maybe you could get away by producing final gcode; have something which can ‘relocate’ it somewhere else (a script - there’s good chance there are already many on the interweb) - use manual positioning of printing head and read values from AM and then apply them to the script, upload gcode and off you go…
Still template with the slot for PCB would help a lot - but only while rest of the template is exactly the same height as PCB as Robox is going to use it for ‘auto-levelling’.
Wouldn’t the printer check bed height at the same points every time?
Instead of printing a sheet the entire size of the bed (with a void for the PCB), one could design a print that has the 1/16″ pillars in the correct locations where the head tests height with adequate tabs to keep the pillars in place and stable. If it was a little bit modular, it could be made as a replacement for the bed, and then fit in the locking tab slots; also, one could add adjustable braces to hold different size PCBs.
The milling/UV laser ideas are good as well. Both would require some kind of bracing to keep the PCB in place.
@saiken good idea - a simple slab was what came first to my mind. Bracing could be similar - instead of PEI sheet similar sheet with hole for ‘standard’ size PCBs could be used. By standard I mean something you come up with. ‘Adapter’ must be exactly the same size as PEI so it can be slotted nicely instead of it along with tabs.
@click The adapter could be printed, just print in sections so that overall its as big as the PEI sheet. I guess it could just be modelled with a couple different size openings and you put in whichever one you want.
It looks like the PEI board is mirrored about the centre, so itd really be modelling half and printing two. There could be models with different size holes - say 2″ long by 1″ wide, then 2″ long by 0.5″ wide, etc - to mix halves to make holes for different sized boards (the two listed would give could give 2×2, 2×1.5, 2×1).
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This reply was modified 4 months, 3 weeks ago by
Shaun.
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This topic was modified 1 year, 11 months ago by
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