Well i must admit I had not been able to perform a successful print since purchasing the printer and was thinking of returning it. However thanks to @exxos and his additional nut (excuse the pun ) I can confirm this method works and the printer is now easy to use with the right flow using default settings.
The Voltera has shaved so much time off my morning in messing about with stencils, end less retries due to smudging etc. I also like the feature that once i placed the components on the board you can reflow the board in place. 20 mins later it was done.
Been having fun with the printer today.. It's hard to see, but I tried to video it.. Where the cog on the printhead assembly actually twists and moves to the left It actually twists the contacts off the thing then the printer freaks out because it thinks the printhead is not connected
I should add that I'm forcing through a generic red syringe which is requiring a hell of a lot of pressure to get the paste to go through, hence why the assembly is twisting.
So what I did is find some plastic and superglued it to the frame as shown on the left side of the image.. Then used some scrap thin sheets of metal from PCB stencils to pad out the gap exactly. The plastic in the top of the head assembly was actually rounded, I filed this square (not shown in images).
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So now the head cannot twist and break connections so easily. And it also cannot twist to the left because the plastic is holding it from all moving..
Before it was coming up various print areas and the cogs would slip now and then causing the prints to basically stop. I have printed around 20 boards now and it has been perfectly fine.
I've been trying to find a source for the metal nozzles as the voltera ones are like £15 a pop. So far while there are various brands, they are all more expensive than the voltera ones, even China knockoffs
The red nozzles work well but a bit big being 0.25mm dia. The next size down is pointless at 0.24mm. The clear ones I've ordered as they are 0.21mm. The green ones I can't get paste to flow at all at 0.18mm. Hoping the 0.21mm work as there isn't any other options.
It doesn't help with the tips being 0.25" long , about 6mm. But that's the shortest I can find. I've tried to cut them as posted before without much luck. So other than buying new official nozzles every few boards, which isn't cost effective,the only other option is to fiddle with the print settings to get them to draw thinner lines. Its possible, 3D printers do it, but it would make life easier with nozzles which are smaller.. If they block, 50p a nozzle I don't care so much about.
So T4 leaded *just* flows out of a 0.25mm nozzle, but totally struggles with a slightly smaller 0.225mm.
A while ago I ordered leadfree T5 paste which I just found and tried. This is exactly like the paste used on the motherboards from JLC.. Where you pretty much have to set fire to the board to get the solder to melt
In terms of trying to assemble flashy clock.. The solder still had not melted and the tops of the chips were burning and blistering they were under that much heat
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That is one board now junked The second board I think maybe salvageable as I had not left it under the heat anywhere near as long.
So emailed my paste supplier and asked if they do low melting temperature T5 paste of any kind leaded or leadfree, I don't care anymore.
My white nozzles came. While I can get the paste to go through, they block up really easily, which is of no great surprise really. Even so, using the smaller nozzle does not really seem to be improving anything over the default grey nozzles
I am pasting Flashy-clock again...
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With the grey nozzles and that has just blocked up as well annoyingly I think the uneven service of the tin plating is really not helping
I have been really now wondering if I could just draw a single thin line across each side of the IC's. I did solder a Videl on a Falcon with such a method a few years ago and some other chips like here https://www.exxosforum.co.uk/forum/viewt ... 212#p17212 but of course while that basically worked, the paste was very uneven. Now with the paste printer I can do a thinner line more accurately. So I am going to try this as it will be a lot faster and less prone of clogging with the nozzles I think as well..
First to bodge the paste layer with a single line. Then delete the actual pads...
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Then print...
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Next to see how shorted out the PLD gets...
EDIT:
First pass it doesn't look like the solder has fully melted...
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I added more flux and left it cooking.. but not sure the heat lamp station thing is really getting hot enough...So I have put in my small PCB oven.. Hopefully the bits on the bottom of the board will not fall off
EDIT2:
Out of the oven...
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Looks like it ended up with just one bridge..I need to try this a few more times, but not got many boards left and these chips are expensive
The next two boards turned out really well using the line of paste method. I did have to extend the paste lines a little bit because there is a small delay between the paste being pushed out.. So it actually misses the first pad basically. So extending the line a tiny bit means when the paste starts flowing it starts on the first pad.
sporniket wrote: Tue Jun 15, 2021 9:29 pm
Very nice, overall the time to build should be reduced by a factor 2 or more I guess ?
Depends how you look at it I guess.. I can get the paste on the boards very quickly now.. (If you don't take into account I have been messing with this all day ) Once I get in the swing and set up to do something, I can do it pretty quickly. Overall this saves having to mess about with stencils, which I cannot really do with my poorly hands anyway. Ultimately I hope it will save trouble shooting later if I can solder more reliably to start with.
) I can confirm this method works and the printer is now easy to use with the right flow using default settings. 
It actually twists the contacts off the thing then the printer freaks out because it thinks the printhead is not connected 
The second board I think maybe salvageable as I had not left it under the heat anywhere near as long.
