Raspberry Pi 4 Experimental Resin 3D Printer -- Episode 414

That's a clever idea, the resin floats on top of another liquid. That reduce wear and tear on the vat screen. Thank you for experimenting with this technology. That's how things evolves.

I assume the liquid needs time to settle down before starting the print, to produce perfectly flat layers.

1. Do you have to lift the part higher than a layer thickness after each layer? Is the resin able to naturally flow under the cured layer or you need to lift the part higher to ensure the resin cover the entirety of the previously cured layer?
2. Do you have a "settle down" time delay before each layer or the lifting of the part is slow enough to not disturb the liquid underneath?
3. Are you able to easily recover unused resin? Does it matter if it get mixed with the liquid underneath? I assume it would separate easily. As long as you reuse it in the same printer with the same separating liquid, it probably doesn't matter if you get some of the separating liquid while recovering the resin...

Sorry, I have so many questions...

Hi, welcome to the community.

I try to answer these questions, if I'm unclear please ask further and I hope I can clarify it for you.

"I assume the liquid needs time to settle down before starting the print, to produce perfectly flat layers." -- Yes, that is correct, but it does not take that long to settle, it is crucial to avoid shocks or impacts during the curing of a layer. in nanodlp you can set wait times for different steps in the sequence, i just gave it as much time as I coulkd effort in my experiments to make sure the waves have set before proceeding.

1. yes, like on most printers the plate lifts between 1mm and 5mm depending on resin and machine. while FEP based machines need that movement(or a sequence of moves) to peel the layer of the fep and let new resin float under the cured one. the CLEM system uses it to let new resin flow in ,but also let out possibly trapped airbubbles(these are a huge pain currently to deal with). Ic also thought about going down a mm and then up to kind of whash the cured layers in the floating liquid. but did not try that out.

2.yes, and I also reduce the movement speed greatly for the last 2-3mm of the move. it is less about disturbing, more about avoiding to break the surface tension. once the surface is penetrated a blob of resin sinks top the bottom. further advances in the floating liquid may solve that problem. for now the resin is not floating but more like balancing on the surface tension(if that makes sense) also the meniscus at the edge of the vat is kinda helping it stay above, but it also makes it very hard to judge the actual height by vision.

3. yes, but it is not that easy. As mentioned the surface tension has to be kept intact. so I have to be very gentle. what worked was removing the liqiud with a straw/pump/pipette and then dumping the resin in a bottle.

when reusing it you need to pour it very slowly so only the upermost resin leaves the bottle, there certainly will always be a rest of mixed resin at the bottom. the plastic tubs that i used for my experiment can only be thrown away once resin has come in contact with the bottom. another reason to turn the whole system upside down to make the liquid reservoir hold more liquid and sinking resin would just turn into waste that you'd remove from time to time, not every after print.

Hope that helped! if you have ideas please share them!

Hi, welcome to the community.

I try to answer these questions, if I'm unclear please ask further and I hope I can clarify it for you.

"I assume the liquid needs time to settle down before starting the print, to produce perfectly flat layers." -- Yes, that is correct, but it does not take that long to settle, it is crucial to avoid shocks or impacts during the curing of a layer. in nanodlp you can set wait times for different steps in the sequence, i just gave it as much time as I coulkd effort in my experiments to make sure the waves have set before proceeding.

1. yes, like on most printers the plate lifts between 1mm and 5mm depending on resin and machine. while FEP based machines need that movement(or a sequence of moves) to peel the layer of the fep and let new resin float under the cured one. the CLEM system uses it to let new resin flow in ,but also let out possibly trapped airbubbles(these are a huge pain currently to deal with). Ic also thought about going down a mm and then up to kind of whash the cured layers in the floating liquid. but did not try that out.

2.yes, and I also reduce the movement speed greatly for the last 2-3mm of the move. it is less about disturbing, more about avoiding to break the surface tension. once the surface is penetrated a blob of resin sinks top the bottom. further advances in the floating liquid may solve that problem. for now the resin is not floating but more like balancing on the surface tension(if that makes sense) also the meniscus at the edge of the vat is kinda helping it stay above, but it also makes it very hard to judge the actual height by vision.

3. yes, but it is not that easy. As mentioned the surface tension has to be kept intact. so I have to be very gentle. what worked was removing the liqiud with a straw/pump/pipette and then dumping the resin in a bottle.

when reusing it you need to pour it very slowly so only the upermost resin leaves the bottle, there certainly will always be a rest of mixed resin at the bottom. the plastic tubs that i used for my experiment can only be thrown away once resin has come in contact with the bottom. another reason to turn the whole system upside down to make the liquid reservoir hold more liquid and sinking resin would just turn into waste that you'd remove from time to time, not every after print.

Hope that helped! if you have ideas please share them!