Any prints from the Beta team?

[kulfsson]

I like the prints that I am seeing and I am trying to gauge the size. Do you have any measurements for us ? I can kind of use the ruler that is in the background of your picture, but not sure if it is in Inches or CM ;-) While I understand that small prints are economical with the resin, I am still wondering if someone wouldn´t like to bite the bullet to print a larger item. I don´t know how the imperfections scale though, but it would be nice to know if they get worse or perhaps lessen with scaling up.

@ijmok: I was the one commenting on the Kickstarter page. I am not counting on the July shipping either, but it would be nice to get an official update about the current status.

[Spelljammer]

The slower the drip the smaller the drops...within reason. A constant drip speed is needed or calibration height vs speed in software. Height of the reservoir changes based on water level as well. A constant height apparatus like a pet waterer could be used.

constant drip height.jpg

[rylangrayston]

The slower the drip the smaller the drops...within reason. A constant drip speed is needed or calibration height vs speed in software. Height of the reservoir changes based on water level as well. A constant height apparatus like a pet waterer could be used.

constant drip height.jpg

bang on !
I have spent the last 3 days building a system like this using almost all the same parts we sent in the kit
its going well and its helping for many reasons

1 less pressure means you dont need to make such a small hole with your valve to set the drip rate, making the valve less sensitive to clogging by small particles ( which is a big problem)
2 like you said it gives you and even height which gives you an even pressure... my bubler only verys in height by 1 mm or less!!!
3 buy covering the top of the second space (above the top of the water that stays at one level ) and piping that air to the height you want your printer to stop at
you can make a printer that auto stops dripping at any height!
4 since you have all that top container volume NOT affecting pressure now you can hold 20 prints worth of water above your printer letting you do 20 prints before you need to recycle water back to the top

This is all working rather well right here infront of me now
in fact last night i left it running and it went for a good 8 hours steady.
The only bug I have to work out with it yet is a design where air stays only in the dripper.. right now it randomly travels down the hose :S

2014-05-27 19.50.15.jpg2014-05-27 20.12.03.jpg

[Aztecphoenix]

My plan is to have my main reservoir below my build reservoir and use a pump to bring the water up to a smaller secondary reservoir with an overflow that drains back into the main, this way the pressure always stays the same.

[mike_biddell]

Is it possible to keep a constant pressure in the saline feed by using syphonic action to pull the water out of the top tank? This will create a column of water of constant length and therefore in theory, constant pressure? Just realised that people are using syphonic action. Not sure why that doesn't create a constant pressure?? The laws of physics say it should !!!!

[jjmouris]

My plan is to have my main reservoir below my build reservoir and use a pump to bring the water up to a smaller secondary reservoir with an overflow that drains back into the main, this way the pressure always stays the same.

Very clever! And you could also run the printer in reverse / lower the resin level as and when you wanted by putting a hose from the bottom of use printing reservoir down to the big bucket.

[Feign]

Is it possible to keep a constant pressure in the saline feed by using syphonic action to pull the water out of the top tank? This will create a column of water of constant length and therefore in theory, constant pressure? Just realised that people are using syphonic action. Not sure why that doesn't create a constant pressure?? The laws of physics say it should !!!!

Sadly, it doesn't work that way. While the water in the siphon is indeed taller than the height in the tanks, it doesn't add to the pressure of the tanks. For instance, in Spellfire's example, only the pressure of the lower tank is relevant because it is what is open to atmosphere. Rather, the top surface of the water in the top tank is under a negative pressure (vaccuum) equal to it's height above the water's surface in the lower tank, which would of course increase as the tank empties.

Fluid dynamics is one of the most counterintuitive mechanical fields. Until you really get into the math of it, a lot of things seem to disobey physics.

[Aztecphoenix]

Very clever! And you could also run the printer in reverse / lower the resin level as and when you wanted by putting a hose from the bottom of use printing reservoir down to the big bucket.

actually, I'm going to have a drain valve in the bottom of the build tank that runs through a custom made "oil" separator before draining into the main reservoir so I can reclaim any excess resin, I actually hope to have it all automated in the end so that as soon as the print is finished the valve is automatically opened, the build tank is drained, and the pump is turned off, I also plan to use three different sized build tanks for different models, no use having a huge build tank (1.5' x 1.5' x 1.5') for a small object the build would take too long as the water would have to fill up so much volume.

also, by having the main tank on the bottom I don't have to worry about the printer being too top heavy at the start of each print meaning one little bump could knock it over causing a huge mess.

[colehard]

I am not sure the separator will be necessary. If you have the drain in the bottom of your build tank you will not get resin unless you drain too far. I strongly recommend setting up your fluid movement ahead of time. Resin on my lips because I rushed my fluid system in a haste to get printing was not a good thing.....

[Aztecphoenix]

I am not sure the separator will be necessary. If you have the drain in the bottom of your build tank you will not get resin unless you drain too far. I strongly recommend setting up your fluid movement ahead of time. Resin on my lips because I rushed my fluid system in a haste to get printing was not a good thing.....

you're right, it isn't necessary, but I want a system that I can start a large print, go to sleep, and have everything done by the time I wake up without any human intervention.