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Unless I'm missing something, this is not exactly a new technology. http://makezine.com/2014/07/26/droplit-the-low-cost-diy-resin-printer/ http://makezine.com/

Unless I'm missing something, this is not exactly a new technology. http://makezine.com/2014/07/26/droplit-the-low-cost-diy-resin-printer/ http://makezine.com/2014/07/26/droplit-the-low-cost-diy-resi... http://www.instructables.com/id/DIY-high-resolution-3D-DLP-printer-3D-printer/ http://www.instructables.com/id/DIY-high-resolution-3D-DLP-p... http://www.3ders.org/articles/20120911-a-list-of-diy-high-resolution-dlp-3d-printers.html http://www.3ders.org/articles/20120911-a-list-of-diy-high-re...

the8472 12y ago
do those also feature the oxygen aspect? I assume that increases their precision.
Apofis 12y ago
In one of the images on their site they're claiming it's different from SLA and much faster.
bri3d 12y ago
They're doing the "growing" on a membrane at the bottom of the tank, instead of layer by layer at the top of the tank. That should let them print really quickly and precisely, even compared to the SLA printers you link. The reason it hasn't been possible in the past is that the polymerization process requires oxygen, which has only previously been available from the air over the liquid resin. Their system has some "secret sauce" for getting it to the bottom of the vat.
- 8dad6bea 12y ago
  You've got it backwards about the role of oxygen--it is being used to inhibit polymerization in this case. They are allowing oxygen to dissolve into a thin layer at the bottom of the vat so that the build doesn't stick to the membrane, and they can have a continuous draw. The true build layer is actually within the liquid, near the bottom, but not on it.
  - bri3d 12y ago
    You're totally right. Oxygen inhibits the polymerization process. Interestingly, oxygen inhibition is also what allows things to be printed in layers (or, in this case continuously) as it allows the newly cured material to bond to the partially-cured inhibited material below it.
iamwil 12y ago
You are. Using UV to cure photo-sensitive resin isn't the innovation, it's using the oxygen permeable membrane. If you look at the Form 1 printer or the B9Creator, there's a mechanical step between every layer where it needs to actuate the platform in order to loosen the resin from the projection window, so it can build the next layer. In the Form 1, it peels the print off, and the B9Creator slides a window. (look for videos on youtube.) In both instances, the amount of time spent actuating the mechanical part adds up, and results in a significant amount of time spent in the print actuating the plate. What the oxygen membrane allows us to do is to skip that step between every layer, and simply keep shining a continuous changing image slice of the object as we're pulling the object out of the resin. Not only does this have the advantage of speeding up prints by orders of magnitude, in materials, the grain of the object influences the type of thing you can built. If you print a stress holding object with the grain orientated in the wrong direction, the part will fail very readily. This way, we have greater design freedom, without worrying about grain direction.
- phkahler 12y ago
  >> What the oxygen membrane allows us to do is to skip that step between every layer, and simply keep shining a continuous changing image slice of the object as we're pulling the object out of the resin. What keeps the oxygen at the bottom of the tank? Why doesn't it diffuse upward and prevent curing? Why doesn't it get sucked upward and prevent curing? Are there limitations on the geometry needed to prevent oxygen from moving up?
- universaltest 12y ago
  Thanks for clearing that up. I was going to ask how this differs from the form 1 which, at first glance, seemed like the same concept. Is the oxygen permeability what keeps the printed object from adhering to the membrane?
  - ObviousScience 12y ago
    The oxygen inhibits the curing, so it only begins to cure ~20um above the membrane, which means that it never sticks, since it never touches the window, and that can just continually pull it upwards.
cma 12y ago
SLA is layered, each layer a knife sweeps over it and refills and smooths the uncured resin layer. This is submerged, so drawing the parts upwards pulls in more fluid automatically so everything can be run continuously. What I don't get is that, hydraulically most of the liquid pulled in is going to come from the oxygenated layer. But I'm guessing that reacts with the resin and neutralizes quickly when it is too far from the diffusion membrane that provides the source of new oxygen.

the8472 12y ago

do those also feature the oxygen aspect? I assume that increases their precision.

Apofis 12y ago

In one of the images on their site they're claiming it's different from SLA and much faster.

bri3d 12y ago

They're doing the "growing" on a membrane at the bottom of the tank, instead of layer by layer at the top of the tank. That should let them print really quickly and precisely, even compared to the SLA printers you link. The reason it hasn't been possible in the past is that the polymerization process requires oxygen, which has only previously been available from the air over the liquid resin. Their system has some "secret sauce" for getting it to the bottom of the vat.

8dad6bea 12y ago
You've got it backwards about the role of oxygen--it is being used to inhibit polymerization in this case. They are allowing oxygen to dissolve into a thin layer at the bottom of the vat so that the build doesn't stick to the membrane, and they can have a continuous draw. The true build layer is actually within the liquid, near the bottom, but not on it.
- bri3d 12y ago
  You're totally right. Oxygen inhibits the polymerization process. Interestingly, oxygen inhibition is also what allows things to be printed in layers (or, in this case continuously) as it allows the newly cured material to bond to the partially-cured inhibited material below it.

iamwil 12y ago

You are. Using UV to cure photo-sensitive resin isn't the innovation, it's using the oxygen permeable membrane. If you look at the Form 1 printer or the B9Creator, there's a mechanical step between every layer where it needs to actuate the platform in order to loosen the resin from the projection window, so it can build the next layer. In the Form 1, it peels the print off, and the B9Creator slides a window. (look for videos on youtube.) In both instances, the amount of time spent actuating the mechanical part adds up, and results in a significant amount of time spent in the print actuating the plate. What the oxygen membrane allows us to do is to skip that step between every layer, and simply keep shining a continuous changing image slice of the object as we're pulling the object out of the resin. Not only does this have the advantage of speeding up prints by orders of magnitude, in materials, the grain of the object influences the type of thing you can built. If you print a stress holding object with the grain orientated in the wrong direction, the part will fail very readily. This way, we have greater design freedom, without worrying about grain direction.

phkahler 12y ago
>> What the oxygen membrane allows us to do is to skip that step between every layer, and simply keep shining a continuous changing image slice of the object as we're pulling the object out of the resin. What keeps the oxygen at the bottom of the tank? Why doesn't it diffuse upward and prevent curing? Why doesn't it get sucked upward and prevent curing? Are there limitations on the geometry needed to prevent oxygen from moving up?
universaltest 12y ago
Thanks for clearing that up. I was going to ask how this differs from the form 1 which, at first glance, seemed like the same concept. Is the oxygen permeability what keeps the printed object from adhering to the membrane?
- ObviousScience 12y ago
  The oxygen inhibits the curing, so it only begins to cure ~20um above the membrane, which means that it never sticks, since it never touches the window, and that can just continually pull it upwards.

cma 12y ago

SLA is layered, each layer a knife sweeps over it and refills and smooths the uncured resin layer. This is submerged, so drawing the parts upwards pulls in more fluid automatically so everything can be run continuously. What I don't get is that, hydraulically most of the liquid pulled in is going to come from the oxygenated layer. But I'm guessing that reacts with the resin and neutralizes quickly when it is too far from the diffusion membrane that provides the source of new oxygen.